JPH03211027A - Injection molding machine - Google Patents

Abstract

PURPOSE:To improve quality by feeding always resin to a fixed position of a screw and making plasticization uniform, by a method wherein a partition plate, which covers a resin loading port provided on a heating cylinder of an inline screw type injection molding machine, interlocks with a movement of the screw and possesses a hole in a vertical direction, is provided. CONSTITUTION:A heating cylinder 1 has a built-in screw 2 and a resin loading port 3 is formed in the upper part of the rear. A partition plate 4 coveres a resin loading port 3, interlocks with a movement of the screw 2 and possesses hole part 6 of a vertical direction. A hopper 5 is foxed on the top by surrounding the hole part 6 and a hydraulic cylinder 10 actuates the partition plate 4. A position of the screw 2 is read out by a position readout instrument 12 with a position sensor 11, a solenoid valve 14 is moved with a position controlling amplifier 13 which has received this output and a movement of the hydraulic cylinder 10 is controlled. Then a feed screw 7 is provided on the outside of the resin loading port 3 in a longitudinal direction of the screw 2 and the a partition plate 8 covering the resin loading port 3 and interlocking with a movement of the screw 2 nay be provided on the lower part of the feed screw 7.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement in an in-line screw injection molding machine that prevents fluctuations in plasticizing capacity caused by forward and backward movement of a screw.

[Conventional technology]

An in-line screw injection molding machine uses its own weight to feed the resin stored in the thermoplastic cylinder into the heating cylinder, plasticizes the resin through the rotational transfer action of the screw, and feeds the resin to the tip of the screw. The screw is pushed back by pressure, its retreated position is detected electrically, the screw rotation is stopped, one shot of molten resin is accumulated at the tip of the heating cylinder, and then the measured resin is placed in the hydraulic cylinder at the rear. This moves the screw forward and injects from the nozzle into the mold.

Therefore, as the volume of one injection increases, the hack stroke of the screw also increases, and when the screw is retracted, the number of flights between the screw compression start point and the resin inlet port will inevitably decrease, and the compression process will begin immediately after resin is supplied. There was a problem in that plasticization tends to be insufficient because of the plasticization, and it is difficult to obtain uniform plasticization.

Therefore, the applicant first proposed an injection molding machine as shown in Fig. 3 as a solution to the above-mentioned problems.
(See Publication No. 46220).

The injection molding machine has a cylindrical body 19 that slides in the heating cylinder 1 of the resin supply zone in conjunction with the forward and backward movements of the screw 16 and is connected to the lower end of the shooter 20 to the resin inlet I8.
The cylinder body 19 is movable within the cutout hole 21 of the heating cylinder 1, so that the resin from the pumper 5 is always supplied to the fixed position of the screw 16. Therefore, plasticization can be made uniform.

[Problem to be solved by the invention]

However, the above injection molding machine has the following problems.

That is, first, when the injection molding machine becomes larger, the shooter 20 and the cylindrical body 19 become larger, and their driving sources become larger, which is contrary to energy saving. Also, the notch hole 2 of the heating cylinder 1
1 needs to be large, which not only makes it difficult to attach the heater, but also makes it easy for foreign matter to get mixed in through the cutout hole 21. Furthermore, when changing colors, it is difficult to clean the resin material that has accumulated inside the cylindrical body 17.

Note that foreign matter can easily enter through the gap between the shooter 20 and the hopper 5.

The object of the present invention is to provide an injection molding machine that eliminates the above-mentioned drawbacks.

[Means to solve the problem]

One of the injection molding machines of the present invention for achieving the above object covers a resin inlet provided in a heating cylinder of an in-line screw type injection molding machine, is linked to the advance and retreat of the screw, and has a hole in the vertical direction. (See Figure 1), and other injection molding machines have a screw in the longitudinal direction outside the resin inlet provided in the heating cylinder of the in-line screw injection molding machine. A feed screw is provided below the feed screw,
A partition plate is provided that covers the resin inlet and is linked to the advance and retreat of the screw (see Figure 2).

