JP4390642B2 - Cutting method for foamed styrene resin sheet and cutting device for foamed styrene resin sheet - Google Patents

Description

The present invention relates to a technique for thermally cutting a foamed styrene resin sheet (hereinafter sometimes referred to as a resin molded body) using a heating element, and in particular, a heating sheet for a molded sheet in which a large number of containers are formed in series. The present invention relates to a foamed styrene resin sheet cutting method and a foamed styrene resin sheet cutting device, which are manufactured by cutting with heat and producing individual containers.

  Conventionally, for example, as a method for cutting a resin molded body, for example, Patent Document 1 uses stainless steel (wire diameter of 0.1 to 2.0 mm) that defines the amounts of Ni, Cr, and Fe as a heating wire. A melt cutting apparatus and a cutting method are described.

  Further, Patent Document 2 discloses a molding process for manufacturing a molded sheet in which a plurality of concave portions constituting a container main body having a flat rectangular flange are aligned in a vertical and horizontal direction on a heat-meltable resin sheet material, and the molded sheet. A container comprising: a corner cutting step in which through holes are formed by heating and melting at portions corresponding to the four corner portions of the flange; and a separation step in which the molded sheet is thermally cut vertically and horizontally to separate the recesses individually. The manufacturing method is described. In this type of resin container manufacturing method, the cutting tool used to thermally cut a molded sheet vertically and horizontally is generally a structure in which a heating wire such as a nichrome wire is stretched vertically and horizontally. is there.

Further, for example, in Patent Document 3, a plurality of recesses to be a container body are formed in a foam sheet, and the periphery of each recess is a substantially square self-heating heating blade (for example, stainless steel) in which at least one corner forms an arc shape. A manufacturing method of a flanged container is described which uses a plurality of thin-walled blades of steel or the like and is attached to a heated blade base via an insulating material at the same time.
JP-A-9-94800 JP-A-9-240710 JP 9-48066 A

  However, in the conventional melt cutting apparatus described in Patent Document 1, stainless steel is used for the heating wire, but the shape is a heating wire having a circular cross section like the conventional nichrome wire. There was a problem that the bending of the wire was large and it was difficult to cut with high accuracy. Moreover, since the amplitude of the heating wire after cutting is large, it is necessary to wait for the next cutting until the amplitude becomes small, resulting in a problem of poor productivity.

  In the conventional method for manufacturing a resin container described in Patent Document 2, there is a problem that the heating wire during the bending is large and cutting with high accuracy cannot be performed. Moreover, since the amplitude of the heating wire after cutting is large, it is necessary to wait for the amplitude to attenuate, and it takes time until the next cutting, resulting in poor productivity.

  Furthermore, in the manufacturing method of the container with a flange described in Patent Document 3, as a self-heating type heating blade, for example, a thin-striped blade such as stainless steel, which is attached to the heating blade via an insulating material Therefore, the heating blade was deformed due to the difference in strain between heating and cooling, and there was a problem in cutting accuracy.

  The present invention has been made in view of the above circumstances, and a resin molded body cutting method and a resin molded body cutting apparatus capable of thermally cutting a resin molded body with high accuracy and continuously at high speed. The purpose is to provide.

In order to achieve the above object, according to the present invention, there is provided a method for cutting a resin molded body by thermally cutting a foamed styrenic resin sheet using a stretched heating wire that generates heat when energized, and the heating wire is , and cross-sectional shape is formed in a strip is larger width than thickness, the ratio of the width to the thickness of the cross-sectional shape of the heating wire is 2.5 to 25, a thickness of the heating wire is 0.2 to 0. is 8 mm, the width of the heating wire is 2.0 to 5.0 mm, the by the movement of the heating wire and / or the foamed styrene resin sheet, the foamed styrene resin sheet in the width direction of the heating wire from one end side toward the other end side so as to cross the heating wire cutting foamed styrene resin sheet characterized by hot cutting the foamed styrene resin sheet be moved relative to the heating wire Proposed method To.

