JPH09267342A - Press molding apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To dispense with the water hole processing to a mold and to prevent the increase of mold production cost, by providing a temp. regulation member passing a fluid as a temp. medium through the inner of the mold to adjust the temp. of the mold for the press molding of a thermoplastic material. SOLUTION: A lower mold 1 and an upper mold 2 are respectively fixed to a holder 1a and a plate 2a by bolts so as to hold a temp. regulation member 4 therebetween. The temp. regulation member 4 is a plate-shaped material having a three-layered structure consisting of a heat insulating plate 5 arranged on the holder plate 2a, a heat receiving plate 6 with a predetermined thickness superposed on the heat insulting plate 5 and having a plurality of the holes serving as fluid passages 9 therein and an electric heating plate 7 superposed on the heat receiving plate 6 to be brought into contact with the lower mold 1 or the upper mold 2. The temp. regulation plate 4 receives heat from a fluid to be changed in temp. and transmits the heat to the molds 1, 2 to regulate the temps. of the molds 1, 2. Therefore, it is unnecessary to provide a passage allowing the fluid to pass to the molds 1, 2 and, by this constitution, the increase of mold production cost can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a press forming apparatus for press forming a thermoplastic material, particularly a stampable sheet applied to a bumper beam of an automobile.

[0002]

2. Description of the Related Art In recent years, stampable sheets have attracted attention as a lightweight material for automobiles. This is a composite material obtained by mixing glass fiber with resin, and is a thermoplastic material that exhibits fluidity when heated and is press-moldable. It is called a stampable sheet because the state of the semi-finished product before forming is sheet-like.

This stampable sheet (hereinafter referred to as "SP sheet") can be easily formed by a normal press-forming apparatus including a pair of molds. As the forming method, first, a predetermined number of SP sheets corresponding to the product weight are heated outside the mold to a predetermined temperature (about 190 to 210 ° C) and softened to some extent, and then to a predetermined temperature (about 40 to 85 ° C). Pour into a heated mold. When this is pressed with a mold, the SP sheet flows in the mold and is spread into the product shape. After this, the SP sheet is cooled and hardened in the mold, the mold is opened and taken out, and the molded product is completed.

[0004]

In the above method, in order to improve the fluidity of the SP sheet during press molding, it is necessary to preheat the mold and maintain the mold temperature at a predetermined temperature before molding. There is.

For this reason, conventionally, a water hole is formed in the mold, and hot water or cold water is passed through the hole to adjust the temperature of the mold.

However, some molds have a divided structure for reasons such as multi-product production. In this case, water holes must be provided in each of the divided blocks forming the mold, and each water hole must have the same position. Since it is also necessary to communicate with each other, there is a problem that the machining of the water hole is troublesome and the die manufacturing cost increases.

[0007]

SUMMARY OF THE INVENTION The present invention is a press-molding apparatus comprising a mold for press-molding a thermoplastic material, wherein a fluid as a temperature medium is passed through the mold to form the mold. A temperature adjusting member for adjusting the temperature is provided.

In the above structure, the temperature adjusting member receives heat from the fluid to change the temperature, and transfers the heat to the mold to adjust the temperature of the mold. That is, the temperature control of the mold is not directly performed by the fluid but indirectly through the temperature control member. Therefore, the mold need not be provided with a passage for allowing the fluid to pass therethrough, which can prevent an increase in mold manufacturing cost.

[0009]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 shows a press molding apparatus according to the present invention. As shown in the drawing, the press molding apparatus comprises a pair of molds, that is, a lower mold 1 and an upper mold 2. The lower mold 1 is fixed to the holder 1a and does not move, and the upper mold 2 is fixed to the plate 2a so that it can be moved up and down in the vertical direction. The upper die 2 can move closer to and away from the lower die 1, and the SP sheet 3 is moved between the upper die 2 and the lower die 1 by approaching or lowering.
Press-mold. The figure shows a state in which the upper mold 2 is at the bottom dead center and the press molding is completed.

Here, in particular, the lower mold 1 and the upper mold 2 each have a temperature adjusting member 4 between them, and the holder 1 is provided at a portion outside the drawing.
It is fixed to a and the plate 2a with bolts or the like.