[Effect]

In the case of the above-mentioned first injection molding machine, the partition plate that covers the resin inlet provided in the heating cylinder is linked to the advance and retreat of the screw, so the resin always passes through the resin inlet from the hole provided in the partition plate and into the screw. Supplied in place.

In addition, in the case of later injection molding machines, the resin moves forward along the groove of the feed screw, but the partition plate below the feed screw is linked to the advance and retreat of the screw.
Resin is always supplied to the fixed position of the screw from the groove through the resin inlet.

〔Example〕

The present invention will be explained below based on the drawings.

FIG. 1 is a sectional view of a main part of an embodiment of an injection molding machine according to the present invention (with a control system for a partition plate added).

In the figure, reference numeral 1 denotes a heating cylinder with a built-in screw 2 and a resin inlet 3 formed at the rear upper part. A partition plate 4 covers the resin input port 3, is interlocked with the advance and retreat of the screw 2, and has a vertical hole 6. A hopper 5 is fixed to the upper surface of the partition plate 4 surrounding the hole 6. There is. 10 is a hydraulic cylinder that operates the partition plate 4, and is controlled as follows. That is, the position of the screw 2 is read by a position sensor 11 attached to the screw 2 with a position reader 12, and a position control amplifier 13 receiving this output operates a solenoid valve 14 to control the movement of the hydraulic cylinder 10. Although hydraulic pressure is used to operate the partition plate 4, the present invention is not limited to this, and pneumatic pressure, electric power, etc. may be used.

FIG. 2 is a sectional view of a main part of another embodiment of the injection molding machine according to the present invention, and numeral 1 denotes a heating cylinder incorporating a screw 2 and having a resin inlet 3 formed at the rear upper part. 7 is a feed screw provided outside the resin inlet 3 in the longitudinal direction of the screw 2, and 8 is a partition installed below the feed screw 7 to cover the resin inlet 3 and move in conjunction with the advance and retreat of the screw 2. It is a board. 9 is a motor that operates the feed screw 7. Note that the partition plate 8 is controlled by a hydraulic cylinder in the same manner as in the previous embodiment.

[Effects of the Invention] The injection molding machine according to the present invention has a partition plate that covers the resin inlet of the heating cylinder and is linked to the advance and retreat of the screw, making it possible to always supply resin to a fixed position on the screw. It has now become possible to provide an injection molding machine that can uniformly plasticize even when molded into a molded product and can produce a molded product with a high-quality appearance.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of main parts showing one embodiment of an injection molding machine according to the present invention (with a control system for the partition plate added), and FIG. 2 is a schematic diagram showing another embodiment of an injection molding machine according to the present invention. FIG. 3 is a sectional view of a main part of a conventional injection molding machine. Explanation of symbols 1 - Heating cylinder - 2 - Screw 3 - Resin inlet 4 - Partition plate 5 - Hopper 6 - Hole 7 - Feed screw 8 - Partition plate 9 - Motor
10 - Hydraulic cylinder 11 - Position sensor 13 - Position control amplifier 15 - Motor 17 - Cylindrical body 19 - Cylindrical body 21 - Notch hole 12 - Position reader 14 - Solenoid valve 16 - Screw 18 - Resin inlet 20 - Shooter

Claims (1)

[Claims] 1. The resin inlet (3) provided in the heating cylinder (1) of the in-line screw injection molding machine is covered, and the hole (3) in the vertical direction is connected to the advance and retreat of the screw (2). 6)
An injection molding machine characterized by being provided with a partition plate (4) having a partition plate (4). 2. A feed screw (7) is installed in the longitudinal direction of the screw (2) on the outside of the resin inlet (3) provided in the heating cylinder (1) of the in-line screw injection molding machine, and the feed screw (7) is An injection molding machine characterized in that a partition plate (8) is provided below, which covers the resin inlet (3) and is linked to the advance and retreat of the screw (2).