Further, according to the present invention, the stretched heating wire that generates heat by energization and the movement of the heating wire and / or the foamed styrene resin sheet move the foamed styrene resin sheet across the heating wire. The heating line is formed in a strip shape whose cross-sectional shape is wider than the thickness, and the ratio of the width to the thickness of the cross-sectional shape of the heating line is 2.5 to 25, The heating wire has a thickness of 0.2 to 0.8 mm, the heating wire has a width of 2.0 to 5.0 mm, and the moving device includes the heating wire and / or the foamed styrene resin sheet . the movement, that is adapted to be moved relative to the heating wire to the foamed styrene resin sheet so as to traverse the heating wire toward the other end from one end side in the width direction of the heating wire Characteristic A cutting device for a foamed styrene-based resin sheet is provided.

When the heating wire material is a Ni—Cr alloy, there is an advantage that it can be obtained at low cost.

  According to the present invention, by using a heating wire composed of a heating element extending in a band shape whose cross-sectional shape is wider than the thickness, compared to the case of using a heating wire having a circular cross-section as in the prior art, during cutting The heating wire is less likely to bend, and the resin molded body can be thermally cut with high accuracy with little deviation from the set cutting dimensions.

  In addition, since the heating wire has a strip shape, the amplitude of the heating wire swinging after cutting is greatly reduced compared to the case of using a heating wire with a circular cross section as in the prior art. Therefore, it is possible to cut the resin molded body efficiently with high productivity.

  Furthermore, since the bending and the amplitude are reduced by using the strip-shaped heating wire for the thermal cutting, the durability is greatly improved as compared with the heating wire having a circular cross section as in the prior art. Unlike conventional heating wires with a circular cross-section, it is not necessary to replace them frequently by cutting, and thermal cutting can be performed continuously for an extremely long time, so that productivity is greatly improved.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Hereinafter, as an embodiment of the present invention, a resin molded body cutting method and a cutting apparatus for cutting a resin container from a resin molded sheet (resin molded body) will be exemplified. FIG. 1 is a perspective view illustrating a resin molded body cutting device of the present invention. This resin-molded body cutting device 3 cuts a molded sheet B formed by aligning a large number of recesses A vertically and horizontally into individual recesses A. As the molded sheet B, various thermoplastic resin sheets can be used, and a foamed styrene resin sheet is particularly preferable.

  The resin molded body cutting device 3 includes a heating wire passing groove 7 provided along the boundary between the recesses A formed in the molded sheet B, and a table 5 on which the molded sheet B is placed, A molded body moving device (moving device) 30 for moving the table 5 up and down between the top dead center and the bottom dead center, and a heating wire stretched in a fixed state vertically and horizontally between the top dead center and the bottom dead center 8.

  The heating wire 8 is stretched between the top dead center and the bottom dead center of the table 5 in a fixed state. As shown in FIG. 2, the heating wire 8 is formed of a heating element that extends in a band shape in which the shape of the cross section S is larger than the thickness. The heating wire 8 is formed in a thin plate shape such that the ratio (H / W) of the width H to the thickness W of the cross section S is 1.5 to 100, preferably 2.5 to 25. . The heating wire 8 is stretched in such a direction that one end side in the width direction (edge surface 8d) is down and the other end side in the width direction (side opposite to the surface 8d) is up. The shaped sheet B is moved across the heating wire 8 from the one end side in the width direction of the heating wire 8 having such a shape, that is, from the lower side of the heating wire 8 to the upper side of the heating wire 8 on the other end side. By doing so, it is thermally cut by the heating wire 8.

  The thickness W in the cross section S of the heating wire 8 may be, for example, 0.1 to 1.0 mm, preferably 0.2 to 0.8 mm. If the thickness W is less than 0.1 mm, there is a concern that the individual cut products that are thermally cut after cutting the molded sheet B are re-fused. On the other hand, when the thickness W exceeds 1.0 mm, the amount of heat and tension applied are increased.

