JP2012125861A - Punching cutting tooth form - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a punching cutting tooth form preventing decline in punching accuracy even when punching speed is increased and thus, to improve productivity of molded products for mass consumption such as food packages and foam trays.SOLUTION: The punching cutting tooth form includes: punching cutters each formed to have an annular shape corresponding to a contour shape of a molded product to punch a thermoformed resin sheet and cut out the molded product formed by thermoforming from the resin sheet ; and a plate-shaped cutter table supporting the punching cutters. The punching cutter is protruded from the surface of the cutter table. Through holes each penetrating through front and back faces of the cutter table are arranged on the inner sides of the punching cutters so as to release air inside the punching cutters to the back face side of the cutter table when the air is compressed by punching the resin sheet. Grooves continued from the through holes to the outer peripheral part of the cutter table are arranged on the back face side of the cutter table so as to emit the air from the back face side of the cutter table to the periphery of the cutter table even when the punching is performed by supporting the cutter table from the back face side by a support material having a flat surface.

Description

  The present invention relates to a punching blade die, and more particularly to a punching blade die used for punching a thermoformed resin sheet.

Conventionally, a container such as a tray or a lid has been produced by thermoforming a resin sheet such as a foamed sheet or a transparent film using a thermoplastic resin.
In this type of thermoforming, a resin mold heated and softened is covered with a molding die in which a recess corresponding to a container shape is formed, and the resin sheet is evacuated from a vacuum hole opened in the recess. A method called a vacuum forming method in which is deformed in accordance with the shape of the recess is employed.

In forming a molded product such as a container, a multi-cavity mold in which a plurality of the concave portions are arranged vertically and horizontally is usually used so that a plurality of molded products can be produced at a time.
And when cutting out the molded product formed on the resin sheet by such thermoforming from the resin sheet, conventionally, a punching blade type such as a Thomson blade type (Bik type) is used (see Patent Document 1 below) ).
This Thomson blade type is composed of a punching blade formed in an annular shape corresponding to the contour shape of a molded product, and a blade base for supporting the punching blade made of plywood or the like. The molded product is cut out by pressing the protruding blade edge of the punching blade against the resin sheet and pressing the resin sheet in the thickness direction with the blade edge.

More specifically, in a general Thomson blade type, a plate having a length substantially equal to the outer peripheral length of a molded product, a blade tip formed along one side edge in the longitudinal direction, and the other side edge serving as a blade base The punching blade is formed by bending the blade into an annular shape so as to have the contour shape of the molded product and welding the ends of the plate blades as necessary.
On the other hand, a slit having the same shape as the ring shape of the punching blade is formed in the blade base using a laser processing machine or the like.
The Thomson blade mold is formed by embedding and fixing the blade base side of the punching blade in the slit of the blade base.
For this reason, the Thomson blade mold can be easily manufactured without requiring a lot of labor, and is widely used in manufacturing sites where many types of molds need to be prepared.

On the other hand, when a molded product is punched from a resin sheet with a Thomson blade mold, there is a problem that the punching position is easily shifted and it is difficult to stabilize the shape of the molded product.
Taking a typical tofu container as an example, the container for tofu has a rectangular opening formed in the container and is provided with a flange portion having a predetermined width so as to surround the opening. When a position shift occurs when punching out, a difference occurs in the distance from the four sides of the rectangular opening to the tip of the furan portion, and the width of the flange portion is made different in one container or is defined by the tip of the flange portion. There exists a possibility that the said rectangular opening may be in the state distorted diagonally with respect to the outline shape of the said container for tofu.
In recent container manufacturing processes, image processing devices and the like have been adopted, and the relative position between the molded product formed on the resin sheet by thermoforming and the punching blade mold has been made accurate, but still The actual situation is that the punching accuracy has not been sufficiently improved.

  In particular, molded products that are consumed in large quantities, such as food packs and foam trays, are required to quickly remove these products from the resin sheet after thermoforming. When the punching speed is improved, misalignment is likely to occur, and it is difficult to improve the productivity of these molded products.

