JPS582061B2 - Raw material supply device for multi-component liquid plastic raw material mixing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a raw material supply device for a multi-component liquid plastic raw material mixing device used in a high-pressure reaction molding machine.

As is well known, multi-component liquid plastic raw material mixing equipment is
It is configured so that liquid plastic raw materials of two or more components are collided and mixed in a mixing chamber, causing a chemical reaction, and then being fed into a mold.

As a device for supplying liquid plastic raw materials to the mixing chamber of the mixing device, for example, the device shown in FIG. 1 is known.

According to this, the electric control section 1 controls the hydraulic control section 2 to operate the first drive cylinder 4a and the second drive cylinder 4b in accordance with the mixing operation of the mixing device 3.

Then, the first raw material supply piston cylinder 5a sucks the first liquid plastic raw material from the first raw material storage tank 6a through the flow path 7a and the switching valve 8a, and transfers the first liquid plastic raw material from the flow path 9a to the mixing chamber (not shown) of the mixing device 3. A first raw material supply port 10 communicating with
At the same time, the second raw material supply piston cylinder 5b is supplied to the flow path 7b from the second raw material storage tank 6b.
The second liquid plastic raw material sucked through the switching valve 8b is supplied from the flow path 9b to the second raw material supply port 10b communicating with the mixing chamber (not shown) of the mixing device 3.

At this time, the forward speed of the piston 11a of the first raw material supply piston cylinder 5a, that is, the supply speed of the first liquid plastic raw material is controlled by the hydraulic control unit 2 and the first flow rate regulating valve 12.
It is controlled by the flow rate of pressure oil sent to the first drive cylinder 4a via a, and the second raw material supply piston cylinder 5
The forward speed of the piston 11b, that is, the supply speed of the second liquid plastic raw material is controlled by the flow rate of the pressure oil sent from the hydraulic control unit 2 to the second drive cylinder 4b via the second flow rate regulating valve 12b. .

In FIG. 1, 14a is a channel for returning the first liquid plastic raw material to the first raw material storage tank 6a, and 14b is a channel for returning the second liquid plastic raw material to the second raw material storage tank 6b.

By the way, in the above supply device, the first flow rate regulating valve 1
2a and the second flow rate regulating valve 12b, the first
The supply rate of the liquid plastic raw material and the second liquid plastic raw material is always constant.

That is, from the start of supply to the end of supply, it is always supplied at a constant speed.

Therefore, the injection speed of the mixed components injected into the mold from the mixing chamber (not shown) of the mixing device 3 is also constant.

However, if the injection speed of the mixed components is constant as described above, the physical properties of the molded article may not be uniform.

That is, the strength decreases as the distance from the gate portion (gate portion) increases.

Particularly when the shape of the molded product is complex, there are various problems such as uneven strength distribution, poor surface finish, and burrs are more likely to appear than in the mold.

The present invention has been made in view of the above circumstances, and its purpose is to provide a liquid plastic raw material supply device for a multi-component liquid plastic raw material mixing device that can change the injection speed of mixed components during the injection process. The aim is to solve the above problems by doing so.

That is, the present invention uses a raw material supply piston cylinder whose supply speed changes from the start of supply to the end of supply when supplying the liquid plastic raw material to the mixing device. The injection speed of the mixed components to be injected is changed.

An embodiment of the present invention will be described below with reference to FIG.

Note that the same parts in the figure as those shown in FIG. 1 are given the same reference numerals, and the explanation thereof will be omitted.

In this embodiment, the first electromagnetic flow regulating valve 16a is used to control the flow rate of pressure oil sent from the hydraulic control unit 2 to the first drive cylinder 4a, and the second A second electromagnetic flow control valve 16b is used to control the flow rate of pressure oil sent to the drive cylinder 4b.

Also, a first detector 19a detects the forward speed and position of the piston 18a of the first raw material supply piston cylinder 17a.
is provided, and a second raw material supply piston cylinder 17b
A second detector 19b is provided to detect the forward speed and position of the piston 18b.

Further, the electric control unit 20 is provided with a speed setting device (not shown) for setting the forward speed of the piston 18a of the first raw material supply piston cylinder 17a.

This speed setting device is designed to be able to set the speed of the piston 18a, as shown in the setting examples shown in FIG. 3A to 3D.

Note that the first electromagnetic flow rate adjustment valve 16a and the second electromagnetic flow rate adjustment valve 16b are controlled by control signals from the electric control section 20.

Further, the detection signal of the first detector 19a and the detection signal of the second detector 19b are input to the electric control section 20.

Next, the operation of the above device will be explained.

First, the speed setter of the electric control section 20 is set to, for example, the speed shown in the table below.

After doing this, the electric control section 20 controls the hydraulic control section 2.
The first and second electromagnetic flow adjustment valves 16a and 16b are controlled to operate the first drive cylinder 4a and the second drive cylinder 4b in accordance with the mixing operation of the mixing device 3.

