Patent Publication Number: US-2021170684-A1

Title: Manufacturing apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based on and claims priority under 35 USC 119 from Japanese Patent Application No. 2019-221536 filed Dec. 6, 2019. 
     BACKGROUND 
     1. Technical Field 
     The present disclosure relates to a manufacturing apparatus that delivers a manufacturing material. 
     2. Related Art 
     Examples of a manufacturing apparatus includes a 3D printer as disclosed in JP-T-2016-531020. 
     In the 3D printer, a void-free reinforced filament is fed to a conduit nozzle. The reinforced filament includes a continuous or semi-continuous core and a matrix material surrounding the core. The reinforced filament is heated to a temperature higher than the melting temperature of the matrix material and lower than the melting temperature of the core before the filament is applied from the conduit nozzle. 
     US-A-2017-0274585 discloses a manufacturing apparatus using a filament. 
     The manufacturing apparatus deposits a first composite filament on a build surface. The softened first composite filament retains an ability to be shaped. Then, the first composite filament is flattened. 
     SUMMARY 
     Aspects of non-limiting embodiments of the present disclosure relate to providing a manufacturing apparatus capable of improving adhesion between manufacturing materials as compared with a case in which a pressing unit having a flat surface presses manufacturing materials to stack the manufacturing materials. 
     Aspects of certain non-limiting embodiments of the present disclosure address the above advantages and/or other advantages not described above. However, aspects of the non-limiting embodiments are not required to address the advantages described above, and aspects of the non-limiting embodiments of the present disclosure may not address advantages described above. 
     According to an aspect of the present disclosure, there is provided a manufacturing apparatus including a delivery unit that delivers at least one linear manufacturing material containing resin, and a pressing unit including an irregularity portion that presses the manufacturing material delivered from the delivery unit, against a target object. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Exemplary embodiment(s) of the present disclosure will be described in detail based on the following figures, wherein: 
         FIG. 1  is a side view illustrating a part of a manufacturing apparatus according to a first exemplary embodiment; 
         FIG. 2  is a perspective view illustrating a part of the manufacturing apparatus according to the first exemplary embodiment as viewed from below; 
         FIG. 3  is a front view illustrating a delivery unit of the manufacturing apparatus according to the first exemplary embodiment as viewed from a downstream position in a moving direction of a manufacturing material; 
         FIG. 4  is a cross-sectional view illustrating a state in which the manufacturing materials are placed on a table of the manufacturing apparatus according to the first exemplary embodiment; 
         FIG. 5  is a diagram illustrating an example of a configuration for adjusting a height of a pressing unit of the manufacturing apparatus according to the first exemplary embodiment; 
         FIG. 6  is a diagram illustrating the pressing unit of the manufacturing apparatus according to the first exemplary embodiment; 
         FIG. 7  is a diagram illustrating a dimension of each part of the pressing unit of the manufacturing apparatus according to the first exemplary embodiment; 
         FIG. 8  is a diagram illustrating a state in which the manufacturing material is pressed by the pressing unit of the manufacturing apparatus according to the first exemplary embodiment; 
         FIG. 9  is a diagram following  FIG. 8 ; 
         FIG. 10  is a diagram illustrating a state in which the manufacturing material is applied in the manufacturing apparatus according to the first exemplary embodiment; 
         FIG. 11  is a diagram illustrating a state in which the applied manufacturing material is made thinner than the applied manufacturing material in  FIG. 10 ; 
         FIG. 12  is a cross-sectional view illustrating an aspect ratio of a pressed manufacturing material; 
         FIG. 13  is a block diagram illustrating functions and a configuration of the manufacturing apparatus according to the first exemplary embodiment; 
         FIG. 14  is a diagram illustrating a pressing unit of a comparative example; 
         FIG. 15  is a diagram illustrating results of comparative experiments; 
         FIG. 16  is a side view illustrating a pressing unit according to a second exemplary embodiment; 
         FIG. 17  is a side view illustrating a pressing unit according to a third exemplary embodiment; and 
         FIG. 18  is a side view illustrating a pressing unit according to a fourth exemplary embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     First Exemplary Embodiment 
     An example of a manufacturing apparatus  10  according to the first exemplary embodiment will be described with reference to the drawings. An upward direction will be denoted by the sign “UH” and a downward direction will be denoted by the sign “DH” in the drawings. 
