JPS6021817B2 - Method and device for determining the quality of injection products in injection molding equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for determining the quality of an injection product in an injection molding apparatus such as a die casting machine or an injection molding machine.

Injection molding equipment supplies molten material into a mold cavity formed at the mating surfaces of a fixed mold and a movable mold to mold a product, but at this time, when the mold temperature is low or the injection pressure is low, If the pressure acting on the molten material supplied into the mold cavity is less than a predetermined value, such as when the mold is small, the molten material will not be able to reach the inside of the mold cavity, and large cavities may form in the product. , some parts may be missing, resulting in defective products.

The occurrence of such defective products cannot be detected until the product is removed or inspected after injection molding, and cannot be detected during the injection molding process.

The present invention was made in view of the above circumstances, and it is possible to check whether the pressure of the molten material in the mold cavity is higher than a predetermined pressure during injection molding by using a mold gas venting device. It is an object of the present invention to provide a method for determining the quality of an injection product and a device therefor, which can detect whether a product is good or bad.

In order to achieve the above object, in the present invention, a valve is slidably held, a piston rod of a cylinder is connected to a valve seat having a valve seat, and the valve opening a gas discharge passage is connected to a cavity. When performing injection by disposing a mold gas venting device in the mold gas discharge passage, which is moved by the injection molten material advancing from the cylinder to close the gas discharge passage, the cylinder is removed from the mold cavity side. The quality of the injection pressure transmission state to the injection product is detected by detecting whether the force acting on the injection pressure is a predetermined force,
As a method of detecting the quality of the force acting on the cylinder from the mold cavity side during injection, the injection molten material injected into the mold cavity during normal injection is transmitted to the piston rod through the valve and spool. 4. Apply force with hydraulic oil sealed in the head end of the cylinder, and check whether the pressure on the head end of the cylinder rises above a specified level during injection. We adopted a method for determining the quality of injection products in injection molding equipment, which uses a detection method using a detection device and issues a signal indicating a product defect when the force acting on the cylinder is insufficient.

The piston rod of the cylinder is connected to a spool that slidably holds the valve and has a valve seat, and the valve opening the gas discharge passage is moved by the injected melt advancing from the cavity and boiling. A gas venting device for the mold is installed in the gas exhaust path of the mold so that the gas exhaust system can be closed, and the injection melt that is injected into the mold cavity during normal injection is passed through the valve and spool. A hydraulic oil sealed circuit is provided to apply a smaller force to the head end of the cylinder than the force transmitted by the piston rod, and a pressure detection device is installed in this hydraulic oil sealed circuit to detect the state of pressure increase during injection. The present invention provides an injection product quality determination device for an injection molding machine, which is equipped with an alarm device that can issue a warning of product defect when the pressure detection device does not operate during injection.

Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

Figures 1 and 2 are for explaining one embodiment of the present invention, and in the figures, 1' is a fixed mold, 2 is a movable mold, and a mold cavity 3 is provided on the abutting surface of both. It is formed.

An injection sleeve 4 is attached to the fixed mold 1 side,
Molten metal is supplied from a checkpoint 4a formed near one end.

A plunger 6 integral with the piston rod 5a of the injection cylinder 5 is slidably mounted in the injection sleeve 4. The plunger 6 has a striker 7 in parallel thereto, and various limit switches are provided at positions where the plunger 6 can come into contact with the striker 7. That is, 8 is a limit switch for detecting the forward limit, 9 is a limit switch for detecting the backward limit, and 10G is a gas vent valve 13, which will be described later.
11 is a mitt switch that instructs to start reducing the pressure inside the cavity 3 by a vacuum generator (not shown); 11 is a mitt switch that instructs the start of high-speed injection;
At this point during injection, 12 detects whether the position sensor 18 that detects the closing of the gas vent valve 13 is operating or not, and detects whether the vacuum sensor of the cavity 3 is operating or not. If the position sensor 8 is activated when the limit switch 12 is activated, the timing of closing the gas vent valve 13 is too early, and the product of that shot is considered to be defective. If the degree sensor does not operate, it is assumed that the degree of vacuum has not been obtained, and the product of that shot is judged to be defective. On the butting surfaces of the fixed mold 1 and the movable mold 2,
A gas vent valve 13 is provided in the middle of the gas exhaust path leading from the mold cavity 3 to the outside of the mold, and is moved by the injection melt advancing from the mold cavity 3 to close the gas exhaust path. There is.

