Method for measuring height difference between nozzle heads and 3D printing apparatus using the method

The invention provides a method for height difference measurement between the print heads and a 3D printer using the method. The 3D printer includes a printing module, a contact sensor, a movement sensor and a controller. The controller makes a 3D print head and the contact sensor contact to each other vertically for generating a contact signal, and obtains a first height value according to a vertical movement distance between the printing module and the contact sensor. The controller makes a color head and the contact sensor contact to each other vertically for generating the contact signal, and obtains a second height value according to a vertical movement distance between the printing module and the contact sensor. The controller obtains a height difference between the 3D print head and the color head according to the first height value and the second height value.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority benefit of Taiwan application serial no. 106100349, filed on Jan. 5, 2017. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention generally relates to a correction technology of a printing apparatus, in particular, to a method for measuring a height difference between nozzle heads and a three-dimensional (3D) printing apparatus using the method.

Description of Related Art

With the development of science and technology, the 3D printing technology has become one of the principally developed technologies. The 3D printing technology is also referred to as the Additive Manufacturing (AM) technology, is one of the rapid prototyping technologies, and may construct a 3D material object in a layer-by-layer printing manner using a bondable material, such as powered metal or plastic, on the basis of a digital prototyping diagram file.

In the prior art, a color of a finished product of the 3D printing is mainly a color of a bondable material, and separate nozzle heads (for example: an extrusion nozzle head) need to be used for bondable materials of different colors. In a case in which there is no room for mounting a plurality of 3D print head, a 3D printing apparatus usually can only print one color or a limited number of colors. To implement colorful 3D printing without increasing a volume of a 3D printing apparatus and costs and to prevent a color of a printed material object from being limited to a color of a material, manufacturers all hope to develop a novel coloring technology for 3D printing and resolve problems derived from the coloring technology.

SUMMARY OF THE INVENTION

The present invention provides a method for measuring a height difference between nozzle heads and a 3D printing apparatus using the method, in which a height difference between a 3D print head and an inkjet print head in the 3D printing apparatus can be measured, so as to enable both of the 3D print head and inkjet print head to perform product printing and product coloring respectively at proper heights.

A 3D printing apparatus of an embodiment of the present disclosure includes a printing module, a contact sensor, a displacement measurer, and a controller. The printing module includes a 3D print head and a color head. The displacement measurer is configured to obtain a vertical movement distance of the printing module or the contact sensor. The controller is coupled to the displacement measurer and contact sensor, where the contact sensor generates a contact signal when the 3D print head or the color head gets in contact with the contact sensor. The controller enables the 3D print head to get in contact with the contact sensor vertically to generate the contact signal, so as to obtain a first height value according to the vertical movement distance of the printing module or the contact sensor and the contact signal and enables the color head to get in contact with the contact sensor vertically to generate the contact signal, so as to obtain a second height value according to the vertical movement distance of the printing module or the contact sensor and the contact signal. In addition, the controller obtains a height difference between the 3D print head and the color head according to the first height value and the second height value.

From another point of view, a method for measuring a height difference between nozzle heads of an embodiment of the present disclosure is applicable to a 3D printing apparatus. The 3D printing apparatus includes a printing module and a contact sensor, and the printing module includes a 3D print head and a color head. The correction method includes the following steps: enabling the 3D print head to get in contact with the contact sensor vertically to enable the contact sensor to generate the contact signal, so as to obtain a first height value according to a vertical movement distance of the printing module or the contact sensor and the contact signal; enabling the color head to get in contact with the contact sensor vertically to enable the contact sensor to generate the contact signal, so as to obtain a second height value according to the vertical movement distance of the printing module or the contact sensor and the contact signal; obtaining a height difference between the 3D print head and the color head according to the first height value and the second height value.

