JPH01295809A - Manufacture of grooved molding - Google Patents

Abstract

PURPOSE:To shorten the manufacturing process of a grooved molding and improve the strength of its grooved portion, by molding and processing integrally the grooved portion and the other portion. CONSTITUTION:Molten resin A is injected into a space S in a mold 15 and held in the pressed state for a specific time. In this case, the grooved portion on the outer periphery of a tray is formed by ring bodies 9a, 9b having projected section formed on split molds 8a, 8b. Next, molds 2, 7 are cooled for a specified time to solidify the molten resin, and then a mounting plate of movable side 4, a backing plate 6, a mold of movable side 7 and split blocks 8a, 8b move integrally to the direction indicated by arrow 20 to open said molds 2, 7. Then, said ring bodies 9a, 9b of the block in the groove of the molding is released. In this state, the bottom face of a molding 21 is pushed by a pushing rod and the molding 21 falls down from the mold 7 of movable side.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for manufacturing a molded article having grooves.

[Conventional technology]

A tray (T1) on which a bobbin (B) is placed and transported to a desired processing position as shown in FIG. 9 is well known. That is,
The tray (T1) is a disc-shaped base (30), a bobbin support stand (31) formed at the center of the machine, and a bobbin insertion peg (32) molded into one body using a resin material. It is publicly known. (33) is an air passage hole.

A bobbin (B) is inserted into such a tray (T1), and the guide plate (35) (3
5) It is transported to a desired position while its direction of movement is regulated by.

In addition, as a tray that can be easily adapted to the recent high-mix, low-volume production system, there is a tray (T2) having I (36) shown in FIGS. 7 and 8. That is, the groove (36)
The tray transfer direction is changed depending on the presence or absence of the groove (
36) A gauge plate that can be entered inside is fixed on the branching path, and the tray with grooves is displaced toward the gauge side, and the tray without grooves is pushed by the gauge and attempts to change its course.The type of tray is detected by an electric sensor. It is effective in that it can be distinguished without using .

[Problem to be solved by the invention]

The above-mentioned grooved tray (T2) is the above-mentioned grooveless tray (T2).
It is injection molded using the same molding machine as T1), and the grooved tray (T2) further feeds the molded product to the groove processing process.
Grooves (3
6) is machined. However, in injection molding, vacuum voids, ie, cavities, may occur inside the mold while the molten synthetic resin is injected into a certain space formed by a mold and cooled and fixed. As shown in Figure 10, the surface layer (38) (39), that is, the surface layer that is in contact with the mold, solidifies first, so when the center solidifies and contracts, the surface layer does not deform and there is a vacuum in the center. A space called a nest (40
) occurs.

Therefore, as shown in Fig. 10, an injection molded tray (T1
) may also have a cavity (40), and by cutting the groove (36), this cavity will be exposed on the groove surface.

In particular, if the nest portion is exposed at a corner portion (41), the tray is likely to become jammed, reducing the strength of the tray itself.

In addition, the surface layer of a molded product generally has a hardened layer that is harder than the inside, and cutting this hardened layer exposes the inner layer, which is less hard, so cutting in the post-process of the molded product is extremely difficult. It's not convenient.

Furthermore, the cutting process itself increases the number of manufacturing steps by one, which may cause errors in groove position, dimensions, etc., or increase costs.

The present invention aims to solve the above problems.

[Means to solve the problem]

The present invention is a method for manufacturing a grooved molded product, in which the groove portion and other portions are integrally molded.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows the mold structure of the molding machine, and shows the mold for the grooved tray. The fixed side is composed of a fixed side mounting plate (1), a fixed side mold (2), and angular pins (3a) (3b).

The movable side has a movable mounting plate (4), spacer blocks (5a) (5b) fixed on the mounting plate (4), and a receiving plate (6) fixed on the blocks (5a) (5b). )
, a movable mold (7) fixed on the receiving plate (6), and a split mold block (8a) that can be slid vertically in the case of Fig. 1 by means of the angular pins (3a) and (3b). (8b) etc. The above mold (2
) (7) forms a certain closed space (S) for tray formation, and split mold blocks (8a) (8
b) A ring body (9a) with a convex cross section formed in (
9b) A groove portion on the outer peripheral surface of the tray is formed. (10) is an eject plate, and the molded product is released from the movable mold (7) and falls by the protrusion of a protruding rod (11) fixed on the plate. (12) is the return pin of the ejector plate (10). (13) (
14) is a cooling water passage for facilitating mold release of the molded product.

