JPH0665476B2 - Molding manufacturing method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a molding by cutting a part of a synthetic resin molded product.

[Conventional technology]

As a method of manufacturing a synthetic resin molding for a vehicle, there is a method of shearing a synthetic resin molded product such as a synthetic resin extruded product or an injection molded product to manufacture the molding. However, when the synthetic resin molded product is sheared, the sheared end face is exposed and the decorative property is impaired, and the edge is dangerous. Therefore, it is necessary to perform end treatment such as forming an end cap on the sheared portion.

In order to improve such a point, a method has been proposed in which a cooled synthetic resin molded article is fused by a cutting blade to which a high-frequency voltage is applied (for example, JP-A-54-11977).

[Problems to be solved by the invention]

However, in such a conventional method, since a high frequency voltage is applied to the cutting blade, the resin in the portion in contact with the cutting blade is melted and a fusing end surface having an appearance different from that of the other portions is formed. At the same time, there is a problem that the fusing end face is disturbed and the decorativeness is impaired because the cutting blade contacts the molten portion.

In order to solve the above problems, the object of the present invention is to cut off a part of a molded product by cutting with a principle different from shearing and fusing, so that a curved end having a continuous appearance with other parts is formed. It is an object of the present invention to propose a method for producing a molding that is formed and has a cut surface that is inconspicuous and that can be cut so as to have excellent decorativeness.

[Means for solving problems]

This invention is a method for producing a molding by cutting a part of a molded product molded from a thermoplastic synthetic resin in a shape larger than the final product shape, and a portion substantially along the cut part of the molded product, The cutting blade is moved from the outer surface side to the back surface side in a state where the inner surface is softened by heating it to a temperature higher than the other parts and higher than the normal temperature to make the inner surface softer than the inner part. Along with advancing toward, the cutting blade is moved toward the cutout side of the molded product before the cutting blade reaches the back surface of the molded product, and the outer surface is stretched without cutting or breaking, and the resin inside is surrounded by the peripheral part. The present invention is a method for manufacturing a molding in which a curved end portion is formed, and the outer surface portion and the back surface portion are welded and cut to cut a part of the molded product. With synthetic resin As such, thermoplastic resins such as styrene resin, vinyl chloride resin, and polyolefin resin can be used. Examples of synthetic resin molded products include extrusion molded products and injection molded products. In heating the synthetic resin molded product, a narrow region substantially along the cut portion is heated to a temperature higher than the other portions and higher than room temperature to soften the inside. At this time, in the state where the outer surface of the synthetic resin molded article is cooled by air at room temperature or the like, a method of heating the entire cutting portion by high frequency dielectric heating is preferable.
You may heat with far infrared rays. The cutting blade is not required to be heated but rather cooled to keep it at a constant temperature. The speed of advance of the cutting blade is such that the outer surface of the synthetic resin molded product is stretched without being cut or broken in the middle, the resin inside moves to the peripheral part, and the curved end is formed. Is desirable. The movement to the cut portion side is preferably performed in a direction substantially perpendicular to the cut surface, but may be slightly shifted. The advancement and the movement to the excision portion side may be performed separately or simultaneously depending on the shape of the cut.

[Work]

In the method for manufacturing a molding of the present invention, a portion substantially along the cut portion of the synthetic resin molded product is heated to a temperature higher than the portion other than the portion and higher than normal temperature to soften the inside, and the outer surface portion is When the cutting blade is advanced from the outer surface side to the back surface side in a state where the hardness is higher than the inside, the outer surface portion is pushed and stretched without being cut or broken by the cutting blade because the hardness is high, Therefore, the softened resin inside moves to the peripheral portion. When the cutting blade further advances in this state, the outer surface portion of the cutting portion is deformed into a curved surface while maintaining an appearance continuous with other portions. Then, when the cutting blade horizontally moves toward the excision portion side, the end portion changes into a flat shape. When the cutting blade further advances toward the back surface side, the end portion is further deformed into a curved surface, and finally an end portion having a shape in which the curved surface and the flat surface are combined is formed. Is cut in the welded state. The cut surface is formed with the outer surface part stretched without shearing or fusing, so it is conspicuous from the outer surface side because it is formed with a narrow width on the back side without exposing the resin inside. In addition, a molding with an excellent appearance can be obtained without performing a terminal treatment such as an end cap.

