JPH0338025B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a die-casting product equipped with a seizure detection control device in order to detect product seizure and prevent accidents such as damage to product ejection pins and core extraction pins in the production of die-cast products. It's about machines.

There are various types of die-casting machines, such as cold chamber die-casting machines, hot chamber die-casting machines, two-piece type with a fixed type and a movable type, and a three-piece type with a fixed type, an intermediate type, and a movable type.
Furthermore, various auxiliary equipment are provided corresponding to the applicable die casting methods such as ordinary die casting method, vacuum die casting method, oxygen displacement die casting method, and scavenging die casting method.

These die-casting machines solidify molten metal under pressure, so they can produce products of superior quality with a cleaner casting surface compared to other methods such as gravity casting. Seizing may occur between the mold and the core. When a burn-in phenomenon occurs,
Due to maintenance of the mold and checking of casting conditions at the location where the problem occurred, operations will be halted during that time and productivity will drop.Not only will the product itself be defective, but the product ejection pin and core will be damaged. This may lead to damage to the pull-out pin. Therefore, it is extremely important to predict the seizure phenomenon in die casting operations, but the seizure phenomenon is affected by a wide variety of factors, including alloy composition, molten metal temperature, product shape, mold release agent, die casting shot spacing, and pressing force. Since there is no appropriate detection means that can be adopted at production sites, until now, based on experience, when a set number of shots has been reached, which takes safety into account, operations are stopped and molds are cleaned. Methods such as processing or continuing die-casting operation until seizure occurs have been adopted, but with the previous method, it was difficult to further reduce the number of stoppages of the die-casting machine and improve productivity appropriately. The latter method has problems such as troublesome recovery measures and monitoring.

The present invention provides that when a seizure phenomenon occurs in a die casting machine that is operated by a pressure medium, for example, is equipped with a hydraulic extrusion cylinder mechanism and a core cylinder mechanism, the operating pressure of the pressure medium flow path for retracting the cylinder is reduced. This idea was created by focusing on abnormal increases. That is, by detecting that their operating pressures have reached a predetermined level, it is detected that the seizure phenomenon is about to occur, or the occurrence of the seizure phenomenon is detected, and the extrusion cylinder mechanism and the core cylinder mechanism are activated. This paper proposes a device for controlling the

The present invention will be described in detail below with reference to the accompanying drawings. The die-casting machine equipped with the seizure detection control device according to the present invention may be of any type, but the first embodiment is an example of a mode that is common to a two-piece type ordinary die-casting machine.
It is shown in the figure and explained with reference to the figure.

In a normal die casting machine, molten metal is supplied by an injection plunger 6 through a sleeve 5 into a cavity formed between a fixed die 2 fixed to a fixed platen 1 and a movable die 4 attached to a movable platen 3, and pressurized. A product 7 is obtained by solidification, and a core cylinder mechanism 9 equipped with a core is disposed at the tip via a core extraction pin 8 depending on the shape of the product.

After solidification under pressure, the mold is opened by advancing the injection plunger 6 and retracting the movable platen 3 in order to take out the product 7, and then the extrusion rod 11 fixedly attached to the extrusion cylinder mechanism 10 is connected to the extrusion plate 12. The product ejecting pin 13 is operated to remove the product 7 from the movable mold 4. On the other hand, in the case of die casting operation in which a core is used depending on the product shape, the core cylinder mechanism 9 is activated, and after the core is pulled out, the extrusion cylinder mechanism 10 is activated.

It should be noted that a plurality of core cylinder mechanisms 9 are arranged in accordance with the number of cores required depending on the product shape, and the extrusion cylinder mechanism 10 can also be arranged on a piston rod that operates the movable platen 3. Of course, it is possible to apply an appropriate structure such as a mode in which a plunger tip is formed and integrated, or a mode in which it is disposed as a single cylinder mechanism in the central space of the piston rod that operates the movable platen 3. It is.

The present invention provides for a die casting machine having these core cylinder mechanisms 9 and/or extrusion cylinder mechanisms 10,
A new pressure detection pipe 1 is added to the pressure medium flow path for retreating.
4 and 14' are branched, and a seizure detection control device consisting of a pressure detection section A and a calculation control section B is connected to each of them, and the calculation control section B is shared depending on the capacity of the device used. FIG. 1 shows an example of a shared configuration.