       FIG. 1  is a diagram illustrating the manufacturing apparatus  10  according to the present exemplary embodiment. The manufacturing apparatus  10  manufactures a three-dimensional object based on shape data. 
     The manufacturing apparatus  10  includes a table  14  having a manufacturing surface  12  on which the three-dimensional object is to be manufactured, and a supply device  16  that supplies manufacturing materials to the table  14 . 
     The supply device  16  includes four reels  20  (it is noted that only one reel is illustrated in  FIG. 1 ) that are rotatably supported by a frame  18 , upstream transport units  24  that respectively transport linear manufacturing materials  22  delivered from the reels  20 , cutting units  26  that respectively cut the manufacturing materials  22  transported by the upstream transport units  24 , and downstream transport units  25  that respectively transport the manufacturing materials  22  from the cutting units  26 . The supply device  16  further includes a delivery unit  28  that delivers the manufacturing materials  22  from the downstream transport units  25  and a shape adjustment unit  30  that presses the manufacturing materials  22  delivered by the delivery unit  28  against a target object so as to adjust shapes of the manufacturing materials. The delivery unit  28  includes first upstream heating units  32  that heat the manufacturing materials  22  passing through the first upstream heating units  32 . 
     Table 
     The table  14  is supported by, for example, a drive table (not illustrated). The drive table drives the table  14  in X-Y directions along a horizontal surface, in height directions (in the upward direction UH and the downward direction DH), and in a rotation direction based on the shape data of the three-dimensional object. With this configuration, the three-dimensional object is manufactured on the manufacturing surface  12  with the manufacturing materials  22  delivered from the supply device  16  to the table  14 . 
     The present exemplary embodiment will describe a case in which the three-dimensional object is manufactured by driving the table  14  based on the shape data. It is noted that the present disclosure is not limited to this case. For example, the supply device  16  may be driven by a manipulator based on the shape data to manufacture the three-dimensional object. 
     Reel 
     The manufacturing material  22  by held in the reel  20  with the manufacturing material  22  being wound on the reel  20 . The wound manufacturing material  22  can be drawn out. 
     Manufacturing Material 
     As illustrated in  FIG. 4  (see also  FIG. 8 ), the manufacturing material  22  includes plural continuous fibers  22 A and a resin  22 B with which the continuous fibers  22 A are impregnated. Examples of the continuous fibers  22 A includes a carbon fiber. The resin  22 B with which the manufacturing material  22  is impregnated is made of thermoplastic resin. Accordingly, the manufacturing material  22  can be softened and deformed when heated, and maintains its shape after cured at room temperature. 
     The continuous fibers  22 A are used in the present exemplary embodiment. It is noted that the present disclosure is not limited to the continuous fibers  22 A. Alternatively, a short fiber or a glass fiber may be used. 
     Transport Unit 
     As illustrated in  FIG. 1 , the upstream transport unit  24  includes a pair of upstream rollers  36  provided upstream  34  of the cutting unit  26  in a moving direction of the manufacturing material  22 . The downstream transport unit  25  includes a pair of downstream rollers  40  provided downstream  38  of the cutting unit  26  in the moving direction. 
     The manufacturing material  22  is sandwiched between the upstream rollers  36 . When the upstream rollers  36  are driven to rotate, the manufacturing material  22  from the reel  20  is delivered to the cutting unit  26 . The manufacturing material  22  delivered from the cutting unit  26  is sandwiched between the downstream rollers  40 . When the downstream rollers  40  are driven to rotate, the manufacturing material  22  from the cutting unit  26  is delivered to the delivery unit  28 . 
     Cutting Unit 
     Upon receipt of a cutting signal from a control device (not illustrated), the cutting unit  26  cuts the manufacturing material  22  between the upstream transport unit  24  and the downstream transport unit  25 . Accordingly, the manufacturing material  22  is cut to a length required in manufacturing. 
     The downstream transport unit  25  delivers the cut manufacturing material  22  to the delivery unit  28 . Accordingly, the three-dimensional object is manufactured using the cut manufacturing material  22  to a specified length. 
     The present exemplary embodiment will describe an example in which the supply device  16  includes the cutting unit  26 . It is noted that the present disclosure is not limited to this configuration. The supply device  16  may not include the cutting unit  26 . 