Japanese Patent Laid-Open No. 09-020325

  The present invention has been made in view of the above-described problems, and provides a punching blade mold that is unlikely to cause a drop in punching accuracy even when the punching speed is improved. As a result, a large amount such as a food pack or a foam tray is provided. The objective is to improve the productivity of the molded products that are consumed.

  The present inventor has intensively studied the behavior when punching a resin sheet by paying attention to the above-mentioned problems, and punched the thermoformed resin sheet using a ring-shaped punch such as a Thomson blade. When pulling out, the molded product formed on the resin sheet is accommodated inside the punching blade, so that the air inside the punching blade is easily compressed, and the punching blade is made of resin sheet It has been found that the air inside the punching blade loses its place to be covered with the lid so that it easily leaks out through the blade tip and the resin sheet.

  The inventor found that such a behavior becomes remarkable when the punching speed is improved, and it is easy to cause a displacement when air passes between the blade edge and the resin sheet. It came to complete.

  That is, the present invention related to a punching blade mold for solving the above-described problems is that the contour of the molded product is cut out from the thermoformed resin sheet and the molded product formed by the thermoforming is cut out from the resin sheet. A punching blade mold comprising a punching blade formed in an annular shape corresponding to the shape, and a plate-shaped blade base that supports the punching blade, wherein the punching blade protrudes from the surface of the blade base, A through hole is provided inside the punching blade so as to allow the air inside the punching blade to escape to the back side when the air inside the punching blade is compressed in the punching of the resin sheet. In order to release the air from the back side of the blade base to the periphery of the blade base even when the punching is performed by supporting the blade base from the back side with a flat support material. Continue from the through hole to the outer periphery of the blade There has been characterized in that provided on the rear surface side of the blade base.

In the present invention, a resin sheet is formed because a through-hole penetrating the blade base from the front and back inside the punching blade and a groove extending from the through-hole to the outer peripheral portion of the blade base are formed on the back surface side of the blade base. Even when the air inside the punching blade is compressed during punching, the air can be released to the periphery of the blade base through the through hole and the groove.
Therefore, even when the punching speed is improved, air can be prevented from passing between the blade edge and the resin sheet, and the resin sheet can be prevented from being displaced.
That is, according to the present invention, it is possible to provide a punching blade mold that is unlikely to cause a drop in punching accuracy even if the punching speed is improved.

The perspective view which showed the resin tray cut out by the punching blade type | mold from the thermoformed resin sheet. The perspective view which showed the punching blade type | mold of one Embodiment. The top view which showed the mode of the back surface side of the punching blade type | mold of the embodiment. The perspective view which shows the usage condition of the punching blade type | mold of the embodiment. The figure which showed a mode that the thermoformed resin sheet was punched with a punching blade type | mold in the XX cross section of FIG.

  Below, the punching blade type | mold of this invention and its usage method are demonstrated, referring a figure for the case where the resin foam sheet is thermoformed and a square-shaped foam tray is produced.

First, a molded product (foam tray) cut out from a resin foam sheet using the punching blade mold of the present embodiment will be described.
The foaming tray is formed by thermoforming a resin foam sheet using a thermoplastic resin, and has a shape as shown in a perspective view of FIG.
The symbol “T” in FIG. 1 indicates a foam tray. As shown in this figure, the foam tray T is formed so that the outline shape in a plan view is substantially rectangular, and the bottom portion An accommodation recess TS for accommodating the contents is formed in the foamed tray T by the TB and the peripheral side wall TW rising so as to spread outward from the outer periphery of the bottom portion TB.
The foam tray T has a flange portion TF that protrudes outward from the upper end of the peripheral side wall TW, and the rectangular outline shape is defined by the tip TFa of the flange portion TF.

  The foam tray T was formed by thermoforming the resin foam sheet, and after the recess corresponding to the housing recess TS was formed in the resin foam sheet, the foam tray T was cut into a shape that was slightly larger than the recess. In order to cut out the foam tray T from the resin foam sheet, the punching blade mold according to this embodiment is used.

