JPH081743A - Injection molding machine - Google Patents

Abstract

PURPOSE:To improve working efficiency by removing automatically resin stuck to a butt surface of a mold by a method wherein a mold-cleaning molding condition-set part wherein a molding condition for cleaning the mold is set is connected to a central processing unit. CONSTITUTION:An injection molding machine which performs injection molding by controlling an actuator with a central processing unit based on molding conditions set in a molding condition-set part. Weighing of injected resin is carried out by extruding resin to a tip side of a screw 12 by rotation of the screw 12 with a hydraulic motor 15. A controller 4 is equipped with the central processing unit 41, and an ordinary molding condition set part and a mold- cleaning molding condition set part 43 which are connected to the central processing unit 41. Further, a switching means which switches the ordinary molding condition set part 42 to the mold-cleaning molding condition set part 43 is connected to the central processing unit. A molding frequency-counter 44 is generally preferably used as the switching means.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to injection molding capable of automatically removing resin adhering to a butting surface of a mold or the like and gas components generated from molten resin by a cleaning operation (cleaning) during operation. Regarding the machine.

[0002]

2. Description of the Related Art In an injection molding machine in which a resin is injected from a nozzle into a mold cavity that has been clamped, a part of the resin or a gas component enters the butt surface of the mold and adheres to that portion. Easy to do. If this adhered resin is left as it is for a long time, its amount may gradually increase to adversely affect the molding, or it may decompose and corrode the mold.

For this reason, conventionally, the attached resin is regularly removed manually by the worker.

[0004]

However, the method of manually removing the adhered resin by the operator is labor-intensive and labor-saving. Also, when continuously molding for a long time, it is necessary to purposely interrupt the molding on the way to remove the adhered resin,
There is a problem that work efficiency decreases.

An object of the present invention is to provide an injection molding machine capable of automatically removing the adhered resin without interrupting the molding operation.

Another object of the present invention is to provide an injection molding machine capable of accurately eliminating wash-molded products and preventing the wash-molded products from being mixed into regular molded products. .

[0007]

In order to achieve the above object, an injection molding machine according to the present invention is an injection molding machine in which a central processing unit controls an actuator based on a molding condition set in a molding condition setting section. In the injection molding machine for performing the above, the mold cleaning and molding condition setting unit for setting molding conditions for cleaning the mold is connected to the central processing unit.

The central processing unit may be connected to a switching means for switching a normal molding condition setting unit for setting molding conditions for normal molding to a mold cleaning molding condition setting unit. It is preferable that the switching means is usually a molding number counter.

The central processing unit may be provided with a function of outputting a sorting signal for sorting the wash-molded products molded under the molding conditions of the mold cleaning-molding condition setting unit.

[0010]

When the normal molding condition setting section is working, a normal regular molded product is molded. When the mold cleaning and molding condition setting part is selected, the normal molding condition becomes the mold cleaning molding condition set in the mold cleaning and molding condition setting part, and the gap between the butt surfaces of the mold is larger than that during normal molding. Occurs, and the washed molded product is molded. In this case, the resin adhered to the abutting surface of the mold until then becomes integrated with the wash-molded product and is removed together with the wash-molded product.

If the switching means is provided, the normal molding condition setting unit and the mold cleaning molding condition setting unit can be switched completely automatically without the need for a button operation by an operator. Also,
When the switching means is the normal molding number counter, the adhered resin can be removed by carrying out washing molding every time a preset number of regular molded articles are molded.

If the central processing unit is provided with a function of outputting a sorting signal, it is possible to properly remove the wash-molded article by the sorting signal.

[0013]

1 to 6 show one embodiment of an injection molding machine according to the present invention. The injection molding machine of this embodiment is a toggle type injection molding machine, and mainly includes an injection device 1, a mold device 2, a mold clamping device 3, and a control device 4.

The injection device 1 advances the screw 12 inserted in the heating cylinder 11 to the left in FIG. 1 by the injection cylinder (actuator) 13 to inject the resin in the heating cylinder 11 into the mold device 2. It is a thing. An injection position sensor 14 is attached to the injection cylinder 13, and the screw 12
A hydraulic motor (actuator) 15 for rotating the screw 12 in the circumferential direction is provided between the and the injection cylinder 13.

The injection resin is measured by rotating the screw 12 by the hydraulic motor 15 and pushing the resin in a molten state to the tip side of the screw 12 while the screw 12 is pressed by the measurement resin pressure.
Is performed by retreating to the right in FIG. The amount of measured resin can be known by detecting the amount of retreat of the screw 12 by the injection position sensor 14.

