Elastic sheet for holding workpiece, sheet holding ring, workpiece holding device, workpiece holding method, and workpiece delivery method

Abstract

To provide an elastic sheet for holding a workpiece, a workpiece holding device, and a workpiece holding method, capable of ensuring sufficient adhesion with no step to a workpiece.SOLUTION: A workpiece holding device 1 comprises: an elastic sheet 3 for holding a workpiece which is formed from a sheet material having elasticity, which has through holes 2 each being smaller than the thickness of a workpiece to be processed, and which allows the workpiece to be put in the through hole 2 in a state in which tension is applied to expand the through hole 2 and in this state, by releasing the tension to cause the through hole 2 to contract, holds the workpiece in the through hole 2; a ring-shaped sheet holding ring 4 for attaching and holding the elastic sheet 3 for holding a workpiece in a stretched state; and a tension applying mechanism 5 which applies tension to the elastic sheet 3 attached to the sheet holding ring 4 in a planar direction.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an elastic sheet for work holding, a sheet holding ring, a work holding device, a work holding method, and a work discharging method suitable for holding small chip components used in electronic devices such as ceramic capacitors.

Background Art

[0002] Small chip components (works) typified by electronic components are required to be further miniaturized along with the high performance of electronic devices. Along with this, for example, it has become difficult to hold the work when forming external electrodes at the ends of the chips. As a technique for holding such small works, for example, a plurality of metal plates with small holes are stacked, and the size of the holes that penetrate is adjusted by moving these metal plates in the diagonal direction, and the chip components that are the works are held in each adjusted hole and external electrodes are formed at the ends of the chips in a masked state. A method has been proposed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above-described chip component electrode forming method, a step corresponding to the plate thickness of the masked metal plate occurs in the external terminal, and since the metal plate is shifted to correspond to the size of the chip, the degree of adhesion to the chip becomes insufficient and a gap is formed, and masking as designed cannot be performed. Furthermore, the shape of the chip is also limited, and for example, it cannot be applied to a columnar work.

[0005] This invention was proposed in view of the aforementioned inconveniences, and its purpose is to provide an elastic sheet for holding workpieces, a sheet holding ring, a workpiece holding device, a workpiece holding method, and a workpiece discharge method that can be easily handled in the manufacturing process by ensuring sufficient adhesion without any steps, even for small workpieces. [Means for solving the problem]

[0006] The present invention was proposed to achieve the above-mentioned objectives, and the present invention described in claim 1 is an elastic sheet for holding a workpiece, comprising an elastic sheet material, having a through hole smaller than the thickness of the workpiece to be processed, and characterized in that the workpiece is placed in the through hole while tension is applied to expand the through hole, and the through hole is contracted by releasing the tension in this state to hold the workpiece in the through hole.

[0007] Claim 2 is an elastic sheet for holding a workpiece according to Claim 1, characterized in that the thickness when the tension is released is set to be smaller than the length of the workpiece, and the end of the workpiece is exposed from the through hole when the tension is released and the workpiece is held in the through hole.

[0008] The item described in claim 3 is a ring-shaped sheet holding ring for mounting and holding the elastic sheet for workpiece holding described in claim 1 or claim 2 in an unfolded state, The sheet retaining ring has a circular opening and is composed of a ring body with a retaining portion on the outside of the opening for holding an elastic sheet, and a preloading ring that applies initial tension to the elastic sheet held in the ring body. The preload ring has a mounting portion for attaching to the ring body, and a ring-shaped upright wall that rises from the mounting portion and fits along the inner circumference of the opening of the ring body. The sheet-holding ring is characterized in that the upright wall, when attached to the ring body, is set to an upright height that can contact the elastic sheet held by the holding part and apply initial tension to the elastic sheet.

[0009] The ring body described in claim 4 comprises a first ring having concentric openings and a second ring superimposed on the first ring, and includes a holding portion for holding an elastic sheet sandwiched between the upper ring and the lower ring.

[0010] The item described in claim 5 is an elastic sheet for holding a workpiece as described in claim 1 or claim 2, A ring-shaped sheet holding ring for attaching and holding the elastic sheet for holding the workpiece in an unfolded state, A tension-applying mechanism that applies tension in the planar direction to the elastic sheet attached to the sheet-holding ring, Equipped with, This workpiece holding device is characterized by applying tension to an elastic sheet using the tension application mechanism to expand the through-hole, placing a workpiece into the through-hole, and then releasing the tension applied by the tension application mechanism to contract the through-hole and hold the workpiece in place.

[0011] The tension-adding mechanism described in claim 6 comprises a sheet-side table to which the sheet-holding ring is attached, and an intrusion-side table that moves relative to the sheet-holding ring attached to the sheet-side table in the axial direction. The sheet-side table has a clamping device for clamping a sheet-holding ring placed in a predetermined position, and a protruding opening in the portion corresponding to the opening of the clamped sheet-holding ring. The aforementioned entry-side table has a tip portion with a smaller diameter than the opening of the sheet-holding ring, and has a plurality of rotating bodies in the shoulder portion that contacts the elastic sheet when it enters the opening of the sheet-holding ring, with the rotational axis of each rotating body being arranged parallel to the tangential direction of the circumference of the shoulder portion. The workpiece holding device according to feature 5.

[0012] The workpiece holding device according to claim 7 is characterized in that a height reference ring protruding from the rotating body toward the elastic sheet is positioned inside the row of rotating bodies.