FIG. 2 is a perspective view of the punching blade mold according to the present embodiment, and reference numeral “1” in the drawing represents the punching blade mold.
As shown also in this figure, the punching blade die 1 according to this embodiment punches out a thermoformed resin foam sheet and cuts out the foam tray T formed by the thermoforming from the resin foam sheet. Therefore, the punching blade 10 formed in an annular shape corresponding to the contour shape of the foaming tray and a plate-shaped blade base 20 that supports the punching blade 10 are provided.
The punching blade 10 is formed by bending a long plate-like plate blade into the ring shape, a blade edge 11 is formed at one end edge corresponding to one side edge of the plate blade, and the other end The side is the blade base 12.
The punching blade 10 is formed so that the shape in plan view is the same rectangle as the contour shape of the foam tray T, and the cutting edge 12a is cut out in the cutting edge 12 toward the cutting edge 11. Is provided at a position corresponding to the center of each side of the rectangle.
That is, the cutting edge 12 is provided with a total of four notches 12a.

The blade base 20 is formed of a rectangular plywood having an area sufficient for arranging a large number of the cutting blades 10 in the vertical and horizontal directions. In the present embodiment, the three cutting blades 10 in the vertical direction and in the horizontal direction. 4 in total, 12 in total.
The blade base 20 is provided with a slit 23 corresponding to the ring shape of the punching blade 10, and the punching blade 10 is fixed to the blade base 20 by inserting the blade base side into the slit 23. Yes.

The slit 23 extends from the front surface 20a of the blade base 20 to the back surface 20b so that the end blade 10 can be inserted until the end surface of the cutting blade 10 is flush with the back surface 20b of the blade base 20. It is provided in a state of penetrating to.
However, it does not penetrate to the back surface 20b at a position corresponding to the notch 12a.
Accordingly, in the punching blade mold 1 according to the present embodiment, the end surface on the blade base side of the punching blade 10 is exposed on the back surface 20b of the blade base 20, but the portion corresponding to the notch 12a is not present in the circumferential direction. It is exposed to be continuous, and the inner region and the outer region of the punching blade 10 are not edge-cut by the punching blade 10, and the regions are connected to each other at the notch 12a. Yes.
Further, the blade base 20 is thinned with respect to the height of the punching blade 10 (width from the blade edge to the blade base) until the end surface on the blade base side is flush with the back surface 20b of the blade base 20. Even when the blade 10 is inserted into the slit 23, the cutting edge 11 of the punching blade 10 can be protruded from the surface 20a.

  Furthermore, as shown in FIG. 5, the punching blade mold 1 is formed by punching a resin foam sheet 50 formed with a product (foam tray) shape from the side that becomes the outer surface of the foam tray T. The protruding height of the punching blade 10 is made higher than the container height of the foaming tray T so that the bottom TB of the foaming tray T and the blade base 20 do not interfere with each other in the region inside the punching blade 10.

The punching blade mold 1 according to this embodiment is configured so that the air inside the punching blade 10 can be released from the back surface 20b of the blade base 20 when the air inside the punching blade 10 is compressed in the punching of the resin sheet 50. A through hole 21 penetrating the blade base 20 on the front and back sides is provided on the inside.
The through hole 21 has a circular opening 21 a on the front surface 20 a of the blade base 20 and also has an opening 21 b having the same shape on the back surface 20 b of the blade base 20, and these openings 21 a and 21 b are formed by the punching blade 10. It is arranged at a position that is approximately the center of the.
That is, the through hole 21 is formed in a state of penetrating the blade base 20 substantially vertically at a substantially central position of the punching blade 10.

  Furthermore, when the punching blade die 1 according to the present embodiment performs the punching by supporting the blade base 20 from the back side with a flat surface support material such as a press board of a general punching press. A groove 22 that continues from the through hole 21 to the outer periphery of the blade base 20 is provided on the rear surface side of the blade base 20 so that the air can be released from the back surface side of the blade base 20 to the periphery of the blade base. Yes.