On the basis of the foregoing, the present invention provides a method for measuring a height difference between nozzle heads and a 3D printing apparatus using the method, in which a height difference between a 3D print head and a color head in the 3D printing apparatus can be measured. The 3D printing apparatus can adjust the 3D print head and the color head separately according to the measured height difference, so as to improve accuracy of horizontal correction of the two types of nozzle heads. In this way, even if both of the 3D print head and the color head are disposed on a same rail, and there is a dimensional error between finished products of nozzle heads of a same type, optimal operating distances can be simultaneously maintained between the two types of nozzle heads and a 3D object according to the method of the present invention, so as to further improve quality of a finished product of the 3D object. Hence, the present invention can enable both of the 3D print head and color head in the 3D printing apparatus to perform product printing and product coloring respectively at proper heights.

In order to make the foregoing features and advantages of the present invention comprehensible, embodiments accompanied with drawings are described in detail below.

DESCRIPTION OF THE EMBODIMENTS

To achieve colorful 3D printing, a 3D printing apparatus may be equipped with two types of independent nozzle heads, where one type of nozzle head is a 3D print head (for example, an extrusion nozzle head), which involves an AM technology of using, for example, Selective Laser Sintering (SLS) and Selective Laser Melting (SLM) technologies to heat powder to a sintering temperature or a melting point to sinter or melt the powder into a layer of thin film with a specific thickness, so as to construct a 3D object. The other type of nozzle head is a color head for coloring a printed object, for example, an inkjet print head. The inkjet print head is configured to spray ink onto and perform coloring on each layer of the printed object constructed by the 3D print head. The color head according to embodiments of the present invention may perform coloring on the printed object in various manners and is not limited to an inkjet print head.

To mount the two types of nozzle heads, a common method is respectively disposing dedicated rails in the 3D printing apparatus for the two types of nozzle heads. Disposing two types of dedicated nozzle head rails needs high costs, easily results in a relatively large volume of the 3D printing apparatus, and occupies relatively large room. Although the types of nozzle heads may also be disposed in a same rail, there may be a dimensional error between finished products of nozzle heads of a same type. When horizontal correction is performed on a rail equipped with multiple nozzle heads, the foregoing dimensional error would causes a result of the correction to be inaccurate. In view of the above, if the two types of nozzle heads are disposed on a same rail, difficulty in horizontal correction is increased, which further causes quality of a finished 3D product to degrade. Therefore, how to maintain accuracy of horizontal correction in a case that the two types of nozzle heads share a same rail is one of the objectives of the present invention.

In order to enable a printing apparatus to maintain quality of a finished product of a 3D object in a case in which both a 3D print head and a color head are disposed on a same rail, the present invention proposes a method for measuring a height difference between nozzle heads and a 3D printing apparatus using the method. The present invention may derive a height difference between a 3D print head and a color head by measuring vertical distances between the two of the 3D print head and color head and a contact sensor. The 3D printing apparatus can adjust the 3D print head and the color head separately according to the measured height difference, so as to improve accuracy of horizontal correction of the two types of nozzle heads.

FIG. 1is a schematic diagram illustrating a 3D printing apparatus100according to an embodiment of the present invention. Referring toFIG. 1, the 3D printing apparatus100may include a printing module110, a contact sensor131, a displacement measurer150, and a controller170. The 3D printing apparatus100may, for example, be a 3D printer. The printing module110may include a 3D print head111and a color head (for example, an inkjet print head113). The 3D print head111may, for example, use the SLS technology, the SLM technology, a Plaster-based 3D Printing (PP) technology, and a Fused Deposition Modeling (FDM) technology. The inkjet print head113may, for example, use a thermal bubble inkjet technology and a piezoelectric technology. The contact sensor131may, for example, be a limit switch or may, for example, be a component, such as a metal gasket or conductive plastic, capable of sending an electronic signal when being in contact with an object. The displacement measurer150may, for example, be a single chip microcomputer having a counting function, a microcontroller, and the like. The controller may, for example, be a central processing unit (CPU), a micro-processor, or an embedded controller that has a programmable general use or special use.