The spool 13a having the valve seat of this gas vent valve 13 is
The spool 13a is connected to a piston rod 14a of a cylinder 14 attached to the fixed mold 1 via a bracket 28, and the spool 13a is inserted into a hole formed in the mold abutting surfaces of the fixed mold 1 and the movable mold 2. will be combined. The gas vent valve 13 is a valve 15 facing the gas exhaust path 3a leading to the mold cavity.
The square rod 15a is slidably attached to the spool 13a, and the valve holder 15a is always moved in the direction of closing the valve 15 by a tension spring 16 attached between the spool 13a and the ceiling. is given the power of Furthermore, a locking device 17 consisting of a ball 29, a compression spring 30, an adjustment bolt 31, etc. installed in the rattan hole of the spool 13a is arranged facing the stepped portion 15b in the middle of the valve twill 15a. ing. When the valve 15 is open, the ball 29 is pressed against the stepped portion 15b, and the valve 15 is prevented from closing with a small force, and the mold cavity 3
The injection melt advancing from the valve head 15 on the underside of the valve 15
When the ball 29 collides with the ball 29 and the inertial force of the melt acts on the valve 15, the valve 15 is pushed upward, and at that time the ball 29 retreats. An arm 32 is provided at the upper part of the valve shaft 15a so as to pass through the wall of the spool 13a, and when the ball 29 of the locking tool 17 is retracted and the valve 15 is closed, a part of the arm 32 is provided. A position sensor 18 is disposed at a position where it can come into contact with and operate. The position sensor 18 is attached to a part of the spool 13a. Note that a bypass passage 33 for gas exhaust detoured in a direction perpendicular to the plane of the paper is provided between the middle of the gas exhaust passage 3a and a position immediately in front of the valve seat portion of the spool 13a. Also, bracket 2
A stopper 34 is attached to a part of the valve 8, and while the spool 13a is rising, the arm 32 hits the stopper 34, and the valve 15, which is in the closed state, can be opened. The gas vent valve 13 has an exhaust path 19, and the exhaust path 19 is connected to a vacuum generator (not shown) so that gas in the mold cavity 3 can be exhausted at the initial stage of injection molding.

The exhaust path 19 is provided with a vacuum degree detection device (not shown). As the switching valve 20 of the two-way switching valve, for example, a switching valve for operating the core may be used, or a switching valve provided separately may be used.

The A boat of the switching valve 20 is connected to the head end side of the cylinder 14 via a pipe 23, a pressure reducing valve 21, a pilot check valve 22, and a pipe 23a.
A pressure detection device such as a pressure switch 24 and a pressure gauge 24a are provided in the piping 23a section between the pilot check valve 22 of 3a and the head end side of the cylinder 14. In addition, the pressure reducing valve 21 and the pilot check valve 22
etc. form a hydraulic oil sealed circuit that applies a force smaller than the force transmitted to the piston rod 14a at the time of injection to the head end side of the cylinder 14. An alarm device is connected to the pressure switch 24. Further, the B boat of the switching valve 20 is connected to the rod end side of the cylinder 14 via a pipe 25.

A pilot circuit for the pilot check valve 22 is branched from a part of the piping 25. In addition, 2
6 is a hydraulic mochi joint part, and 27 is a tank. Next, the operation of this embodiment configured as above will be explained.

First, by the action of the pressure reducing valve 21 and the pilot check valve 22, a force smaller than the force transmitted to the piston rod 14a via the valve 15 and the spool 13a by the molten metal injected into the cavity 3 during normal injection is applied to the cylinder. 14
Let it work with hydraulic oil sealed in the head end side of the unit.

The pressure switch 24 is set so that it does not operate at the pressure set by the pressure reducing valve 21, but operates when a predetermined force is applied to the piston rod 14a during injection under normal injection pressure. In this state, when a predetermined amount of molten metal is supplied into the injection sleeve 4 and an injection command is issued,
The injection cylinder 5 is actuated, the plunger 6 moves forward, and molten metal is supplied into the mold cavity 3.

At this time, most of the gas in the cavity 3 is exhausted by the vacuum generator through the gas exhaust path 3a, the bypass, and the gas vent valve 13, but when the setting sun starts to be supplied into the mold cavity 3, the inside of the cavity 3 The remaining gas is pushed by the molten metal, passes through the gas vent valve 13, and is discharged outward from the discharge passage 19. Eventually, the molten metal filling the cavity 3 collides with the valve 15, and the valve 15 is pushed upward against the action of the locking tool 17 due to the inertial force of the molten metal.
5 is closed. Therefore, the molten metal is not discharged outside the mold. At this time, by closing the valve 15, the injection pressure acting on the molten metal in the cavity 3 acts on the valve 15,
It acts on the spool 13a.

Therefore, an upward pressing force is applied to the entire gas vent valve 13, which is applied to the cylinder 1 via the piston rod 14a.
4. Since hydraulic oil is supplied to the head end side of the cylinder 14, if the pressing force corresponding to the predetermined molten metal pressure set by the pressure switch 24 is not applied to the hydraulic oil on the head end side, Pressure switch 24 does not operate.

If the pressure switch 24 is configured to issue an alarm when the set pressure is not reached, it will be detected that the pressure of the molten metal in the mold in the currently performed injection operation is insufficient. This is a warning that the product is defective. For example, during injection when normal injection pressure is being transmitted,
It is assumed that a metal pressure of 500 k9' acts on the molten metal in the cavity 3 and on the valve 15, and as a result, a force of 1 force on acts on the piston rod 14a of the cylinder 14. Then, by the action of the pressure reducing valve 21, the pressure acting on the head end side of the cylinder 14 is set at 10k9/ft, and the pressure at which the pressure switch 24 operates is set at 15k9/ft.
keep it as a ground. When injection is performed in this state, if the mold temperature is low or the hot water flow is poor, for example, 400 kg
/Only the ground metal pressure acts on the molten metal.

