JPS6283109A - Resin supplyer for molding machine - Google Patents

Abstract

PURPOSE:To permit powdery resin to be dropped stably by using a system in which a gas is blown into a supplying section for the powdery resin between a hopper and then molding machine body. CONSTITUTION:A supporter 2 is attached to the lower end of a hopper for powdery resin as a raw material, and a supply port 6 with fitting seat plate 5 is provided to the cylinder 4 of a screw 3. A ring like spacer 8 with a pipe 7 through which a gas is blown out is provided between the supply port 6 and the seat plate 5 of the cylinder 4. The pipe 7 is bent to be directed toward the hopper. The spacer 8 can be attached by vertically moving the hopper 1.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to an injection molding machine, an extruder (ram extruder) (hereinafter referred to as
It belongs to the field of molding machines such as molding machines, etc., and specifically relates to a resin supply device for stably supplying raw material resin from a hopper to a molding machine.

(Prior Art) Factors for stabilizing resin molding include the shape of the screw, its rotation speed, the temperature of the cylinder or barrel, the shape of the mold, its temperature, the shape of the die, its temperature, etc. However, these factors are controlled when the supplied resin has already melted and has a certain degree of fluidity, and if unstable raw material resin had been supplied before the resin melted, In many cases, it becomes difficult to perform stable molding.

The raw material resin also differs depending on its state, ie, whether it is in the form of pellets or powder.

Generally, resin is often in powder form when producing raw materials, but if it is in powder form, it may be scattered around when the bag is broken during transportation or when it is supplied to a molding machine. For this reason, the polymeric resin is supplied in the form of pellets that are pelletized and cut into a certain size.

However, some polymeric materials cannot be pelletized and are supplied in powder form.

For example, vinyl chloride, fluorocarbon, ultra-high molecular weight polyethylene, etc.

When molding, whether the resin should be in pellet form or powder form is determined by the type of resin and the diameter of the molding machine's screw.

When the diameter of the screw is 40B or more, it often does not depend on the form of the resin, and when the diameter of the screw is 40m+w or less, it often depends on the form of the resin.

In particular, when the diameter of the screw is 18W or less, there is a limit to the height of the flight due to problems with the strength of the screw, and the flight may become smaller than the dimensions of the pellet. In this case, a problem arises in that the resin is not supplied at the supply section of the screw. One solution in this case is
This problem can be solved by changing the form of the resin to a powder, but if the resin is made into a powder, the supply itself becomes unstable in many cases.

Therefore, as a method for stably supplying powdered resin to the supply section of the screw 1-, there is a method of providing a screw for forced feeding at the top of the supply section, or a method of supplying powdered resin in the supply section. In addition, mechanical vibration or ultrasonic vibration is applied, which promotes the falling of the powdered resin and prevents it from stagnation.

(Problems to be Solved by the Invention) The problem with the first two methods above is that the shape and dimensions of the feeding screw vary depending on the dimensions and shape of the hopper used and the functions of the molding machine used. must be designed to
In addition, it is necessary to consider the installation of a power source for rotating this screw, which may result in an expensive product.

The problem with the second method is that when applying mechanical vibration like the first method, an external power source is required, which is difficult to install in a small molding machine, and ultrasonic When applying vibration, the natural frequency must be found, which creates a complicated problem.

(Means for Solving the Problems) The idea of the present invention is that, as a result of various studies to solve the above problems, powdered resin does not fall down by itself in a stable manner into the feeding section of the screw of the molding machine. This is because, unlike in the case of pellets, when powdered, the surface area of the resin increases, and the complex shapes of the powder become intertwined with each other, making their natural fall unstable. They discovered that by supplying gas from the outside, the particles can be spaced apart, eliminating friction between particles and allowing stable natural fall.

The present invention has been made based on this, in which gas is blown into a powder resin supply section between the hopper and the molding machine body.

(Example) Embodiments of the present invention will be described below based on the drawings.

The drawing is a cross-sectional view of the device of the invention.

The support member (
2) is attached, and the cylinder (4) of the screw (3) is provided with a supply port (6) with a mounting seat plate (5).