In this embodiment, the controller170may enable the 3D print head111or inkjet print head113to get in contact with the contact sensor131vertically, and the contact sensor131can generate a contact signal CS when the 3D print head111or inkjet print head113gets in contact with the contact sensor131. The displacement measurer150can obtain a vertical movement distance of the printing module110or the contact sensor131.

Specifically,FIG. 1is used as an example, in which a 3D printing apparatus may further include a printing platform130and a motor190, and the motor190may, for example, be a step motor. In the embodiment ofFIG. 1, the contact sensor131may be disposed on the printing platform130. The displacement measurer150may be disposed inside the motor190, and the motor190may be coupled to the printing module110or the printing platform130and configured to move the printing module110or the printing platform130. InFIG. 1, the motor190being coupled to the printing module110is used as an example. The controller170may control the printing module110by means of the motor190, so as to enable the 3D print head111or inkjet print head113to move downward vertically to get in contact with the contact sensor131vertically. When the 3D print head111gets in contact with the contact sensor131, the contact sensor131may generate a contact signal CS, and the contact signal CS is transmitted to the controller170. In a process in which the printing module110moves vertically to the contact sensor131, the displacement measurer150obtains a vertical movement distance H1of the printing module110by measuring operation of the motor190, and transmits information H corresponding to the vertical movement distance H1to a control panel170. When the control panel170receives the contact signal CS, the control panel170may obtain a first height value according to the information H corresponding to the vertical movement distance H1.

Similar to the foregoing steps, when the inkjet print head113gets in contact with the contact sensor131, the contact sensor131may generate a contact signal CS, and the contact signal CS is transmitted to the controller170. In a process in which the printing module110moves vertically to the contact sensor131, the displacement measurer150obtains a vertical movement distance H2of the printing module110by measuring operation of the motor190, and transmits information H corresponding to the vertical movement distance H2to a control panel170. When the control panel170receives the contact signal CS, the control panel170may obtain a second height value according to the information H corresponding to the vertical movement distance H2.

In the foregoing embodiment, a step motor is used to move the printing module110, so that the displacement measurer150can learn a movement distance of the 3D print head111or inkjet print head113in a manner of using a counter. In another embodiment, the displacement measurer150may also obtain a distance of the 3D print head111or inkjet print head113by using fixed point information provided by a processor. When this embodiment is applied, the displacement measurer150may be enabled to calculate a movement distance of the 3D print head111or inkjet print head113in various manners, which is not limited to the foregoing embodiment.

When the controller170obtains a first height value corresponding to a distance between the 3D print head111and the contact sensor131and a second height value corresponding to a distance between the inkjet print head113and the contact sensor131, a console may obtain a height difference ΔH between the 3D print head111and the inkjet print head113by perform subtraction on a first height1and the second height value.

In another embodiment, the motor190may be coupled to the printing platform130, control the printing platform130, and thus, enable the contact sensor131to move upward vertically to get in contact with the 3D print head111or inkjet print head113vertically. In this embodiment, the displacement measurer150may obtain the vertical movement distance H1of the printing platform130by measuring operation of the motor190. Likewise, the displacement measurer150may obtain the vertical movement distance H2of the printing platform130by measuring operation of the motor190. Hence, the console may obtain a height difference ΔH between the 3D print head111and the inkjet print head113by performing subtraction on the first height1and the second height value. In addition to the foregoing steps, the rest steps of this embodiment are approximately the same as those of the foregoing embodiment, and the descriptions thereof are omitted herein.