     Delivery Unit 
     As illustrated in  FIG. 2 , the delivery unit  28  is formed into a rectangular block shape. As illustrated in  FIG. 3 , the delivery unit  28  includes a rectangular recess portion  41  extending in a length direction. Four cylindrical bodies  42  are arranged side by side along a bottom surface and accommodated in the rectangular recess portion  41 . A block  44  is inserted into the rectangular recess portion  41  so as to prevent the cylindrical bodies  42  from being detached. 
     The first upstream heating unit  32  (not illustrated) is provided on an outer peripheral portion of each cylindrical body  42 . The first upstream heating unit  32  is implemented by, for example, a heater including an electric heating wire. Each heater heats a corresponding cylindrical body  42  based on a heating signal from the control device, so as to heat, from the outer peripheral portion, the manufacturing material  22  passing through the corresponding cylindrical body  42  to a specified temperature. 
     Accordingly, as illustrated in  FIG. 4 , the delivery unit  28  applies the four manufacturing materials  22  onto the manufacturing surface  12  of the table  14  such that the four manufacturing materials  22  are arranged side by side and adjacent to each other. The manufacturing surface  12  of the table  14  is an example of the target object. Here, examples of the target object include a manufacturing material  22  that has been applied onto the table  14  as a lower layer as well as the manufacturing surface  12  of the table  14 . 
     Shape Adjustment Unit 
     As illustrated in  FIG. 1 , the shape adjustment unit  30  includes an extending unit  50  extending downwards from the frame  18 , and a pressing unit  52  replaceably attached to a lower end portion of the extending unit  50 . The extending unit  50  includes an extending unit body  50 A fixed to the frame  18 , and an operation shaft  50 B extending from the extending unit body  50 A. The extending unit body  50 A adjusts an extension amount of the operation shaft  50 B based on an operation signal from the control device (not illustrated). 
     As illustrated in  FIG. 5 , for example, a laser displacement meter  54  is provided at a tip end of the extending unit  50 . The laser displacement meter  54  measures a distance from a lower portion of an outer peripheral surface  52 A of the pressing unit  52  to the target object. The control device adjusts the extension amount of the operation shaft  50 B such that the distance measured by the laser displacement meter  54  becomes a target distance. The shape adjustment unit  30  adjusts and controls a shape of the manufacturing material  22  in a thickness direction by pressing the pressing unit  52  against the manufacturing material  22 . 
     Here, in place of the method described above, the following method may be used as a method for setting the distance from the outer peripheral surface  52 A of the pressing unit  52  to, for example, the manufacturing surface  12  of the table  14 . That is, the method calculates the distance based on the extension amount of the operation shaft  50 B, using an initial value when the pressing unit  52  is pressed against the manufacturing surface  12  as a reference. 
     Pressing Unit 
     As illustrated in  FIG. 6 , the pressing unit  52  is formed in a columnar shape. As illustrated in  FIG. 1 , the pressing unit  52  is rotatably supported by the operation shaft  50 B via a shaft portion  56  that passes through a center CL. An extending direction of the shaft portion  56  intersects the moving direction of the manufacturing material  22  moved by the transport units  24  and  25 . The pressing unit  52  rotates with the outer peripheral surface  52 A being in contact with the manufacturing material  22  that is supplied and applied onto the table  14 , so as to move in a length direction of the manufacturing material  22 . 
     As illustrated in  FIG. 6 , the outer peripheral surface  52 A of the pressing unit  52  is formed with an irregularity portion  60  that presses the manufacturing materials  22  delivered from the delivery unit  28  against the target object. It is noted that the irregularity portion  60  is exaggerated in the drawings. 
     The irregularity portion  60  includes four recess portions  62  arranged in a length direction of the pressing unit  52 . Each recess portion  62  is formed into a V shape and extends in a circumferential direction. 
     The recess portions  62  are arranged in the length direction such that the recess portion  62  and a protruding portion  64  having a triangle cross section are alternately formed on the outer peripheral surface  52 A of the pressing unit  52 . The recess portions  62  and the protruding portions  64  constitute the irregularity portion  60  of the pressing unit  52 . 
     As illustrated in  FIG. 7 , a width W of each recess portion  62  constituting the irregularity portion  60  in a direction intersecting the manufacturing material  22 , that is, the width W of each recess portion  62  in the length direction of the pressing unit  52  is larger than an outer dimension G of the manufacturing material  22  (for example, G&lt;W≤2G). A depth D of the recess portion  62  is smaller than the outer dimension G of the manufacturing material  22  (for example, 0.4G&lt;D&lt;G). 
     Accordingly, variation in pressure for filaments can be reduced when the irregularity portion  60  presses the manufacturing material  22 . 
