JPH0511018B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a mold clamping force setting method for a toggle type injection molding machine.

(Background technology) Injection molding machines with a toggle type mold clamping device for each mold are often used in insert molding, connection molding, complex part molding, etc.; When replacing the mold clamping force, it is necessary to accurately position the nozzle touch position or side core position at a predetermined position.

Specifically, the toggles of the mold clamping devices of opposing molds are fully extended, and both molds are aligned at the parting line (an imaginary line set so that the centers of the injection nozzles touch and injection is performed). ) to set the initial position, then retract the toggle of each mold clamping device, and rotate the tie bar nuts holding the ends of the toggles to move the entire mold clamping device in the direction of the parting line. The mold clamping force is set by moving the tie bar a predetermined amount and fixing the tie bar with a lock nut. Note that the mold clamping force is set by the above-mentioned amount of movement, that is, the amount of push-in.

However, since these limitations are made manually using a jig or the like, there are disadvantages in that the work is time-consuming and the setting accuracy is poor.

(Objective of the Invention) The present invention has been proposed in view of the above points, and its purpose is to automatically perform mold clamping force setting work, save time and effort, and improve setting accuracy. An object of the present invention is to provide a method for setting mold clamping force for a toggle type injection molding machine.

(Disclosure of the Invention) The present invention will be described in detail below with reference to the drawings showing embodiments.

FIG. 1 shows an embodiment embodying the present invention, in which A shows the state before the mold is replaced, and B and C show the operation after the mold is replaced. Note that the figure shows a case where molding is performed using two opposing molds, and one mold clamping device is not shown. Furthermore, the number of molds is not limited to this, and may be any number.

To explain the configuration in FIG. 1A, a sliding space is formed on the platen 5 by an upper cover 6 and a guide 7, and sliding arms 3 and 4 with molds 1 and 2 attached to their tips are inserted into this space. It is designed to slide. Further, the rear end of the sliding arm 4 is connected to a mold clamping holding block 13 through a mold clamping link 10 and a cylinder holding link 11, and a rod of a mold clamping cylinder 12 is attached to an intermediate connection point of the mold clamping link 10. The main body of the mold clamping cylinder 12 is attached to the intermediate connection point of the cylinder holding link 11, and as the rod of the mold clamping cylinder 12 expands and contracts, a so-called toggle composed of the mold clamping link 10 and the cylinder holding link 11 expands and contracts. The sliding arm 4 is then moved. Next, a tie bar 14 is fixed to the mold clamping holding block 13, and a tie bar nut 16 is screwed into the tie bar 14 after passing through a tie bar block 15 fixed on the platen 5. By rotating the tie bar nut 16, the tie bar 14 is fixed. The entire mold clamping device can be moved by pushing and pulling. Then, it can be fixed by tightening with a lock nut 17.

Further, in addition to the general configuration described above, the present invention has a configuration for automating the setting of mold clamping force. That is, mold stepped parts 1a and 2a are provided at the upper ends of the molds 1 and 2, and a predetermined push-in amount is achieved by restricting the forward movement of the molds by a stopper 8 provided in the upper cover 6. A predetermined mold clamping force can be set. That is, when the mold 1 is fully extended with the toggle of the mold clamping device fully extended, the stopper 8 is moved so that the stopper 8 and the mold stepped portion 1a come into contact at a position where the tip extends beyond the parting line L _P by the pushing amount d ₁ . Set the position of one end, and then move the mold 2 to the stopper 8 and the mold stepped part 2a at the position where the tip protrudes from the parting line L _P by the pushing amount d ₂ with the toggle of the mold clamping device fully extended. The position of the other end of the stopper 8 is set so that the two ends are in contact with each other. In addition, the amount of push-in d ₁ ,
_d2 is determined according to the amount of shrinkage of the mold clamping device, etc. when the mold is clamped with the set mold clamping force against the parting line L _P. Moreover, FIG. 2 shows the state seen from above of the upper cover 6, and the stopper 8 is fitted and fixed in a stopper guide groove 6a provided in the upper cover 6, and the stopper 8 is fixed by being fitted into a stopper guide groove 6a provided in the upper cover 6. is configured to receive it in a direction perpendicular to it.
On the other hand, returning to FIG. 1 to explain the structure, the tie bar nut 16 is provided with teeth around it, which mesh with the gear 18 so that it can be automatically rotated and stopped by the operation of the motor 19. Note that as the motor 19, an electric motor or a hydraulic motor can be applied.

Figure 1A shows the state before the molds are replaced, but when the molds are clamped, molds 1 and 2 are in contact at the parting line L _P , and in this state, the broken line from below shows The injection nozzle 9 shown rises,
Injection of molten resin is performed.

When replacing the mold, open the mold using each mold clamping cylinder, position each mold clamping device at the rearmost end on the tie bar block side using the motor, and then replace the mold 1,
2 is removed from each sliding arm 3, 4, and molds 1', 2' having different thicknesses, parting line positions, etc. are attached to the sliding arms 3, 4.