In another embodiment, the displacement measurer150may also be individually disposed outside the motor190. As long as the displacement measurer150is enabled to measure operation of the motor190and transmit the obtained vertical movement distance information H corresponding to the printing module110or printing platform130to the control panel170, a user could adjust a disposition manner of the displacement measurer150at will according to use requirements, and the present invention is not limited thereto. In other words, one of the objectives of the embodiments of the present invention is to obtain the height difference ΔH between the 3D print head111and the inkjet print head113, and application of this embodiment may be achieved by using the contact sensor131and displacement measurer150in many manners, which are not limited to manners in the embodiments of the present invention.

FIG. 2AandFIG. 2Bare schematic diagrams illustrating vertical distances between both of a 3D print head and an inkjet print head and a contact sensor according to an embodiment of the present invention, where the apparatus inFIG. 2A, 2Bincludes a printing module210, a printing platform230, a 3D print head211, an inkjet print head213, and a contact sensor231, operating manners and functions of the foregoing apparatus are all the same as those of the apparatus in the embodiment ofFIG. 1, and the descriptions thereof are omitted herein. First refer toFIG. 2A. In the embodiment ofFIG. 2A, the 3D print head211and the inkjet print head213in the printing module210are fixedly disposed relative to each other, and the 3D print head211is closer to the printing platform230than the inkjet print head213.

In the embodiment ofFIG. 2A, in order to measure a first height value corresponding to a distance between the 3D print head211and the contact sensor231and a second height value corresponding to a distance between the inkjet print head213and the contact sensor231to obtain a height difference ΔH between the 3D print head211and the inkjet print head213, the printing module210or the printing platform230needs to perform vertical movement twice. The printing module210moving vertically is used as an example, a controller (not shown inFIG. 2A) may further align the inkjet print head213with the contact sensor231, and after the two are aligned, the printing module210moves downward vertically to enable the inkjet print head213to get in contact with the contact sensor231. Because the 3D print head211is closer to the printing platform230than the inkjet print head213, in a process in which the printing module210moves downward vertically, the 3D print head211might first get in contact with the printing platform230, and at this time, the printing module210is stuck and stops moving downward vertically, resulting in that the inkjet print head213cannot get in contact with the contact sensor231. In order to resolve this problem, in the embodiment ofFIG. 2A, the contact sensor231may be disposed on an edge of the printing platform230. In view ofFIG. 2A, if the contact sensor231is disposed on an edge of the printing platform230, the 3D print head211can be prevented from touching the printing platform230in a process in which the inkjet print head213gets in contact with the contact sensor231(that is, descending to the dashed line), so that the contact proceeds smoothly.

In addition, the embodiment ofFIG. 2Balso provides another method for resolving the foregoing problem, referring toFIG. 2B. In the embodiment ofFIG. 2B, a height difference between the contact sensor231and the printing platform230is greater than a height difference ΔH between the 3D print head211and the inkjet print head213. Therefore, when the inkjet print head213gets in contact with the contact sensor231, the 3D print head211does not touch printing platform230, so that the contact proceeds smoothly.

In both of the embodiments ofFIG. 2AandFIG. 2B, the contact sensor231is disposed on the printing platform230. However, the contact sensor231may also be disposed outside the printing platform230. Along as the 3D print head211and inkjet print head213can get in contact with the contact sensor231successfully, a user may dispose the contact sensor231in an area outside a print area233of the printing platform230at will according to use requirements, and the present invention is not limited thereto.

The present invention does not limit a sequence in which the 3D printing apparatus obtains the first height value and the second height value.FIG. 2Bis used as an example, and the controller may first enable the inkjet print head213to get in contact with the contact sensor231, so as to obtain a second height value corresponding to a distance between the inkjet print head213and the contact sensor231. Subsequently, the controller recovers original relative positions of the inkjet print head213and contact sensor231before the vertical movement by moving the printing module210or printing platform, that is, returning the inkjet print head213. After the returning of the inkjet print head213is completed, the controller may further enable the 3D print head211to get in contact with the contact sensor231, so as to obtain a first height value corresponding to a distance between the 3D print head211and the contact sensor231.