The temperature adjusting member 4 includes a heat insulating plate 5 arranged on the holder 1a or the plate 2a, a heat receiving plate 6 having a predetermined thickness, which is superposed on the heat insulating plate 5, and a heat receiving plate 6 which is superposed on the heat receiving plate 6. The heat transfer plate 7 is in contact with the mold 1 or the upper mold 2 to form a plate-shaped member having a three-layer structure. In particular, a fluid passage 9 is defined by a plurality of holes 8 inside the heat receiving plate 6, and a fluid as a temperature medium, here, water is passed through the fluid passage 9. The fluid may be a liquid other than water or a gas such as air.

The hole 8 is formed in the front-back direction of the mold (thickness direction in the drawing).
It can be easily machined by forming a straight line extending to the. Then, for example, the ends of all the holes 8 are communicated or merged with each other, and water having a predetermined temperature is supplied to the entire holes 8 by a pump or the like (not shown). The heat receiving plate 6 receives heat from water, changes in temperature, and transfers the heat to the heat transfer plate 7.
The heat transfer plate 7 is made of a copper plate having a high thermal conductivity, and transfers the received heat to the lower mold 1 or the upper mold 2. Lower mold 1 or upper mold 2
Receives heat on the entire lower surface or upper surface thereof, and is thereby adjusted to a temperature suitable for each step of press molding.

The temperature adjusting member 4 having the above-mentioned structure has a strength that can withstand a pressing load, and in addition, the lower mold 1 is designed to have a strength that can support the weight of the lower mold 1. ing.

Here, the lower mold 1 and the upper mold 2 have a divided structure composed of a plurality of divided blocks 10a. In the lower die 1 in the figure, the die width direction (left and right direction in the figure)
Divided blocks 10a, 10b, 10c, 1 in order from the right side
0d is connected. In the upper mold 2, the divided blocks 11a and 11b are connected in order from the right side in the mold width direction.

These molds 1 and 2 are formed by pressing the SP sheet 3 into a substantially dish shape. In the lower mold 1, rib grooves 12 for forming ribs on the lower surface of the molded product are provided between the divided blocks 10a.

FIG. 2 shows, as an example, the divided blocks 10b,
The rib groove 12 between 10c is expanded and shown. The same configuration is adopted between the other divided blocks 10a. The rib groove 12 is formed into a V-shaped cross section by mechanically cutting the boundary surface between the divided blocks 10b and 10c.

That is, in the divided block 10b, an inclined surface 14b which is almost vertical is cut at the upper end of the boundary surface 13b, and the divided block 10c is formed in the upper end of the boundary surface 13c with the inclined surface 14c and the lower end thereof. Part 1 that is continuous with
5c is cut. And the boundary surface 1 of each other
The rib groove 12 is completed by joining 3b and 13c. Here, a very small gap is formed between the boundary surfaces 13b and 13c, so that gas is released during rib formation and, at the same time, the SP sheet 3 is prevented from flowing out. In addition, the lower part of the boundary surface 13c of the divided block 10c is also cut into a slightly concave shape so that gas can be discharged from the gap formed by this.

Next, as for the upper mold 2, as shown in FIG. 1, the rib groove as described above is not provided between the divided blocks 11a and 11b. The boundary surfaces 16a and 16b between the divided blocks 11a and 11b are simply flat joint surfaces. The positions of these boundary surfaces 16a and 16b are aligned with the boundary surfaces of the divided blocks 10a and 10b of the lower mold 1 in the mold width direction.

Particularly, the rightmost divided blocks 10a and 11a
Since the SP sheet 3 is formed in a curved shape directed downward between them, the divided block 11a of the upper mold 2 has a vertical portion 17 which is superposed on the divided block 10a of the lower mold 1 from the outside. There is.

Next, the operation of this mode will be described.

In the above embodiment, the lower mold 1 and the upper mold 2
Is composed of a plurality of divided blocks 10a ..., 11a ..., so that by removing any of the divided blocks 10a. It is possible to easily manufacture a molded product having a different shape.

For example, as shown in FIG. 3, if the divided blocks 10a and 11a located at the right end are removed and another divided block 11c is attached instead of the divided block 11a, a plate-shaped molded article can be manufactured. . At this time, the vertical portion 18c of the divided block 11c contacts the right boundary surface 18b of the divided block 10b to form a rib on the right end of the molded product.

