JPS60193623A - Changing method of resin and color for injection molding machine - Google Patents

Abstract

PURPOSE:To change a resin and a color thereof rapidly, and to reduce a wasteful resin for a color change by repeating the forward movement and stoppage of a screw in a short time, disturbing the flow of the resin and giving impacts. CONSTITUTION:A new resin is charged into a hopper 1, a screw 7 is turned only by a predetermined stroke, and the resin is plasticized. The operation of the forward movement A, stoppage, forward movement A and stoppage of the screw is repeated several times. In this case, the screw 7 is not turned, a distance in which the screw forward moves once is set, and the screw is made to reach to the limit of forward movement several times. The screw 7 reaches to the limit of forward movement, the screw 7 is rotated again and the resin is plasticized, and the above-mentioned stroke is repeated. Consequently, the flow of the resin is disturbed by repeating the forward movement and stoppage of the screw in a short time, and impacts are given. Accordingly, the resin adhering on the screw and a cylinder is peeled off, the resin and a color can be changed rapidly, and the amount of wasteful resin is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION When changing the resin or changing the color in an injection molding machine, the following method is generally used, and this can be done manually or automatically.

The conventional resin change and color change will be explained with reference to FIG. 1. First, all the resin in the bosoba 1 is removed using the discharge port 2. Further, the resin remaining in the screw cylinder 3 that has been used for molding until now is removed by repeating screw rotation and injection. Next, new resin is put into hopper 1, and the screw rotation, plasticization, and injection are repeated until the resin and color change.

However, the general injection molding machine shown in Fig. 1 has a structure in which turbulence does not easily occur in the flow of resin, so the resin 10 between the taper part 8 of the end camp 4 and the taper part 9 of the screw is replaced with new resin. There were drawbacks that made it difficult to replace.

Further, since the check ring portion 5 has a complicated flow path, there is a drawback that the resin surrounded by the screw head 6 and the check ring 5 and the resin 11 attached to the wall are difficult to replace with new resin.

The present invention has been proposed in order to eliminate the above-mentioned drawbacks of the conventional method, and its purpose is to quickly change colors and reduce the amount of wasted resin used for color changes.

To achieve this objective, the present invention rapidly advances and stops the screw, disrupting the flow of the resin and applying impact, thereby quickly changing the resin and color, and reducing wasted resin. The purpose of the present invention is to provide a method for changing resin and color in an injection molding machine, which can be carried out by changing the resin and color of an injection molding machine.

Embodiments of the present invention will be described below based on the injection molding machine shown in the drawings.When changing resin and changing colors, operations are performed in the following manner. Note that the method of the present invention can be performed manually or automatically.

First, in FIG. 1, new resin is put into the hopper 1, and then the DJ screw 7 is rotated by a predetermined stroke to plasticize the resin.

This stroke setting can also be done using a limit switch, potentiometer, encoder, timer, etc.

Next, in one injection stroke, the operation of advancing the screw 7, stopping it, moving it forward A, and stopping it is repeated several times.

Note that the screw 7 does not rotate at this time. At this time, set the distance to move forward at one time, and reach the forward limit in several times. Note that the distance traveled in one movement can be set using a limit switch, an encoder, a potentiometer, a timer, etc.

Next, after the screw 7 reaches its forward limit, the screw 7
Rotate to effect plasticization and repeat the above process. Note that B indicates the backward direction. Reference numeral 11 denotes a resin portion surrounded by the check ring portion 5 and the check ring portion 12 of the screw head 6.

As described above, according to the present invention, by repeatedly advancing and stopping the screw in a short period of time, the resin flow is removed by repeatedly advancing and stopping the screw in a short time. By disturbing and applying impact, resin adhering to screws and cylinders can be peeled off, allowing for rapid resin and color changes.

In the case of the embodiment described above, the screw is not rotating during the repeated movement of advancing and stopping the screw during the injection stroke, but the screw is rotated during the repeated movement of advancing and stopping the screw. In this case, shearing in the circumferential direction is added, making it possible to change colors even more effectively.

Furthermore, by rotating the screw only while the screw is moving forward or stopping, and applying an impact to the movement in the circumferential direction, effective resin and color changes are possible. Furthermore, after the screw reaches its forward limit, rotate the screw for the set time while applying force F to the screw to push it forward, then release the rear F,
If a method of plasticizing by rotating the screw is used in combination, it will be even more effective.

[Brief explanation of drawings]

The drawing is a side sectional view of a conventional general injection molding machine screw section. Explanation of the main parts of the diagram 1 - Hopper 3 - Screw cylinder 7 - Screw A - Forward direction Applicant Mitsubishi Heavy Industries, Ltd. Chuubishi Engineering Co., Ltd.

Claims (1)

[Claims] In an injection molding machine, the screw advances and stops repeatedly in a short period of time, disrupting the flow of resin and applying impact.
A method for changing resin and color for an injection molding machine, which is characterized by quickly changing resin and color.