The controller may also choose not to return the 3D print head211or inkjet print head213.FIG. 2Bis used as an example, in another embodiment, the controller may first enable the inkjet print head213to get in contact with the contact sensor231, so as to obtain a second height value corresponding to a distance between the inkjet print head213and the contact sensor231. After the second height value is obtained, the controller may control the printing module210to make it return to a reset height. When the printing module210returns to the preset height, the console horizontally moves the movement printing module210to align the 3D print head211with the contact sensor231, so as to subsequently execute a relevant procedure of obtaining a first height value corresponding to a distance between the 3D print head211and the contact sensor231. In the foregoing process, because horizontal correction of the nozzle heads is not finished, the inkjet print head213is lifted up to a preset height, so as to prevent the inkjet print head213from being stuck by the contact sensor231or any other possible mechanism during horizontal movement. The console may also choose to not to ascend to a preset height and directly perform horizontal movement of the inkjet print head213or 3D print head211. For example, the console may first enable the inkjet print head213to get in contact with the contact sensor231, so as to obtain a second height value corresponding to a distance between the inkjet print head213and the contact sensor231. After the second height value is obtained, because the inkjet print head213is closer to the printing platform230than the 3D print head211, the console may directly horizontally move the movement printing module211to align with the contact sensor231, so as to subsequently execute a relevant procedure of obtaining a first height value corresponding to a distance between the 3D print head211and the contact sensor231. In this embodiment, the console can obtain a first height value and a second height2without returning the 3D print head211or inkjet print head213, so that a horizontal correction time of the 3D printing apparatus can be shortened.

FIG. 3A,FIG. 3B, andFIG. 3Care schematic diagrams illustrating contact sensor types according to an embodiment of the present invention. Referring toFIG. 3A, a printing module310, a 3D print head311, an inkjet print head313, and a contact sensor331ofFIG. 3Arespectively correspond to the printing module110, the 3D print head111, the inkjet print head113, and the contact sensor131ofFIG. 1A. In the embodiment ofFIG. 3A, the contact sensor331may be a limit switch331. When the 3D print head311or inkjet print head313gets in contact with the limit switch331, the 3D print head311or inkjet print head313presses down an elastic object333on the limit switch331, according to which the limit switch331may transmit a contact signal CS to a control panel, so as to enable the control panel to obtain a vertical movement distance of the printing module310or limit switch331.

FIG. 3BandFIG. 3Cproposes an embodiment of another type of contact sensor. In the embodiment ofFIG. 3BandFIG. 3C, the contact sensor331may be one or a combination of a conductive contact335and a conductive contact337. First refer toFIG. 3B. In the embodiment ofFIG. 3B, a conductive object320may be disposed on an outer side of the 3D print head311and the inkjet print head313, and the conductive object320may be a metal thin film or a metal housing. When the 3D print head311or inkjet print head313gets in contact with the limit switch331, the conductive object320disposed on the outer side of the 3D print head311or inkjet print head313may connect the conductive contact335and the conductive contact337, according to which the limit switch331may transmit a contact signal CS to a control panel, so as to enable the control panel to obtain a vertical movement distance of the printing module310or limit switch311. In addition, generally, a body of the 3D print head311is made of a metal material. In this case, the outer side of the 3D print head311may also be not provided with the conductive object320and connect the conductive contact335and the conductive contact337by means of a conductive function of the 3D print head311.

Subsequently, please refer toFIG. 3C. The embodiment ofFIG. 3Cassumes a situation that the 3D print head311or inkjet print head313per se is charged. For example, in the case in which the 3D print head311per se is charged with a negative voltage, the contact sensor331may be constituted by only one conductive contact335charged with a positive voltage. When the 3D print head311gets in contact with the limit switch331, the 3D print head311is electrically connected to the conductive contact335, according to which the limit switch331may transmit a contact signal CS to a control panel, so as to enable the control panel to obtain a vertical movement distance of the printing module310or limit switch311.

