JPH0562569B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <<Industrial Application Field>> The present invention relates to a method for molding a powder slush, and more particularly to a method for molding a molded article with as uniform a thickness as possible.

<<Prior art>> As shown in FIGS. 4a and 4b, a molding device used in the powder slush molding method includes a powder box 1 containing thermoplastic resin powder P.
and a mold 2, such as an electroforming mold, which has the upper opening of the powder box 1 fixed in the shape of a cold oval.

The molding order using this device is as follows.

The mold 2 is heated in advance and set on the box 1, and by rotating the box 1, the powder P moves, contacts the inner surface of the mold 2 and melts, and then cools down. It solidifies while remaining attached.

In this state, mold 2 is removed from box 1 and the resin adhering to the inner surface is peeled off to obtain a resin molded product that follows the mold surface shape of mold 2, making it relatively soft. This is a method adopted as a molding method for resin molded bodies.

<<Problems to be Solved by the Invention>> However, this molding method has a drawback in that the wall thickness varies depending on the flow direction of the resin powder P when the box 1 is rotated.

For example, when box 1 is rotated clockwise as shown in the figure, powder P comes into contact with point A on the surface of the mold due to flow, and then moves to point B as the rotation angle changes. However, in this case, due to the difference in contact time, the thickness of the area A is thick and the thickness of the area B is thin, and the thickness is unevenly distributed due to the shape of the mold surface. This has become noticeable and has the disadvantage of being difficult to adjust.

This invention solves the above-mentioned problems by minimizing the time difference in the contact of the powder with the mold surface during rotation, and by bringing the powder into contact with the mold surface at the same time as possible at each location, uneven distribution of wall thickness can be prevented. It is an object of the present invention to provide a powder slush molding method that eliminates the need for powder slush and allows molded bodies of uniform thickness to be obtained.

<<Means for Solving the Problems>> In order to achieve the above object, the molding method of the present invention includes a powder box containing thermoplastic resin powder, and a molding method in which the upper opening of the powder box is fixed in a cold shape. By rotating the powder box, the powder is brought into contact with the heated inner surface of the mold and melted, thereby making it possible to obtain a resin molded body having a shape that follows the shape of the mold. In the powder slush molding method, a plurality of partition plates whose lengths and angles can be adjusted are provided inside the powder box toward the mold surface of the mold.

≪Operation≫ When the powder box is rotated, the powder stored inside it flows while being divided by each partition plate, and falls to each part of the mold surface through the partition plates, so the time due to the flow is reduced, It is possible to eliminate uneven distribution of the amount of powder deposited depending on the direction of rotation.

<<Example>> Hereinafter, an example of the method of this invention will be described in detail using the drawings.

1a to 1e show a first embodiment of the invention. The figure illustrates a case where the method of the present invention is applied to the skin of an integrally molded door trim, and the inner surface of a mold 2 such as an electroforming mold is molded into the curved shape of the door trim.

Further, the inside of the powder box 1 is filled with a powder P made of a thermoplastic resin such as vinyl chloride powder.

Further, inside the box 1, there are provided a plurality of partition plates 10 which are arranged diagonally in the vertical direction when the box 1 is stopped rotating, and the upper ends of the partition plates 10 are opposed to various parts of the mold surface of the mold 2.

The angle of each partition plate 10 can be adjusted from the outside via a pin 12, and the inclination angle can be adjusted according to the rotation speed.

Next, a slush molding method using the above molding apparatus will be explained.

First, the mold 2 is heated in advance to a temperature higher than the melting point of the powder P.

Then, after attaching the mold 2 to the upper surface of the box 1 and sealing the inside, when the box 1 is rotated clockwise from the molding preparation state shown in a, the powder P is first dislodged as shown in b. It flows and rides on each partition plate 10.

When the box 1 is tilted almost vertically due to continued rotation, the powder P placed in a divided state on each partition plate 10 begins to slide according to the respective tilt angles, as shown in c, and then rotates. As shown in d, the particles fall onto various parts of the mold surface of the mold 2 in a divided state as shown in d.

Therefore, the supply time difference of the powder P to each part of the mold surface of the mold 2 is averaged, and the molding thickness of each part is averaged.

That is, the powder P falling through each partition plate 10 comes into contact with the heated mold surface almost simultaneously, melts, and adheres to the mold surface, so that the thickness of the molded product taken out after molding is It is uniform regardless of direction.

When the molding is completed, that is, one rotation is completed, the remaining powder P flows back through the partition plate 10, is biased to one side depending on the direction of rotation, and accumulates inside the box 1 at an oblique level, as shown in e. Therefore, the molding completion box 1 is swung, and the a
The same molding operation may be repeated after adjusting to the horizontal level as shown in the figure.

Note that this time difference adjustment of the amount of adhesion is related to the rotational speed of the box 1 and the degree of inclination of the partition plate 10 with respect to the fluidity of the powder P, so the degree of inclination of the partition plate 10 is adjusted according to the rotational speed to achieve the target thickness. The inclination angle may be fixed to provide the most uniform thickness.

FIG. 2 shows a second embodiment of the invention.

In this embodiment, the length of each partition plate 20 is sequentially shortened in the direction of rotation, and by changing the length sequentially in this way, the unevenness of the remaining powder P after one rotation in the clockwise direction can be reduced. This eliminates the need for level adjustment for each molding.

FIG. 3 shows a third embodiment of the present invention. In this embodiment, the lengths of each partition plate 30 are sequentially shortened as in the second embodiment. A wall portion 32 for preventing backflow is provided protruding from the bottom. And each partition plate 30
The powder P filled between the two flows backward at the initial stage of rotation and tries to fall to the box 1 side, but
Since it is stopped by the wall portion 32, a constant amount of powder P can be supplied to each part of the mold surface.

≪Effects of the Invention≫ As explained in detail through the embodiments above, in the powder slush forming method according to the present invention, when the powder box is rotated, the powder stored therein is transferred to each partition plate. Since the powder flows in a partitioned state and falls to each part of the mold surface through the partition plate, the time difference due to the flow is alleviated, and uneven distribution of powder adhesion depending on the direction of rotation can be eliminated, and the thickness of the molded object is reduced. The thickness can be made uniform in each part, allowing for highly accurate molding.

[Brief explanation of the drawing]

1A to 1E are explanatory sectional views showing a first embodiment of the present invention, FIG. 2 is an explanatory sectional view showing a second embodiment of the invention, and FIG. 3 is an explanatory sectional view showing a third embodiment of the invention. FIGS. 4a and 4b are explanatory sectional views showing a conventional powder slush forming method. 1... Powder box, 2... Molding mold, 1
0, 20, 30...Partition plate, P...Powder.

Claims (1)

[Claims] 1. A powder box containing thermoplastic resin powder and a mold fixed to the powder box with its upper opening closed, the powder being heated by rotating the powder box. In a powder slush molding method in which a resin molded body having a shape that follows the shape of a mold is obtained by contacting the inner surface and melting, a powder slush is placed inside the powder box toward the mold surface of the mold. A powder slush forming method characterized by providing a plurality of partition plates whose lengths and angles are adjustable.