In addition, the said through-hole 21 may be provided one each with respect to each cutting blade 10 so that it may illustrate in the figure, and if necessary, a several through-hole may be provided inside the one punching blade 10. FIG. .
The size of the through-hole 21 is not particularly limited. However, when the through-hole 21 is excessively small, the air passage resistance increases. For example, the diameter in the cross section can be several mm to several cm. .
Further, as illustrated in the drawing, the cross-sectional shape of the through hole 21 does not need to be circular, and the through direction may be formed obliquely with respect to the blade base.

Also, the width, depth, extending direction, and the like of the groove 22 are not particularly limited. Usually, a groove having a width of several mm to several tens of mm and a depth of several mm is cut from the through hole 21 to the blade base. What is necessary is just to provide linearly to 20 outer peripheral parts.
However, a plurality of punching blades 10 are arranged on the blade base 20 so that the molded product can be cut out at a time from a resin sheet on which a plurality of molded products are formed like the punching blade mold 1 according to the present embodiment. In the punching blade mold 1, a plurality of grooves are provided for one through hole 21 so that the air flow on the back surface side of the punching blade mold 1 is not biased, and the air that has flowed into the through holes is supplied to these through holes 21. It is preferable that any one of them can be discharged to the periphery of the blade base 20, and it is preferable to provide a groove that allows communication between one through hole and another through hole.

In this regard, a description will be given with reference to FIG. 3 showing the state of the back side of the punching blade mold 1 according to the present embodiment. In the case where a plurality of punching blades 10 are arranged vertically and horizontally in the blade base 20. If so, it is preferable to provide the grooves 22 so as to form a lattice shape with the through holes 21 provided inside the punching blade 10 as intersections.
As shown in the drawing, the groove 22 illustrated in FIG. 3 has a shape that passes through a connecting portion 24 in which the blade base 20 connects the inside and outside of the punching blade 10 in the notch 12 a of the punching blade 10. Are arranged in a lattice shape (a grid pattern), and the ends thereof are opened at the outer peripheral portion of the blade base 20, more specifically, at the side end surface 20 e of the blade base 20.
By providing the groove 22 in such a form, even when the air in the inner region of the punching blade 10 is compressed when the thermoformed resin foam sheet is punched, the air follows the various paths and the blade base 20 It is possible to reach the outer periphery of the.
Therefore, even when punching at a higher speed, air can be effectively released to the outside, and punching displacement of the foam tray T can be prevented.
That is, by providing the groove 22 as illustrated in FIG. 3, the effect of the present invention that it is difficult to cause a decrease in punching accuracy even if the punching speed is improved can be exhibited more remarkably.

Next, how to use such a punching blade mold 1 will be described. In general, not only when producing a foam tray using a resin foam sheet, but also when molding a resin sheet by thermoforming the resin sheet. Using a long belt-shaped resin sheet, a thermoforming process and a punching process are continuously performed on the resin sheet.
For example, with reference to FIG. 4 which is a perspective view showing an outline of this continuous process, the resin foam sheet 50 is heated by a heating zone (FIG. 4) for softening the resin foam sheet 50 to such an extent that it can be molded. (Not shown), a molding zone A1 in which the resin foam sheet 50 is thermoformed with a molding die 40 in which concave portions 41 corresponding to the shape of the foaming tray T to be manufactured are arranged vertically and horizontally, and is formed by thermoforming in the molding zone A1, A punching zone for punching out the foamed tray T as the final product from the resin foamed sheet 50 by punching the resin foamed sheet and the unseparated foamed tray 51 (hereinafter also referred to as “product 51 before punching”) with the punching blade mold 1. A2, in order to manufacture a foam tray by passing through an end material processing zone (not shown) for processing the remaining end material 52 from which the foam tray has been punched in the punching zone A2. The use is consumed.

