JP2678721B2 - Method for molding thermoplastic substrate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a method for molding a thermoplastic base material in which melting, feeding and press molding of a base material are continuously carried out.

[0002]

2. Description of the Related Art For example, Japanese Patent Publication No. 4-5524 discloses that
As shown in FIG. 5, after heating, kneading, and melting the base material with the extruder 51, the required amount is temporarily stored in the measuring cylinder 52, and the molten base material is transferred from the measuring cylinder 52 to the joint arm 53. Through the die 55, and then the material is discharged from the die 55, and the molten base material 63 is placed on the lower molding die 62 in a predetermined pattern. A method of molding a thermoplastic substrate for clamping 62 is disclosed.

The joint arm 53 has its base end side fixed to the measuring cylinder 52, and the die 55 is fixed to the tip end portion of the arm 53. As described above, the molten base material is transferred from the die 55 to the lower molding die 62. When supplying, the measuring cylinder 52 is moved by the pulse motor 54 in a plane substantially parallel to the upper surface of the lower molding die 62. This allows the die 55
As shown in FIG. 5, it rushes between the upper and lower molds 61 and 62, and this die 55 moves above the lower mold 62 in a plane substantially parallel to the upper surface of the mold 62, and at this time, The molten base material is supplied to the die 55 by the operation of the cylinder 52,
The molten base material 63 is supplied from the die 55 onto the lower mold 62.

[0004]

However, in such a molding method, in order to improve the production efficiency, for example, as shown in FIG.
When A and 62B are set to produce two products at the same time, it is necessary to move the die 55 in the direction indicated by the arrow in the figure.

In this case, the moving distance of the die 55 is more than twice as long as in the case of molding with a single molding die, and the molding cycle time is extended by that amount, so that a significant improvement in production efficiency cannot be expected. Moreover, when the die is clamped by the press, the molten base material 63 placed on the first forming die 62A.
It is expected that there will be a large difference in the resin temperature between the first part of A and the last part of the molten base material 63B placed on the second molding die 62B, and there will be variations in the physical properties of the product.

Further, in this molding method, the measuring cylinder 5
Even when 2 discharges a predetermined amount of the molten base material from the die and the measuring cylinder 52 retracts, the joint arm 53 and the die 55 are all filled with the molten base material. . Therefore, in the conventional molding method, the die 55
When a predetermined amount of molten base material was discharged from the die, a guillotine-type blade provided on the end face of the die opening was used to cut the flow of the molten base material and close the opening. It was difficult to completely cut the substrate material, and the molten substrate material sometimes remained attached to the blade. In this case, as the die 55 moves, the molten base material is stretched and falls out of the lower molding die, so a great deal of labor is required for its cleaning work.

An object of the present invention is to provide a method for molding a thermoplastic base material which eliminates the above-mentioned conventional drawbacks.

[0008]

In order to achieve the above-mentioned object, the present invention heats, kneads, and melts a base material with an extrusion molding machine, and then temporarily stores a required amount in a measuring cylinder and melts the molten base. Material The material is supplied from the measuring cylinder to the die through the joint arm, discharged from the die, placed on the lower mold in a predetermined pattern, and then the upper and lower molds of the press are clamped. In the molding method, the molten base material is split inside the die, guided to each cavity while adjusting the flow rate with a control valve provided in each flow path, and discharged from each die through the manifold and land of the cavity. After that, a method of molding a thermoplastic base material is proposed in which the die opening is closed by a rotary stopper provided at the tip of the land.

[0009]

In the method for molding a thermoplastic base material of the present invention, the molten base material can be placed on a plurality of lower molds at the same time, and the molding cycle time is set on a single lower mold. This is the same as in the case, and the temperature difference between the molds of the placed molten base material is reduced to such an extent that there is no practical problem.

After discharging a predetermined amount of molten base material,
The rotating stopper provided at the tip of the land cuts the flow of the molten base material and closes the die opening to stop the discharge, so the molten base material adheres to the die opening and moves the die. At the same time, the problem of being stretched and falling out of the lower mold does not occur.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will now be described in detail with reference to the drawings. The basic construction and operation of this embodiment will be described in the section "Prior Art" with reference to FIG. There is no difference from what has been described, so a description thereof will be omitted.

FIG. 1 is a view showing a cross section of a die 55 used in the method for molding a thermoplastic substrate according to the present invention when it is horizontally cut, and FIG. 2 is a sectional view taken along line AA of FIG. It is sectional drawing seen in the arrow direction. In this example, a case where the molten base material is supplied to two lower molds 41, 41 having the same shape is shown. Although not shown in the drawings, the outer surface and the inside of the die 55 are maintained at a predetermined temperature by a plate heater and a cartridge heater (not shown). Unlike the conventional die shown in FIGS. 5 and 6, the die 55 shown here is configured as follows.

When the molten base material is supplied to the lower molding dies 41, 41, the molten base material that has flowed in the flow path having a circular cross section in the joint arm 53 by the operation of the measuring cylinder is left and right in the die 55. Branched to. Different from the inside of the T-joint of a general pipe, a branch pin 11 having a conical tip projects into the flow path at this branch point so that the molten base material can be smoothly split left and right. The flow-divided molten base material is partially blocked by a control valve 21 provided in each flow path 12 so that the left and right flow rates are adjusted to be the same. The flow rate of each control valve 21 is adjusted by rotating the adjustment bolt 22.

The molten base material that has passed through the control valve 21 is guided downward by the sleeves 23 inserted in the respective flow paths 12. Since the tip end surface of each sleeve 23 is a curved curved surface, the molten base material is smoothly introduced into each cavity 30. In this way, the molten base material is
The flow is divided inside the die 55, and the flow is guided to each cavity 30 while the flow rate is adjusted by the control valve 21 provided in each flow path 12.

