JPH085097B2 - Injection molding machine purging method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of purging an injection molding machine for discharging a resin material in a heating cylinder at the time of completion of molding or material change.

[0002]

2. Description of the Related Art Conventionally, in an injection molding machine, at the time of completion of molding or material change, a purging process for discharging all the residual resin material in the heating cylinder to empty it is performed. In this case, in order to perform the purge process in the manual mode, the material supply from the hopper to the heating cylinder is stopped, and if the operator turns on the switch for starting the purge, the screw rotation operation and screw forward operation are repeated to heat the cylinder. The residual resin material in the cylinder can be discharged. At this time, the injection device is moved backward with respect to the mold and the injection nozzle is separated from the mold (no nozzle touch), and the screw speed in the screw rotation operation and the screw advance operation is the same as the measurement step in the molding cycle. The metering speed and injection speed set in the injection process were used as they were.

[0003]

When focusing on the injection speed of an injection molding machine, there are various types from a relatively low speed machine to a molding machine speeded up as in recent years. In the purging process in the molding machine, since the injection speed is high, the purge speed is also high. As a result,
When performing the purge process in the manual mode, the residual resin material in the heating cylinder is vigorously ejected to the outside from the injection nozzle.Therefore, depending on the type of resin material and molding conditions, high-temperature molten resin may scatter around. , There was a problem that the worker got burned and the surrounding things were damaged.

The present invention solves the problems existing in the prior art as described above, and by reliably preventing the scattering of the resin material from the injection nozzle during the purging process,
An object of the present invention is to provide a method for purging an injection molding machine, which is capable of eliminating the occurrence of burns, property damage, etc. of an operator and further improving safety and workability.

[0005]

In the purging method for an injection molding machine according to the present invention, when the resin material in the heating cylinder 11 is discharged, a purge-dedicated speed Vp lower than the injection speed Vi of the screw 12 is previously set. Is set, and when the purge start operation is performed, the presence or absence of nozzle touch to the mold 13 is detected.
By leaving, along with the absence of nozzle touch executes the purge process by purging dedicated speed Vp, nozzle
When there is a rutouch, the injection process is executed at the injection speed Vi.
The feature is that it is made to do.

[0006]

According to the purging method for the injection molding machine of the present invention, the speed dedicated to the purging process, that is, the speed Vp dedicated to the purging, which is lower than the injection speed Vi of the screw 12, is set in advance.

When the purge starting operation is performed,
It is detected whether or not there is a nozzle touch on the die 13, that is, whether or not the injection nozzle is touching the die 13 by the advance of the injection device, and when there is no nozzle touch, the purge process is executed at the purge-dedicated speed Vp. As a result, even in the case of an injection molding machine that performs high-speed injection, the ejection speed of the resin material from the injection nozzle at the time of performing the purging process is reduced, and the resin material is prevented from scattering from the injection nozzle.

On the other hand, when there is a nozzle touch, the resin material from the injection nozzle is injected into the cavity of the mold 13, so that the resin material is injected at the original injection speed Vi .

[0009]

Next, preferred embodiments according to the present invention will be described in detail with reference to the drawings.

First, the structure of an injection molding machine which can carry out the purging method according to the present invention will be described with reference to FIG.

In FIG. 2, M is an injection molding machine, which is an injection device 1.
5 and a mold 13 is provided in front of the injection device 15. The injection device 15 has a heating cylinder 11 at a front portion thereof, an injection nozzle 16 is provided at a front end of the heating cylinder 11, and a hopper 17 is provided at a rear upper end of the heating cylinder 11. Then, the screw 12 is inserted into the heating cylinder 11. On the other hand, the injection device 15 has an injection cylinder 18 at the rear.
The rear end of the screw 12 is connected to the ram 19 of the injection cylinder 18, and the rotary shaft 20s of the oil motor 20 provided at the rear end of the injection cylinder 18 is spline-connected to the rear end of the ram 19.

The injection device 15 is moved forward and backward by a moving device (not shown). As a result, the injection nozzle 16 comes into contact with the mold 13 during forward movement, that is, a nozzle touch state (see virtual line 16s in FIG. 2), and the injection nozzle 16 separates from the mold 13 during backward movement.

On the other hand, 31 is a hydraulic circuit showing a part of the drive system, which comprises a hydraulic pump 32 and an oil tank 33,
The hydraulic pump 32 and the oil tank 33 are connected to the front chamber and the rear chamber of the injection cylinder 18 via a four-port switching valve (servo valve) 34. Further, the control system includes a servo control circuit section 35 and a central control section 36. In the servo control circuit unit 35, operation data on the injection device 15 side, for example, a screw forward pressure signal Spf detected from the injection cylinder 18,
The screw retreat pressure signal Spr, the injection speed signal Sv obtained from the detection result of the screw position detection sensor 37, and the like are given, and the servo control circuit section 35 gives a control signal Sc to the servo valve 34. A series of controls for the injection cylinder 18 is performed.

