JPS6064817A - Method of changing molding material in cylinder of injection molder - Google Patents

Abstract

PURPOSE:To shorten the period during which a molder is stopped, by incorporating limit switches in a control circuit including a relay, timer, counter, etc., repeating automatically the operation by which the molding material remaining in a cylinder is forced out of the cylinder, and washing the inside of the cylinder automatically after the completion of the extrusion. CONSTITUTION:Limit switches provided at the injection end and the metering end of a cylinder 1 of an injection molder are incorporated in a control circuit including a relay, timer, counter, etc., to repeat automatically the operation where the material remaining in the cylinder 1 is forced out, and after the forcing out is completed, the inside of the cylinder is automatically carried out. That is, when the injection molding of a predetermined amount is completed, a screw 2 at the injecting mechanism has completed the metering of the next shot and has been retracted. By the retracted lever 4, the metering side switch LS2 is in the operating state. In this state, first a required amount of a washing material (Q) is charged into a hopper 3. Then the injecting mechanism section of a molder operating circuit is separated from other parts by a change-over switch, a start button of a material changing circuit is operated to repeat automatically the injection and metering, the material (P) remaining in the cylinder is forced out and the cylinder is washed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical field to which the invention pertains] This invention relates to a method for changing molding material during setup work in an injection molding machine. It is desirable to shorten or automate the time required for changing molding materials during setup work.

[Prior art and its problems]

In an injection molding machine, after the planned amount of molding is completed, if the next material to be used is of a different η, or if the material is the same but has a different color, the material must be changed.

That is, the remaining molding material that has been used so far in the cylinder is discharged, the inside of the cylinder is cleaned, and then new molding material is injected. Conventionally, when the planned amount of molding is completed, the molding operator manually operates the push button switch on the injection molding machine, repeating the "needle valve" and "one injection" process.
The molded phase t1 remaining in the cylinder is pushed out of the cylinder/direction, and only then is "Sowa for cleaning" injected into the cylinder for cleaning. In this conventional method,
Until the inside of the cylinder is cleaned, the molding operator has to manually operate the 17-inch pusher for each injection molding machine, making it impossible to use this idle time to perform other tasks. This resulted in a series of setup operations, which increased the injection molding machine's stoppage time and lowered the operating rate.

[Purpose of the invention]

This invention eliminates the above-mentioned drawbacks, and once the planned amount of molding is completed, the molding operator only needs to put the cleaning material into the hopper and operate the start push button switch, and the remaining molding material is automatically removed. The object of the present invention is to provide a method in which extrusion is repeated and cleaning is performed when the molding material is used up.

[Key points of the invention]

This invention incorporates limit switches provided at the injection end and metering end of the cylinder in a 7#:l injection molding machine into a control circuit composed of relays, timers, counters, etc., and eliminates molding material remaining in the cylinder. The work of extruding the material out of the cylinder is automatically repeated repeatedly, and the inside of the cylinder is automatically cleaned after extrusion is completed.

[Embodiments of the invention]

Embodiments of the invention will be described based on the drawings.

FIG. 1 is a longitudinal sectional view of an injection mechanism section of an injection molding machine, and FIG. 2 is a material layer control circuit diagram for operating the same injection mechanism section.

In the injection mechanism part in Fig. 1, 1 is a cylinder, 2 is a screw,
3 is the hopper, 4 is the limit switch operating lever, LSI
is the limit switch on the injection end side, LS2 is the limit switch on the metering side, P is the molding phase, and Q is the cleaning material. When the injection molding of the planned quantity is completed, the screw 2 in the injection mechanism section finishes metering the next shot and retreats.

The lever 4 is in the state shown in Figure 1 and has been retracted.
Therefore, the metering end side limit switch LS2 is in the operating state. In this state, the required amount of cleaning material Q is first put into the hopper 3. Next, use a switch to disconnect the injection mechanism from other parts of the molding machine operation circuit. Next, when the start button of the material change circuit is operated, "injection" and "measuring" are automatically repeated, and the remaining molding 11.
Press P, and the cleaning material Q enters into the cylinder 1 to perform cleaning. This operation will be explained in detail based on FIG. In Fig. 2, R1 and -1 are the excitation coils of the first relay, and R1-2, R1-a, and R1-4 are all R1.
-1 is the a contact activated by R2-1 is the excitation coil of the second relay, R2-2 and R2-a are both R2
-1 is the a contact activated by R3-1, R31 is the excitation coil of the third relay, R3-2 is the b contact activated by R3-1, R3-3, R3-4, R3-5 are R3
-1 is the a contact actuated by R4-1, R4-1 is the excitation coil of the fourth relay, R4-2 is the b contact actuated by R4-1, T-1 is the timer, T-2 is the open time contact of the timer. , C-1 is a counter.