In the hydraulic circuit of the injection cylinder 13, a proportional pressure control valve 16 and a proportional flow control valve 17 which are electromagnetic valves are provided.
Etc. are provided. The injection pressure of the resin is controlled by the pressure control valve 16, and the injection speed is controlled by the flow rate control valve 17. The injection device 1 is movable left and right in FIG. 1 with respect to the mold device 2.

The mold unit 2 will be described. The fixed platen 2
One end of four tie bars 21 (only two are shown in the drawing) is fixed to 0, and an end plate 22 is attached to the other end of the tie bar 21. The end plate 22 has a threaded portion 21 a of the tie bar 21 screwed into a nut body 23, and is moved in the axial direction of the tie bar 21 by rotation of the nut body 23 by a hydraulic motor (actuator) 24.

A movable plate 25 is provided between the fixed plate 20 and the end plate 22. The movable plate 25 is movable left and right along the tie bar 21 in FIG. Molds 26 and 27 are individually attached to the fixed platen 20 and the movable platen 25, respectively. The movable platen 25 is provided with a mold clamping position sensor 28, and the hydraulic motor 22 is equipped with a mold thickness position sensor 2.
9 are provided.

The mold clamping device 3 comprises a mold clamping cylinder (actuator) 31 and a toggle link mechanism 32. The mold clamping cylinder 31 is attached to the end plate 22, and the toggle link mechanism 32 has one end at the end plate 22.
The other end is connected to the movable platen 25, and the crosshead 32a is connected to the piston rod 31a of the mold clamping cylinder 31, and is provided between the end plate 22 and the movable platen 25. The mold clamping device 3 is a mold clamping cylinder 31.
Of the movable plate 25 via the toggle link mechanism 32 by the extension operation of
Is pushed toward the fixed plate 20 to clamp the molds 26 and 27 between the fixed plate 20 and the movable plate 27.

Since the mold clamping force of the molds 26 and 27 by the mold clamping device 3 is proportional to the extension amount of the tie bar 21 during mold clamping, when the mold thickness is the same, the fixed platen 20 and the end plate 22 are fixed. The smaller the interval, the larger. The mold clamping force is adjusted by rotating the nut body 23 with the hydraulic motor 24.
The die thickness position sensor 29 detects the rotation amount of the nut body 23 at this time, that is, the position of the end plate 22.

The control unit 4 includes a central processing unit 41 and a normal molding condition setting section 42 connected to the central processing unit 41.
A mold cleaning / molding condition setting unit 43, a normal molding frequency counter (switching unit) 44, a mold cleaning / molding frequency counter 45, a mold thickness retreating amount setting unit 46 during mold cleaning / molding, an input circuit 47, an output circuit 48, and the like. Have. The sensors 14, 28, 29 are connected to the input circuit 47, and the central processing unit 41 has
Pressure control valve 16 via D / A converter 49 and amplifier 50
And the flow control valve 17 are connected. Also, the output circuit 4
8, solenoid valves and the like provided in hydraulic circuits such as actuators 13, 15, 24 and 31 are connected.

The normal molding condition setting section 42 is used for molding a regular molded product, and injection conditions A such as injection pressure and speed (A is a normal molding condition, and a mold cleaning molding condition B described later).
And for convenience. ), The resin measured value A, the cooling time A, the mold clamping force A, etc. are set. Further, the mold washing and molding condition setting unit 43, the injection condition B, the measured value B, the cooling time B, when cleaning the molds 26 and 27,
The mold opening stop position B and the like are set.

The mold washing and molding condition B is usually set as follows with respect to the normal molding condition A, but in some cases, a part thereof may be reversed. Injection pressure under injection conditions; A ≧ B Injection speed under injection conditions; A ≦ B Measurement value; A ≦ B Cooling time; A ≧ B

The normal molding number counter 44 indicates the number of times the regular molded product is molded, and the mold washing and molding number counter 45 indicates
The number of times of cleaning and molding of the molds 26 and 27 is set respectively. In addition, the mold thickness retraction amount setting unit 46 during mold cleaning and molding
Is for setting the amount of retreat of the end plate 22 to the left in FIG. 1 when the molds 26 and 27 are washed and molded.

The above-mentioned amount of retreat cannot be generally stated depending on the type of resin, the injection (filling) pressure, the structure of the mold, etc., but when the injection is completed, the abutting surfaces 26f, 27f of the molds 26, 27 are made. Between 0.2 and 3 mm, preferably 0.1.
The gap g of 5 to 2 mm (FIG. 4) is set to a small value. The central processing unit 41 has a function of outputting a sorting signal for sorting the wash-molded products molded under the mold wash-molding conditions.