As described above, since it is not necessary to replace the entire mold when molding another part, and only a part of the mold can be recombined for partial punching, so that the mold can be handled. As the capacity is increased, the work of changing the mold can be facilitated and the work time can be shortened. Moreover, since it is not necessary to individually manufacture the entire mold for each part, it is possible to prevent an increase in mold manufacturing cost due to an increase in the number of parts. Then, by using a mold material having a minimum required size in accordance with the shape of the divided blocks, the cutting allowance can be suppressed to a minimum, which can suppress an increase in the mold material and the processing cost.

In particular, in the above embodiment, since the lower die 1 is divided at the position of the rib groove 12, it is possible to easily obtain the rib groove 12 by mechanically cutting the divided blocks 10a. The processing cost of 12 can also be reduced. That is, in the conventional integrated type, the rib groove is formed by performing the electric discharge machining on the surface of the die, but since the depth dimension of the rib groove is relatively large,
The processing required a long time. According to such machining, the machining is facilitated and the machining time can be greatly shortened, whereby the machining cost of the rib groove can be reduced. By the way, in order to control the temperature of such a divided structure mold,
Conventionally, water holes are individually provided in each divided block. However, in this case, it was necessary to align the positions of the water holes between the divided blocks, and it was troublesome to process the water holes. Further, it is necessary to allow water to pass between the water holes without leaking, and it is troublesome to process the joint. And furthermore,
Water holes have to be provided at various positions according to the shape of the mold, and the position, shape, etc. of the water holes are complicated, and there is a problem that the mold manufacturing cost increases.

Therefore, in such a configuration, the divided blocks 10a ..., 11a ... Are not provided with water holes, but instead the lower mold 1 and the upper mold 2 are provided with the temperature adjusting members 4, and the temperature adjusting members 4 are provided. The temperature of the molds 1 and 2 is indirectly adjusted via the temperature adjusting member 4 by being hung over and brought into contact with each of the divided blocks 10a. As a result, it is possible to prevent an increase in die manufacturing cost, and at the same time, it is not necessary to align the water holes at the time of reassembling the die.

In this embodiment, since the temperature adjusting member 4 is laid on the entire bottom surface of each of the divided blocks 10a ..., 11a ..., Each of the divided blocks 10a.
Since the temperature distribution in the height direction of ... can be made substantially uniform and the temperature of the molding surface can also be made substantially uniform, molding defects and the like due to temperature differences can be prevented in advance. In this case, the molded product is preferably a flat part whose height dimension (indicated by H in FIG. 1) is as small as possible, and at most 100 m.
It is preferably m or less. The mold temperature is preferably 85 ° C or lower.

Further, since the hole 8 as a water hole is provided inside the temperature adjusting member 4, the hole shape can be set independently of the shape of the mold, and for example, as described above, the hole shape can be a straight line which is easy to process. . The hole shape and the number of holes can be changed appropriately.

Although the preferred embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and various other embodiments are possible. For example, the temperature adjusting member is provided on the side of the mold. You can also Further, the above embodiment is an application example to the SP sheet, but the present invention can be applied to any thermoplastic material such as resin or plastic material.

[0030]

The present invention exhibits the following excellent effects.

(1) It is not necessary to provide a water hole in the mold, and an increase in mold manufacturing cost can be prevented.

(2) It is possible to easily change the mold type in a short time.

[0033]

[Brief description of drawings]

FIG. 1 is a vertical sectional front view of a press molding apparatus according to the present invention.

FIG. 2 is an enlarged vertical front view showing a rib groove.

FIG. 3 is a vertical sectional front view showing the mold after the rearrangement.

[Explanation of symbols]

1 Lower mold 2 Upper mold 3 Stampable sheet (thermoplastic material) 4 Temperature control member 10a, 10b, 10c, 10d, 11a, 11b, 1
1c division block

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Claims (2)

[Claims] 1. A press molding apparatus comprising a mold for press-molding a thermoplastic material, the temperature adjustment for controlling the temperature of the mold by allowing a fluid as a temperature medium to pass through the mold. A press forming apparatus characterized in that a member is provided. 2. The press molding apparatus according to claim 1, wherein the mold comprises a plurality of divided blocks.