On the other hand, the central control unit 36 controls the speed setting data D
The v and the pressure setting data Dp are given to the servo control circuit section 35, and the overall control of the molding machine is controlled. The central controller 36 includes a condition setting section 38 and an automatic mode setting switch 3
9, an injection device position confirmation switch 40, a release switch 41 for releasing the purge at the purge dedicated speed Vp, and the like. The condition setting unit 38 has a function of setting the purge-dedicated speed Vp based on the conditions described later. Further, the automatic operation is performed by turning on the automatic mode setting switch 39. Furthermore, by turning on the injection device position confirmation switch 40, it is possible to confirm whether or not the position of the injection device 15 is at the nozzle touch position. Therefore, a position sensor (not shown) that detects the position of the injection device 15 (the injection nozzle 16) is provided. On the other hand, when the release switch 41 is turned on, the purge-dedicated speed V
It is possible to forcibly switch from p to the injection speed Vi.

Next, a method for purging an injection molding machine according to the present invention will be described with reference to the flow chart shown in FIG. 1 and FIG.

First, the condition setting unit 38 is used in advance to set the purge-dedicated speed Vp, which is lower than the injection speed Vi of the screw 12. In this case, in particular, when the injection speed in the molding cycle is approximately 300 mm / sec or more, it is desirable to set the purge-dedicated velocity to approximately less than 100 mm / sec.

On the other hand, during the purging process in the manual mode, the material supply from the hopper 17 is stopped, and the operation for starting the purging, that is, the switch for starting the purging is turned on (step 1). As a result, the central control unit 36 determines whether or not there is a nozzle touch, that is, the injection nozzle 16 is in the mold 13.
It is detected whether or not is touched (step 2). In this case, the detection is performed by the injection device position confirmation switch 40 described above.
You can directly use the data that can be confirmed by. Then, when there is no nozzle touch, the purge-dedicated speed Vp, which is relatively low, is selected (step 3), and the screw 12 is advanced at the purge-dedicated speed Vp to execute the purge process (step 4). Therefore, even with an injection molding machine that performs high-speed injection, the ejection speed of the resin material from the injection nozzle 16 at the time of performing the purge process is reduced, and the resin material is prevented from scattering from the injection nozzle 16.

On the other hand, when there is a nozzle touch, the normal injection speed Vi is selected (step 5), and this injection speed Vi is selected.
Injection into the mold 13 is performed (step 4). Even when there is no nozzle touch, the release switch 41 is manually turned on to turn on the normal injection speed Vi.
The purging process can be executed by. In this case, high-speed injection
It is possible to check the state and the like, and the operator manually selects in a conscious state, so that the operator can be alerted to the scattering of the resin material and the safety can be improved.

In the actual purging process, the purge start switch is turned on to confirm whether or not the automatic mode setting switch 39 is turned on in addition to the presence or absence of nozzle touch. Then, the purge-dedicated speed Vp is selected only when it is not on, while the normal injection speed Vi is selected when it is on. This is because, in the automatic mode, even if the switch for starting the purge is turned on, the purge is not started when there is no nozzle touch, so that the operator can confirm the conditions for the purge processing. You can

The embodiment has been described in detail above.
The present invention is not limited to such an embodiment.
For example, although the injection molding machine is exemplified by a hydraulic type, an electric motor type can be used in a similar manner. Other details,
The method and the like can be arbitrarily changed without departing from the gist of the present invention.

[0021]

As described above, according to the purging method for the injection molding machine of the present invention, the speed for exclusive use of purging which is lower than the injection speed of the screw is set in advance, and when the purging start operation is performed, the mold is To detect the presence or absence of nozzle touch
More, along with the absence of nozzle touch executes the purge process by purging dedicated rate, when a nozzle touch
In this case, the injection process is executed according to the injection speed.Therefore, it is possible to reliably prevent the scattering of the resin material from the injection nozzle due to the purge process, and to prevent the occurrence of accidents such as burn accidents and property damage that the worker may not expect. It has a remarkable effect that the safety and workability can be dramatically improved.

[Brief description of drawings]

FIG. 1 is a flowchart for explaining a purging method according to the present invention,

FIG. 2 is a block diagram of an injection molding machine that can perform the purging method,

[Explanation of symbols]

 M Injection molding machine 11 Heating cylinder 12 Screw 13 Mold Vp Purging speed

Claims (1)

[Claims] 1. In a purging method of an injection molding machine for discharging a resin material in a heating cylinder, when a purge exclusive speed lower than an injection speed of a screw is set in advance and a purging start operation is performed, Whether the nozzle touches the mold
As a result of the detection, when there is no nozzle touch, the purge process is executed at the above-mentioned page-dedicated speed , and
When there is a slip touch, the injection process is performed at the above injection speed.
A method for purging an injection molding machine, the method comprising: