Workpiece unit and method for producing same

A workpiece unit containing a workpiece body is provided. A method for producing the workpiece unit is also provided. The workpiece body contains a plurality of sections. The sections divide the processing surface of the workpiece body. The size of each section of the workpiece body can be adjusted or selected according to the demand so that it is possible to increase utilization efficiency of the workpiece body.

REFERENCE TO RELATED APPLICATION

The present invention is based upon the priority of Japanese patent application No. 2015-056572 filed on Mar. 19, 2015, the disclosure of which is incorporated herein in its entirety by reference thereto.

TECHNICAL FIELD

The present invention relates a workpiece comprising a workpiece body for machining processing and a method for producing same.

BACKGROUND

In machining processing of workpiece body such as ceramic, metal etc. into three-dimensional shape, a workpiece unit is machined by holding ends thereof. This workpiece body is referred to also as “blank”. For example, in the dental industry, an outer edge region of a circular plate (disk) shaped zirconia dedicated as a workpiece body is held by a processing apparatus and the prosthesis is cut out.

In a method for producing a dental prosthesis described in Patent Literature 1 (PTL 1), a blank is fixed to a processing apparatus by attaching a ring to an outer edge of a blank by means of an adhesive and fixing the ring to a chuck of a processing apparatus.

SUMMARY

The following analyses are given in view of the present invention disclosure.

For example, when a workpiece body (blank) or a product made from the workpiece body is colored, the composition of the workpiece body differs from color to color. The workpiece body described in PTL 1 has one composition for each workpiece body surrounded by the ring. When a dental prosthesis is produced from the workpiece body described in PTL 1, the workpiece body having a color (composition) corresponding to a color of a patient's natural tooth is selected. The workpiece is formed to a predetermined size suitable for the processing apparatus. Usually, it is possible to produce a plurality of dental prostheses having the same composition from one workpiece body. However, even when the demand for the workpiece body (for example, composition and color) is small, that is, even when the size required to produce the prosthesis may be small, the workpiece body described in PTL 1 must be produced in the predetermined size. For this reason, most of part of the workpiece body not used for processing is wasted.

Therefore, it is desired that the workpiece body can be used efficiently according to the demand for the composition.

According to a first aspect of the present disclosure, a workpiece unit is provided that comprises a workpiece body (a to-be-worked body) having a plurality of sections. The sections divide processing surface (surface-to-be-worked) of the workpiece body.

According to a second aspect of the present disclosure, a method for producing a workpiece unit is provided, comprising:preparing a plurality of sections dedicated to be components of a workpiece body,making the workpiece body having a first surface, a second surface arranged on a side opposite to the first surface and an outer circumferential portion provided between the first surface and the second surface, by combining a plurality of the sections,preparing a holding member having a ring shape,expanding the holding member by heating,inserting the workpiece body into a ring of the holding member, andmounting the holding member to the outer circumferential portion of the workpiece body, by allowing the holding member to cool and shrink.

The size of each section of the workpiece body can be adjusted or selected according to the demand such as composition and color etc. As a result, it is possible to reduce the portion that is not used for processing and is wasteful, and it is possible to increase utilization efficiency of the workpiece body.

PREFERRED MODES

In the following description, the reference numbers are added for understanding the present invention, but not for limitation of the invention to the exemplary embodiments shown in the drawings. In each exemplary embodiment, the same numbers are added to the same elements. The dimensions and the size ratios in the drawings are not for limitation to the modes shown in the drawings.

Preferable modes of the above aspects will be described below.

According to a preferred mode of the above first aspect, a plurality of sections is formed integrally.

According to a preferred mode of the above first aspect, a plurality of the sections has the same shape respectively.

According to a preferred mode of the above first aspect, a workpiece unit further comprises a holding member surrounding at least an outer circumferential portion of a workpiece body.

According to a preferred mode of the above first aspect, the workpiece body is divided per sections.

According to a preferred mode of the above first aspect, at least two of the sections have different compositions.

According to a preferred mode of the above first aspect, the section(s) has (have) form(s) engaging with adjacent section(s).

According to a preferred mode of the above first aspect, the workpiece unit further comprises a cushioning (or buffer) material arranged between adjacent sections.

According to a preferred mode of the above first aspect, the cushioning material comprises a resin.

According to a preferred mode of the above first aspect, the holding member maintains a combination (combined assembly) of a plurality of sections.

According to a preferred mode of the above first aspect, the holding member is composed of a plurality of portions. The portions of the holding member are arranged in each section of the workpiece body respectively.

According to a preferred mode of the above first aspect, the workpiece unit further comprises a covering member surrounding the outer circumferential portion(s) of the section(s).

According to a preferred mode of the above first aspect, portion(s) of the holding member is (are) at least a part of the covering member.

According to a preferred mode of the above first aspect, the covering member has a shape that engages with a covering member surrounding adjacent section(s).

According to a preferred mode of the above first aspect, the holding member is arranged continuously along an outer circumferential portion.

According to a preferred mode of the above first aspect, the holding member has a ring shape.

According to a preferred mode of the above first aspect, the holding member has a thickness smaller than that of the workpiece body.

According to a preferred mode of the above first aspect, the holding member is arranged at a central area in the thickness direction of the workpiece body.

According to a preferred mode of the above first aspect, the holding member is composed of two or more parts.

According to a preferred mode of the above first aspect, each of parts of the holding member has a concave portion or a convex portion respectively. The parts are arranged so as to fit together with the concave portion and the convex portion.

According to a preferred mode of the above first aspect, the holding member is plastic.

According to a preferred mode of the above first aspect, the workpiece body has at least one first positioning portion in a portion facing the holding member. The holding member has a second positioning portion that engages with at least a part of the first positioning portion.

According to a preferred mode of the above first aspect, the first positioning portion has a concave or convex shape. The second positioning portion has a shape fitting or engaging with the first positioning portion. At least a part of one of the first positioning portion and the second positioning portion is fitted or engaged with at least a part of the other.

According to a preferred mode of the above first aspect, one of the first positioning portion and the second positioning portion has the concave shape and the other has the convex shape. The convex shape has a width equal or larger than that of the concave shape. A part of the convex shape is inserted in the concave shape.

According to a preferred mode of the above first aspect, the first positioning portion is arranged over the entire circumference of the workpiece body.

According to a preferred mode of the above first aspect, the first positioning portion or the second positioning portion has a groove shape.

According to a preferred mode of the above first aspect, the first positioning portion or the second positioning portion has a conical or columnar shape.

According to a preferred mode of the above first aspect, the holding member is bonded to the workpiece body by an adhesive.

According to a preferred mode of the above first aspect, the holding member and the workpiece body are in direct contact with each other.

According to a preferred mode of the above first aspect, the workpiece body has a first surface dedicated as a processed surface, a second surface arranged on a side opposite to the first surface and a protrusion arranged on an outer circumferential portion provided between the first surface and the second surface.

According to a preferred mode of the above first aspect, the workpiece body has a plate shape. The protrusion protrudes from a side surface of the workpiece body.

According to a preferred mode of the above first aspect, the protrusion has a third surface directed in the same direction as the first surface, a fourth surface directed in the same direction as the second surface and a fifth surface connecting the third surface and the fourth surface.

According to a preferred mode of the above first aspect, the workpiece body has a first surface dedicated as a processed surface, a second surface arranged on a side opposite to the first surface and a protrusion arranged on an outer circumferential portion provided between the first surface and the second surface. The holding member is arranged on at least a part of the outer side of the protrusion.

According to a preferred mode of the above first aspect, the workpiece body has a plate shape. The protrusion protrudes from a side surface of the workpiece body. The holding member is arranged at least in a protruding direction of the protrusion.

According to a preferred mode of the above first aspect, the protrusion has a third surface directed in the same direction as the first surface, a fourth surface directed in the same direction as the second surface and a fifth surface connecting the third surface and the fourth surface. The holding member covers at least a part of the fifth surface.

According to a preferred mode of the above first aspect, the holding member has a first surface directed in the same direction as the third surface of the protrusion and a second surface directed in the same direction as the fourth surface of the protrusion.

According to a preferred mode of the above first aspect, the first surface of the holding member forms the same plane as the third surface of the protrusion or exists on a side closer to the first surface of the workpiece body than the third surface of the protrusion.

According to a preferred mode of the above first aspect, the second surface of the holding member forms the same plane as the fourth surface of the protrusion or exists on a side closer to the second surface of the workpiece body than the fourth surface of the protrusion.

According to a preferred mode of the above first aspect, the holding member further covers at least a part of the third and fourth surfaces of the protrusion.

According to a preferred mode of the above first aspect, the protrusion has a thickness substantially same as that of the holding member.

According to a preferred mode of the above first aspect, the protrusion has a width of 0.3 mm to 2 mm in the protruding direction.

According to a preferred mode of the above first aspect, the protrusion is arranged at a central area in the thickness direction of the workpiece body.

According to a preferred mode of the above first aspect, a planar shape of the sections has a sector shape.

According to a preferred mode of the above first aspect, a plurality of the sections is combined to form the workpiece body having a circular planar shape.

According to a preferred mode of the above first aspect, a plurality of the sections has the same shape respectively.

According to a preferred mode of the above first aspect, one of the sections is a portion which is not processed by a processing apparatus.

According to a preferred mode of the above first aspect, the one section is smaller than the size which can be fixed on the processing apparatus.

According to a preferred mode of the above first aspect, the workpiece body is ceramic, metal or resin.

According to a preferred mode of the above first aspect, the workpiece body is a pre-sintered body in which zirconia crystal grains are not completely sintered.

According to a preferred mode of the above first aspect, the workpiece body has a worked item which is formed by processing the workpiece body and connected to the protrusion or the outer edge portion of the workpiece body.

According to a preferred mode of the above second aspect, in a step for expanding a holding member, the holding member is heated to 60° C. to 150° C.

According to a preferred mode of the above second aspect, the holding member comprises engineering plastic.

A workpiece unit (or assembly) according to a first exemplary embodiment of the present disclosure will be explained.FIG. 1shows a schematic plan view showing a workpiece unit according to the first exemplary embodiment.FIG. 2shows a schematic cross-sectional view of the workpiece unit along line IT-IT ofFIG. 1.

A workpiece unit (or assembly)10has a workpiece body1and a holding member2arranged on at least a part of a side wall of the workpiece body1. The workpiece body1is processed for example by a processing apparatus. For example in a field of the dentistry, dental products are produced from the workpiece body1. As dental products, for example, prosthesis such as a ceramic frame, full contour crown etc. can be mentioned. It is preferable that the dental prosthesis has a tooth crown form. Further, the dental product may also comprise, for example, an orthodontic product (for example, an orthodontic bracket), and a dental implant product (for example, a dental implant abutment). The holding member2assists the workpiece unit10to be held or fixed on the processing apparatus. For example, when the workpiece unit is held or fixed on the processing apparatus, at least the holding member2of the workpiece unit10is held by the processing apparatus.

The workpiece body1has a first surface1adedicated as a processed surface (surface-to-be-worked) and a second surface1barranged on a side opposite to the first surface1a. It is preferable that the first surface1aand the second surface1bare parallel or substantially parallel.

It is preferable that the workpiece body1has a plate shape. In the exemplary embodiment shown inFIG. 1, the workpiece unit10and the workpiece body1have a circular planar shape, but they are not limited to circular but also may have a planar shape such as an elliptical shape or a polygonal shape.

The workpiece body1is physically divided into a plurality of sections11. One workpiece body1is configured by combination of a plurality of the sections11. At least two sections11of a plurality of the sections11can differ in composition respectively. For example, each section11can contain different colorants from each other. At least two of the sections11of a plurality of the sections11may have the same composition or all of the sections11may have the same composition. The main material of each section11may be identical or different from one another. It is preferable that one section11is smaller than a size which can be held or fixed on the processing apparatus.

At least one of a plurality of the sections11can be a part which is processed by the processing apparatus. At least one of a plurality of the sections11can be a part which is not processed by the processing apparatus. At least one of a plurality of the sections11can be a dummy workpiece body that is adapted for compensating the size of the workpiece body1and for making the workpiece body1to the size which can be held on the processing apparatus.

It is preferable that the workpiece body1is divided by each section11so as to divide the first surface1aand the second surface1bof the workpiece body1. The number of sections11for one workpiece body1can be selected appropriately. A size of one section11can be appropriately adjusted according to demand etc of each composition etc. A plurality of the sections11may have different sizes from each other or may have the same size.

A shape of each section11may be any shape. A plurality of the sections11may have different shapes from each other or may have the same shape. When the planar shape of the workpiece1is circular, it is preferable to divide the workpiece body1so that the section(s)11pass(es) through the central area of the circle. For example, each section11can have a fan (sector)-shaped planar shape. When the sections11have fan shapes, it is preferable that the radius of the fan shapes is the same. As a result, the workpiece body1having a circular shape or an elliptical shape can be formed by combining a plurality of the sections11in radial-wise such that each arc thereof is continuous. It is preferable that the sum of the central angles of a plurality of the sections11is 360°. The center angle of each fan-shape may be any angle, for example, 45°, 60°, 90°, 120°, 180° (i.e., semi-circular, semi-elliptical, etc.), 240°, 270°, 300°, 315° etc.

It is preferable that a plurality of the sections11has the same thickness. As a result, both the first surface1aand the second surface1bcan be formed in a plane. Further, it is also easy to align the thickness direction when the workpiece unit10is fixed on the processing apparatus.

In the exemplary embodiment shown inFIG. 1andFIG. 2, the workpiece body1has a first section11a, a second section11band a third section11c. The first section11a, the second section11band the third section11chave the same shape. The first section11a, the second section11band the third section11chave the same size. The first section11a, the second section11band the third section11chave a planar shape in which both surfaces thereof are fan-shaped. The central angle of the fan shape (sector) is 120°. The first section11a, the second section11band the third section11care arranged in radial-wise to form the circular workpiece body1. Both surfaces of the first section11a, the second section11band the third section11care arranged on the same plane respectively, and the first surface1aand the second surface1bare formed in a plane.

FIG. 3toFIG. 6show a schematic plan view of a workpiece body showing an example of a plane shape of sections.FIG. 3toFIG. 6show states in which the sections forming one workpiece body are separated. In the exemplary embodiment shown inFIG. 3, the sections11a,11band11chave a fan-shaped plane shape with a central angle of 120°. In the mode shown inFIG. 4, the sections11aand11bhave a semi-circular planar shape. In the mode shown inFIG. 5, the section11ahas a semi-circular planar shape, and the sections11band11chave a fan-shaped planar shape with a central angle of 90°. In the modes shown inFIG. 3toFIG. 5, the radius of each section is the same size. In the mode shown inFIG. 6, although the sections11ato11fdo not have a fan-shaped planar shape, they are configured so as to form a circle together.

FIG. 7shows a schematic plan view of a workpiece body showing another mode of a workpiece body. The sections11may be in direct contact with each other with respect to the adjacent sections11. Alternatively, as shown inFIG. 7, the workpiece body1may further include a cushioning (buffer) material6in at least a part between adjacent sections11. The cushioning material6is preferably a material that is able to absorb irregularities at the end faces of the section11. The cushioning material6may be an adhesive for joining the sections11with each other. For the cushioning material6, for example, a resin sheet can also be used. In the exemplary embodiment shown inFIG. 7, the cushioning material6is disposed entirely between the sections142, but the cushioning material6may be partially disposed between the sections11. By using the cushioning material6, it is possible to suppress non-alignment of combination due to irregularities at the end faces of the sections11. Further, by using the adhesive as the cushioning material6, it is possible to increase the strength of junction between the sections11.

FIG. 8shows a schematic side view of a workpiece body showing another form of a workpiece body. The section11may have an engaging portion that engages with an adjacent section11at the end face facing to the adjacent section11. As shown inFIG. 8, the engaging portion is formed, for example, at a concave portion11gformed at the end face of the section11aand on the end face of the section11b, and can be configured as a convex portion11hengaging with the concave portion11g. In addition to the engaging portion, the workpiece body1may further have a cushioning material6as shown inFIG. 7. By providing the engaging portion, it is possible to increase the strength of junction between the sections11.

A holding member2is disposed on at least a part of the outer circumferential portion1ccorresponding to the side face of the workpiece body1. It is preferable that the holding member2surrounds the outer circumferential portion1cof the workpiece body1. It is preferable that the holding member2maintains the combination (assembly) of a plurality of the sections11. It is preferable, for example, that a plurality of the sections11is maintained in the form of the workpiece body1by the contraction force of the holding member2. The production cost can be reduced by using the holding member2in order to reduce the waste portion (remaining portion) of the workpiece body1. In addition, the producing cost can be reduced by decreasing an amount of raw material used for the workpiece body1, since a mold for manufacturing the workpiece body2can be down-sized by the width of the holding member2.