[0013] The workpiece holding device according to any one of claims 5 to 7 is characterized in that it comprises a feeder mechanism that supplies a workpiece into the expanded through-hole when tension is applied to the elastic sheet by the tension-applying mechanism to expand the through-hole.

[0014] The workpiece holding device according to any one of claims 5 to 7 is characterized by comprising: a vibration adding mechanism that applies vibration to the elastic sheet in a state in which tension is applied to the elastic sheet by the tension adding mechanism and the through hole is expanded; and a workpiece supply mechanism that supplies a plurality of workpieces onto the elastic sheet.

[0015] The workpiece holding device according to any one of claims 5 to 9 is characterized in that the entry-side table is provided with a seating support facing the entry-side surface of the elastic sheet.

[0016] Claim 11 describes a workpiece holding device according to claim 10, characterized in that a magnetic force generating means is provided on the back side of the seating surface of the seating support, and a magnetic force is applied to a workpiece containing a magnetic material to guide it into the through-hole of the elastic sheet.

[0017] Claim 12 describes a hole expansion step that transforms a first state in which an elastic sheet having through holes smaller than the thickness of the workpiece to be processed is spread and stretched, into a second state in which a tension stronger than the tension on the elastic sheet in the first state is applied to the elastic sheet, thereby expanding the size of the through holes compared to the through holes in the first state, A workpiece insertion step involves inserting the workpiece into the enlarged through hole, This method for holding a workpiece is characterized by reducing the tension of an elastic sheet while the workpiece is inserted into the through-hole, thereby contracting the through-hole due to the elasticity of the elastic sheet, and holding the workpiece with its edge exposed from the through-hole.

[0018] The invention according to claim 13 is a method for discharging a workpiece, characterized in that, with respect to an elastic sheet that holds a workpiece by the elastic contraction force of the elastic sheet within the holes of the elastic sheet described in claim 1 or 2, tension is applied in the plane direction of the elastic sheet to expand the size of the through holes, and in this expanded state, a force is applied from one side to the other side of the plane of the elastic sheet to discharge the workpiece.

[0019] The invention according to claim 14 is a method for discharging a workpiece as described in claim 12, characterized in that the workpiece is discharged by pressing the workpiece from one side of the elastic sheet toward the other side by a pressing member.

[0020] The invention according to claim 15 is a method for discharging a workpiece as described in claim 12, characterized in that a pressure difference is generated between one side and the other side of the elastic sheet to discharge the workpiece.

[0021] The invention according to claim 16 is a method for discharging a workpiece as described in claim 12, characterized in that a magnetic force is applied from one side to the other side of an elastic sheet that holds a workpiece containing a magnetic material, and the workpiece is discharged by this magnetic force.

Advantages of the Invention

[0022] According to the present invention, the following excellent effects can be achieved. According to the invention described in claim 1, since it has through holes smaller than the thickness of the workpiece to be processed, the workpiece is placed into the through holes in a state where the through holes are expanded by applying tension, and the through holes are contracted by releasing the tension in this state, the workpiece can be made to adhere closely to the inner surface of the through holes, enabling good masking. Also, it is less likely to be restricted by the shape of the workpiece.

[0023] According to the invention described in claim 2, since the thickness in the state where the tension is released is set to be smaller than the length of the workpiece, the end portion of the workpiece can be exposed from the through holes in a state where the tension is released and the workpiece is held within the through holes, broadening the scope of processing applications in subsequent processing.

[0024] According to the invention described in claim 3, a ring-shaped sheet holding ring for mounting and holding an elastic sheet for workpiece holding in an unfolded state is provided, the sheet holding ring comprising a ring body having a circular opening and a holding portion on the outside of the opening for holding an elastic sheet, and a preloading ring for applying initial tension to the elastic sheet held by the ring body, the preloading ring having an attachment portion for attaching to the ring body, and a ring-shaped upright wall that rises from the attachment portion and fits along the inner circumference of the opening of the ring body, the upright wall is set to an upright height such that, when attached to the ring body, it abuts the elastic sheet held by the holding portion and applies initial tension to the elastic sheet, so that even if the elastic sheet expands due to a temperature rise or experiences partial stress changes in a subsequent process while the workpiece is inserted into the through hole, the preloading can disperse and absorb the deflection and distortion of the elastic sheet.Therefore, it is possible to prevent problems such as the workpiece coming out of the through hole.

[0025] According to the invention described in claim 4, the ring body comprises a first ring having concentric openings and a second ring superimposed on the first ring, and is equipped with a holding portion for holding the elastic sheet sandwiched between the upper ring and the lower ring, making it easy to attach the elastic sheet and ensuring secure attachment.

[0026] According to the invention described in claim 5, the device comprises an elastic sheet for holding a workpiece, a ring-shaped sheet holding ring for mounting and holding the elastic sheet in an unfolded state, and a tension-applying mechanism for applying tension in the planar direction to the elastic sheet mounted on the sheet holding ring. Therefore, by applying tension to the elastic sheet using the tension-applying mechanism to expand the through-hole, a workpiece can be placed into the through-hole, and by releasing the tension applied by the tension-applying mechanism in this state, the through-hole can be contracted and the workpiece can be held inside the through-hole, allowing the workpiece to be brought into close contact with the inner surface of the through-hole, resulting in good masking. Furthermore, it is less limited by the shape of the workpiece.