The process in this punching zone A2 will be described with reference to FIG.
In the present embodiment, the resin foam sheet 50 is introduced into the punching zone A2 from the molding zone A1 while the resin foam sheet 50 is held horizontally with the inner surface of the foam tray T facing upward.
The punching zone A2 is provided with a press device having a press board 6 that can move up and down, and the press board 6 is a plate-like body that is slightly larger than the punching blade mold 1 according to the present embodiment. The press apparatus is provided with the plate surface arranged in the horizontal direction.
The press device is provided with a second press board 7 (hereinafter also referred to as “upper press board 7”) fixedly disposed so as to face the press board above the press board 6, The upper press board 7 and the lower press board 6 that can be moved up and down (hereinafter also referred to as “lower press board 6”) have a distance between them approaching the thickness of the punching blade 10 of the punching blade mold 1 or less. It is equipped with the said press apparatus so that it may obtain.

  In the punching zone A2, the resin foam sheet 50 thermoformed in the molding zone A1 is introduced between the upper press board 7 and the lower press board 6 so that the outer surface side of the product 51 before punching, that is, The punching blade die 1 is formed so that the surface side from which the punching blade 10 protrudes faces upward so that the punching blade die 1 can be punched from the lower surface side of the resin foam sheet 50. It is arranged on the upper surface side.

  That is, the punching blade mold 1 is set in the press device so that the punching can be carried out by supporting the blade base 20 from the back side with the lower press board 6, and when the punching blade mold 1 is punched It is set in the said press apparatus so that it can move up and down with the lower press board 6 used as the support material for supporting.

  In the punching blade mold 1 according to this embodiment, the punching blades 10 are arranged in the same arrangement as the arrangement of the concave portions 41 in the molding die 40, and a plurality of pre-punching products 51 formed by the molding die 40 are arranged. It can be cut out from the resin foam sheet 50 as individual foam trays T at one time by one-shot punching with the press device.

The behavior at the time of punching will be described with reference to FIG. 5. The resin foam sheet 50 introduced from the molding zone A1 into the punching zone A2 has a bottom surface and a portion corresponding to the peripheral side wall of the product 51 before punching. The bulging portion is placed on the punching blade mold 1 in such a manner that the bulging portion is accommodated inside the punching blade 10 (FIG. 5A).
Thereafter, the lower press board 6 that supports the punching blade mold 1 from the back side is moved upward to lift the resin foam sheet 50 from the lower side by the cutting edge 11 of the punching blade 10, and the upper surface of the resin foam sheet 50. The lower press board 6 is moved upward until the side comes into contact with the lower surface side of the upper press board 7.
Further, when the lower press board 6 is moved upward by an amount corresponding to the thickness of the resin foam sheet 50, the cutting edge 11 of the punching blade 10 comes into contact with the lower surface side of the upper press board 7 and cuts the resin foam sheet 50 from the lower surface side. It will be.

At this time, the time until the cutting edge 11 of the punching blade 10 starts to penetrate from the lower surface side of the resin foam sheet 50 and penetrates to the upper press board side is usually instantaneous for 1 second or less.
Further, the time from when the expanded portion of the resin foam sheet 50 starts to be accommodated inside the punching blade 10 to when the foamed tray that has been cut out is removed from the inside of the punching blade 10 is usually thermoformed in the molding zone A1. The time required for this is approximately the same as that required for a few seconds.

Therefore, if the through-hole 21 is not provided as in the punching blade mold 1 according to the present embodiment, the inner region 10x of the punching blade 10 is deformed by deformation of the resin foam sheet 50 when the bulging portion is accommodated or when punching starts. When the air is compressed, the air loses its place and tries to leak to the outside through the space between the blade edge 11 and the resin foam sheet 50, making it difficult to accurately cut the shape of the foam tray T.
Further, when only the through-hole 21 is provided, a plate-like body having a flat surface on the lower press board 6 as a support material for supporting the punching blade mold 1 according to the present embodiment from the back side of the blade base 20. Since the through hole 21 is blocked from the back side by the lower press board 6 from the back side, the groove 22 is provided on the back side of the blade base from the foamed resin sheet 50. This is important in accurately cutting the shape of the tray T.