It is preferable that the holding member2is continuously arranged along the outer circumferential portion1c. The holding member2preferably has a shape corresponding (or adapted) to the planar shape of the workpiece body1. The holding member2can have, for example, an annular, annular, and tubular or ring shape. The holding member2is preferably arranged over the entire circumference of the side wall of the workpiece body1. A gap (or gaps) may exist between the holding member2and the workpiece body1.

FIG. 9andFIG. 10show a schematic partial cross-sectional view of a workpiece unit according to the first exemplary embodiment.FIG. 9andFIG. 10are schematic partial cross-sectional views of the holding member2and the workpiece body1.FIG. 9shows a mode without an adhesive andFIG. 10shows a mode with an adhesive3. As shown inFIG. 9, the holding member2can cover at least a part of the outer circumferential portion1cof the workpiece body1without using an adhesive. The inner circumferential portion2cof the holding member2and the outer circumferential portion1cof the workpiece body1are in direct contact with each other in at least a part thereof. Alternatively as shown inFIG. 10, the holding member2can cover at least a part of the outer circumferential portion1cof the workpiece body1via the adhesive3that joins the workpiece body1and the holding member2.

When the adhesive3is not used, it is possible to prevent the force due to thermal expansion of the holding member2from being transmitted to the workpiece1body via the adhesive. As a result, even if it is exposed to a high temperature after processing, it is possible to suppress occurrence of defects (for example, fracture of the workpiece body1or worked item) due to a difference in thermal expansion coefficient between the workpiece body1and the holding member2. Further, when it is desired to remove the holding member2from the workpiece body1after processing, the holding member2can be easily removed from the workpiece body1.

The holding member2may have a first surface2adirected in the same direction as the first surface1aof the workpiece body1, a second surface2bdirected in the same direction as the second surface1bof the workpiece body1and a inner circumferential portion2carranged between the first surface2aand the second surface2band directed in the direction of the outer circumstantial portion1cof the workpiece body1. It is preferable that the first surface2aof the holding member2and the first surface1aof the workpiece body1are parallel or substantially parallel. It is preferable that the second surface2bof the holding member2and the second surface1bof the workpiece body1are parallel or substantially parallel. The first surface2aof the holding member2can exist on a side closer to the second surface1bof the workpiece body1than the first surface1aof the workpiece1. Similarly, the second surface2bof the holding member2can exist on a side closer to the first surface1aof the workpiece body1than the second surface1bof the workpiece1. That is, it is preferable that a step is formed between the first surface1aof the workpiece body1and the first surface2aof the holding member2. It is preferable that a step is formed between the second surface1bof the workpiece body1and the second surface2bof the holding member2. It is preferable that the holding member has a thickness t2thinner than an entire thickness t1of the workpiece body1. Hereby the positioning is facilitated when the workpiece unit10is fixed on the processing apparatus.

It is preferable that the holding member2is disposed at a central area of the workpiece body1in the thickness direction of the workpiece body1. That is, it is preferable that the center of the holding member2in the thickness direction overlaps with the center of the workpiece body1in the thickness direction. Hereby the positioning is facilitated when the workpiece unit10is set on the processing apparatus.

It is preferable that the workpiece unit10is symmetrical with respect to the extending direction of the first surface1aand the second surface1bof the workpiece body1. For example, it is preferable that both of the first surface1aand the second surface1bof the workpiece body1can be set on the processing apparatus such that they are directed toward a processing tool (usually the upper side).

A thickness t3of the holding member2may be any thickness as long as the thickness does not hinder the processing of the workpiece body1. It is preferable that a thickness t2of the holding member2is thinner than a thickness t1of the workpiece body1. This makes it easier to hold the workpiece unit10on the processing apparatus. The thickness t2of the holding member2is preferably 1 mm or more, more preferably 2 mm or more, and even more preferably 4 mm or more. This is for keeping the strength for holding by the processing apparatus.

A width w1of the holding member2may be any width as long as it allows the workpiece unit10to be held on the processing apparatus.

As a material of the workpiece body1or the sections11for example, ceramic, metal, resin or the like can be used. As an example of the ceramic, a material containing at least one of zirconia, alumina and crystallized glass can be mentioned. As an example of metal, titanium and titanium alloys etc. can be mentioned. As an example of resin, acrylic resin, methacrylic resin, ABS (acrylonitrile butadiene styrene) resin, polycarbonate, polypropylene, polystyrene, polyester, polyether ketone, Teflon (registered trademark) and the like can be mentioned. Further, a composite material (composite resin) in which inorganic filler is filled in these resins can also be mentioned as an example of resin.

In the case that a section11is a section which is not processed (dummy workpiece body), as the material for the section11not processed, in addition to the above mentioned materials, any material can be used as long as it allows the workpiece unit10to be held on the processing apparatus and has strength which makes it possible to process the section11to be processed.

When the workpiece body1is used, for example, for cutting out a dental product, the workpiece1can be a zirconia pre-sintered body which is sintered in a state in which the zirconia crystal grains are not completely sintered. The zirconia pre-sintered body contains zirconia and a stabilizer that suppresses phase transition of the zirconia crystal phase. For example, the stabilizer suppresses the phase transition of the crystal phase of the sintered body from tetragonal to monoclinic phase when it becomes a sintered body. As the stabilizer, for example, oxides such as calcium oxide (CaO), magnesium oxide (MgO), yttrium oxide (Y2O3) and cerium oxide (CeO2) etc. can be mentioned. The stabilizer is preferably added in such an amount that the tetragonal zirconia grains can be partially stabilized. For example, when yttria is used as the stabilizer, the content of yttria is preferably 2 mol % to 8 mol %, more preferably 2.5 mol % to 6.5 mol %, with respect to the total mol number of zirconia and yttria. If the content of the stabilizer is excessively increased, though the phase transition can be suppressed, the bending strength and the fracture toughness are lowered. On the other hand, if the content of the stabilizer is too low, though the lowering of the flexural strength and the fracture toughness can be suppressed, progress of the phase transition will be insufficiently suppressed. It should be noted that zirconia partially stabilized by addition of a stabilizer is called “a partially stabilized zirconia”. The content of the stabilizer in the zirconia sintered body can be measured by for example, inductively coupled plasma (ICP) emission spectroscopic analysis, fluorescent X-ray analysis etc.

The size dl of the whole of the workpiece body1and the thickness t1of the workpiece body1can be selected appropriately in accordance with purpose.

It is preferable that the material of the holding member2is such a material which is not greatly deformed by the pressure occurring when it is fixed on the processing apparatus. Further, it is preferable that the material of the holding member2is such a material that can be attached to the workpiece body1by a method described below. As a material of the holding member2, for example, engineering plastic, polypropylene, polystyrene, acrylic resin, ABS (acrylonitrile butadiene styrene) resin, polycarbonate, polyester, polyether ketone, Teflon (registered trademark), metal and wood etc. can be used. Further, the above examples of resins can also include a composite material (composite resin) in which inorganic filler is filled in these resins.

Information can be added to the holding member2. For example, information with a symbol such as a letter or a barcode can be provided by printing, stamping, sealing, etc. at a position where the holding member2can be visually recognized. The information includes, for example, lot number, color tone (shade), contraction ratio (shrinkage ratio upon sintering), upper and lower discrimination etc.

A method for producing the workpiece unit according to the first exemplary embodiment will be explained.

First, each section11is produced. Partially stabilized zirconia powder is prepared, which is zirconia particles containing a stabilizer. A type and concentration of the stabilizer can be selected appropriately. A particle size and particle size distribution of the zirconia crystal grains are selected appropriately. As a method for adding the stabilizer to the zirconia particles, a suitable method such as hydrolysis process, neutralization coprecipitation process, alkoxide process, solid phase process etc. can be selected appropriately. If necessary, an additive is added and mixed to the prepared partially stabilized zirconia powder. When wet mixing is used, the composition is dried.

Next, the composition is pressure-molded into a predetermined shape. For example, the composition is pressure-molded into the shape of the section11. As the pressure-molding method, a suitable method can be selected appropriately. The applied pressure may be, for example 20 MPa or more. After the pressure-molding, the composition for sintering may be further subjected to CIP (Cold Isostatic Pressing), for example, at a pressure of 150 MPa or more. After the pressure-molding, the molded body may be processed into a desired shape by cutting, grinding etc.

Next, the molded body is fired at a temperature at which the zirconia grains are not sintered, to form a pre-sintered body. A condition of pre-sintering may be, for example 800° C. to 1200° C. as a pre-sintering temperature and a keeping time thereof may be 1 hour to 12 hours. The pre-sintered body may be processed into a desired shape by cutting, grinding etc. For example, the pre-sintered body may not be formed into the shape of the section11at the time of molding, but be formed into the shape of the section11after preparing the pre-sintered body.