Then, the piston 18a moves forward at a speed of 150 mm/sec.

That is, the first liquid plastic raw material is heated at 150 mm/s.
The raw material is sent from the flow path 9a to the first raw material supply port 10a of the mixing device 3 at a supply speed of ec.

At this time, the piston 18b also moves forward at the same time as the piston 18a, and the second liquid plastic raw material is transferred to the second liquid plastic material in the mixing device 3.
The raw material is sent to the raw material supply port 10b.

Note that the speed of the piston 18b varies depending on the mixing ratio of the first liquid plastic raw material and the second liquid plastic raw material.

That is, when the first liquid plastic raw material and the second liquid plastic raw material are in the same amount, they move forward at a speed of 150 mm/sec like the piston 18a.

The forward speed and position of the piston 18a are detected by the first detector 19a.
When the first detector 19a detects that the piston 18a has moved forward by 50 mm from the time when mixing was started in the mixing device, the electric control unit 20 controls the first electromagnetic flow regulating valve 16a. A control signal is output.

Then, the flow rate of the pressure oil sent from the hydraulic control unit 2 to the first drive cylinder 4a is throttled, and the forward speed of the piston 18a is reduced from 150 mm/sec to 10.0 mm/sec.

That is, after the piston 18a moves forward by 50 mm, the first
Liquid plastic raw material is fed at a feed rate of 100 mm/sec.

At this time, the piston 18b is similarly decelerated, and the second liquid plastic raw material is also supplied at a supply rate that matches the supply rate of the first liquid plastic raw material.

When the first detector 19a detects that the piston 18a has moved forward to 100 mm, a control signal is output from the electric control section 20 to the first electromagnetic flow rate regulating valve 16a, and the hydraulic control section 2 outputs a control signal to the first electromagnetic flow regulating valve 16a. The flow rate of the pressure oil sent to the drive cylinder 4a is further reduced, and the forward speed of the piston 18a is reduced from 100 mm/sec to 50 mm/sec.

At this time, the piston 18b is similarly decelerated, and the second liquid plastic raw material is supplied at a supply rate that matches the supply rate of the first liquid plastic raw material.

When the piston 18a advances to 150 mm, the mixing device 3 enters the mixing rest state.

That is, the first raw material supply port 10a and the second raw material supply port 10b of the mixing chamber are closed.

At this time, the first liquid plastic raw material passes through the channel 14a and returns to the first raw material storage tank 6a, and the second liquid plastic raw material also passes through the channel 14b and returns to the second raw material storage tank 6b.

The pistons 18a and 18b then return to their original positions.

At the same time, from the first raw material storage tank 6a to the flow path 7a
, the first liquid plastic raw material is transferred to the first liquid plastic material via the switching valve 8a.
It is sucked into the raw material supply piston cylinder 17a, and the second
The second liquid plastic raw material is sucked into the second raw material supply piston cylinder 17b from the raw material storage tank 6b via the flow path 7b and the switching valve 8b.

Then, the same operations as described above are repeated.

In this way, when the supply speed of the first liquid plastic raw material and the second liquid plastic raw material sent to the mixing chamber of the mixing device 3 is changed in three steps, the injection rate of the mixed components injected from the mixing chamber into the mold is will also change accordingly.

That is, when injecting at a position far from the gate of the mold, the injection speed becomes faster, and as it approaches the gate, the injection becomes slower.

Therefore, the physical properties of the molded product are uniform, the surface finish is good, and no burrs come out of the mold.

In addition, in the above example, a case was shown in which the supply speed of the liquid plastic raw material was slowed down in three stages (see Fig. 3 A), but the present invention is not limited to this. It is possible to change the speed even further, and an example of the speed change is shown in FIG.

As explained above, according to the present invention, the supply rate of the liquid plastic raw material can be changed.

Therefore, problems such as non-uniform physical properties of the molded product and poor surface finish, as in the conventional method, do not occur.

[Brief explanation of drawings]

FIG. 1 is a flow sheet for a conventional device, FIG. 2 is a flow sheet for an embodiment of the present invention, and FIG. 3 is a graph showing temporal changes in the forward speed of a piston. 3... Mixing device, 17a... First raw material supply piston cylinder, 17b... Second raw material supply piston cylinder, 6a... First raw material storage tank, 6b. ...Second raw material storage tank, 7a, 7b.
...Flow path, 9a, 9b...Flow path, 10a
......First raw material supply port, 10b...Second
Raw material supply port, 16a...First electromagnetic flow rate adjustment valve, 16b...Second electromagnetic flow rate adjustment valve, 18a,
18b... Piston, 19a... First
Detector, 19b...Second detector, 20...
...Electrical control section.

Claims (1)

[Claims] A raw material supply piston cylinder whose supply speed changes from the start of supply to the end of supply of liquid plastic raw material is arranged in each supply flow path connecting each raw material storage tank and each raw material supply port of the mixing device. A raw material supply device for a multi-component liquid plastic raw material mixing device, characterized by the following.