〔Example〕

Hereinafter, the present invention will be described with reference to the embodiments of the drawings. FIG. 1 is a front view showing a cutting device of an embodiment, FIG. 2 is a plan view thereof,
FIG. 3 is a perspective view of a cutting blade, FIGS. 4 to 8 are sectional views taken along the line AA of FIG. 2 showing a cutting step, FIG. 9 is a perspective view of a manufactured molding, and FIG. -B cross section, No.
FIG. 11 is a sectional view taken along line CC.

In the figure, reference numeral 1 is a cutting device, which has a pedestal 3 made of FRP on which a synthetic resin molded product 2 is mounted, a die 4 made of ceramic, a ground electrode 5 made of copper, and a pedestal 6 made of ceramic. Cradle
Clamps 7 and 8 are arranged to face 3 and 6, respectively, and can be reciprocated by fluid pressure cylinders 9 and 10, respectively. Dice 4
A cutting blade 12 is provided so as to face a gap 11 formed between the ground electrode 5 and the ground electrode 5, and reciprocates by a fluid pressure cylinder 13 and horizontally moves to cut the molded product 2 with the die 4. It has become. The cutting blade 12 is made of ceramic, a material obtained by vapor-depositing ceramic on a non-magnetic metal, or the like, and has a tapered surface 12a on the side of the cut-off portion 14 of the molded product 2. Although the cutting edge is not very sharp, its tip is smooth. Preferably. The cutting blade 12 is formed in the cut shape of the molded product 2.

A high-frequency electrode 15 made of copper is provided on the upper part of the cutting blade 12 on the side of the die 4 and is connected to a high-frequency power source 16, and a high-frequency voltage is applied between the high-frequency electrode 16 and the ground electrode 5 so that the vicinity of the cutting part 17 of the molded product 2 is It is designed for high frequency induction heating. The cutting blade 12 and the high frequency electrode 15 are arranged so as to overlap each other in a shape as shown in FIG.
The cutting blade 12 is adapted to reciprocate along the high frequency electrode 15, and the die 4 and the gap 11 also have shapes corresponding thereto. The earth electrode 5 is connected to the earth 18, and the pedestal 6 is connected to the fluid pressure cylinder 19. 20 is a side guide and 21 is a stopper. 22 is a manufactured molding, 23 is an end portion, and 24 is a cut surface.

The molding 22 is manufactured by extrusion molding a synthetic resin,
A synthetic resin molded product 2 manufactured by injection molding or the like is placed on the cutting device 1 as shown in FIG.
The molded product 2 is clamped by driving the clamp 10 and 8 by driving the clamp 10. At this time, the pedestal 6 and the stopper 21 are positioned by the fluid pressure cylinder 19. Then, a high frequency voltage is applied between the high frequency electrode 15 and the ground electrode 5 to heat the resin near the cut portion 17 of the molded product 2 to a temperature higher than room temperature by high frequency dielectric heating. The resin in the vicinity of the cut portion 17 of the molded product 2 due to high-frequency dielectric heating self-heats to the outer surface 2a, inside
Both 2b are evenly heated to room temperature or higher, but the outer surface
2a is exposed to normal temperature air and is always cooled, so
It becomes lower than 2b. Then, when the inner surface 2b is heated to such an extent that it softens, the outer surface portion 2a has a higher hardness than the inner surface 2b. In this state, when the cutting blade 12 is advanced from the outer surface side by the fluid pressure cylinder 13 as shown in FIG. 5, the outer surface portion 2a
6 has a high hardness, and as shown in FIG. 6, it is pushed by the cutting blade 12 so as to be stretched as it is without being cut or broken, and the resin in the inside 2b moves to the peripheral portion.
At this time, since the tapered surface 12a is formed on the cutting portion 14 side of the cutting blade 12, the resin is extruded along the tapered surface 12a. When the cutting blade 12 is further advanced in this state, the outer surface portion 2a of the cutting portion 17 of the portion to be the molding 22 is deformed into a curved surface while maintaining the appearance continuous with the other portion, and the end portion.
A curved surface portion 23a is formed on 23. In this state, when the cutting blade 12 is horizontally moved toward the excision portion 14 side as shown in FIG. 7, the outer surface portion 2a is cooled by air at room temperature and has a high hardness as described above. As shown in FIG. 7, without being cut or broken by the cutting blade 12, it is stretched as it is, the resin in the inside 2b is pushed and moves to the cutting portion 14 side, and a horizontal surface portion 23b is formed at the end portion 23. . When the cutting blade 12 is further advanced, as shown in FIG.
c is formed. Thus, the molded product 2 is cut with the end portion 23 having a shape in which the curved surface and the horizontal surface are combined and the outer surface portion and the back surface portion are welded, and the molding 22 as shown in FIGS. 9 to 11 is manufactured. It The cutting surface 24 formed by the cutting blade 12 has a back surface portion in a state where the resin of the inside 2b is not exposed to the outer surface side and the outer surface portion 2a and the back surface portion 2c are adhered to each other.
It is formed near 2c and is inconspicuous from the outer surface side. Therefore, even if the cutting surface 24 is not processed with an end cap or the like,
The molding 22 having an excellent appearance is obtained and can be used as it is.