In the above steps, a plurality of the sections11constituting the workpiece body1is produced. Then, the workpiece1as described above is produced by combining a plurality of the sections11. As necessary, the cushioning (buffer) material6is incorporated between the sections11. The combining step of the sections11may be performed at the time of attaching the holding member2described later.

Next, the holding member2is prepared. A method of manufacturing the holding member2is not particularly restricted. For example, the holding member2can be manufactured by using injection molding, extrusion molding, cutting processing (forming by cutting) etc. In the case of the ring-shaped holding member2, for example, the holding member2is expanded by heating. A heating temperature of the holding member2can be appropriately selected according to the material of the holding member2. For example, when the holding member2is engineering plastic, the heating temperature of the holding member2is preferably 60° C. or greater, more preferably 80° C. or greater. Further, the heating temperature of the holding member2is preferably 150° C. or less, for example may be 120° C. or less or 100° C. or less. Next, the workpiece body1is inserted into the holding member2in a state that the holding member2is expanded. Next, the holding member2and the workpiece body1are aligned with each other, and then the holding member2is cooled. The holding member2contracts by cooling. As a result, the holding member2is mounted on the workpiece body1(so-called shrink fitting method). According to this method, the holding member2can be mounted to the workpiece body1without using an adhesive.

FIG. 11andFIG. 12show in a schematic cross-sectional view of the workpiece unit an example of the workpiece unit after the workpiece body is processed.FIG. 11shows a state in which the first section11ais processed but the second section11bis not processed.FIG. 12is a schematic partial cross-sectional view of the holding member portion. The processing apparatus can be set so as to process a specific part (for example, the specific section11) of the workpiece body1. For example, it is possible to set so as to process only the position of the first section11a. The workpiece unit10A is attached to the processing apparatus, then the worked item4is formed by processing such as cutting the workpiece body1. The worked item4can be cut out in such a state that the outer edge portion1eof the workpiece body1remains in a frame shape and the worked item is connected to the outer edge portion1e. The worked item4is for example a dental product as described above. By forming the worked item4, a cut portion5which was cut is formed in the workpiece body1. The outer edge portion1eis formed along the outer circumferential portion1cby forming the worked item4and the cut portion5. The outer edge portion1eis a processing margin and acts as a frame of the worked item4. The worked item4is connected to the outer edge portion1eby a connecting portion4a. It is preferable that the shape of the first positioning portion which will be described bellow will be formed in such a shape that does not cause adverse effects such as falling out of the worked item4after processing.

According to the first exemplary embodiment, the workpiece body can comprise a plurality of the sections having different compositions. A size and shape of each section can be adjusted according to demand. Hereby, it is possible to increase utilization efficiency of the workpiece body and reduce the waste portion of the workpiece body. It is also possible to produce and sell the workpiece body for each section. Further, it is possible to produce the worked item having different compositions by the processing apparatus in one processing step.

A workpiece unit according to a second exemplary embodiment of the present disclosure will be explained.FIG. 13shows a schematic plan view of the workpiece unit according to the second exemplary embodiment.FIG. 14shows a schematic plan view of the section unit according to the second exemplary embodiment. In the first exemplary embodiment, one holding member is applied to the section or sections. In the second exemplary embodiment, a part of the holding member is disposed for each section.

The workpiece unit150according to the second exemplary embodiment includes a plurality of section units21. Each section unit21has a section11and a covering member12disposed on at least a part of a side face of the section11. The section11may be the same as the section of the first exemplary embodiment. A size of one section unit can be smaller than a size that can be held on the processing apparatus.

In the mode shown inFIG. 14, the covering member12surrounds an outer circumferential portion (side face) of the section11. The covering member152can be the same as the holding member in the first exemplary embodiment except that it surrounds one section. The covering member12forms the holding member that is held by the processing apparatus, when the workpiece unit20is formed by combining a plurality of the section units21. A part of one covering member12constitutes a part of the holding member. By combining a plurality of the section units21, the holding member is formed such that a part of the covering member12continuously surrounds the combination of the sections11. For example, when the section11has a fan shape (sector), a portion of the covering members12which is arranged on the circular arc section of the section11constitutes the holding member. A portion of the covering member12not constituting the holding member can act as a buffering portion which facilitates joining with the adjacent section smoothly.

The section units21can be joined with each other by an adhesive (not shown). Alternatively, an engaging portion may be provided for engaging the covering members12with each other in a portion where the covering members12face each other.

FIG. 15shows a schematic plan view of a section unit having a different form from that shown inFIG. 14. In the mode shown inFIG. 14, the covering member is arranged over the entire circumference of the section. In the section unit22according to the mode shown inFIG. 15, the covering member13is disposed merely on a part of the side face of the section11. By combining the section units22in the same manner as the combination shown inFIG. 13, it is possible to constitute the workpiece unit as shown inFIG. 1. The covering member13is disposed on a portion that functions as a holding member when the selection units are combined. In the mode inFIG. 15, the covering member13is arranged along the circular arc portion of the section11. The covering member13is not provided on a portion of the side surface of the section11which faces the adjacent section11when the partitioning units22are combined. The section unit22shown inFIG. 15is the same as that of the section unit shown inFIG. 14except that the placement position of the covering member13is different.

The section units22can be joined with each other by an adhesive (not shown). Alternatively, an engaging portion may be provided for engaging the sections11with each other in a portion where the sections11face each other.

Other modes in the second exemplary embodiment than those described above can be the same as those in the first exemplary embodiment. The second exemplary embodiment can be combined with at least one of the exemplary embodiments described above as far as possible.

According to the second exemplary embodiment, the same effects as those of the first exemplary embodiment can be obtained. Since it can be produced or sold for each section unit, the user can arbitrarily set the combination of compositions in the workpiece unit by producing or purchasing the section unit according to the demand.

A workpiece unit (assembly) according to a third exemplary embodiment of the present disclosure will be explained.FIG. 16shows a schematic plan view of the workpiece unit according to the third exemplary embodiment.FIG. 17shows a schematic plan view of a dummy workpiece body according to the third exemplary embodiment. In the second exemplary embodiment, the workpiece unit is constituted of a plurality of the section units which are combined. In the third exemplary embodiment, the workpiece unit30is constituted by using one section unit.

The workpiece unit30has a section unit21and a dummy workpiece body31. The section unit21is the same as the section unit21according to the second exemplary embodiment. The dummy workpiece body31makes it possible to hold the section unit21on the processing apparatus by compensating the size of the section unit21. The dummy workpiece body31can have a holding portion31afor holding itself on the processing apparatus. The holding portion31ahas the same function as the holding member. The holding portion31amay be formed integrally as a part of the dummy workpiece body31or may be formed as a separate member. In the exemplary embodiment shown inFIG. 16andFIG. 17, the dummy workpiece body31has such a planar shape that three section units21are combined. In the exemplary embodiment shown inFIG. 16andFIG. 17, the dummy workpiece body31has such a planar shape as to form a circular shape by combining with the section unit21.

A shape and size of the dummy workpiece body31can be designed according to the shape and size of the section unit21. The dummy workpiece body31has a thickness that can be held on the processing apparatus. Material of the dummy workpiece body31may be any material as long as it can be held on the processing apparatus and the section can be processed. As a material of the dummy workpiece body31, for example, the same material as the holding member can be used.

The dummy workpiece body31and the section unit21can be joined to each other by an adhesive (not shown). Alternatively, an engaging portion may be provided for engaging the dummy workpiece body31and the section unit21in a portion(s) where the dummy workpiece body31and the section unit21face each other.

It is preferable that the dummy workpiece body31can be used repeatedly. It is preferable that the section unit21is attachable and detachable to and from the dummy workpiece body31.

FIG. 18shows another mode from the mode shown inFIG. 16. The workpiece unit33has a section (workpiece body)23, a dummy workpiece body34for holding the section23, and an adhesive24for joining the section23and the dummy workpiece body34. The dummy workpiece body34has an annular or tubular structure with an opening bored in the size of the section23. The dummy workpiece body34can have a holding portion34afor holding on the processing apparatus. In the mode shown inFIG. 18, the section23is fitted concentrically in the opening of the dummy workpiece body34and joined by the adhesive24. A size (for example, radius) of the section23can be 80% or less, 60% or less, 50% or less, or 40% or less of the size (for example, radius) that can be held on the processing apparatus.

It is preferable that the dummy workpiece body34has such a strength that the dummy workpiece body is not deformed during processing by the processing apparatus.