[0027] According to the invention described in claim 6, the tension-applying mechanism comprises a sheet-side table to which the sheet-holding ring is attached, and an intrusion-side table that moves relative to the sheet-holding ring attached to the sheet-side table in the axial direction. The sheet-side table has a clamping device for clamping the sheet-holding ring placed in a predetermined position, and an intrusion opening in a portion corresponding to the opening of the clamped sheet-holding ring. The intrusion-side table has a tip portion with a smaller diameter than the opening of the sheet-holding ring, and has a plurality of rotating bodies in a shoulder portion that contacts the elastic sheet when it intrudes into the opening of the sheet-holding ring. The rotational axis of each rotating body is arranged parallel to the tangential direction of the circumference of the shoulder portion. Therefore, tension is not only applied to the elastic sheet by the relative movement of the sheet-holding table and the intrusion-side table, but the direction of the tension is also changed by the rotating bodies, and the tension can be applied uniformly in a radial direction from the center of the elastic sheet. Consequently, the occurrence of distortion when expanding the through hole can be prevented.

[0028] According to the invention described in claim 7, a height reference ring that protrudes further toward the elastic sheet than the rotating body is positioned inside the row of rotating bodies, so that the height of the elastic sheet can be reliably aligned by this height reference ring.

[0029] According to the invention described in claims 8 and 9, when tension is applied to the elastic sheet by the tension-applying mechanism to expand the through-holes, a feeder mechanism or workpiece supply mechanism is provided to supply workpieces into the expanded through-holes, thereby enabling efficient supply of multiple workpieces onto the elastic sheet.

[0030] According to the invention described in claim 10, the entry-side table is equipped with a seating support facing the entry-side surface of the elastic sheet, so that the length of the end of the workpiece protruding from the through hole can be made uniform, and the accuracy of subsequent machining can be improved.

[0031] The invention described in claim 11 provides a magnetic force generating means on the back side of the seating surface of the seating support, allowing a magnetic force to be applied to a workpiece containing a magnetic material and guided into the through-hole of the elastic sheet, thereby enabling efficient introduction of the workpiece into the through-hole.

[0032] The method described in claim 12 involves a hole expansion step, which transforms a first state in which an elastic sheet having a through-hole smaller than the thickness of the workpiece to be processed is spread and stretched, into a second state in which a tension stronger than the tension on the elastic sheet in the first state is applied to the elastic sheet to enlarge the size of the through-hole compared to the first state; a workpiece insertion step, which involves inserting the workpiece into the enlarged through-hole; and a hole contraction step, which involves weakening the tension on the elastic sheet from the state in which the workpiece is inserted into the through-hole, thereby contracting the through-hole due to the elasticity of the elastic sheet. As a result, the workpiece can be held in place through these steps, allowing the inner surface of the through-hole to be in close contact with the workpiece, and good masking of the workpiece can be achieved. Furthermore, it is less limited by the shape of the workpiece.

[0033] According to the invention described in claims 13, 14, and 15, when a workpiece is held in a hole in the elastic sheet described in claim 1 or 2 by the elastic contraction force of the elastic sheet, tension is applied in the direction of the surface of the elastic sheet to enlarge the size of the through hole, and in this enlarged state, a force is applied from one side of the surface of the elastic sheet to the other to discharge the workpiece, thereby enabling efficient removal of the workpiece from the through hole in the elastic sheet. [Brief explanation of the drawing]

[0034] [Figure 1] This is a perspective view of the holding device. [Figure 2] This is a cross-sectional view of the holding device. [Figure 3] These are explanatory diagrams of the seat retaining ring, where (a) is an exploded view of the seat retaining ring, (b) is a cross-sectional view of the seat retaining ring shown in (a) in an exploded state, (c) is a perspective view of the elastic sheet being held between the upper and lower rings, (d) is a cross-sectional view of the state shown in (c), (e) is a perspective view of the seat retaining ring with the preload ring attached, and (f) is a cross-sectional view of the state shown in (e). [Figure 4] This is an enlarged cross-sectional view of the ring portion of the sheet retaining ring. [Figure 5] This diagram illustrates the process just before the sheet-holding ring is placed on the tension-applying device; (a) is a perspective view, and (b) is a cross-sectional view. [Figure 6] This is an explanatory diagram of a retaining device in which a sheet retaining ring is attached to a tensioning device, where (a) is a perspective view, (b) is a cross-sectional view, and (c) is an enlarged cross-sectional view of the shoulder portion equipped with a height reference ring and a rotating body. [Figure 7] This diagram illustrates the process just before inserting the workpiece into the through-hole. (a) is a perspective view of the holding device with the through-hole of the elastic sheet expanded, (b) is a cross-sectional view of the holding device shown in (a), and (c) is a perspective view showing the elastic sheet and workpiece with the through-hole expanded. [Figure 8] This diagram illustrates the state in which the workpiece is inserted into the through hole. (a) is a perspective view of the holding device, (b) is a cross-sectional view of the holding device shown in (a), (c) is a perspective view of the elastic sheet with the workpiece inserted, and (d) is an enlarged cross-sectional view of the workpiece and the through hole with the workpiece inserted. [Figure 9] This diagram illustrates the state after inserting the workpiece and releasing the tension. (a) is a perspective view of the holding device, (b) is a cross-sectional view of the holding device shown in (a), and (c) is an enlarged perspective view of the state after the workpiece is inserted into the through-hole of the elastic sheet. [Figure 10] This is an explanatory diagram showing the process of forming an external electrode on the end of a workpiece inserted into a through-hole in an elastic sheet. [Figure 11] This is an explanatory diagram showing the state of workpiece retrieval. (a) is a cross-sectional view of the device with the sheet holding ring set, (b) is a cross-sectional view of the device with tension applied to the elastic sheet, and (c) is a perspective view of the device with the sheet holding ring removed. [Modes for carrying out the invention]

[0035] Embodiments of the present invention will be described below with reference to the drawings. As shown in Figures 1 and 2, the workpiece holding device 1 is generally composed of an elastic sheet 3 having multiple through holes 2 smaller than the thickness of the workpiece W to be processed, a ring-shaped sheet holding ring 4 for mounting and holding the elastic sheet 3 in an unfolded state, and a tension application mechanism 5 for applying tension in the planar direction to the elastic sheet 3 mounted on the sheet holding ring 4.