At this time, the piston rod 14a has 1
Only 3bn of force acts. Therefore, the pressure in the hydraulic oil sealed circuit is only a pressure corresponding to a force of 13 n, so the pressure switch 24, which is set to a pressure corresponding to a force of 15 n, does not act. On the other hand, during normal injection, a metal pressure of 500 kg/ground acts on the piston rod 14a, as described above, and the lhP
A force of n acts.

As a result, the pressure in the actuating enclosed circuit becomes a pressure corresponding to a force of 1 yen, so that the pressure switch 24 is actuated. In this way, if the pressure switch 24 acts during injection, it is known that a predetermined metal pressure has acted on the molten metal in the cavity 3, and if the pressure switch 24 does not act, it can be seen that a predetermined metal pressure has acted on the molten metal. It turns out that it is not.

Therefore, depending on the action or inaction of the pressure switch 24, it is possible to determine whether the metal pressure is good or bad and whether the injection product is good or bad. When the pressure switch 24 does not work, it is possible to notify the worker of a defective product with an alarm or a lamp, and it is also possible to stop the operation of the die-casting machine. In this case, when detecting the operation or inaction of the pressure switch 24,
Within an extremely short period of time regulated by the injection stroke and timer, and when no injection is being performed, even if the pressure in the hydraulic oil sealing circuit is lower than the set pressure of the pressure switch 24,
Do not issue alarms regarding product defects. In the above embodiment, the pressure switch 24 was used as the pressure detection device, but a pressure sensor that can detect changes in pressure every moment may be used instead.

When this pressure sensor is used, a similar pressure sensor is placed on the head end side of the injection cylinder 6, and the pressure fluctuations of each pressure sensor are expressed in a graph on a monitor device based on the output signals from both pressure sensors. It can also be used as a criterion for quality control. In this case, the metal pressure transmission rate within the cavity 3 can be easily determined based on the pressure of the injection cylinder 5 and the pressure detected by the pressure sensor on the gas vent valve 13 side. In this way, in the present invention, since the configuration as described in the claims is adopted, the quality of the pressure of the melt supplied into the cavity is connected to the head end side of the cylinder for the gas vent valve. It can be easily detected by the action of a pressure sensing device in the hydraulic oil sealed circuit.

Then, at the time of injection, it is possible to immediately determine whether the injection product is good or bad. Furthermore, the results can be used for injection control, making it easier to obtain high-quality injection products.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram and hydraulic circuit diagram showing one embodiment of an apparatus for carrying out the method of the present invention, and FIG. 2 is a partially enlarged sectional view of FIG. 1. 1...Fixed mold, 2...Movable mold, 3
...Cavity, 4...Injection sleeve, 5...Injection cylinder, 6...Plunger, 1
3...Gas vent valve, 13a...Sleeve, 14...Cylinder, 15...Valve, 20...Switching valve, 21...
...Reducing valve, 22...Pilot check valve,
24...Pressure switch. Hate 1, hate Europe, 2 hate

Claims (1)

[Scope of Claims] 1. A piston rod of a cylinder is connected to a spool that slidably holds a valve and has a valve seat, and the valve, which opens a gas discharge passage, is blown by the injected melt advancing from the cavity. When a mold gas venting device that can be moved to close the gas exhaust path is placed in the gas exhaust path of the mold and injection is performed, the force acting on the cylinder from the mold cavity side is a predetermined force. By detecting whether or not the injection pressure is being transmitted to the injection product, it is possible to detect whether the injection pressure is being transmitted to the injection product. A force smaller than the force transmitted to the piston rod via the valve and spool by the injected molten material injected into the mold cavity during injection is applied to the head end side of the cylinder with hydraulic oil sealed, A method is used that uses a pressure detection device to detect whether the pressure at the head end of the cylinder rises above a specified level during injection, and a signal indicating a product defect is issued when the force acting on the cylinder is insufficient. A method for determining the quality of injection products in injection molding equipment. 2. A piston rod of a cylinder is connected to a spool that slidably holds a valve and has a valve seat, and the valve, which opens a gas discharge passage, is moved by the injected melt advancing from the cavity to open the gas discharge passage. A gas venting device for the mold is provided in the gas exhaust path of the mold, and the gas venting device is configured to close the gas venting device of the mold so that the injection melt injected into the mold cavity during normal injection is transmitted to the piston rod via the valve and spool. A hydraulic oil sealed circuit is provided to apply a force smaller than the force exerted on the head end of the cylinder, and this hydraulic oil sealed circuit is equipped with a pressure detection device that detects the state of pressure increase during injection. A device for determining the quality of an injection product in an injection molding machine, which is equipped with an alarm device that can issue a warning of product defect when the detection device does not operate.