     Plural recess portions  62  that constitute the irregularity portion  60  are provided in an arrangement direction in which the manufacturing materials  22  are arranged. A pitch P from a center of one of two adjacent recess portions  62  to a center of the other adjacent recess portion  62  is equal to or less than twice the outer dimension G of the manufacturing material  22  (for example, G&lt;P≤2G). 
     Specifically, in the present exemplary embodiment, the outer dimension G of the manufacturing material  22  is 0.5 mm, and the width W of the recess portion  62  is 1.0 mm which is larger than the outer dimension G of the manufacturing material  22 . The depth D of the recess portion  62  is 0.4 mm which is smaller than the outer dimension G of the manufacturing material  22 . 
     The pitch P from the center of one of the two adjacent recess portions  62  to the center of the other adjacent recess portion  62  is 1.0 mm which is equal to or less than twice the outer dimension G of the manufacturing material  22 . The entire width Z of the recess portions from an edge of the recess portion  62  on one side to the other edge of the recess portion  62  on the other side is 4.0 mm. 
     Then, as illustrated in  FIGS. 8 and 9 , the pressing unit  52  presses, against the target object, the plural manufacturing materials  22  which are arranged side by side and joins adjacent manufacturing materials  22  together, so as to form a pressed manufacturing material  66  in which the plural manufacturing materials  22  are joined together and form irregularities on a surface of the pressed manufacturing material  66 . 
     The present exemplary embodiment describes a case in which the plural manufacturing materials  22  are pressed and joined together, so as to form the pressed manufacturing material  66  in which the plural manufacturing materials  22  are joined together. It is noted that the present disclosure is not limited to this case. For example, the pressed manufacturing material  66  may be formed by pressing one manufacturing material  22 . 
     Here, the control device can control an aspect ratio indicating a ratio of a width ZH of the pressed manufacturing material  66  to a thickness ZT of the pressed manufacturing material  66  as illustrated in  FIG. 10 ,  FIG. 11  (an example in which a press force from the pressing unit  52  is large), and  FIG. 12  by adjusting the extension amount of the operation shaft  50 B such that the distance measured by the laser displacement meter  54  (see  FIG. 5 ) becomes the target distance. The aspect ratio of the pressed manufacturing material  66  is 2 or more and 5 or less. It has been found from experimental results that the aspect ratio is preferably 2 or more and 5 or less. 
     As illustrated in  FIG. 12 , the width ZH of the pressed manufacturing material  66  is a dimension from one side edge  66 A of the pressed manufacturing material  66  to the other side edge  66 B of the pressed manufacturing material  66 . The thickness ZT of the pressed manufacturing material  66  is a dimension into which a cross-sectional area of the pressed manufacturing material  66  is converted. More specifically, the thickness ZT of the pressed manufacturing material  66  is a value obtained by dividing the cross-sectional area of the pressed manufacturing material  66  by the width ZH. 
     A method for adjusting the aspect ratio includes, but not limited to, adjusting a shape of the manufacturing materials  22 , changing a surface shape of the irregularity portion  60 , changing a heating temperature of the irregularity portion  60 , and changing a separation distance between the irregularity portion  60  and the target object. 
     As illustrated in  FIG. 1 , the supply device  16  includes a second upstream heating unit  70  that heats the manufacturing materials  22  upstream  34  of the pressing unit  52  in the moving direction of the manufacturing materials  22 . The second upstream heating unit  70  is a device that blows hot air towards the delivery unit  28 . For example, the second upstream heating unit  70  heats manufacturing materials  22  overall by blowing the hot air to the manufacturing materials  22  passing through the rectangular recess portion  41  of the delivery unit  28 , so as to aggregate the manufacturing materials  22 . 
     The second upstream heating unit  70  may be a device that heats the manufacturing materials  22  with radiant heat. 
     The supply device  16  includes a downstream heating unit  72  that is provided downstream  38  of the first upstream heating unit  32  in the moving direction of the manufacturing materials  22 . The downstream heating unit  73  heats the manufacturing materials  22 . 
     The downstream heating unit  72  is a device that blows hot air towards the pressing unit  52 . The downstream heating unit  72  heats the pressing unit  52  so as to heat the manufacturing materials  22  pressed by the pressing unit  52 . 
     The downstream heating unit  72  may be a device that heats the pressing unit  52  with radiant heat. 