[0036] The elastic sheet 3 is made of a circular sheet material with elasticity, such as silicone rubber. In its natural state without tension applied, if the workpiece W, such as a ceramic capacitor, is a rectangular prism, numerous through-holes 2 smaller than the workpiece W are provided in the central area. Its thickness is set to be slightly shorter than the length of the workpiece W. In the embodiment shown in the drawing, the dimensions of the workpiece W are 0.5 mm × 0.5 mm × 1.0 mm (length × width × length), and the through-holes 2 are set to be slightly smaller, as rectangles of 0.4 mm × 0.4 mm. To create the aforementioned through-holes 2, processing methods such as laser processing, punching, and die forming can be used. The arrangement of the holes can be selected as appropriate, and in the elastic sheet 3 shown in the drawing, they are arranged in a grid pattern.

[0037] The ring-shaped sheet-holding ring 4 for mounting and holding the elastic sheet 3 in an unfolded state consists of a ring body having a circular opening and a holding portion for holding the elastic sheet on the outside of the opening, and a preloading ring for applying initial tension to the elastic sheet held by the ring body. The embodiment of the ring body shown in Figure 3 consists of a lower ring 11 that functions as a first ring having a through-hole 11a as an opening smaller than the diameter of the elastic sheet 3, and an upper ring 12 that functions as a second ring having a through-hole 12a (i.e., an opening) similar to the lower ring 11 and is placed over the upper surface of the lower ring 11 to sandwich the elastic sheet 3 between them. The ring is configured so that a preloading ring 13 for applying tension to the elastic sheet 3 sandwiched between the upper ring 12 and the lower ring 11 can be attached from below and integrated. Furthermore, on the surfaces where the upper ring 12 and the lower ring 11 overlap, interlocking steps are formed as clamping portions 15, and a recess 16 for fitting the preload ring 13 is formed along the inner circumference on the lower surface of the lower ring 11. The preload ring 13 has a ring-shaped flange portion 18 that fits into the recess 16 as a mounting portion, and a ring-shaped upright wall 19 is formed that rises from the inner circumference of the flange portion 18 and can be fitted near the inner circumference of the through-opening hole 11a of the lower ring 11.

[0038] To attach the elastic sheet 3 to the sheet holding ring 4, the elastic sheet 3 is placed on the lower ring 11 with the elastic sheet 3 naturally spread out, and then the upper ring 12 is placed over it, sandwiching the outer circumference of the elastic sheet 3 between the two rings 11 and 12. In this state, the screw 21 is tightened from above, and the outer circumference of the elastic sheet 3 is sandwiched by the clamping portions 15 of the two rings 11 and 12. In this state, as shown in Figures 3(c) and (d), the elastic sheet 3 is stretched without being subjected to much tension on the plane connecting the inner circumferences of the clamping portions 15.

[0039] Subsequently, as shown in Figures 3(e), (f) and 4, the upright wall 19 is inserted into the through-hole 11a of the lower ring 11 with the preload ring 13 facing the elastic sheet 3 from below, so that the tip of the upright wall 19 contacts the lower surface of the elastic sheet 3, and is further raised towards the upper and lower rings 11. When the flange portion 18 of the preload ring 13 is fitted into the recess 16 of the lower ring 11, the upright height of the flange portion 18 of the upright wall 19 from the upper surface is set to be higher (larger) than the distance from the clamping portion 15 to the lower surface of the elastic sheet 3, so the upper peripheral edge of the upright wall 19 pushes up the elastic sheet 3 (see Figure 4), thereby applying preload (initial tension) to the elastic sheet 3, and in order to maintain this state, the screw 22 is tightened from below the preload ring 13 to fix it in place. When the elastic sheet 3 is installed in this manner, only initial tension is applied to the elastic sheet 3, so the size of each through-hole 2 is hardly enlarged. In the above embodiment, one side is 0.44 mm.

[0040] Next, we will describe the tension-applying mechanism 5 that applies tension to the elastic sheet 3 attached to the sheet-holding ring 4. In the embodiments shown in Figures 1 and 2, the tension-applying mechanism 5 is generally composed of a sheet-side table 31 that moves up and down with the sheet-holding ring 4 attached, and a protruding member 32 that remains stationary regardless of the up and down movement of the sheet-side table 31 and contacts the elastic sheet 3 to apply tension; in other words, a member that moves relative to the sheet-side table 31 in the axial direction of the sheet-holding ring 4 attached to the sheet-side table 31.

[0041] The thrust member 32 is provided on an upper beam 36 that connects the upper ends of the left and right uprights 35 erected on the base 34, and has a circular ring-shaped fixed support base 37 that is slightly smaller than the opening through which the sheet holding ring 4 passes. A height reference ring 39 is placed on the outer shoulder portion 38 of this fixed support base 37 (the portion that will come into contact with the elastic sheet 3 when thrust into the opening of the sheet holding ring 4) as a tension-adding member, and a plurality of rotating bodies 40 are arranged in a circular position just outside the height reference ring 39, and a round seating support base 41 is provided inside the height reference ring 39 that is slightly larger than the area in which the through hole 2 of the elastic sheet 3 is made.