Pressure detection pipes 14, 14' are branched from the retreating pressure medium channels of the cylinder mechanisms 9, 10, and there are pressure detectors 15, 15' and a pressure signal for converting the detected pressure into an electrical signal of a predetermined pressure unit. converter 1
6 and 16' are connected in series.

An appropriate pressure sensor can be applied to the pressure detector 15, and its pressure detection capacity is selected depending on the target metal and the capabilities of the cylinder mechanisms 9 and 10. For example, in the case of aluminum die casting, a pressure sensor of about 3000 psi is used. be done.

The pressure detection terminal is connected via an amplifier if desired.
Analog-to-digital signal converters (hereinafter referred to as "A/D converters") 17, 17' are connected to constitute a pressure detection section A, which converts the analog signals from the pressure detectors 15, 15' into digital signals, Send to calculation control unit B.

The arithmetic control section B determines whether the detection signal from the pressure setting device 18 into which a set value is digitally input and the pressure detection section A exceeds the set value input from the pressure setting device 18, and also uses the determination result. Toni hydraulic control section 2
0, and when the detection signal exceeds a set value, controls the operation of the core cylinder mechanism 9 and the extrusion cylinder mechanism 10, which operate in response to the operation command from the calculation circuit 19. Furthermore, if desired, an alarm 21 which warns with a lamp or a buzzer that the detection signal exceeds a set value, and a measured value and a set value if desired (also displayed on the pressure setting device 18). A display 22 for displaying , a recorder 23 for measuring measured values and set values, etc. are attached. In this case, calculation control unit B
may be used in common as shown in FIG. 1, but it is also possible to use separate systems for the core cylinder mechanism and for the extrusion cylinder mechanism.

The number of pressure setting devices 18 corresponds to the number of installed cylinder mechanisms 9 and 10, but since a plurality of pressure setting devices 18 are often provided especially for the core cylinder mechanism 9 depending on the shape of the product, it is possible to accommodate variations in the product type. It is desirable to provide a number that will yield the desired results.

The specific setting values to be input to the pressure setting device are determined by taking into account the type of metal to be die-cast, the pressure resistance of the core pull-out pin and product ejection pin used, the separation pressure when seizing occurs, the degree of safety against seizing, etc. However, for aluminum die casting, the appropriate weight is about 40 to 50 kg/cm ² .

When the detected pressure reaches a set value in response to a command signal from the arithmetic circuit unit 19, the hydraulic control unit 20 stops further backward movement of the cylinder mechanisms 9 and 10, and closes the core extraction pin and product ejection pin. Hydraulic control to prevent damage and return the cylinder mechanism to its previous state, and to complete retraction without reaching the damage pressure of the core pin or product ejection pin. The control operation is performed by controlling the operation of the solenoid valve 24, pump 25, etc.

If the arithmetic control unit B has a capacity that can be used commonly for the core cylinder mechanism and the extrusion cylinder mechanism, control operations can be performed by constructing a sequence control circuit as illustrated in Fig. 2. can.

The operating procedure of this device under such sequence control is as follows.

When the casting operation of the die-casting machine is completed, the timer is activated to start opening the mold, and the movable mold 4 is moved back a predetermined distance. When the mold opening is completed, the make contact Cr-1 operates to operate the core cylinder mechanism 9, and the core pull-out pin 8 retreats.If the retreat hydraulic pressure is normal, following the retreat movement of the product ejecting pin 13, the product is removed. Make contact of extrusion cylinder mechanism 10
Cr-2 is activated, the product ejecting pin 13 retreats,
If the backward hydraulic pressure is normal, one die-casting shot will be completed normally.

However, the retreating hydraulic pipes 14 and 1 in the core cylinder mechanism 9 or the extrusion cylinder mechanism 10
When the operating pressure at 4' becomes higher than the set value, the respective backward movement is stopped.

That is, in the core cylinder mechanism 9, the hydraulic pipe line 1
When the oil pressure of 4' exceeds the set value, solenoid valve SOL-1 24' operates and relay R
1 is activated, the hydraulic pump is stopped, and a warning lamp is activated.
An alarm is issued by L ₁ or a buzzer.