The central processing unit 41 of the control unit 4 controls the actuators 13, 15, 24 according to the setting contents set in the setting units 42, 43, 46 and the counters 44, 45 and the output signals of the sensors 14, 28, 29. , 31, control
Although injection molding is performed, the actual control will be described with reference to the flowchart of FIG. In addition, the injection device 1, the mold device 2, and the basic structure of the mold clamping device 3, the mold cleaning and molding condition setting unit 43, the counters 44 and 45, and the mold thickness retreat amount setting unit 46 during mold cleaning and molding are excluded. The basic structure of the control device 4 is well known.

When the operation is started, normal regular molding is performed under the molding conditions set in the normal molding condition setting section 42 (step S1). That is, when injection is performed under the injection condition A (step S2), the normal molding number counter 44
Are counted (step S3), and it is determined whether or not the set number of times has been reached (step S4). If the set number of times has not been reached, the weight is measured with the measured value A (step S5), after cooling for the cooling time A in step S6, the mold is opened (step S7), and the molded product protrudes at the mold opening completion position. (Step S8). In step S9, the measured values A and B are determined. If the measured value is A, the process returns to step S1.

In the case of normal molding, as shown in FIG. 2, the molds 26 and 27 are clamped with their abutting surfaces 26f and 27f in close contact with each other without a gap. Therefore, as shown in FIG. 3, the resin P injected from the injection device 1 into the cavity C through the sprue portion a, the runner portion b, and the gate portion d is applied to the abutting surfaces 26f and 27f of the molds 26 and 27. A normal molded product M is obtained without entering a large amount. Reference numeral e is an air vent portion provided for degassing the cavity C, and the resin P does not enter this portion either.

If the set number of times is reached in step S4, the weighing value B is weighed (step S10). If the measured value is B in step S9, the next step S1
1, the mold thickness is retracted, that is, the end plate 22 is retracted to the left in FIG. 1 by the set value of the mold thickness retracted amount setting unit 46. When the end plate 22 is retracted, the abutting surfaces 26f, 2 of the molds 26, 27 are in the injection finished state after the mold clamping.
There is a minute gap g between 7f.

Next, the normal molding number counter 44 is reset (step S12), and mold washing molding is performed (step S13). That is, when the injection is performed under the injection condition B (step S14), the mold cleaning and molding number counter 45 counts (step S15), and it is determined whether or not the set number has been reached (step S16).

If the set number of times has not been reached, the measured value B
Is measured (step S17), and after cooling for the cooling time B in step S18, the mold is opened (step S1).
9) At the same time, the central processing unit 41 outputs a defect (classification) signal (step S20), and the wash-molded product is ejected at the middle position of the mold opening (step S21). The measured values A and B are determined in step S22. If the measured values are B, the process returns to step S13.

In the case of mold cleaning and molding, as shown in FIG. 4, a gap g is formed between the abutting surfaces 26f and 27f of the molds 26 and 27 in the injection completed state after the mold clamping. Therefore, the resin P injected from the injection device 1 into the cavity C through the sprue part a, the runner part b, and the gate part d has the abutting surface 26 of the molds 26, 27 as shown in FIG.
A large amount will enter into f and 27f.

At this time, a small amount of the adhered resin adhered to the abutting surfaces 26f and 27f of the mold in the normal molding is heated by the large amount of the molten resin that has entered the abutting surfaces 26f and 27f, and is integrated with it. And is removed from the molds 26 and 27 together with the washed molded product Ma.

Since the washed molded product Ma is a defective product, it must be separated from the normal molded product M. The defect signal in step S20 is output to, for example, a sorting robot (not shown) to activate it. In the illustrated embodiment, a normal molded product M
Since the washed molded product Ma and the washed molded product Ma are projected from the mold at different mold opening positions (the former is the mold opening completion position, and the latter is the mold opening midway position), they are not mixed even by themselves.

When the set number of times is reached in step S16, the weighing value A is weighed (step S23). If the measured value is A in step S22, the next step S
24, the end plate 22 is moved forward and returned to the normal molding position. Next, the mold washing and molding number counter 45 is reset (step S25), and the process proceeds to step S1.

7 to 9 show another embodiment of the present invention. The injection molding machine of this embodiment is a direct pressure type injection molding machine, and the mold clamping device 3 includes a large hydraulic cylinder (actuator) 52. The hydraulic cylinder 52 is provided with a mold clamping force sensor 53. Injection device 1 and mold device 2
The structures of the fixed plate 20 and the movable plate 25 except the end plate 22 are the same as those of the injection molding machine of FIG.