Other modes in the third exemplary embodiment than those described above can be the same as those in the first and the second exemplary embodiments. The third exemplary embodiment can be combined with at least one of the exemplary embodiments described above as far as possible.

According to the third exemplary embodiment, the same effects as those of the first exemplary embodiment can be obtained. It is not necessary to enlarge the workpiece body to a size in which the workpiece body can be held on the processing apparatus. Hereby, even when the workpiece body has a composition with low demand, it can be processed without requiring a workpiece body of another composition.

A workpiece unit according to a fourth exemplary embodiment of the present disclosure will be explained.FIG. 19shows a schematic plan view of a workpiece unit according to the fourth exemplary embodiment.FIG. 20shows a schematic cross-sectional view of the workpiece unit along line XX-XX inFIG. 19.FIG. 21shows a schematic partial cross-sectional view of a holding member portion.

In the workpiece unit40according to the fourth exemplary embodiment, in addition to the configuration of the first exemplary embodiment, the workpiece body41further has a protrusion41c. The holding member2is disposed on at least a part of the protrusion41c.

The workpiece body41has a first surface41adedicated as processing surface (surface-to-be-worked) and a second surface41barranged on a side opposite to the first surface1a. It is preferable that the first surface41aand the second surface41bare parallel or substantially parallel. It is preferable that the workpiece body41has a plate shape. In the exemplary embodiment shown inFIG. 19, the workpiece unit40and the workpiece body41have a circular planar shape, but it is not limited to have a circular one and they also may have a planar shape such as an elliptical shape or a polygonal shape.

The workpiece41has the protrusion41cfor holding the workpiece unit40on the processing apparatus along at least a part of the side wall, that is, on the outer edge of the first surface41aand the second surface41bor on the outer circumstantial portion41gprovided between the first surface41aand the second face41b. It is preferable that the protrusion41cis continuously arranged over the entire circumference of the outer circumstantial portion41gof the workpiece body41. That is, it is preferable that the protrusion41chas a ring shape or an annular shape. The protrusion41cmay have a form protruding from the side face of the workpiece body41. For example, the protrusion41ccan protrude in a direction substantially perpendicular [sic. parallel] to the first surface41aand the second surface41bbetween the first surface41aand the second surface41bof the workpiece body41. Further, the protrusion41cis located on the outer circumferential portion41gof the workpiece body41, and can have such a form in which the end portion of the workpiece body41is thinner than the other portions.

At least one section can have at least a part of the protrusion41cof the workpiece body41. It is possible to make the protrusion41ccontinuously by combining a plurality of the sections42ato42d.

The protrusion41cmay have a third surface41ddirected in the same direction as the first surface41aand a fourth surface41edirected in the same direction as the second surface41b. The protrusion41cmay have a fifth surface41fconnecting the third surface41dand the fourth surface41e. It is preferable that the third surface41dand the fourth surface41eare parallel or substantially parallel. It is preferable that the third surface41dand the first surface41aare parallel or substantially parallel. It is preferable that the fourth surface41eand the second surface41bare parallel or substantially parallel. It is preferable that the third surface41dand the fifth surface41fare perpendicular or substantially perpendicular. It is preferable that the fourth surface41eand the fifth surface41fare perpendicular or substantially perpendicular. It is preferable that the first surface41aand the second surface41bare perpendicular or substantially perpendicular to the fifth surface41f. It is preferable that the thickness t12of the protrusion41cis thinner than the entire thickness t11of the workpiece body41. That is, it is preferable that a step is formed between the first surface41aand the third surface41d. It is preferable that a step is formed between the second surface41band the fourth surface41e. Hereby the positioning is facilitated, when the workpiece unit40is fixed on the processing apparatus. It should be noted that the first surface41aand the third surface41dmay form the same plane. Further, the second surface41band the fourth surface41emay form the same plane.

The thickness t12of the protrusion41cis preferably 1 mm or more, more preferably 2 mm or more, and still more preferably 4 mm or more. This is for holding the workpiece unit40during processing and for reinforcing the workpiece body41after processing.

The width w11of the protrusion41cis preferably 2 mm or less, more preferably 1.7 mm or less, and still more preferably 1.5 mm or less. An amount of the waste of the material of the workpiece41increases, if the width w11of the protrusion41cis too large. The width w11of the protrusion41cis preferably 0.3 mm or more, more preferably 0.4 mm or more, more preferably 0.6 mm or more, and further preferably 0.8 mm or more. The protrusion41chas a function of reinforcing the workpiece body41after processing. Therefore, in order to reinforce the workpiece body41after processing, a certain width is required for the protrusion41c.

It is preferable that the protrusion41cis arranged at a central area of the workpiece body41in the thickness direction of the workpiece body41. That is, it is preferable that the center in the thickness direction of the protrusion41coverlaps with the center in the thickness direction of the workpiece body41. Hereby the positioning is facilitated, when the workpiece unit40is set on the processing apparatus.

The size d12of the whole of the workpiece body41and the size d13of the first surface41aand the second surface41bdedicated as a surface-to-be-processed (termed “processing surface”) of the workpiece body41can be determined appropriately

The holding member2is disposed on at least a part of the outer side of the protrusion41c. It is preferable that the holding member2is arranged at least in the protruding direction of the protrusion41c. It is preferable that the holding member2is continuously arranged along the fifth surface41fcorresponding to the side face of the protrusion41c. That is, the holding member2covers at least a part of the fifth surface41fof the protrusion41c. The fifth surface41fof the protrusion41cand the inner circumferential portion2cof the holding member2face each other. At least a part of the fifth surface41fof the protrusion41cand the inner circumferential portion2cof the holding member2can directly contact each other. It is preferable that the first surface2aof the holding member2and the third surface41dof the workpiece body41are parallel or substantially parallel. It is preferable that the first surface2bof the holding member2and the fourth surface41eof the workpiece body41are parallel or substantially parallel.

The third surface41dof the protrusion41cand the first surface2aof the holding member2can form the same plane. Similarly, the fourth surface41eof the protrusion41cand the second surface2bof the holding member2can form the same plane. This is to ensure that the holding member2and the protrusion41ccompletely overlap each other. In this case, the thickness t13of the holding member2is the same as the thickness t12of the protrusion41c. Alternatively, the first surface2aof the holding member2can exist on a side closer to the first surface11aof the workpiece body41than the third surface41dof the protrusion41c. Similarly, the second surface2bof the holding member2can exist on a side closer to the second surface41bof the workpiece body41than the fourth surface41eof the protrusion41c. This is for making it easier to hold the workpiece unit40on the processing apparatus. In this case, the thickness t13of the holding member2is thicker than the thickness t12of the protrusion41c.

The thickness t13of the holding member2may be any thickness as long as it does not hinder the processing of the workpiece body41. The thickness t13of the holding member2is preferably thinner than the thickness t1of the workpiece body41and more preferably equal to the thickness t12of the protrusion41c. This is for making it easier to hold the workpiece unit on the processing apparatus. The thickness t13of the holding member2is preferably 1 mm or more, more preferably 2 mm or more, and still more preferably 4 mm or more. This is for maintaining the strength of holding by the processing apparatus.

It is preferable to hold the protrusion41cand the holding member2on the processing apparatus with their engaged portion. Therefore, it is preferable that the width w12of the holding member2has a width that can be held on the processing apparatus together with the width w11of the protrusion41c.

A method for producing the workpiece unit40can be the same as the method for producing according to the first exemplary embodiment.

The forms of the protrusion and the holding member may take a form different from the exemplary embodiments shown inFIGS. 19 to 21.FIGS. 22 to 25show other examples of the protrusion and the holding member.

In the workpiece unit50shown inFIG. 22, the holding member52is arranged so as to cover not only the fifth surface41fof the protrusion41cbut also at least a part of the third surface41dand the fourth surface41e. That is, the holding member52may have a groove portion for accommodating the protrusion41con the side of the workpiece body41. The holding member52can be arranged so that the protrusion41cis fitted into the groove portion.

The width w14of the protrusion41cis preferably the same as the width w11shown inFIG. 20. The width (w14+w15) of the holding member52is preferably the same as the width (w11+w12) shown inFIG. 20. The thickness t14of the protrusion41cis preferably 1 mm or more in order to ensure the strength. The thickness t15of the holding member52is preferably equal to or less than the thickness of the workpiece body41in order to hold it on the processing apparatus.

In the workpiece unit60shown inFIG. 23, the holding member62can be arranged so as to cover the fifth surface41fand either the third surface41dor the fourth surface41eof the protrusion41c. In the exemplary embodiment shown inFIG. 23, the holding member62is arranged so as to cover the third surface41dand the fifth surface41fof the protrusion41c.