The molten base material in each cavity 30 is first spread by a manifold 31 having a circular cross section to a width corresponding to the width dimension of the die opening, and then by lands 32 consisting of parallel planes with narrow intervals. In the embodiment, the discharge product from the die is rectified so as to form a sheet-like pattern. As described above, the molten base material passes through the manifold 31 and the land 32 of each cavity 30, and then passes through the die opening 3 of the die 55.
8 (FIG. 3) and is supplied onto each of the lower molding dies 41, 41.

As can be seen from FIG. 3, which is a sectional view taken along the line BB of FIG. 2, a cylindrical shape is formed in the end edge of each land 32 by forming a slit 36 corresponding to the thickness and length of the land 32 in the center. Stoppers 35 are provided respectively. 2 and 3, the stopper 35 is shown in a closed state. The stopper 35 can be rotated by a driving device (not shown) to cut the flow of the molten base material and close the die opening 38 to prevent the molten base material from dripping. In this way, after the molten base material is discharged from the die 55, the die opening 38 is closed by the rotary stopper 35 provided at the tip of the land 32. The cutting method using this stopper 35 is Then, unlike the conventional guillotine method, the molten base material is not cut, and the material does not stick to the blade.

Since the die opening 38 is opened in a fan shape as shown in FIG. 3, the molten base material cut by the stopper 35 does not adhere to the die tip edge 37, and the forming dies 41, 41 are formed. It is placed in a predetermined position above. The molten base material placed on each of the lower molds 41, 41 is shown in FIG. 4 with reference numerals 42, 42. Such base material 42,
The mold 42 is molded by clamping the upper and lower molds of the press 56, which is no different from the conventional one (see FIG. 5).

According to the molding method of the above-described embodiment, as the locus is shown by the arrow in FIG. 4, the movement of the die 55 is only a simple forward / backward reciprocation, so the molding cycle time is 1
Although the required time is the same as when the number of pieces is 2, the production efficiency is increased because the number of pieces is 2 pieces. The difference in weight between the left and right molded products manufactured in this manner is 1% by weight or less, which is within a range that causes no practical problem.

In the above embodiment, two identical molding dies 4 are used.
In the case of manufacturing the same product with 1, 41, each flow path 12
In addition to the adjustment of the adjusting valve 21 provided in the above, the conical tip of the flow dividing pin 11 is biased, the tip shapes of the left and right sleeves 23 are changed, and the closing timing of the two stoppers 35 is adjusted to obtain different shapes. It is also possible to feed the two lower molds with different weights and different patterns of molten base material.

Further, a molten base material is supplied from a plurality of die openings 38 onto a single lower mold to mold the molten base material, and the molten base material is partially different in thickness or partially provided with ribs. It is also possible to manufacture molded products having different weight distributions. Further, the molten base material is diverted into three or more flow passages, or a through hole is provided in the flow dividing pin to partially pass the molten base material to form a flow passage, and a predetermined amount is provided from three or more die openings. It is also possible to discharge.

In the above embodiments, the method of molding a single layer base material is shown. However, as disclosed in the above Japanese Patent Publication No. 4-5524, the skin layer material is placed between the upper and lower molds. Positioning or vacuum forming with the upper mold, placing the molten base material on the lower mold, and then applying the method to simultaneously manufacture multiple composite compacts that clamp the upper and lower molds. You can

[0022]

According to the method for molding a thermoplastic base material of the present invention, the molten base material can be simultaneously placed on a plurality of lower molding dies, and the molding cycle time is one lower molding die. Since it is no different from the case of mounting on, the molding efficiency can be improved.

Further, the temperature difference between the molds of the molten base material before press molding is reduced as compared with the method of sequentially placing the molds on a plurality of molds, so that there is no change in the physical properties of the molded product by the molds. .

Further, after discharging a predetermined amount of the molten base material, the die opening is closed by the rotary stopper provided at the tip of the land to stop the discharging, so that the molten resin adheres to the die and the die It will not be stretched as it moves and will not fall out of the lower mold.

[Brief description of the drawings]

FIG. 1 is a view showing a cross section obtained by horizontally cutting a die used in the method for molding a thermoplastic substrate of the present invention.

FIG. 2 is a cross-sectional view of a cross section taken along line AA of FIG. 1 as seen in the direction of the arrow.

FIG. 3 is a cross-sectional view of a section taken along the line BB of FIG. 2 as seen in the direction of the arrow.

FIG. 4 is a plan view illustrating a locus of movement of a die according to the embodiment of the present invention.

FIG. 5 is a side view of essential parts showing an example of a thermoplastic substrate molding apparatus that continuously performs melting, supply, and press molding of a base material.

FIG. 6 is a plan view illustrating a locus of movement of a die in a conventional example.

[Explanation of symbols]

 12 flow path 21 control valve 30 cavity 31 manifold 32 land 35 stopper 38 die opening 41 lower molding die 42 molten base material 51 extrusion molding machine 52 measuring cylinder 53 joint arm 55 die 56 press 61 upper molding die 62 lower molding die 63 Molten base material

Claims (1)

(57) [Claims] 1. A base material is heated by an extruder, kneaded, and melted, and then a required amount is temporarily stored in a measuring cylinder, and the molten base material is supplied from a measuring cylinder to a die through a joint arm. , Discharged from the die, after being placed on the lower mold in a predetermined pattern, in the molding method of the thermoplastic substrate in which the upper and lower molds of the press are clamped, the molten substrate material is diverted inside the die, It is guided to each cavity while adjusting the flow rate with the control valve provided in each flow path, discharged from the die through the manifold and land of the cavity, and then the die opening is made with the rotary stopper provided at the tip of the land. 1. A method for molding a thermoplastic substrate, which comprises closing.