       FIG. 13  is a block diagram illustrating functions and a configuration of the manufacturing apparatus  10 . 
     The cutting units  26  are provided in a cutting section  80  that cuts the manufacturing materials  22 . The cutting units  26  cut the manufacturing materials  22  passing through the cutting units  26  to a specified length based on the cutting signals from the control device. The transport units  24  and  25  are provided in a transport section  82  that transports the manufacturing materials  22 . The transport units  24  and  25  transport the manufacturing materials  22  to the delivery unit  28 . 
     The first upstream heating unit  32  is provided in a first upstream heating section  84  that heats the manufacturing materials  22 . The first upstream heating unit  32  heats and melts the manufacturing materials  22 . The second upstream heating unit  70  is provided in a second upstream heating section  86  that heats manufacturing materials  22  overall. The second upstream heating unit  70  aggregates the manufacturing materials  22 . 
     The shape adjustment unit  30  provided in a manufacturing material shape adjustment and control section  88  adjusts a shape of the manufacturing materials  22 . The downstream heating unit  72  is provided in a downstream heating section  90  that heats the manufacturing materials  22 . The downstream heating unit  72  causes the manufacturing surface  12  to hold the manufacturing materials  22 . 
     Comparative Experiments 
       FIGS. 14 and 15  are diagrams illustrating comparative experiments. 
     The comparative experiments include an example J and a comparative example C. In the example J, the metal pressing unit  52  includes the irregularity portion  60  on the outer peripheral surface  52 A as described in the exemplary embodiment described with reference to  FIG. 7 . In the comparative example C, a metal cylindrical pressing unit  100  has no irregularity portion on an outer peripheral surface  100 A as illustrated in  FIG. 14 . 
     Parameters such as the width W, the depth D, and the pitch P of the recess portions  62  of the irregularity portion  60  formed in the pressing unit  52  of the example J are the same as those of the pressing unit  52  illustrated in  FIG. 7 . 
     The manufacturing material  22  used for manufacturing has a circular cross section. As illustrated in  FIG. 15 , a thickness and a width of the manufacturing material  22  are about 0.7 mm (an outer dimension of the manufacturing material  22  may be 0.5 mm). The manufacturing material  22  used for manufacturing by the pressing unit  52  of the example J and the manufacturing material  22  used for manufacturing by the pressing unit  100  of the comparative example C have the same bending modulus. 
     Then, the pressing unit  52  of the example J is mounted on the manufacturing apparatus  10 , and a three-dimensional object is manufactured with one manufacturing material  22 . Also, the pressing unit  100  of the comparative example C is mounted on the manufacturing apparatus  10 , and a three-dimensional object is manufactured using one manufacturing material  22 . At this time, a target value is set such that a ratio of the width ZH to the thickness ZT of the pressed manufacturing material  66  is 1:2, and the manufacturing apparatus  10  is controlled using the target value. The width ZH and the thickness ZT of a cross-sectional shape of the pressed manufacturing material  66  after the manufacturing process is measured. 
     As illustrated in  FIG. 15 , a different between the width ZH and the thickness ZT of the pressed manufacturing material  66  that is formed using the pressing unit  52  of the example J is smaller than a difference between the width ZH and the thickness ZT of the pressed manufacturing material  66  that is formed using the pressing unit  100  of the comparative example C. Accordingly, experiment result is obtained which shows a ratio of the width ZH to the thickness ZT is approximate to the target value of 1:2. 
     Effects 
     Effects of the present exemplary embodiment having the above configurations will be described. 
     The manufacturing apparatus  10  according to the present exemplary embodiment includes the pressing unit  52  having the irregularity portion  60  that presses the manufacturing materials  22  delivered from the delivery unit  28  against the target object. 
     Therefore, as compared with a case in which the manufacturing materials  22  are stacked by being pressed with a pressing unit having a flat surface, adhesion between the manufacturing materials  22  can be improved. 
     Adhesion between the manufacturing materials  22  and adhesion between the manufacturing materials  22  and the manufacturing surface  12  can be improved in particular in manufacturing a curved shape. 
     Since two sides of the manufacturing material  22  are regulated by the irregularity portion  60 , dimensional accuracy in a width direction of the three-dimensional object can be improved. 
     The width W of the recess portion  62 , which constitutes the irregularity portion  60  of the pressing unit  52 , in a direction intersecting the manufacturing material  22  is larger than the outer dimension G of the manufacturing material  22 . 