Further, in the control device 4, the mold thickness retreating amount setting unit 46 during mold cleaning and molding is omitted from FIG. 1, and the mold clamping force B is added to the mold cleaning and molding condition setting unit 43. The mold clamping force sensor 53 is clamped to the input circuit 47, and the mold clamping force is A> B.
Is set to The magnitude of the mold clamping force B cannot be generally stated in this case as well, but in the injection completed state, the abutting surface 26
The gap g in the same range as described above is set between f and 27f.

FIG. 9 shows a flow chart of this injection molding machine. As is clear from the comparison with the flowchart of FIG. 6, step S1a and step S13a are added to the flowchart of FIG. 6, and steps S11 and S24 are omitted. This will be described. In step S1a, the mold clamping force is the mold clamping force A under the normal molding condition, and in step S13a, the mold clamping force is the mold clamping force under the mold washing and molding condition. If the measured value is B in step S9, the process immediately proceeds to step S12. If the measured value is A in step S22, the process immediately proceeds to step S25.

In the injection molding machine of this embodiment, since the main difference between normal molding and mold washing molding is the difference in the mold clamping force, the mold clamping force is large or small. It does not work (see FIGS. 7 and 8).

In the present invention, either one or both of the counters 44 and 45 may be omitted, and the normal molding and the mold washing molding may be switched by operating a push button or the like. Switching between normal molding and mold cleaning molding
It is also possible to use another signal, for example, a signal for switching the resin production lot. The present invention can also be implemented in an electric injection molding machine.

[0041]

As described above, according to the present invention, in the injection molding machine for performing injection molding by controlling the actuator by the central processing unit based on the molding condition set in the molding condition setting unit, Since the mold cleaning and molding condition setting unit that sets the molding conditions for cleaning the mold is connected, the resin adhering to the butt surface of the mold can be automatically removed without interrupting the molding operation. And can be removed rapidly. Therefore, it is possible to save labor and improve work efficiency.

When the switching means is provided, the switching between normal molding and mold washing molding can be automatically performed without button operation, etc., and unmanned operation becomes possible. Further, if the switching means is a normal molding number counter, washing molding can be automatically performed every time a regular number of molded articles are molded by a preset number. Furthermore, if the central processing unit is provided with a function of outputting a sorting signal, it becomes possible to accurately remove the wash-molded product.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of an injection molding machine according to the present invention.

FIG. 2 is a front view showing a mold clamping state in normal molding.

FIG. 3 is a front view showing a butting surface of a mold after completion of normal molding.

FIG. 4 is a front view showing a mold clamping state in mold cleaning and molding.

FIG. 5 is a front view showing a butting surface of a mold after completion of mold cleaning and molding.

FIG. 6 is a flow chart of the injection molding machine of FIG.

FIG. 7 shows another embodiment of the present invention and is a front view of a mold clamping state in normal molding of a direct pressure injection molding machine.

FIG. 8 is a front view showing a mold clamping state in mold washing molding of the injection molding machine of FIG. 7.

9 is a flow chart of the injection molding machine of FIG. 7.

[Explanation of symbols]

 1 Injection Device 2 Mold Device 3 Mold Clamping Device 4 Control Device 13 Injection Cylinder (Actuator) 15 Hydraulic Motor (Actuator) 24 Hydraulic Motor (Actuator) 31 Clamping Cylinder (Actuator) 41 Central Processing Unit 42 Normal Molding Condition Setting Section 43 Mold cleaning / molding condition setting unit 44 Normal molding number counter (switching unit) 52 Hydraulic cylinder (actuator)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masakazu Ohno 2-11-14 Kugahara, Ota-ku, Tokyo Sankyo Kasei Co., Ltd.

Claims (4)

[Claims] 1. In an injection molding machine for performing injection molding by controlling an actuator by a central processing unit based on a molding condition set in a molding condition setting unit, a molding condition for cleaning a mold is set in the central processing unit. An injection molding machine, characterized in that a mold cleaning molding condition setting unit is connected. 2. The central processing unit is connected to a switching means for switching a normal molding condition setting unit for setting molding conditions for normal molding to a mold cleaning molding condition setting unit. Injection molding machine. 3. The injection molding machine according to claim 2, wherein the switching means is a normal molding number counter. 4. The central processing unit is provided with a function of outputting a sorting signal for sorting the wash-molded products molded under the molding conditions of the mold cleaning-molding condition setting unit.
The injection molding machine according to 2 or 3.