That is, as shown in FIG. 5B, when the resin foam sheet 50 is punched, the air flow F1 in which the air in the inner region 10x of the punching blade 10 flows into the through hole 21 from the opening in the surface 20a of the blade base. An air flow F <b> 2 is formed that discharges the air to the periphery of the blade base 20 through a groove 22 that is formed and communicates the space surrounding the side end surface 20 e of the blade base 20 and the through hole 21 on the back surface 20 b of the blade base 20. .
As a result, the relative position between the blade edge 11 and the product 51 before punching can be prevented from shifting during punching.

The foaming tray T cut out from the resin foam sheet 50 in the punching process is accommodated inside the punching blade 10, and the through-hole is also used when the foaming tray T is taken out from the inside of the punching blade 10. 21 and the groove 22 act effectively.
That is, if the through-hole 21 or the like is not provided, the space between the foam tray T and the blade base 20 is expanded when the foam tray T is removed from the inside of the punching blade 10, and the space is decompressed. A force that pulls back to the inside of the punching blade 10 acts on the foam tray T. However, in the punching blade mold 1 of this embodiment, the inner region 10x of the punching blade 10 passes through the groove 22 and the through hole 21. Since the air can flow in, the foaming tray T can be easily taken out.

That is, according to the present invention, even if the punching speed is improved, not only the punching accuracy is hardly lowered, but also the removal speed of the punched molded product can be improved.
Therefore, the tact time of the punching process can be shortened while suppressing the deterioration of the quality of the molded product to be obtained, and as a result, the manufacturing cost of the molded product can be reduced.

In addition, the said foaming tray T is generally consumed in large quantities, and the improvement of productivity is requested | required more.
Therefore, in the point that the effect of the present invention is remarkably easily exhibited, in the present embodiment, the usage mode of the punching blade mold of the present invention is described by taking the case where the foamed tray is cut out from the resin foam sheet as an example. The punching blade mold of the present invention can be used not only for foaming trays having such a shape, but also for cutting out molded products from resin foam sheets formed in container shapes other than trays such as a bowl shape.
It can also be used for punching foam molded products other than containers.
Furthermore, in this embodiment, the resin foam sheet is exemplified as the resin sheet to be punched.For example, when forming a molded product such as a tofu container by thermoforming a film-like resin sheet, The punching blade mold of the present invention can also be used in the case of producing a molded product such as a transparent lid or a food pack of a food container.
In addition, conventionally known matters in the punching blade mold can be appropriately adopted in the punching blade mold of the present invention as long as the effects of the present invention are not significantly impaired.

DESCRIPTION OF SYMBOLS 1 Punching blade type | mold 6 Lower press board 7 Upper press board 10 Cutting blade 10x Inner area | region 11 Cutting edge 12 Cutting edge 20 Cutting edge part 20 Cutting edge 21 Through-hole 22 Groove 40 Molding die 50 Resin foam sheet A1 Molding zone A2 Punching zone T Foaming tray

Claims (2)

A punching blade formed in an annular shape corresponding to the contour shape of the molded product, and the punching blade, in order to punch out a thermoformed resin sheet and cut out the molded product formed by the thermoforming from the resin sheet. A punching blade mold having a plate-shaped blade support for supporting, and projecting the punching blade from the surface of the blade rest;
A through hole is provided inside the punching blade so as to allow the air inside the punching blade to escape to the back side when the air inside the punching blade is compressed in the punching of the resin sheet. In order to release the air from the back side of the blade base to the periphery of the blade base even when the punching is performed by supporting the blade base from the back side with a flat support material. A punching blade mold characterized in that a groove extending from the through hole to the outer peripheral portion of the blade base is provided on the back surface side of the blade base.   A plurality of the cutting blades are arranged in the blade base so that the molded products can be cut out at once from a resin sheet on which a plurality of molded products are formed, and through holes provided inside the plurality of cutting blades are provided. The punching blade type according to claim 1, wherein the grooves are provided in a lattice shape as intersections.

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