     Therefore, the manufacturing materials  22  can be easily positioned as compared with a case in which the width W of the recess portion  62  is smaller than the outer dimension G of the manufacturing material  22 . 
     The depth D of the recess portion  62  is smaller than the outer dimension G of the manufacturing material  22 . 
     Therefore, a crushing margin for the manufacturing material  22  can be provided as compared with a case in which the depth D of the recess portion  62  is larger than the outer dimension G of the manufacturing material  22 . 
     The pressing unit  52  presses and join together the plural manufacturing materials  22 , which are arranged side by side, so as to form the irregularities on the pressed manufacturing material  66  in which the plural manufacturing materials  22  are joined together. 
     Therefore, manufacturing efficiency can be improved as compared with a case in which one manufacturing material  22  is pressed to form the pressed manufacturing material  66 . 
     The plural recess portions  62 , which constitute the irregularity portion  60 , are provided in an arrangement direction in which the manufacturing materials  22  are arranged. The pitch P from the center of one of two adjacent recess portions  62  to the center of the other adjacent recess portion  62  is equal to or less than twice the outer dimension G of the manufacturing material  22 . 
     Therefore, a density of protruding portions formed on the pressed manufacturing material  66  can be prevented from lowering as compared with a case in which the pitch P between adjacent recess portions  62  is larger than twice the outer dimension G of the manufacturing material  22 . 
     The aspect ratio indicating the ratio of the width ZH of the pressed manufacturing material  66  to the thickness ZT of the pressed manufacturing material  66  is 2 or more and 5 or less. 
     Therefore, the pressed manufacturing material  66  can be prevented from spreading in the width direction as compared with a case in which the aspect ratio of the pressed manufacturing material  66  is larger than 5. 
     The upstream heating units  32  and  70  that heat the manufacturing materials  22  are provided upstream  34  of the pressing unit  52  in the moving direction of the manufacturing materials  22 . 
     Therefore, irregularities can be easily formed as compared with a case in which the manufacturing materials  22  are heated only from a downstream position. 
     The pressed manufacturing material  66  can be more easily joined as compared with a case in which the manufacturing material  22  is heated only from an upstream position. 
     Therefore, the pressed manufacturing material  66  can be more easily adhered as compared with a case in which the downstream heating unit  72  is not provided. 
     The downstream heating unit  72  heats the pressing unit  52  so as to heat the manufacturing material  22  pressed by the pressing unit  52 . 
     Therefore, irregularities can be easily formed as compared with a case in which the manufacturing material  22  is directly heated downstream of the pressing unit  52 . 
     The present exemplary embodiment describes a case in which the recess portions  62  of the irregularity portion  60  of the pressing unit  52  are formed into a V-shaped groove. It is noted that the recess portions  62  are not limited to this case, but may have the following shapes. 
     Second Exemplary Embodiment 
     As illustrated in  FIG. 16 , the recess portions  62  of the irregularity portion  60  of the pressing unit  52  may be formed into a groove having an arc cross section. The second exemplary embodiment provides the same effect as the first exemplary embodiment. 
     Third Exemplary Embodiment 
     As illustrated in  FIG. 17 , the recess portions  62  of the irregularity portion  60  of the pressing unit  52  may be formed into a groove having a trapezoidal cross section. The third exemplary embodiment provides the same effect as the first exemplary embodiment. 
     Fourth Exemplary Embodiment 
     As illustrated in  FIG. 18 , the recess portions  62  of the irregularity portion  60  of the pressing unit  52  may be formed into a V-shaped groove, and adjacent recess portions  62  may be separated such that the cylindrical outer peripheral surface  52 A remains between the recess portions  62 . The fourth exemplary embodiment provides the same effect as the first exemplary embodiment. 
     The pressing unit  52  has a cylindrical shape in the exemplary embodiments. It is noted that the pressing unit  52  is not limited to the cylindrical shape, but may have a plate shape. 
     The heating units  32 ,  70  and  72  may be omitted. 
     The foregoing description of the exemplary embodiments of the present disclosure has been provided for the purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure to the precise forms disclosed. Obviously, many modifications and variations will be apparent to practitioners skilled in the art. The embodiments were chosen and described in order to best explain the principles of the disclosure and its practical applications, thereby enabling others skilled in the art to understand the disclosure for various embodiments and with the various modifications as are suited to the particular use contemplated. It is intended that the scope of the disclosure be defined by the following claims and their equivalents.