[0042] Multiple rotating bodies 40 have a diameter smaller than the inner diameter of the opening of the seat retaining ring 4 and are arranged at the same height on the shoulder portion outside the height reference ring 39 where the elastic seat 3 makes contact. The axis of each rotating body 40 is positioned parallel to the tangential direction of the circumference of the fixed support base 37 and is configured to rotate individually. The fixed support base 37, the outer shoulder portion 38, the height reference ring 39, the row of rotating bodies 40, and the seating support base 41 are arranged concentrically and are located concentrically with the seat retaining ring 4.

[0043] The height reference ring 39 regulates the position of the lower surface of the elastic sheet 3 (i.e., the surface on the side of the protruding member 32) regardless of the vertical position of the sheet holding ring 4. In other words, it is a member that regulates the height (gap) from the flat upper surface of the seating base 41 to the lower surface of the elastic sheet 3. Specifically, as shown in Figure 6(c), it is a wall-shaped circular ring that rises from the fixed support base 37 inside the row of the lower rotating body 40, with its circular upper end (tip) contacting the surface of the elastic sheet 3 on the side of the protruding member 32 to regulate the position of the elastic sheet 3, thereby regulating the distance (workpiece protrusion height described later) between the surface of the elastic sheet 3 and the upper surface (seating surface) of the seating base 41.

[0044] The rotating body 40 can smoothly and efficiently change the direction of the tension applied to the elastic sheet 3. When arranged concentrically as described above, the tension can be applied uniformly radially from the center of the concentric circles, thereby ensuring uniform elongation and preventing distortion of the elastic sheet 3. Therefore, each through hole 2 can be expanded while maintaining a similar shape. Specifically, the rotating body 40 can be any member that can rotate easily with little resistance, such as a ball bearing, roller bearing, or roller, and that can change the direction of the tension.

[0045] The aforementioned seating support 41 is positioned to fit the workpiece W, with a gap of 0.25 mm in the embodiment, so that the distance between the upper surface and the lower surface of the elastic sheet 3 is equal to the protrusion length of the workpiece W. Alternatively, the seating support 41 may be configured to have upper and lower through holes at positions 90 degrees apart in the circumferential direction, and a sheet support pin may be provided from below, with its tip slightly protruding from the surface of the seating support 41, thereby supporting the elastic sheet 3 from below to prevent deflection (not shown). The seating support 41 may also be made vertically adjustable, allowing the distance between it and the elastic sheet 3 to be adjusted in accordance with the size of the workpiece W, together with the height reference ring 39. Furthermore, a magnetic force generating means, such as an electromagnet, may be provided on the back side of the seating surface of the seating support 41, so that in the case of a workpiece containing a magnetic material, a magnetic force can be applied to the workpiece to guide it into the through hole 2 of the elastic sheet 3.

[0046] A drive mechanism 44 for moving the seat-side table 31 up and down is provided between the left and right uprights 35 mentioned above. Specifically, a bearing 47 is provided on the lower beam portion 46 that connects the lower parts of the left and right uprights 35, and a lifting drive shaft 48 is provided passing through the bearing 47. A stepped belt 50 is stretched between a pulley 49 attached to the lifting drive shaft 48 that protrudes below the bearing 47 and a pulley (not shown) of the drive motor. The male threaded portion of the lifting drive shaft 48 that protrudes above the bearing 47 is screwed into a part of the seat-side table 31, which will be described later, and the seat-side table 31 moves up and down by rotating the lifting drive shaft 48 with the drive motor.

[0047] The seat-side table 31 is generally configured to include a mounting table 53 on which the seat-holding ring 4 rests, having a through-opening 53a larger than the upper part of the aforementioned intrusion member 32; leg pieces 54 extending downward from both sides of the mounting table 53; and a cross beam 55 connecting the upper and lower parts of the leg pieces 54 from left to right. The aforementioned lifting drive shaft 48 is screwed into a female screw portion 56 provided on the cross beam 55, and a guide portion 57 is disposed between the leg pieces 54 and the upright 35. Therefore, as described above, when the drive motor rotates the lifting drive shaft 48 in one direction, the female screw portion 56 moves upward, and the leg pieces 54 are guided by the guide portion 57 and rise. When it rotates in the other direction, the female screw portion 56 moves downward, and the leg pieces 54 are guided by the guide portion 57 and descend. This allows the mounting table 53 to move up and down with the seat-holding ring 4 on it. Furthermore, the mounting table 53 of the sheet-side table 31 is specifically provided with clamping devices 58 at each of the four corners of the rectangular mounting table 53, and these clamping devices 58 are configured to clamp the sheet-holding ring 4 that is placed in a predetermined position.

[0048] Next, when forming external electrodes on both ends of the ceramic capacitor chip as the workpiece W, the procedure for holding multiple chips (method for holding the workpiece W) will be described. First, prepare the elastic sheet 3. This elastic sheet 3 has numerous through holes 2 that are smaller than the diameter of the workpiece W to be processed. Specifically, for a workpiece W with sides of 0.5 mm and a length of 1.0 mm, the through holes 2 in the natural state without tension are 0.4 mm in size and arranged in a grid pattern. The silicone rubber sheet has a thickness of 0.55 mm. This section will specifically describe the hole expansion process, which transforms the elastic sheet 3 from a first state, where it is spread out and stretched, to a second state, where a tension stronger than the tension on the elastic sheet 3 in the first state is applied to the elastic sheet 3, thereby expanding the size of the through-hole 2 compared to the first state.