The worker sees the alarm and presses the snap switch to release it.
While canceling the alarm state using SW-1, the retreating movement of the core cylinder mechanism is completed by manual operation, etc., and work such as cleaning the surface of the core extraction pin and replacing the core extraction pin is performed.

Similarly, when the oil pressure in the hydraulic line 14 of the product extrusion cylinder mechanism 10 exceeds the set value, the solenoid valve SOL-2 24 is activated and the relay R ₂ is activated.
is activated, the hydraulic pump is stopped, and an alarm is issued by the alarm lamp _L2 and the buzzer.Then, while canceling the alarm state using the release snap switch SW-2, complete the retraction movement of the product ejector pin, and then release the product ejector pin. Perform work such as surface cleaning or pin replacement.

The surface of the core extraction pin and product ejection pin 13 is usually cleaned by removing the coating layer formed on the surface by brush polishing or chemical polishing.
This is done by applying a mold release agent, etc.

Other types of sequence control circuits in the arithmetic control section may be applied depending on the die-casting machine used, and a control system with two set values may also be used. For example, a value (T ₁ ) that allows for several shots before burn-in occurs.
There are two types of set values: and a seizure limit value (T ₂ ), and when the set value (T ₁ ) is reached, the cylinder mechanism is temporarily stopped, and then the cylinder mechanism continues to move backward, and the backward hydraulic pressure is If T ₂ is not reached, the retraction operation is completed anyway, the current casting operation is completed, and the pin cleaning process is performed. On the other hand, if the retreat hydraulic pressure reaches T ₂ midway, the pin will be damaged, so the retreat operation is completely stopped, and after using auxiliary separation means such as burner heating, the retreat operation is completed manually. be able to.

Above, an embodiment in which the present invention is applied to a two-piece die-casting machine using a normal die-casting method has been described with reference to drawings. However, if the core cylinder mechanism and extrusion cylinder mechanism are equipped with a hydraulic mechanism or compressed air mechanism that uses pressure medium, the same function can be achieved by attaching a seizure detection control device to the pressure medium pipeline. Therefore, it can be applied to other die-casting machines not illustrated as appropriate.

Furthermore, according to the present invention, it becomes possible to practically detect the seizure phenomenon between the die-cast product, the mold, and the core, thereby preventing damage to product ejection pins and core extraction pins, and It becomes possible to continue the die-casting operation up to the limit where the sticking phenomenon occurs, and the productivity of die-casting can be significantly improved. Due to the area effect, this is mainly used to detect seizure, but it can also be used as a secondary method to detect cast burrs that rarely occur near the insertion openings of product ejection pins and core extraction pins. , excellent practical effects are exhibited.

[Brief explanation of the drawing]

FIG. 1 is a conceptual explanatory diagram showing an example of an embodiment of the present invention, and FIG. 2 is a circuit diagram showing one aspect of a sequence control circuit in an arithmetic control section of the device of the present invention. 8... Core pull-out pin, 9... Core cylinder mechanism, 10... Extrusion cylinder mechanism, 13... Product extrusion pin, 14, 14'... Pressure detection conduit,
15, 15'...Pressure detector, 16, 16'...Pressure signal converter, 17, 17'...Analog-digital signal converter, 18...Pressure setting device, 19...
Arithmetic circuit section, 20... Hydraulic control section, 24, 24'
...Solenoid valve.

Claims (1)

[Claims] 1. In a die-casting machine equipped with an extrusion cylinder mechanism and/or a core cylinder mechanism, a pressure detection pipe is branched into the retreating pressure medium flow path of each cylinder mechanism, and a pressure detection terminal and analog
It is determined whether the detection signal from the pressure detection section A consisting of a digital signal converter, the pressure setting device and the pressure detection section exceeds the set value input from the pressure setting device, and if it is judged that it exceeds the set value, hydraulic pressure is controlled. an arithmetic control section B consisting of an arithmetic circuit section that gives an operation command to extrude the core and/or a retreat stop to the core; and the hydraulic control section that operates in response to the operation command from the arithmetic circuit section; Furthermore, if desired, a burn-in detection control device is installed, which comprises an alarm, a set value and set value display, and a measured value and set value recorder attached to the arithmetic control section B. Die casting machine with detection control device.