The holding member62has a first surface62adirected in the same direction as the second surface41band the fourth surface41eof the workpiece body41. It is preferable that the holding member62is arranged so that the first surface62aforms the same plane as the fourth surface41eof the protrusion41cor exists on a side closer to the second surface41bthan the fourth surface41eof the protrusion41c. This is for stabilizing the attachment of the workpiece unit60on the processing apparatus. It is preferable that the holding member62is arranged at a central area in the thickness direction of the workpiece body41. In this case, the position of the protrusion41ccan be displaced from the center in the thickness direction of the workpiece body41.

The width w16of the protrusion41cis preferably the same as the width w11shown inFIG. 20. The width (w16+w17) of the holding member62is preferably the same as the width (w11+w12) shown inFIG. 20. The thickness t16of the protrusion41cis preferably 1 mm or more in order to ensure the strength. The thickness t17of the holding member62is preferably equal to or less than the thickness of the workpiece body41in order to hold it on the processing apparatus.

In the workpiece unit70shown inFIGS. 24 and 25, the holding member72is composed of two or more parts.FIG. 25is a plan view of the holding member72seen from the side surface. In the exemplary embodiment shownFIGS. 25 and 26, the holding member72has a first portion72acovering the third surface41dof the protrusion41cand a second portion72bcovering the fourth surface41eof the protrusion41c. The fifth surface41fof the protrusion41cis covered with the first portion72aand the second portion72b. The first portion72aand the second portion72bhave at least one engaging portion respectively on a side facing the fifth surface41fof the protrusion41c. For example, the first portion72aand the second portion72bare arranged so that the concave and convex portions are fitted on a side of the fifth surface41fof the protrusion41c. In the exemplary embodiment shown inFIG. 22, the boundary line between the first portion72aand the second portion72bis extending in a meander-shape.

In the first portion72aand the second portion72b, it is preferable that the regions where the concave and the convex portions are formed have the same shape. It is more preferable that the first portion72aand the second portion72bhave the same shape as a whole. It is more preferable that the first portion72aand the second part72bare the same parts. In this case, the producing and management of the holding member72can be simplified.

According to the exemplary embodiment shown inFIGS. 25 and 26, it is possible to prevent positional displacement of each part by providing engaging portions on each part of the holding member72. When the holding member72is composed of a plurality of parts, it is possible to facilitate attachment of the holding member72to the workpiece body41.

In the exemplary embodiment shown inFIG. 24the protrusion is provided, however the holding member can be composed of two or more parts also in a mode in which no protrusion exists.

InFIG. 26a further mode (variant) according to the fourth exemplary embodiment is shown. The workpiece body41and the holding member2can also be joined by an adhesive43at least partly. The adhesive43is preferably arranged within a range of the thickness of the protrusion1cand the holding member2. It is preferable that a material of the adhesive43is a material that does not cause positional displacement between the workpiece body41and the holding member2. As the adhesive43, for example, a thermosetting resin, a photocurable resin, or the like can be used. The adhesive43can be applied, for example, when the holding member cannot be attached by the shrink fit method.

Other modes in the fourth exemplary embodiment than those above can be the same as in the first to third exemplary embodiments. The fourth exemplary embodiment can be combined with at least one of the exemplary embodiments described above as far as possible.

According to the fourth exemplary embodiment, the same effects as those of the first exemplary embodiment can be obtained.

The form of the workpiece body41after processing is the same as that shown inFIGS. 11 and 12, but the workpiece body41after processing further has the protrusion41con the outer edge portion1e(FIGS. 11 and 12). The worked item4is connected to at least one of the outer edge portion1eand the protrusion41c. After processing as shown inFIGS. 11 and 12, even if the width of the outer edge portion of the workpiece body41becomes thinner and no sufficient strength can be obtained only by the outer edge portion, in the workpiece unit according to the second exemplary embodiment, it is possible to reinforce the outer edge portion of the workpiece41by the protrusion41c. That is, the thickness of the outer edge portion of the workpiece body41can be partially secured by the protrusion41c. Hereby, even when an impact is applied to the workpiece body41after processing, fracture of the workpiece body41can be suppressed. In addition, it is possible to increase the allowable range of positional displacement (tolerance) in attaching the workpiece unit40to the processing apparatus by providing the protrusion41c.

A workpiece unit according to a fifth exemplary embodiment of the present disclosure will be explained.FIG. 27shows a schematic partial cross-sectional view of a workpiece unit according to the fifth exemplary embodiment.FIG. 28shows a schematic exploded cross-sectional view of a workpiece body and a holding member.

In the workpiece unit80according to the fifth exemplary embodiment, the workpiece body81has at least one first positioning portion81din a portion of an outer circumferential portion81cwhich faces a holding member82. The holding member82has at least one second positioning portion82din a portion of an inner circumferential portion82cwhich faces the workpiece body81. The first positioning portion81dand the second positioning portion82dare portions for determining the position of the holding member82relative to the workpiece body81. The first positioning portion81dand the second positioning portion82dcan also prevent the holding member82from being misaligned relative to the workpiece81.

At least one section can have at least a part of the first positioning portion81dof the workpiece body81. It is possible to make the first positioning portion81dcontinuously by combining a plurality of the sections.

The first positioning portion81dand the second positioning portion82dcan be arranged at positions where they correspond to each other. The first positioning portion81dand the second positioning portion82dmay have shapes corresponding to each other. For example, it is preferable that the first positioning portion81dand the second positioning portion82dhave such positions and such shapes that at least a part of one is engaged with the other. In the exemplary embodiment shown inFIGS. 27 and 28, the first positioning portion81dis formed as a concave portion. The second positioning portion82dis formed as a convex portion that fits into the concave portion of the first positioning portion81d. The positions of the first positioning portion81dand the second positioning portion82dmay be an any positions as long as the outer circumferential portion81cof the workpiece body81and the inner circumferential portion82cof the holding member92face each other.

It is preferable that at least a part of the tip of the convex portion can be inserted into the concave portion. It is preferable that the convex portion has a shape and a size which comes into contact with the opening and/or the inner wall of the concave portion when it is inserted into the concave portion. For example, it is preferable that the width of the convex portion (for example, the size in the direction that connects the first surface81aand the second surface81bof the workpiece body81(vertical direction in the frame)) is larger than the width of the concave portion (the size in the vertical direction in the frame). In this way, it is possible to suppress a positional displacement of the holding member82relative to the workpiece body by fitting or engaging the first positioning portion81dand the second positioning portion82d.

FIGS. 29 to 32show schematic plan views of examples of the first positioning portion81dand the second positioning portion82d. AlthoughFIGS. 29 to 32show the first positioning portion81din plan views, but the second positioning portion82dalso has a planar shape corresponding to the shape of the first positioning portion81d. The illustration and explanation of the second positioning portion82dare omitted. For example, as shown inFIGS. 29 and 30, the first positioning portion81dcan be formed as a continuous groove. The first positioning portion81dmay be a linear groove as shown inFIG. 29, or it also may be a groove of zigzag or meander-shape as shown inFIG. 30. For example, as shown inFIGS. 31 and 32, the first positioning portion81dmay be formed as at least one partial or discontinuous point-like concave portion (for example, a conical or columnar shape) or a fragmental groove. A dotted line formed by the first positioning portion81dmay be linear as shown inFIG. 31, or it may be zigzag or meander-shape as shown inFIG. 32. AlthoughFIGS. 29 to 32show the first positioning portion81dhaving a regular shape, the first positioning portion81dmay have an irregular shape.

Although in the exemplary embodiment shown inFIGS. 27 and 28, the first positioning portion81dand the second positioning portion82dhave one triangular cross section, but the first positioning portion81dand the second positioning portion82dcan have other cross-sectional shapes.FIGS. 33 to 36show schematic partial cross-sectional views of examples of the first positioning portion81dand the second positioning portion82d. For example, as shown inFIG. 33, the first positioning portion81dand the second positioning portion82dmay have a polygonal cross section such as a rectangle etc. As shown inFIG. 34, the first positioning portion81dmay have a cross-sectional shape (hemispherical shape) such as a semi-circular, semi-elliptical etc. On the other hand, the second positioning portion82dmay have a sectional shape (hemispherical shape) such as a semi-circular, semi-elliptical similar to that of the first positioning portion81d, or as shown inFIG. 34may have a different shape(s) (Triangular shape inFIG. 34) from the first positioning portion81d. As shown inFIG. 35, a part of the second positioning portion82dmay be engaged with the first positioning portion81d. In the exemplary embodiment shown inFIG. 35, the width w22of the second positioning portion82dis equal to or larger than the width w21of the first positioning portion81d. A part of the second positioning portion82dis inserted into the first positioning portion81d, and the first positioning portion81dand the second positioning portion82dcontact with each other partially at the upper and lower ends of the first positioning portion81d. In this case, the outer circumferential portion81cof the workpiece body81and the inner circumferential portion82cof the holding member82may not contact with each other. Alternatively, as shown inFIG. 35, the holding member82may be deformed by its shrinkage, for example, and partially contact the outer circumferential portion81cof the workpiece body81at the upper and lower ends of the inner circumferential portion82c. Further, as shown inFIG. 36, in one cross section, the first positioning portion81dand the second positioning portion82dcan have a plurality of concave or convex portions.