In the above embodiment, the molded product 2 may be an extrusion molded product or an injection molded product, and may have a core material inside or a decorative film on the outer surface. When applied to injection-molded articles, one injection mold can be used to produce moldings having different dimensions or molding shrinkage rates, such as molding articles of different materials. The gap 11 is preferably provided, but it is not always necessary. Further cutting blade
It is preferable to form a lubricious coating of polytetrafluoroethylene resin or the like on the 12 cutting edges. Further, by blowing cold air of a constant temperature onto the cutting edge of the cutting blade 12 and the outer surface portion 2a of the molded article 2 to cool, the temperature of the cutting edge can be prevented from rising, and
This is preferable because the outer surface portion 2a can be surely kept at a lower temperature than the inner portion 2b. The shape of the end portion 23 of the molded product 2 can also be changed to a design shape in which the curvature, shape and the like are changed by changing the combination of the forward movement and the horizontal movement of the cutting blade 12.

〔The invention's effect〕

According to the present invention, a portion of the thermoplastic synthetic resin molded article that is substantially along the cut portion is heated to a temperature higher than room temperature to soften the inside, and the outer surface portion is cut in a state where the hardness is higher than the inside. Move the blade toward the advancing and resecting part to stretch the outer surface without cutting or breaking it, and move the resin inside to the peripheral part to form curved end parts, and to form the outer surface part and the back surface. Since the parts are cut in a welded state, the end of the combined shape of the curved surface and the flat surface or the shape with a variable curvature that has a continuous appearance with other parts is formed and cut. It is possible to manufacture a molding having an excellent appearance by making the surface inconspicuous by a simple operation.

[Brief description of drawings]

FIG. 1 is a front view showing a cutting device of an embodiment, FIG. 2 is a plan view thereof, FIG. 3 is a perspective view of a cutting blade, and FIGS. 4 to 8 show A- in FIG. A sectional view, FIG. 9 is a perspective view of the manufactured molding, FIG. 10 is its BB sectional view, and FIG. 11 is a CC sectional view. In the drawings, the same reference numerals indicate the same or corresponding parts, 2 is a synthetic resin molded product, 2a is an outer surface portion, 2b is an inner portion, 2c is a back surface portion,
3, 6 is a pedestal, 5 is an earth electrode, 7 and 8 are clamps, 12 is a cutting blade, 14 is a cutting part, 15 is a high frequency electrode, 17 is a cutting part, 22 is a molding, 23 is an end part, 24 is a cutting part. The surface.

Claims (3)

[Claims] 1. A method for producing a molding by cutting a part of a molded product molded from a thermoplastic synthetic resin in a shape larger than the final product shape, and a method for manufacturing a molding by cutting a part of the molded product substantially along a cut portion. , The cutting blade is heated to a temperature higher than the other parts and higher than the normal temperature to soften the inside so that the hardness of the outer surface is higher than that of the inside, and the cutting blade is moved from the outer surface side to the back surface side. Along with advancing toward, the cutting blade is moved toward the cut portion side of the molded product before the cutting blade reaches the back surface of the molded product, and the outer surface is stretched without cutting or breaking, and the internal resin is surrounded. A method for manufacturing a molding, in which a molded product is cut off by forming a curved end portion and cutting the outer surface portion and the back surface portion in a welded state. 2. The method according to claim 1, wherein the heating is performed by high-frequency dielectric heating while the outer surface of the synthetic resin molded article is cooled. 3. The method according to claim 1 or 2, wherein the movement toward the cut portion is performed in a direction substantially perpendicular to the cut surface.