[0049] As shown in Figure 3, the elastic sheet 3 is placed in its natural position between the upper ring 12 and the lower ring 11, sandwiching the outer circumference of the elastic sheet 3, and in this state, the upper ring 12 and the lower ring 11 are fastened from above with four screws 21. Then, the flange portion 18 of the preload ring 13 is fitted into the recess 16 of the lower ring 11 from below, and the upright wall 19 rising from the flange portion 18 is brought into contact with the lower surface of the elastic sheet 3, slightly pushing up almost the entire surface of the elastic sheet 3 and applying a weak tension, and the four screws 22 are tightened from below to maintain this first state. In this first state, the tension (preload) is very slight, so the size of the through hole 2 is about 0.44 mm on each side and about 0.5 mm thick.

[0050] Next, the sheet holding ring 4 is set in the workpiece holding device 1 and tension is applied to the elastic sheet 3 by the tension application mechanism 5 to expand the through hole 2. Specifically, as shown in Figures 5 and 6, with the sheet-side table 31 raised, the sheet holding ring 4 is lowered from above to a predetermined position so that the row of rotating bodies 40 fits into the opening of the preload ring 13, and then clamped by the clamping device 58. In this state, as shown in Figure 6(c), the upper end of the height reference ring 39 is in contact with the lower surface of the elastic sheet 3, but the rotating bodies 40 are spaced apart from the lower surface of the elastic sheet 3.

[0051] Then, from the initial state described above, the seat-side table 31 is gradually lowered by the drive motor. As a result, the circularly arranged rows of rotating bodies 40 come into contact with the underside of the elastic seat 3, and as the seat-side table 31 is lowered further, as shown in Figure 7, the rows of rotating bodies 40 push up the elastic seat 3 relatively, thereby adding tension to the elastic seat 3. Even when this state is reached, the distance between the underside of the elastic seat 3 and the upper surface of the seating support 41 is maintained at the initial specified dimension by the height reference ring 39.

[0052] When a stronger tension is applied to the elastic sheet 3 than in the first state, each through-hole 2 is expanded. Specifically, when tension is applied until the thickness of the elastic sheet 3 is about 0.38 mm, the size of the through-hole 2 is expanded to 0.6 mm on each side, reaching a second state large enough to accommodate the workpiece W (hole expansion process).

[0053] Next, as shown in Figures 7 and 8, a large number of workpieces W are supplied from above and inserted into the expanded through-holes 2 (workpiece insertion process). For this insertion of workpieces W, a parts feeder (feeder mechanism) may be used to insert the workpieces W in alignment with the through-holes 2. Although not shown in the drawings, for example, when inserting elastic sheets in a horizontal direction, a parts feeder may be configured to sequentially align workpieces by applying vibration to a passage formed in a spiral shape diagonally upward on the inner circumferential surface of the ball of the parts feeder, allowing the workpieces to move through a passage formed in a straight line from the inclined upper end of the passage, with an outlet provided downward at the end of the passage facing the through-holes 2, and workpieces being fed out one by one from the outlet and inserted into the through-holes 2. This insertion operation may be carried out sequentially while moving until all workpieces are inserted into the through-holes 2. Alternatively, multiple rows of passages may be provided, and workpieces may be fed out from multiple outlets at once and inserted into multiple through-holes. In short, there may be one or more passages. Furthermore, in a device for setting the elastic sheet 3 in the vertical direction, a configuration in which the workpiece is inserted into the through hole from the side is also possible. In this case as well, the parts feeder may have a single row or multiple rows of passages.

[0054] Furthermore, the workpiece W may be supplied onto the elastic sheet 3 from a hopper or stocker (supply hopper mechanism) and dropped into the through-hole 2. In this case, the workpiece can be efficiently placed in the elastic sheet 3 while it is being vibrated by a vibration-adding mechanism (not shown), such as a vibrator.

[0055] Furthermore, if the workpiece W contains a magnetic material, for example, if the internal electrodes of the workpiece are made of a magnetic material such as nickel, a magnet may be placed under the seating surface of the seating base 41 to actively pull the workpiece in using magnetic force. By applying magnetic force in this way, the workpiece can be efficiently pulled into the through hole, and the accuracy of the workpiece's protruding length can be improved by ensuring that the end of the workpiece is securely in contact with the upper surface of the seating base 41. Furthermore, a configuration may be adopted in which the workpieces are transferred to an adhesive pallet in their predetermined positions, and these workpieces are inserted simultaneously. This configuration allows for efficient insertion of the workpieces into the through-holes.

[0056] When the workpiece W is inserted into the through-hole 2 as described above, a seating support 41 is positioned below the elastic sheet 3, and the distance between the upper surface of the seating support 41 and the lower surface of the elastic sheet 2 is maintained at 0.25 mm by the height reference ring 39. As a result, the lower end of the workpiece W inserted into the expanded through-hole 2 is supported by the seating support 41, and the lower end protrudes a predetermined length from the lower surface of the elastic sheet 3, while the upper end protrudes from the upper surface of the elastic sheet 3, at which point it stops. In this embodiment, both the upper and lower ends of the workpiece W protrude by 0.25 mm.