It is preferable that the first positioning portion81dand/or the second positioning portion82dhas such a depth and/or a height which is equal to a depth and/or a height in which the first positioning portion81dand the second positioning portion82dcan engage with each other. The depth and/or the height of the first positioning portion81dand/or the second positioning portion82dmay be, for example, 0.5 mm or more.

A method for producing the workpiece unit80can be the same as the method for producing according to the first exemplary embodiment.

Other modes in the fifth exemplary embodiment than those described above can be the same as in the first to fourth exemplary embodiments. The fifth exemplary embodiment can be combined with at least one of the exemplary embodiments described above as far as possible.

According to the fifth exemplary embodiment, the same effects as those of the first exemplary embodiment can be obtained.

According to the fifth exemplary embodiment, the holding member82can be attached to the workpiece body81at an appropriate position by fitting the first positioning portion81dand the second positioning portion82d. Further, even after the holding member82is attached to the workpiece body81, the first positioning portion81dand the second positioning portions82dplay a role of slip prevention, and the positional displacement of the holding member82relative to the workpiece body81can be suppressed.

A workpiece unit according to a sixth exemplary embodiment of the present disclosure will be explained.FIG. 37shows a schematic partial cross-sectional view of a workpiece unit according to the sixth exemplary embodiment.

In the fifth exemplary embodiment, the first positioning portion of the workpiece body is the concave portion, and the second positioning portion of the holding member is the convex portion. In a workpiece unit90according to the sixth exemplary embodiment, the concave and convex portions are reversed between the workpiece body91and the holding member92. That is, the first positioning portion91farranged on an outer circumferential portion91cof the workpiece body91is the convex portion. The second positioning portion92farranged on an inner circumferential portion92cof the holding member92is the concave portion corresponding to the first positioning portion91f.

A method for producing the workpiece unit90can be the same as the method for producing according to the first exemplary embodiment.

Other modes in the sixth exemplary embodiment than those described above can be the same as in the first to fourth exemplary embodiments. The sixth exemplary embodiment can be combined with at least one of the exemplary embodiments described above as far as possible.

According to the sixth exemplary embodiment, the same effects as those of the first and fifth exemplary embodiments can be obtained.

A workpiece unit according to a seventh exemplary embodiment of the present disclosure will be explained. In the seventh exemplary embodiment, the fifth and sixth exemplary embodiments are combined with the fourth exemplary embodiment.FIGS. 38 to 41show schematic partial cross-sectional views of a workpiece unit according to the seventh exemplary embodiment.FIGS. 38 to 41show one example according to the seventh exemplary embodiment respectively.

In the workpiece unit100shown inFIG. 38, the first positioning portion and the second positioning portion according to the fifth and sixth exemplary embodiments are applied to the configuration according to the fourth exemplary embodiment shown inFIG. 21. The first positioning portion101hof the workpiece body101can be arranged on a fifth surface101fof the protrusion101c. The second positioning portion102dof the holding member102can be arranged at a position corresponding to the first positioning portion101h. The configurations of the first positioning portion101hand the second positioning portion102dcan be the same as those of the fifth and sixth exemplary embodiments.

In a workpiece unit110shown inFIG. 39, the first positioning portion and the second positioning portion according to the fifth and sixth exemplary embodiments are applied to the configuration according to the fourth exemplary embodiment shown inFIG. 22. The first positioning portion101hof the workpiece body101can be arranged on a fifth surface101fof the protrusion101c. The second positioning portion112aof the holding member112can be arranged at a position corresponding to the first positioning portion101h. The configurations of the first positioning portion101hand the second positioning portion112acan be the same as those of the fifth and sixth exemplary embodiments.

In a workpiece unit120shown inFIG. 40, the first positioning portion and the second positioning portion according to the fifth and sixth exemplary embodiments are applied to the configuration according to the fourth exemplary embodiment shown inFIG. 23. The first positioning portion101hof the workpiece body101can be arranged on the fifth surface101fof the protrusion101c. The second positioning portion122bof the holding member122can be arranged at a position corresponding to the first positioning portion101h. The configurations of the first positioning portion101hand the second positioning portion122bcan be the same as those of the fifth and sixth exemplary embodiments.

In a workpiece unit130shown inFIG. 41, the first positioning portion and the second positioning portion according to the fifth and sixth exemplary embodiments are applied to the configuration according to the fourth exemplary embodiment shown inFIG. 24. The first positioning portion101hof the workpiece body101can be arranged on the fifth surface101fof the protrusion101c. The second positioning portion132cof the holding member132can be arranged at a position corresponding to the first positioning portion101h. The configurations of the first positioning portion101hand the second positioning portion132ccan be the same as those of the fifth and sixth exemplary embodiments.

In each mode according to the seventh exemplary embodiment, the configuration is shown in which the first positioning portion of the workpiece body is the concave portion, and the second positioning portion of the holding member is the convex portion. Also in each mode according to the seventh exemplary embodiment, similarly to the sixth exemplary embodiment, the concave portion and the convex portion can be reversed between the workpiece body and the holding member. That is, the first positioning portion disposed at the protrusion of the workpiece body has a convex portion, and the second positioning portion disposed at the inner circumferential portion of the holding member can have a concave portion (not shown).

Although in each mode according to the seventh exemplary embodiment, the configuration is shown in which the first positioning portion of the workpiece body is arranged on the fifth surface of the protrusion, the first positioning portion may be arranged on at least one of the third surface and the fourth surface of the protrusion. The second positioning portion can be arranged at a position corresponding to the first positioning portion.

A method for producing the workpiece unit according to the seventh exemplary embodiment can be the same as the method for producing according to the first exemplary embodiment.

Other modes in the seventh exemplary embodiment than those described above can be the same as in the first to sixth exemplary embodiments. The seventh exemplary embodiment can be combined with at least one of the exemplary embodiments described above as far as possible.

According to the seventh exemplary embodiment, the same effects as those of the first to sixth exemplary embodiments can be obtained.

A workpiece unit according to an eighth exemplary embodiment of the present disclosure will be explained. In the first exemplary embodiment, the sections are physically separated from each other. In the eighth exemplary embodiment, at least two sections in a workpiece body are not physically separated and can be integrally formed. A schematic plan view and a schematic cross-sectional view of the workpiece unit according to the eighth exemplary embodiment can be the same as those inFIGS. 1 and 2.

It is preferable that the adjacent sections11are joined with each other. Therefore, it is preferable that a material of the adjacent sections11is such a material that can be bonded to each other by firing, and it is more preferable that the main materials are the same. For example, the adjacent sections11may be zirconia which is different in type and/or contents of additive such as colorants.

A method for producing a workpiece unit according to the eighth exemplary embodiment is the same as the method for producing described in the above exemplary embodiments except that a plurality of the sections11is integrally formed. Regarding molding of a workpiece, first, a mold having a desired shape of the section is formed by providing removable partitions in the mold. The partitions are located at boundaries of the sections. Next, after feeding the composition to an area of each section, the partition is removed. Next, a molded body in which a plurality of compositions is integrated can be formed by pressure-molding the compositions. A method performed after sintering (or firing) of the molded body is the same as in the above exemplary embodiments.

Other modes in the eighth exemplary embodiment than those described above can be the same as those according to the first to seventh exemplary embodiments. The eighth exemplary embodiment can be combined with at least one of the exemplary embodiments described above as far as possible.

According to the eighth exemplary embodiment, the same effects as those of the first to seventh exemplary embodiments can be obtained. In addition, members for holding a plurality of the sections, such as the holding member and the adhesive etc. are unnecessary.

A workpiece unit according to a ninth exemplary embodiment of the present disclosure will be explained.FIG. 42shows a schematic plan view of a workpiece unit according to a ninth exemplary embodiment.FIG. 43shows a schematic cross-sectional view of the workpiece unit along line XXXXIII-XXXXIII inFIG. 42. In the above exemplary embodiments, the workpiece unit has the holding member, but in the ninth exemplary embodiment, the workpiece unit140has no holding member.