It is worth notating that the present invention is not limited to using a single contact sensor.FIG. 3Ais used as an example, and 3D printing apparatus may also, for example, be equipped with two contact sensors on the printing platform330. The two contact sensors need to be maintained at the same horizontal height by means of horizontal correction. In this case, when the controller vertically moves the movement printing module310or printing platform330, the 3D print head311and the inkjet print head313may respectively get in contact with a contact sensor331and a contact sensor332vertically. In this embodiment, because the inkjet print head313is closer to the printing platform330than the 3D print head311, the 3D print head311first gets in contact with the contact sensor331, according to which the contact sensor331may transmit a contact signal CS1to the control panel, so as to enable the control panel to obtain a current vertical movement distance H1of the printing module310or contact sensor331and thus, obtain a first height value corresponding to a distance between the 3D print head311and the contact sensor331. After the 3D print head311gets in contact with the contact sensor331, and the inkjet print head313gets in contact with the contact sensor332, according to which the contact sensor332transmits a contact signal CS2to the control panel, so as to enable the control panel to obtain a current vertical movement distance H2of the printing module310or contact sensor332and thus, obtain a second height value corresponding to a distance between the inkjet print head313and the contact sensor332, thereby obtaining a height difference ΔH between the 3D print head311and the inkjet print head313.

FIG. 4is a flowchart illustrating a method for measuring a height difference between nozzle heads according to an embodiment of the present invention. The method for measuring a height difference between nozzle heads is applicable to the printing apparatus100in the embodiment ofFIG. 1. The correction method includes the following steps. Step410: A controller170may enable a 3D print head111to get in contact with a contact sensor131vertically to enable the contact sensor131to generate a contact signal CS, and the controller170obtains a first height value according to a vertical movement distance H1of a printing module110or the contact sensor131and the contact signal CS. Subsequently, step S430: The controller170may enable a color head (for example, an inkjet print head113) to get in contact with the contact sensor131vertically to enable the contact sensor131to generate a contact signal CS, and the controller170obtains a second height value according to a vertical movement distance H2of the printing module110or the contact sensor131and the contact signal CS. Step S450: The controller170may obtain a height difference ΔH between the 3D print head111and the color head according to the first height value and the second height value. It should be noted that a sequence of steps S410and S430can be adjusted by a user according to requirements, and the present invention is not limited thereto.

Specifically, step S410further includes the following steps before the step that a console170enables a 3D print head111to get in contact with a contact sensor131vertically. Step S411: A control panel170controls the 3D print head111in the printing module110to be located above the contact sensor131. Subsequently, step S413: The control panel170controls the printing module110or a printing platform130to vertically move, so as to enable the 3D print head111to get in contact with the contact sensor131vertically. On the other than, step S430further includes the following steps before the step that the console170enables a color head to get in contact with the contact sensor131vertically. Step S431: The control panel170controls the color head in the printing module110to be located above the contact sensor131. Subsequently, step S433: The control panel170controls the printing module110or a printing platform130to vertically move, so as to enable the color head to get in contact with the contact sensor131vertically.

In conclusion, the present invention provides a method for measuring a height difference between nozzle heads and a 3D printing apparatus using the method, in which a height difference between a 3D print head and a color head in the 3D printing apparatus can be measured. The 3D printing apparatus can adjust the 3D print head and the color head separately according to the measured height difference, so as to improve accuracy of horizontal correction of the two types of nozzle heads. In this way, even if both of the 3D print head and the color head are disposed on a same rail, and there is a dimensional error between finished products of nozzle heads of a same type, optimal operating distances can be simultaneously maintained between the two types of nozzle heads and a 3D object according to the present invention, so as to further improve quality of a finished product of the 3D object.

Although embodiments of the present invention are disclosed as above, they are not intended to limit the present invention. Any person of ordinary skill in the art may make some variations or modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.