When the automatic setting of the mold clamping force starts, oil is supplied to the mold clamping cylinder of one mold 1', the toggle is fully extended, and the tie bar nut is rotated by the motor and gear, and the tie bar nut is rotated in the direction of the parting line. Move the mold clamping device to The mold 1' also moves at the same time as the mold 1', and when the stopper 8 and the mold stepped portion 1a' come into contact, the rotation of the motor is stopped (see FIG. 1B). Note that when contact with the stopper 8 occurs, the current value of the motor or the oil pressure of the mold clamping cylinder increases, so a sensor (not shown) is provided to detect the increase in current or oil pressure, and the signal is used to control the motor. control.

Subsequently, the mold clamping cylinder is operated to open the mold 1', and the mold 2' side is now operated. That is, oil is supplied to the mold clamping cylinder 12, the toggle is fully extended, the tie bar nut 16 is rotated by the motor 19 and the gear 18, and the mold clamping device is moved in the direction of the parting line _LP . The mold 2' also moves at the same time, and when the stopper 8 and the stepped part 2a' of the mold come into contact, the rotation of the motor is stopped (see FIG. 1C).

Through the above operations, mold 1' is pushed in from the parting line L _P with the toggle fully extended, d ₁
The tip of the mold 2' will be in a position where the toggle is fully extended and the tip will be in a position where the tip protrudes from the parting line L _P by the amount of drive d ₂ , so high-pressure oil is applied to both mold clamping cylinders. is supplied and when both molds 1' and 2' are clamped, the two molds come into contact at the parting line L _P and a predetermined mold clamping force can be obtained.

Next, FIG. 3 shows another embodiment,
The tip of the stopper is configured in multiple stages, making it possible to select the amount of push-in. That is, as _shown in _{FIG .}
A step A with an end at the position and l ₁ ′ from the center position,
Step B with the end at l ₂ ' position and from the center position
A stepped portion C having ends at positions l ₁ ″ and l ₂ ″ is formed,
As shown in FIG. 3A, the amount of insertion of the stopper 8' into the stopper guide groove 6a is changed by the actuator 20, so that the contact position with the mold stepped parts 1a, 1a', 2a, 2a' can be changed. ing. In addition, 2
Reference numeral 1 denotes a stroke adjuster for adjusting the forward stroke of the stopper 8', and the other construction is the same as that shown in FIG. Therefore, according to this embodiment, it is possible to select the mold clamping force, and there is an advantage that efficient molding can be performed.

In the above description, a case has been described in which the mold clamping device is moved back and forth using tie bars and tie bar nuts, but it goes without saying that the present invention can be applied to other configurations, such as those using taper keys.

(Effects of the Invention) As described above, the present invention is a toggle type in which the mold opening/closing operation is performed by expanding and contracting the toggle, and the entire mold clamping device can be moved on the platen by moving the end holding position of the toggle. When setting the mold clamping force of an injection molding machine in which a mold clamping device is provided for each opposing mold, the advance limit of the mold is set at a position that is offset from the set parting line by the amount of push-in to obtain the set mold clamping force. After replacing the molds, the entire mold clamping device is moved forward with the toggle of the mold clamping device of one mold fully extended, and the mold is checked to see if its forward movement is restricted by the aforementioned means. When this is confirmed, the forward movement is stopped and the toggle is retracted to open the mold, and with the toggle of the mold clamping device of the other mold fully extended, the entire mold clamping device is advanced, and the mold is advanced by the above-mentioned means. Since the forward movement is stopped when it is confirmed that the mold clamping force is regulated, the work of setting the mold clamping force can be done automatically, which has the effect of not only requiring less time and effort but also improving the setting accuracy.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the configuration and operation of an injection molding machine showing one embodiment of the present invention, FIG. 2 is a partial detailed configuration diagram of FIG. 1, and FIG. 3 is a configuration diagram showing another embodiment. be. 1, 1', 2, 2'...Mold, 1a, 1a', 2
a, 2a'...Mold stepped part, 3, 4...Sliding arm, 5...Platen, 6...Top cover,
6a... Stopper guide groove, 7... Guide,
8, 8'... Stopper, 9... Injection nozzle, 1
0...Mold clamping link, 11...Cylinder holding link, 12...Mold clamping cylinder, 13...Mold clamping holding block, 14...Tie bar, 15...Tie bar block, 16...Tie bar nut, 17...Lock nut, 18...Gear, 19...Motor, 20
... Actuator, 21 ... Stroke adjuster, L _P ... Parting line.

Claims (1)

[Claims] 1 Injection molding in which each opposing mold is equipped with a toggle-type mold clamping device that opens and closes the mold by expanding and contracting the toggle, and can move the entire mold clamping device on the platen by moving the end holding position of the toggle. When setting the mold clamping force of the machine, a means is provided to restrict the advance limit of the mold at a position that is shifted by the amount of push-in to obtain the set mold clamping force with respect to the set parting line. The entire mold clamping device is moved forward with the toggle of the mold clamping device fully extended, and when it is confirmed that the mold is restricted from advancing by the above-mentioned means, the forward movement is stopped and the toggle is retracted to close the mold. The mold clamping device of the other mold is opened, the toggle of the mold clamping device of the other mold is fully extended, and the entire mold clamping device is advanced, and when it is confirmed that the mold is restricted from advancing by the above means, the advancement is stopped. A mold clamping force setting method for a toggle type injection molding machine characterized by setting the mold clamping force by