A workpiece body141has a first surface141c[sic.141a], a second surface141band a protrusion141cwhich replaces the holding member. A protrusion141cis continuously arranged on an outer circumstantial portion of the workpiece body141. The protrusion141cmay be a part of the workpiece body141. It is preferable that each of the sections151ato151chas the protrusion141c. A basic form of the protrusion141ccan be the same as the protrusion in the fourth exemplary embodiment. It is preferable that the width w31of the protrusion141cis equal to the width that can hold the workpiece unit141on the processing apparatus. A shape, size and position of the protrusion141ccan be the same as those of the holding member and/or the combinations of the holding member and the protrusion in the above exemplary embodiments.

The protrusion141ccan be formed, for example, by cutting a top end and a bottom end of the outer edge portion after fabricating the plate-like workpiece body.

Other modes in the ninth exemplary embodiment than those described above can be the same as in the first to eighth exemplary embodiments. The ninth exemplary embodiment can be combined with at least one of the exemplary embodiments described above as far as possible.

According to the ninth exemplary embodiment, the same effects as those of the first to eighth exemplary embodiments can be obtained. Further, the step of attaching the holding member can be omitted.

The disclosure of the Patent Literature as mentioned above is incorporated herein by reference thereto. It is to be noted that the workpiece unit and the method for producing according to the present invention are described based on the exemplary embodiments described above but they are not restricted thereto. Rather, it is possible for the workpiece unit and the production method to include various types of variations, changes or modifications or improvements of a wide variety of the disclosed elements (including the individual elements of the individual claims, the individual elements of the individual exemplary embodiments or examples, the individual elements of the individual figures etc.) within the entire disclosure of the present invention (including Claims and Drawings) and based on the basic technical concept of the present invention. Further, various combinations, replacements and selections of the various disclosed elements (including, for example, each element in the Claims, each element in the exemplary embodiments and examples and each element in the drawings) are possible within the entire disclosure of the present invention.

Further problems, objectives and developments of the present invention are apparent from the entire disclosure of the present invention including Claims.

With respect to numerical values and ranges disclosed in the present application, it should be interpreted that all numerical values or small ranges included in the ranges are specifically disclosed even if there are no explicit disclosure.

A part or all of the above described exemplary embodiments may also be expressed as following remarks (termed as “mode” or “modes”), but not restricted thereto.

a workpiece body having a protrusion, and

a holding member arranged on at least a part of an outer side of the protrusion.

The workpiece unit according to the Mode, wherein

the workpiece body has a plate shape,

the protrusion protrudes from a side surface of the workpiece body, and

the holding member is arranged at least in a protruding direction of the protrusion.

The workpiece unit according to the Mode(s), wherein

the workpiece body has a first surface, a second surface arranged on a side opposite to the first surface and an outer circumferential portion provided between the first surface and the second surface, and

the protrusion is arranged on the outer circumferential portion.

The workpiece unit according to the Mode(s), wherein

the protrusion is arranged continuously along the outer circumferential portion of the workpiece body, and

the holding member has a ring shape.

The workpiece unit according to the Mode(s), wherein

the protrusion has a third surface directed in the same direction as the first surface, a fourth surface directed in the same direction as the second surface and a fifth surface connecting the third surface and the fourth surface, and

the holding member covers at least a part of the fifth surface.

The workpiece unit according to the Mode(s), wherein

the holding member has a first surface directed in the same direction as the third surface of the protrusion and a second surface directed in the same direction as the fourth surface of the protrusion.

The workpiece unit according to the Mode(s), wherein

the first surface of the holding member forms the same plane as the third surface of the protrusion or exists on a side closer to the first surface of the workpiece body than the third surface of the protrusion.

The workpiece unit according to the Mode(s), wherein

the second surface of the holding member forms the same plane as the fourth surface of the protrusion or exists on a side closer to the second surface of the workpiece body than the fourth surface of the protrusion.

The workpiece unit according to the Mode(s), wherein

the holding member further covers at least a part of the third surface and the fourth surface of the protrusion.

The workpiece unit according to the Mode(s), wherein

the workpiece body has at least one first positioning portion in a portion of the protrusion which faces the holding member, and

the holding member has a second positioning portion that engages with at least a part of the first positioning portion.

a workpiece body and

a holding member arranged on at least a part of an outer circumferential portion of the workpiece body, wherein

the workpiece body has at least one first positioning portion in a portion which faces the holding member, and

the holding member has a second positioning portion that engages with at least a part of the first positioning portion.

The workpiece unit according to the Mode, wherein

the first positioning portion has a concave or convex shape,

the second positioning portion has a shape which fits with the first positioning portion, and

at least a part of one of the first positioning part and the second positioning part is fitted with at least a part of the other.

The workpiece unit according to the Mode(s), wherein

the first positioning portion is arranged over the entire circumference of the workpiece body.

The workpiece unit according to the Mode(s), wherein

the first positioning portion or the second positioning portion has a groove shape.

The workpiece unit according to the Mode(s), wherein

the first positioning portion or the second positioning portion has a conical or columnar shape.

The workpiece unit according to the Mode(s), wherein

the workpiece body has a protrusion protruding from the outer circumferential portion,

the first positioning portion is arranged at the protrusion, and

the holding member is arranged at least in a protruding direction of the protrusion.

The workpiece unit according to the Mode(s), wherein

the protrusion is arranged continuously along the outer circumferential portion of the workpiece body, and

the holding member has a ring shape.

The workpiece unit according to the Mode(s), wherein

the workpiece body has a first surface and a second surface arranged on a side opposite to the first surface,

the outer circumferential portion is arranged between the first surface and the second surface,

the protrusion has a third surface directed in the same direction as the first surface, a fourth surface directed in the same direction as the second surface and a fifth surface connecting the third surface and the fourth surface, and

the holding member covers at least a part of the fifth surface.

The workpiece unit according to the Mode(s), wherein

the holding member is composed of two or more parts.

The workpiece unit according to the Mode(s), wherein

each of parts of the holding member has a concave portion or a convex portion respectively, and

the parts are arranged so as to fit together with the concave portion and the convex portion.

The workpiece unit according to the Mode(s), wherein

the workpiece body is ceramic, metal or resin.

The workpiece unit according to the Mode(s), wherein

the workpiece body is a pre-sintered body in which the zirconia crystal grains are not completely sintered.

The workpiece unit according to the Mode(s), wherein

the protrusion is a part of the pre-sintered body.

The workpiece unit according to the Mode(s), wherein

the holding member is bonded to the workpiece body by an adhesive.

The workpiece unit according to the Mode(s), wherein

the holding member and the workpiece body are in direct contact with each other.

The workpiece unit according to the Mode(s), wherein

the holding member is plastic.

The workpiece unit according to the Mode(s), wherein

the protrusion has a thickness substantially the same as that of the holding member.

The workpiece unit according to the Mode(s), wherein

the protrusion has a width of 0.3 mm to 2 mm in the protruding direction.

The workpiece unit according to the Mode(s), wherein

the protrusion is arranged at a central area in the thickness direction of the workpiece body.

The workpiece unit according to the Mode(s), wherein

the workpiece body is formed by processing the workpiece body and has a worked item connected to the protrusion or the outer edge portion of the workpiece body.

A method for producing a workpiece unit, comprising:preparing a workpiece body having a first positioning portion on an outer circumferential portion,preparing a holding member having a second positioning portion, andmounting the holding member to the outer circumferential portion of the workpiece body so as to correspond the first positioning portion to the second positioning portion.
[Mode 32]

The method for producing the workpiece unit according to the Mode, whereinthe first positioning portion is a concave portion or convex portion, andin the mounting the holding member, the first positioning portion and the second positioning portion are fitted with each other.
[Mode 33]

A method for producing a workpiece unit, comprising:preparing a workpiece body having a protrusion on an outer circumferential portion,preparing a holding member, andmounting the holding member on the outer side of the protrusion.
[Mode 34]

The method for producing the workpiece body according to the Mode(s), whereinthe mounting the holding member comprises:expanding the holding member having a ring shape by heating,inserting the workpiece body into a ring of the holding member, andshrinking the holding member by cooling.
[Mode 35]

The method for producing the workpiece body according to the Mode(s), wherein

the workpiece body has a protrusion protruding from the outer circumferential portion, and

the first positioning portion is arranged at the protrusion.

INDUSTRIAL APPLICABILITY

The present disclosure can be applied, for example, to the production of a dental prosthesis.

REFERENCE SIGNS LIST