The split blocks (8a>(8b) above) can be replaced depending on the type of groove in the tray, and each block
(8a) (8b) are the sliding surface (6) of the receiving plate (6).
a) (6b), and has an inclined hole through which the angular pins (3a) and (3b) pass.

Next, a process of molding a tray using a molding machine equipped with the above mold will be described.

The molding process is shown in FIGS. 2 to 6. In FIG. 2, a mold (15) matching the tray shape is set. The resin pellets (P) (P), which are introduced from the hopper (16) into the heater (17), are melted and moved forward by the rotation of the plasticizer U=-(18), and when plasticization is completed, the screw (P)
8) rotation is stopped. Subsequently, as shown in Fig. 3, the fluid cylinder (19) operates and the screw (18) moves forward, injecting the molten resin (A) in the heater into the space (S) in the mold (15). , the pressurized state is maintained for a certain period of time.

This state is shown in FIG. Next, the molds (2) and (7) are cooled for a certain period of time, and when the molten resin solidifies, the screw (18) rotates and retreats as shown in Fig. 4, and the movable side mounting plate (4), receiving plate (6), The movable side mold (7) and the split mold blocks (8a) (8b) move together in the direction of the arrow (20), and the molds (2) (7) are opened. At this time, the molded product (21) moves integrally with the movable mold (7), and the split mold blocks (8a) (8b) are regulated by the angular pins (3a) (3b). 1
The ring bodies (9a) and (9b) of the block moved from the state shown in the figure to the state shown in FIG. 6, and which were in the groove of the molded product, are released from the mold. In this state, the ejector play shown in the first diagram) (10)
The protruding rod (11) integrated with (10) pushes the bottom of the molded product (21) and moves the molded product (21) from the movable mold (7) to the position shown in Fig. 4. Let it fall like that.

The molded product (21) manufactured in this way is removed from unnecessary parts, and holes at the tips of the pegs (FIG. 7 (33)) are bored to form a completed grooved tray (T3).

FIG. 12 shows a tray (T
3) shows a cross-sectional view. In other words, by integrally molding the groove part (22) with the other parts (30), (31), and (32), the cavities that conventionally occur will not be exposed on the surface surface, and therefore the fracture strength in the groove part will be increased. Upload to width. According to experiments, the strength of the groove in the tray according to the present invention is 1.45 times greater than that of a tray molded from the same material in which the groove is cut and the bottom of the groove is not rounded (23), that is, there is no chamfering. Moreover, the strength of the tray of the present invention was 1.1 times that of a tray in which the grooves were cut and the bottoms of the grooves were rounded.

Furthermore, as shown in FIG. 12, a hard surface called a skin layer (24) is formed on the surface layer of the injection molded tray.
In particular, since both surfaces (24a) and (24b) of the groove (22) form a skin layer, the wear caused by the metal gauge plate that enters the groove when the tray is used is greatly reduced compared to a cut groove.

〔Effect of the invention〕

As described above, in the present invention, the groove is formed by integral molding with other parts without cutting only the groove part of the molded product, so the manufacturing process is shortened, and
The strength of the groove portion can also be improved, and the life of the product can be greatly extended.

[Brief explanation of the drawing]

Figure 1 is a sectional view of a mold for carrying out the method of the present invention, Figures 2 to 4 are schematic diagrams showing the principle of injection molding, and Figure 5 is a state in which molten resin is injected into the mold. A cross-sectional view showing
Fig. 6 is a sectional view showing the mold in an open state, Fig. 7 is a sectional front view of the grooved tray, Fig. 8 is a perspective view thereof, and Fig. 9 is a sectional front view showing the non-grooved tray in use. , FIG. 10 is a half-sectional view of an injection-molded tray without grooves, and FIG. 11 is a half-sectional view showing the tray in FIG. 10 with grooves cut.
FIG. 12 is a half-sectional view of a grooved tray manufactured according to the present invention. (2) Fixed side mold (7) Movable side mold (8a) (8b) Split mold block (9a) (9
b) Ring body (21) Molded product (22) Groove portion (73) -, -) Ray

Claims (1)

[Scope of Claims] A method for manufacturing a molded product with grooves, characterized in that the groove portion and other portions are integrally and simultaneously molded.