[0057] Then, once the workpiece W is inserted into the expanded through-hole 2, the sheet-side table 31 is raised to return to its initial state, as shown in Figure 9. This releases the tension on the elastic sheet 3, causing the through-hole 2 to contract due to the elastic force of the elastic sheet 3. This contraction, accompanied by elastic force, tightens the inner surface of the through-hole 2 around the workpiece W, holding it in a nearly tight seal. Once this state is reached, the clamping device 58 is loosened and the sheet-holding ring 4 is removed, allowing the process to move to the next step with the workpiece W still held in the through-hole 2.

[0058] In the next step, for example, the sheet holding ring 4 is placed in the chamber and subjected to processing such as vapor deposition or sputtering. When a metal film is formed on the end of the workpiece W in this manner, the inner surface of each through-hole 2 of the elastic sheet 3 adheres tightly to the middle part of the workpiece W without any gaps, and only the end of the workpiece W protrudes. As a result, an external electrode can be formed only on this protruding end, and a step-free external electrode can be formed on five surfaces, including the end face. Furthermore, even if the temperature of the elastic sheet rises and the elastic sheet itself expands due to thermal expansion during the above processing, the preload is applied, so even if the elastic sheet expands due to thermal expansion during or after processing, the tension will only decrease slightly, preventing gaps from forming between the inner surface of the through-hole and the workpiece. Therefore, a decrease in the masking function during processing can be prevented, and high-quality processing can be achieved. In addition, even if the elastic sheet 3 is subjected to partial stress changes in the process after the workpiece is held in the through-hole, the preload can disperse and absorb the deflection and strain of the elastic sheet 3. Therefore, problems such as the workpiece coming out of or shifting from the through-hole 2 can be prevented.

[0059] Once the formation of the external electrodes is complete, the sheet holding ring 4 is removed from the chamber and set in the workpiece recovery device 61, as shown in Figure 11, to remove the workpiece W. This workpiece recovery device 61 has a configuration almost identical to the holding device 1 described above, but instead of a seating base 41, it is equipped with a recovery cavity 62.

[0060] To recover the workpiece W using the workpiece recovery device 61 (workpiece discharge method), the sheet holding ring 4 is placed on the mounting table 53 and fixed with a clamp 58, and the mounting table 53 is lowered to expand the through-hole 2. Then, the workpiece W in the through-hole 2 can fall and be recovered into the recovery cavity 62. In this case, if the workpiece W is made easier to detach from the elastic sheet by vibrating the elastic sheet 3, pressing the workpiece W downward from above with a pressing device 63 (see Figure 11(b)), or reducing the pressure inside the recovery cavity 62, the workpiece W can be recovered efficiently. In the case of a workpiece containing a magnetic material, a magnetic force may be applied from one end of the elastic sheet holding the workpiece toward the other, and the workpiece may be ejected by this magnetic force. Furthermore, the elastic sheet from which the workpiece has been discharged can be reused after cleaning. Alternatively, the workpiece recovery device 61 may be configured as a dual-purpose device by removing the seating support base 41 of the holding device 1 and attaching a component having a recovery cavity 62 to that part. In short, by applying a pressing or suction force to the workpiece from one end of the elastic sheet towards the other, the workpiece can be removed (discharged) efficiently, facilitating its separation.

[0061] Furthermore, the workpiece W to be processed is not limited to the aforementioned rectangular prism; it may also be a cylinder, a polygon, or any shape that fits into the through hole 2. Alternatively, the sheet may be oriented vertically when inserting the workpiece W.

[0062] Furthermore, the embodiments described above should be considered in all respects to be illustrative and not restrictive. The present invention is not limited to the above description and is shown in the claims, including all modifications in the sense and scope equivalent to the claims. For example, the tension-applying mechanism has the function of expanding the through-hole of the elastic sheet, comprising a sheet-side table to which a sheet-holding ring is attached, and an intrusion-side table attached to the sheet-side table that moves relative to the sheet-holding ring in the axial direction. At least one of the sheet-side table and the intrusion-side table only needs to be able to move vertically, and the direction of movement may also be horizontal. Also, the sheet-holding ring is not limited to a configuration that is divided vertically, but only needs to be able to be attached in an unfolded state of the elastic sheet. [Explanation of Symbols]

[0063] 1 Holding device 2 through holes 3 Elastic Sheet 4 Sheet retaining ring 5. Tension application mechanism 11 Lower ring 11a Through opening hole 12 Upper Ring 12a Through opening hole 13 Preload Ring 15 Clamping part 16 depression 18 Flange section 19 Standing wall 21 screws 22 screws 31 Seat-side table 32 Intrusion Member 34 Base 34 35 Upright 36 Upper beam 37 Fixed support base 38 Outer shoulder section 39 Height reference ring 40 Rotating Bodies 41. Support stand for seating 44 Drive mechanism 46 Lower beam part 47 Bearings 48 Lifting drive shaft 49 Pulley 50-section belt 53 Mounting Table 53a Through opening 54 leg piece 55 Crossbeam 56 Female threaded section 57 Guide section 58 Clamping tool 61 Workpiece Recovery Device 62 Recovery space 63 Pressing tool

Claims

1. An elastic sheet for holding a workpiece, comprising a sheet material having heat resistance and elasticity suitable for vapor deposition and sputtering processing, having a through hole smaller than the thickness of the workpiece to be processed, and wherein a workpiece is placed inside the through hole in a state in which the through hole is expanded by applying tension, and wherein the through hole is contracted by releasing the tension in this state to hold the workpiece inside the through hole in a masked state with the inner surface of the through hole in close contact with the side of the workpiece.

2. An elastic sheet for holding a workpiece as described in Claim 1, characterized in that the thickness of the elastic sheet when the tension is released is set to be smaller than the length of the workpiece, and the elastic sheet is configured so that the end of the workpiece is exposed from the through hole when the tension is released and the workpiece is held in the through hole.