The support member (2) of this hopper (1) and the cylinder (4)
A ring-shaped spacer (8) with a gas blowing pipe (7), which is an important component of the present invention, is interposed between the supply port (6) and the mounting seat plate (5). This pipe (7
) is bent toward the hopper (1).

The spacer (8) can be installed without moving the hopper (1) in the vertical direction.

The thickness of the ring-shaped spacer (8) is D, and its inner diameter is A.
゛, Assuming that the height of the upward pipe inside the spacer (8) is h, its inner diameter is d, and the inner diameter of the supply port (6) of the cylinder (4) is A, there will be differences depending on the scale of the molding machine. However, the preferred relationship is as follows.

A' ≦A ・ ・ ・ ・ ・■D
≦A″ ・ ・ ・ ・ ・■1/3 D≦h
≦3D ・ ・ ・■1/100 A'≦d＜A'
...■Here, if the resin supply port of the molding machine is rectangular, A is the length of the diagonal.

The amount of gas sent from the pipe (7), expressed in terms of the required gas pressure, is I KPa to 15 MPa, preferably 10 KPa to 10 MPa.

The type of gas used is preferably an inert gas such as dry air, nitrogen gas, Freon gas, or helium gas.

The number of gas blowing pipes may be one or more, but it is necessary that the total cross-sectional area satisfies the condition (2) above.

Further, the gas used may be supplied continuously into the hopper or intermittently. The cycle in the case of intermittent supply is 10 sec to 10 sec, preferably 10 sec.
sec to 10 sec.

Next, the specific dimensions are A = 5011rm, D =
40+*, h = 6 (hm, d = 1.0 m), and installed this in an injection molding machine with a mold clamping force of 22 tons and a screw diameter of 18 m, and supplied nitrogen gas at 0.5 Pa. It was used at a pressure of

The resin used was ultra-high molecular weight polyethylene (Hize Sox Million 240M manufactured by Mitsui Petrochemical Industries), and the injection molding conditions were: plasticization time with a screw of 7 seconds;
The injection time was 2 seconds, the curing time was 10 seconds, the ejection time was 1.5 seconds, the interval was 4 seconds, and the total cycle time was 23 seconds.

The shape of the resulting molded product was a disc-shaped center with a diameter of 60 m and a thickness of 3 nm, with a convex part having a diameter of 1511 m and a height of 61 m at the center, and a gate was provided in the central part.

When this molded product was injection molded without using the spacer of the present invention, 50 pieces were randomly selected from 1000 shots and the amount of M was measured, and the variation was 0.56%. there were. On the other hand, when injection molding is performed using the apparatus of the present invention, 10
The results of measuring 50 samples randomly selected from 0.00 shots had a variation of 0.05%, which was about 1/10 of that obtained without using a spacer.

(Effects of the Invention) Although the present invention only provides a gas outlet in the resin supply section between the resin hopper and the molding machine body, it is possible to When supplying resin to the molding machine body, stable supply is possible.
This makes it possible to efficiently produce molded products with high precision and good quality.

Moreover, it can be installed in any molding machine, operates stably, has few failures, and can be provided at low cost.

Note that the inert gas from the gas outlet also functions to prevent oxidation of the resin within the cylinder and prevent a decrease in molecular weight.

[Brief explanation of drawings]

The drawing is a cross-sectional view of the device of the invention. Code 1...Hopper 2...Supporting member 3...Screw 4...Cylinder 5...Mounting seat plate 6... Supply port A...pipe 8...Ring-shaped spacer

Claims (4)

[Claims] (1) A resin supply device for a molding machine in which a gas outlet is provided in the resin supply section from the hopper to the molding machine main body. (2) The resin supply device for a molding machine according to claim 1, wherein the gas outlet is oriented toward the hopper. (3) The resin supply device for a molding machine according to claims 1 and 2, wherein the number of gas blow-off ports is single or plural. (4) A resin supply device for a molding machine according to any one of claims 1 to 3, wherein the gas is continuously or intermittently blown out from the gas outlet.