C-2 is the b contact of the counter, LSI is the IJ limit switch on the injection end side, LS2 is the limit switch on the metering end side, P
BI and PH1 are push button switches for closing operation, and PH2 is a push button switch for opening operation.

The number of reciprocations of the screw 2 to push out all of the molding material P and cleaning material $1Q that have been used so far out of the cylinder 1 can be predicted to some extent, so the number of times is set in the counter C. Also, since the "weighing" time is set, a time longer than that time is set in the timer T-1. After making this preparation, press the push button switch P.
Press lh (closed circuit) to utilize this feather change control circuit. That is, the excitation coil R1-1 of the first relay is excited,
As a result, the a contacts of the first relay R1-2, R13°R
1-4 is closed, and even if the closing operation of the push button switch PB is stopped (FBI returns to open), the first
The relay is self-maintaining. Next, push button switch PB-
When you press 3, the excitation coil R2-1 of the second relay is energized, which causes the a contacts R2-2 and R2- of the second relay to be activated.
3 is closed. Relay 2 is self-held by closing R2-2, and 5ol-A is activated by closing R2-3.
Perform "ejection". At the end of injection, limit switch LS-1 is activated at the injection end 7, and excitation coil R3 of the third relay is activated.
-1 is energized, the b contact R3-2 of the third relay is opened, and the a contact R"31 R34y R"s is closed. By closing R3-3, the third relay is self-holding, and by opening R3-2, 9S (M-A stops and R
With 34 cycles SOA! -B operates and starts "weighing". Further, due to the closing of R3-5, the counter C-1 counts the first time. When the screw 2 that performs the "measuring" operation moves backward and reaches the measuring end, the limit switch LS
2 is activated, the excitation coil R4-1 of the fourth relay is excited, and when the b contact R4-2 of relay 4 is opened, the excitation coil R3-1 becomes non-excited, and the b contact R3-2゜a
Contacts R3-a, R3-4, and R3-5 each return,
801-B stops due to the opening of R3-4, and R3-2
S(M-A) is operated by closing the circuit. In this way, when there is a sufficient amount of material in the cylinder 1, the screw 2 reciprocates by the operation of the limit switches LSI and LS2, and the material in the cylinder 1 is removed. Push out and force cylinder 1
When the amount of material decreases, even if the screw 2 performs the "measuring" operation, it does not fully retreat, and in this case, the limit switch LS2 does not operate.In this case, the preset timer T
-1, the contact T-2, which limits the disconnection for a certain period of time, is opened and the excitation coil R3-1 of the relay 3 is de-energized, and the a contact R3-
Due to the opening of 4, SOA! -B motor stops and b contact R3
-2 (7) When the circuit opens, sOl-A operates and “injection”
``Repeat the total iJ.

In this way, the limit switch LSI#LS2
Due to the operation of , limit switch LSt and timer T-
1 performs "injection" and "measurement" to push the material out. When the number of times set in counter C-1 is repeated, b contact C
-2 is a closed circuit, and excitation coil R1-1 is non-excited,
The a-contacts R1-2, R1-3, and R1-4 are restored and the material layer control circuit becomes inactive.

As a result, the operator can automatically discharge the molding material and clean the inside of the cylinder by pressing the start button once.

〔Effect of the invention〕

According to this invention, the limit switches provided at the injection end and metering end of the cylinder are relays.

It consists of timers, counters, etc., and is integrated into the control circuit.
The work of extruding molding material remaining inside the cylinder out of the cylinder is performed repeatedly automatically, and the inside of the cylinder is also automatically cleaned after extrusion is completed, so that workers are not required to do other work during this time. This enabled setup work, which shortened the molding machine's stoppage time and improved its operating rate.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view of the injection mechanism of an injection molding machine, and FIG. 2 is a powder change control circuit diagram used in an embodiment of the present invention.
Limit switch, P: Molding material, T-1: Timer.

Claims (1)

[Claims] In an injection molding machine, the molding material remaining in the cylinder is extruded and then cleaned, and the limit switches installed at the injection end and metering end of the cylinder are connected to a control circuit consisting of relays, timers, counters, etc. The process of assembling and extruding the molding material remaining inside the cylinder out of the cylinder is automatically repeated, and after the extrusion is completed, the system