  The width H in the cross section S of the heating wire 8 may be, for example, 1.5 to 10 mm, preferably 2.0 to 5.0 mm. If the width H is less than 1.5 mm, there is a concern that the deflection and amplitude of the heating wire 8 will increase. On the other hand, if it exceeds 10 mm, the amount of heat and tension applied will increase.

  Preferred examples of the material constituting the heating wire 8 include nichrome (corresponding to the Ni—Cr alloy according to the present invention), stainless steel, and the like. Both ends of the heating wire 8 are connected to a power source (not shown) and used in a heated state. In this example, one end side of the heating wire 8 in the longitudinal direction is fixed, the other end side is connected to the tension cylinder 17, and the heating wire 8 is stretched with a desired tension. The vertical heating wire 8a and the horizontal heating wire 8b are stretched with slightly different heights.

  In the present embodiment, the heating wire 8 is stretched horizontally, but the stretching direction of the heating wire 8 is different from the one end in the width direction of the heating wire 8 by moving the table 5 (in this case, rising). It suffices that the heating wire 8 is crossed while being cut by the heating wire 8 toward the end side, and the heating wire 8 may be tilted in the vertical direction and stretched. (That is, it is not always necessary to make the width direction of the heating wire 8 coincide with the moving direction of the resin molded body, and the heating wire 8 has different heights at one end and the other end in the longitudinal direction of the heating wire 8. 8) The heating wire 8 is inclined and stretched, so that the cutting of the heating wire 8 becomes a point cut, and the temperature drop is less than in the case of wire cutting, and the sharpness is good. To be kept.

  Stainless steel is known to have excellent tensile strength in a heated state, and even if the resin molded body is repeatedly cut, it is difficult for the heating wire to extend, and an improvement in durability can be expected. preferable. However, as a result of intensive studies by the present inventors, it has been found that very high durability can be obtained even with a heating wire made of a Ni—Cr alloy, and it is advantageous to use a nichrome wire in that it can be obtained at a low cost. It is.

  By using the heating wire 8 having such a configuration, the heating wire 8 has a strip shape, so that the heating wire 8 may be bent during cutting as compared with the case of using a heating wire having a circular cross section as in the past. As a result, the molded sheet (resin molded body) B can be thermally cut with high accuracy with little deviation from the set cutting dimension.

  In addition, since the heating wire 8 has a strip shape, the amplitude of the heating wire 8 swinging after cutting is greatly reduced as compared with the case where a heating wire having a circular cross section as in the conventional case is used. Therefore, it is possible to almost eliminate the time for waiting for cutting, and to efficiently cut the molded sheet (resin molded body) B with high productivity.

  Furthermore, since the bending and the amplitude are reduced by using the strip-shaped heating wire 8 for thermal cutting, the durability is greatly improved as compared with a heating wire having a circular cross section as in the prior art. Unlike conventional heating wires with a circular cross-section, it is not necessary to replace them frequently by cutting, and thermal cutting can be performed continuously for an extremely long time, so that productivity is greatly improved.

  Further, by cutting the molded sheet (resin molded body) B with the belt-shaped heating wire 8, it was cut out from the molded sheet (resin molded body) B at the time of cutting as compared with the conventional heating wire having a circular cross section. Since the end faces of the individual cut pieces are heated for a relatively long time by the surface 8c forming the width of the heating line 8, the end faces of the individual cut pieces are melted and then re-hardened and hardened. The end face of the object is reinforced. Moreover, generation | occurrence | production of a cutting waste etc. can also be suppressed by carrying out a thermal fusing with the heating wire 8. FIG.

  The strip-shaped heating wire applied to the method for cutting a resin molded body and the cutting apparatus according to the present invention can employ various shapes in addition to the above-described forms. For example, as shown in FIGS. 3a and 3b, either or both ends (edge surfaces) in the width H direction in the cross-sectional S shape of the heating wire 35 may have a sharp blade shape. . By making the edge part of such a heating wire into a sharp blade shape, cutting can be performed with higher accuracy and cutting becomes easy. The edge of the heating wire may be a saw blade or a wave blade.

  Further, as shown in c and d of FIG. 3, the belt-like heating wire may be composed of two or more portions having different rigidity. The heating wire 36 has a heat-resistant high-rigidity portion 36a at an intermediate portion. By forming such a high-rigidity portion 36a on the heating wire 36, sufficient strength can be maintained even when the thickness W of the heating wire 36 is reduced, and bending and vibration can be further reduced.

  Further, as shown in FIGS. 4A and 4B, a seam-like heat-resistant high-rigidity portion 37a may be formed at one end of the heating wire 37. By forming such a highly rigid portion 37a at one end of the heating wire 37, even if the thickness W of the heating wire 37 is reduced, sufficient strength can be maintained, and bending and vibration can be further reduced.

  Further, as shown in FIG. 4 c, a seam-like heat-resistant high-rigidity portion 38 a having a diameter larger than the thickness W of the heating wire 38 may be formed at one end of the heating wire 38. Such a high-rigidity portion 38 a has a shape that extends from the side surface of the heating wire 38. Such a heating wire 38 is used for, for example, thermal cutting of a peripheral portion of the outermost periphery of the molded sheet (resin molded body) B, and an unnecessary peripheral portion is removed by a high-rigidity portion 38 a protruding from the side surface of the heating wire 38. be able to.

  In the embodiment described above, the molded sheet (resin molded body) is moved toward the heating wire by the molded body moving device for cutting. On the contrary, the heating wire is moved toward the resin molded body for cutting. May be performed. FIG. 5 is a perspective view showing a resin molded body cutting device according to the second embodiment of the present invention. As shown in FIG. 2, the resin molded body cutting device 51 uses a heating wire 8 formed of a heating element extending in a band shape in which the shape of the cross section S is wider than the thickness. A heating wire moving device (moving device) 52 for moving the heating wire 8 horizontally toward the resin molding is provided.

  The heating wire 8 is stretched around the holding body 57 via the tension cylinder 56. The holding body 57 is connected to the heating wire moving device 52 and moved horizontally to move the heating wire 8 horizontally. The heating wire 8 is stretched in such a direction that one end side in the width direction is the front side in the movement direction and the other end side in the width direction is the rear side in the movement direction.

  While heating the heating wire 8 by energization, the resin molding 53 can be cut by moving the heating wire 8 horizontally toward the table 55 on which the block-like resin molding 53 is placed. In this case, when the heating wire 8 is horizontally moved while cutting the resin molded body 53, the resin molded body 53 is relatively cut across the heating wire 8 from one end to the other end in the width direction of the heating wire 8. Realized. Further, the resin molded body cutting device for cutting the resin molded body of the resin block is not limited to the configuration in which the heating wire is moved, and the heating stretched so as to extend in the horizontal direction or the vertical direction. A configuration including a molded body moving device that horizontally moves the resin molded body with respect to the wire and cuts it into the heating wire can also be adopted. Both the heating line moving device and the molded body moving device function as a moving device according to the present invention. Moreover, as the moving device according to the present invention, a moving device having both functions of a heating wire moving device and a molded body moving device can be employed. In either case, the resin molded body is thermally cut so as to cross the heating wire 8 while being cut by the heating wire 8 from one end side in the width direction of the heating wire 8 toward the other end side.

  Moreover, as a cutting apparatus of a resin molding, it is not limited to the thing of the structure mentioned above, The thing of various structures is employable. That is, as a cutting device for a resin molded body according to the present invention, a stretching support mechanism (including a tension cylinder 17) that supports a heating wire formed in a strip shape whose cross-sectional shape is wider than the thickness is stretched. And a molded body moving device and / or a heating line moving device, and the resin molded body is directed from one end side to the other end side in the width direction of the heating line by the molded body moving device and / or the heating line moving device. Any structure may be adopted as long as the resin molded body is cut by the heating wire by moving relative to the heating wire so as to cross the heating wire.

  Further, the cutting of the sheet-shaped resin molded body 53 is not limited to the configuration of cutting one sheet at a time, and a plurality of stacked sheets can be cut at once (in this case, a plurality of resin molded body cutting devices are used as cutting apparatuses). It is preferable to provide a holder for maintaining the laminated state of the resin molded body).

  In addition, as a resin molded object of the cutting | disconnection object of this invention, a foamed resin board, a foamed resin block, etc. other than the sheet | seat (foamed resin sheet) formed with foamed resin materials other than the foaming polystyrene mentioned above may be sufficient. In addition, a non-foamed resin sheet, a resin plate, a resin block, or the like can be used. Examples of the foamed resin material other than foamed polystyrene include foamed polyethylene, foamed polypropylene, and foamed polyurethane. Examples of the non-foamed resin sheet, resin plate, and resin block include those made of polystyrene, polyethylene, polypropylene, and polyurethane.

Example 1
Eleven strip-shaped heating wires of nichrome (manufactured by Nippon Metal Industry Co., Ltd., product number NTK No1 nichrome ribbon) having a thickness of 0.6 mm, a width of 3 mm, and a length of 1200 mm were stretched in parallel in the vertical direction at intervals of 100 mm. Six similar heating wires were stretched parallel to the horizontal direction at intervals of 200 mm below 25 mm in the vertical direction. The stretching was performed with a tension of 118 (N) per heating wire. Each heating wire was horizontally stretched so that the width direction was vertical. The heating wire was energized to generate heat. Molded foam sheet (length 1040 mm, width 1040 mm, thickness 2 mm) in which 50 concave portions with a depth of 25 mm constituting the resin container main body are formed vertically and horizontally on a foamed polystyrene sheet (product number N-220D, manufactured by Sekisui Plastics Co., Ltd.) ) One piece was cut by passing the heated wire through a heated wire at a cutting speed of 71 (mm / sec) from the lower side to the upper side of the stretched heated wire, thereby producing 50 resin containers. The cutting accuracy was good, the time required for cutting was 0.4 seconds, and the maximum deflection of the heating wire was 20 mm. The vertical amplitude of the heated wire after cutting was small, and after 4 seconds, the next molded foam sheet was cut. And even if such cutting was repeated 50,000 times, the heating wire was not broken or damaged.

(Example 2)
Eleven strip-shaped heating wires of nichrome (manufactured by Nippon Metal Industry Co., Ltd., product number NTK No1 nichrome ribbon) having a thickness of 0.6 mm, a width of 3 mm, and a length of 1200 mm were stretched in parallel in the vertical direction at intervals of 100 mm. Six similar heating wires were stretched in parallel in the lateral direction at an interval of 200 mm below 28 mm in the vertical direction. The tension was performed with a tension of 59 (N) per heating wire. Each heating wire was horizontally stretched so that the width direction was vertical. The heating wire was energized to generate heat. Molded foam sheet (length 1040 mm, width 1040 mm, thickness 2 mm) in which 50 concave portions with a depth of 25 mm constituting the resin container main body are formed vertically and horizontally on a foamed polystyrene sheet (product number N-220D, manufactured by Sekisui Plastics Co., Ltd.) ) 45 sheets of laminated heating wires were laminated from the lower side to the upper side of the molded foam sheet with a cutting speed of 15 (mm / sec) and cut by passing the heating wires to produce 2250 resin containers. The cutting accuracy was good, the time required for cutting was 20 seconds, and the maximum deflection of the heating wire was 22 mm.

(Comparative Example 1)
A nichrome wire having a circular cross-section with a diameter of 0.6 mm (manufactured by KANTHAL, product number NIKROTHAL N80) was used as the heating wire. Other than that, cutting was attempted under the same conditions as in Example 1 above. However, as a result of the horizontal heating wire flexing and coming into contact with the vertical heating wire, a short circuit occurred and the cutting was terminated.