3. A ring-shaped sheet retaining ring for mounting and retaining an elastic sheet for retaining a workpiece, the sheet being made of an elastic sheet material, having a through hole smaller than the thickness of a workpiece to be processed, the through hole being expanded by applying tension to place a workpiece into the through hole, and the through hole being contracted by releasing the tension in this state to retain the workpiece within the through hole, The sheet retaining ring has a circular opening and is provided on the outside of the opening with a ring body having a retaining portion for retaining the elastic sheet, and is composed of a preload ring for applying an initial tension to the elastic sheet retained by the ring body, The preload ring has an attachment portion that is attached to the ring body, and a ring-shaped upright wall that stands up from the attachment portion and fits into an opening of the ring body along an inner periphery thereof, The sheet retaining ring is characterized in that the upright wall is set to an upright height such that, when attached to the ring body, it can abut against the elastic sheet held by the retaining portion and apply initial tension to the elastic sheet.

4. The sheet retaining ring described in claim 3, characterized in that the ring body consists of a first ring having concentric openings and a second ring that is superimposed on the first ring, and is provided with a retaining portion that holds an elastic sheet sandwiched between the first ring and the second ring.

5. A sheet retaining ring as described in claim 3 or 4, characterized in that the thickness of the elastic sheet for holding the workpiece when the tension is released is set to be smaller than the length of the workpiece, and when the tension is released and the workpiece is held within the through hole, the end of the workpiece is exposed from the through hole.

6. An elastic sheet for holding a workpiece according to claim 1 or claim 2, A ring-shaped sheet holding ring for mounting and holding the elastic sheet for holding the workpiece; a tension applying mechanism that applies tension in a surface direction to the elastic sheet attached to the sheet holding ring, a tension applying mechanism applies tension to the elastic sheet to expand the through hole, and a workpiece is placed in the through hole in this state, and the tension applied by the tension applying mechanism is released in this state to contract the through hole and hold the workpiece in the through hole; the tension applying mechanism includes a sheet side table to which the sheet holding ring is attached, and an insertion side table that moves relatively in the axial direction of the sheet holding ring attached to the sheet side table, the sheet side table has a clamping tool for clamping the sheet holding ring placed at a predetermined position, and a projection opening at a portion corresponding to the opening of the clamped sheet holding ring; the insertion side table has a tip portion with a smaller diameter than the opening of the sheet holding ring, and has a plurality of rotating bodies at a shoulder portion that comes into contact with the elastic sheet when the tip portion is inserted into the opening of the sheet holding ring, and the rotation center axis of each rotating body is arranged parallel to a tangent direction of a circumference of the shoulder portion, A workpiece holding device, characterized in that a height reference ring protruding toward the elastic sheet side further than the rotating bodies is positioned inside the row of rotating bodies.

7. An elastic sheet for holding a workpiece, the sheet being made of an elastic sheet material and having a through hole smaller than the thickness of a workpiece to be processed, the through hole being expanded by applying tension and a workpiece being placed into the through hole, and the tension being released in this state to shrink the through hole and hold the workpiece within the through hole, A tension applying mechanism applies tension to the elastic sheet to expand the through hole, and a workpiece is placed in the through hole in this state. In this state, the tension applied by the tension applying mechanism is released to contract the through hole and hold the workpiece in the through hole. The entry side table is provided with a seating support facing the entry side surface of the elastic sheet, A workpiece holding device comprising: a magnetic force generating means for applying magnetic force to a workpiece including a magnetic body so that the workpiece can be guided into a through hole of an elastic sheet.

8. A work holding device as described in Claim 7, characterized in that the thickness of the elastic sheet for holding the workpiece when the tension is released is set to be smaller than the length of the workpiece, and when the tension is released and the workpiece is held within the through hole, the end of the workpiece is exposed from the through hole.

9. A hole expansion process for converting a first state in which the elastic sheet for holding a workpiece as described in claim 1 or claim 2 is spread and taut, into a second state in which a tension stronger than the tension applied to the elastic sheet in the first state is applied to the elastic sheet, thereby enlarging the size of the through hole compared to the first state; and a workpiece inserting step of inserting a workpiece into the enlarged through hole; A method for holding a workpiece, comprising: a hole shrinking process in which the tension of the elastic sheet is reduced from a state in which the workpiece is inserted into a through hole, causing the through hole to shrink using the elasticity of the elastic sheet; and a process in which the workpiece is held in a masked state in which an end of the workpiece is exposed from the through hole and the inner surface of the through hole is in close contact with the side surface of the workpiece.

10. A method for discharging a workpiece, comprising: applying tension in the surface direction of the elastic sheet to the elastic sheet for holding a workpiece as described in claim 1 or 2, which holds the workpiece by the elastic contraction force of the elastic sheet, to expand the size of the through hole; and applying a force from one side of the surface of the elastic sheet to the other side in this expanded state to discharge the workpiece.

11. A method for discharging a workpiece as described in claim 10, characterized in that the workpiece is discharged by pressing the workpiece from one side of the elastic sheet toward the other side with a pressing member.

12. A method for discharging a workpiece as described in claim 10, characterized in that the workpiece is discharged by generating a pressure difference between one side and the other side of the elastic sheet.

13. A method for discharging a workpiece as described in claim 10, characterized in that a magnetic force is applied from one side of an elastic sheet holding a workpiece containing a magnetic material to the other side, and the workpiece is discharged by said magnetic force.

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