(Comparative Example 2)
A nichrome wire having a circular cross-section with a diameter of 0.6 mm (manufactured by KANTHAL, product number NIKROTHAL N80) was used as the heating wire. Other than that, cutting was attempted under the same conditions as in Example 2 above, but as a result of the vertical heating wire flexing and coming into contact with the horizontal heating wire, it was short-circuited and could not be cut.

(Comparative Example 3)
Using a nichrome wire having a circular cross-section with a diameter of 0.6 mm as a heating wire (product number NIKROTHAL N80, manufactured by KANTHAL), a horizontal heating wire is stretched 70 mm below in the vertical direction, and other than that, the same as in Example 1 above Cutting was attempted as a condition. The cutting accuracy was within an allowable range, but the time required for cutting was 1 second, and the maximum deflection amount of the heating wire was 60 mm. And the vertical amplitude of the heating line after cutting was large, and it was not possible to start cutting the next molded foamed sheet unless it waited for 6 seconds until the vibration was settled. And when such cutting was repeated 300 times, the heating wire was broken.

(Comparative Example 4)
Using a nichrome wire with a circular cross section of 0.6 mm in diameter (product number NIKROTHAL N80) as the heating wire, a horizontal heating wire is stretched 80 mm downward in the vertical direction, and the cutting speed is 5 (mm / sec) Cutting was performed in the same manner as in Example 2 except that. Although the cutting accuracy was within an allowable range, the time required for cutting took 60 seconds, and the maximum deflection of the heating wire was 70 mm.

It is a perspective view which shows the cutting device of the resin molding of this invention. It is a perspective view which shows a heating wire. It is a perspective view which shows other embodiment of a heating wire. It is a perspective view which shows other embodiment of a heating wire. It is a top view which shows the cutting device of the resin molding of other embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 3 ... Cutting device of resin molding, 5 ... Table, 7 ... Groove, 8 ... Heating wire, 17 ... Tension cylinder, 30 ... Molding body moving device (moving device), 52 ... Heating wire moving device (moving device), A ... recess, B ... molded sheet.

Claims (4)

Using a stretched heating wire that generates heat by energization, a method for cutting a resin molded body that thermally cuts a foamed styrene resin sheet ,
The heating wire is formed in a strip shape whose cross-sectional shape is wider than the thickness, the ratio of the width to the thickness of the cross-sectional shape of the heating wire is 2.5 to 25, and the thickness of the heating wire is 0.00. a 2～0.8Mm, the width of the heating line is the 2.0 to 5.0 mm, by the movement of the heating wire and / or the foamed styrene resin sheet, the heating wire the foamed styrene resin sheet foamed styrene which the foamed styrene resin sheet be moved relative to the heating wire so as to cross the heating wire toward the other end from one end of the width direction, characterized in that thermal cutting Cutting method of resin sheet . The method for cutting a foamed styrene resin sheet according to claim 1, wherein the heating wire is made of a Ni-Cr alloy. Has a heating wire which is stretched which generates heat by energization, and a moving device for moving by the foamed styrene resin sheet by the movement of the heating wire and / or foam styrene resin sheet so as to traverse the heating wire,
The heating wire is formed in a strip shape whose cross-sectional shape is wider than the thickness, the ratio of the width to the thickness of the cross-sectional shape of the heating wire is 2.5 to 25, and the thickness of the heating wire is 0.00. a 2～0.8Mm, wherein the width of the heating wire is 2.0 to 5.0 mm, the mobile device by movement of the heating wire and / or the foamed styrene resin sheet, the foamed styrene resin foamed styrene resin sheet characterized by being adapted to be moved relative to the heating wire so as to cross the heating wire toward the other side of the sheet from one end side in the width direction of the heating wire Cutting device. The cutting apparatus for a foamed styrene resin sheet according to claim 3, wherein a material of the heating wire is a Ni-Cr alloy.

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