JPH09182946A - Spraying method of die casting machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a die casting machine having long die life by selecting the optimum spraying condition among data base information of preliminary experiment and spraying a spraying material on die cavity face so as to form an uniform thickness coated film. SOLUTION: A die surface temp. measured right before shotting together with a die shape information are inputted to a personal computer 320. The computer 320 finds the optimum spraying condition mostly suitable for the condition based on a given program, while displaying the condition on a CRT screen, sends an operation command to a spraying controller 310 or robot controller. By this method, a spraying device 200 and spray robot can execute spraying with a prescribed spraying flow rate, spray moving speed, spraying distance and spraying injection angle.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spraying method of a die casting machine for casting an aluminum alloy or a magnesium alloy in a mold, and in particular, the coating film of the spraying agent applied to the mold cavity surface is uniform without any unevenness. In addition, the present invention relates to a spraying method for a die casting machine, which prevents excessive thermal stress on the surface of the mold that occurs during spraying as much as possible.

[0002]

2. Description of the Related Art Conventionally, a method of spray-applying a spray agent such as a mold release agent or a heat retaining agent to the die cavity surface of a die casting machine is, for example, as shown in FIG. The spraying agent is blown under pressure to feed the spraying agent from the filter 3 and is sent to the spraying device 10 via the solenoid valve 4 and the flow rate adjusting valve 5, and the spraying air supplied from the compressor 6 is supplied to the solenoid valve. Spray device 1 via 7 and pipe 8
No. 1 to spray spray agent and then spray nozzle 1
0a to the pair of left and right platens (fixed platen 11A, movable platen 11B) attached to the mold 12 (fixed mold 1
2A, the movable mold 12B) was sprayed on the surface. The spray device 10 is configured to reciprocate vertically in the center vertical direction of both molds 12A, 12B in the open state by an actuator such as a hydraulic cylinder 9, and a plurality of sprays attached to the side surface of the spray head 10A of the spray device 10. It was taken into consideration that the nozzle 10a uniformly and evenly applied the entire surface of the die 12 to be sprayed. Further, the adjustment of the supply amount of the spray agent L spray-applied to the mold 12 was controlled by adjusting the opening degree of the flow rate adjusting valve 5 provided between the tank 1 of the spray agent L and the spray device 10. Thus, the conventional spraying method of the die casting machine, by keeping the flow rate of the spray agent and the spray distance between the spray nozzle and the mold cavity surface constant,
The spray agent was sprayed onto the mold under constant spray conditions.

[0003]

However, in such a spraying method of spray spraying, when a molded product having the same shape is molded by the same mold, the spraying is always performed at a constant flow rate and at a constant spraying rate. Despite spray spraying while maintaining the distance, uneven coating (excessive or insufficient film thickness) sometimes occurred in the coating film. In addition, when the spray distance is too short or is not an appropriate distance, or due to the cooling action of the spray agent on the mold at the bent portion of the mold cavity surface, excessive thermal stress (tensile stress) is generated on the surface of the mold. There is a problem in that it causes hair cracks and damages the mold. The present invention
The present invention is intended to propose a spraying method that prevents such uneven coating film adhesion and prevents excessive tensile stress due to thermal stress on the surface of the mold.

[0004]

In order to solve the above-mentioned problems, in the present invention, in the first invention, in a spray method of a die casting machine in which a spray agent is sprayed onto a die cavity surface of the die casting machine, For a given mold shape and mold cavity surface initial temperature, preliminary experiments were conducted using various combinations obtained by changing spray conditions such as spray flow rate, spray distance, spray nozzle moving speed, etc. By measuring the film thickness of the coating film, the mold temperature change and the thermal stress generated on the mold surface,
While accumulating in the database, for the mold shape and mold cavity surface initial temperature to be provided for the shot,
Optimum spray conditions that form a uniform film thickness and have a low mold thermal stress are selected from the information in the database of the preliminary experiment, and the spray agent is sprayed onto the mold cavity surface under the optimum spray conditions. I did it. Further, in the second invention, the film thickness in the first invention is determined by measuring a step obtained by partially cutting the coating film with a contact type roughness meter. Further, in the third invention, in the first invention or the second invention, the thermal stress generated on the mold surface is
It was calculated by the CAE analysis method based on the measured value of the mold temperature change.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, in advance,
For a given mold shape and mold cavity surface initial temperature, preliminary experiments were conducted using various combinations obtained by changing spray conditions such as spray flow rate, spray distance, spray nozzle moving speed, etc. By measuring the film thickness of the film, the mold temperature change and the thermal stress generated on the mold surface,
While accumulating in the database, for the mold shape and mold cavity surface initial temperature to be provided for the shot,
Optimum spray conditions that form a uniform film thickness and have a low mold thermal stress are selected from the information in the database of the preliminary experiment, and the spray agent is sprayed onto the mold cavity surface under the optimum spray conditions. As a result, the spray conditions that match the mold surface temperature that differ for each shot are selected from the information in the database accumulated in the preliminary experiment and the most appropriate spray condition with less adhesion unevenness and excessive thermal stress is selected. Spraying spray agent onto the mold surface under these spray conditions (spray flow rate, spray distance, spray nozzle moving speed, etc.) reduces adhesion unevenness and prevents excessive thermal stress in the mold. To do. Therefore, a coating film having a uniform film thickness is formed and hair cracks are prevented from occurring in the mold, so that the life of the mold is extended. Further, in the second invention, since the film thickness is measured by measuring the step difference obtained by partially cutting the coating film with the contact type roughness meter, the film thickness can be measured easily and with high accuracy. Can measure the thickness of the coating film. Further, in the third invention, during the spraying work, the thermal stress generated on the mold surface which is almost impossible to be measured is
Since it is calculated by the CAE analysis method based on the measured value of the mold temperature change, the mold thermal stress can be easily estimated. The temperature of the mold surface is measured in a non-contact manner using an infrared radiation thermometer.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. 1 to 3 relate to an embodiment of the present invention,
FIG. 1 is an overall configuration diagram of a die casting machine, FIG. 2 is an overall configuration diagram of a die casting machine showing another embodiment, and FIG. 3 is an explanatory diagram of a creation procedure for constructing a database from preliminary experiment results.

FIG. 1 shows an embodiment of the overall structure of a die casting machine 100 according to the present invention.
00 is equipped with a spray device 200 and a control device 300 that controls the spray device 200 as an accessory device.
The spray device 200 includes a hydraulic cylinder (or an air cylinder) 2 horizontally fixed in the mold opening / closing direction on an upper portion of a stand 22 standing on the top of the fixed platen 11A.
4, a spray body 26 attached to the tip of the piston rod 24a, a motor 27 and a hydraulic cylinder 28 disposed below the spray body 26, and a spray head fixed to the lower end of the piston rod 28a of the hydraulic cylinder 28. 28, and a plurality of circumferential spray nozzles 20a that hang down below the spray head 28 and face each other in the mold direction.
The spray head 20 provided with is configured to be movable in the horizontal mold opening / closing direction, the vertical direction, and the rotation direction around the vertical axis by operating and driving the hydraulic cylinders 24 and 28 and the motor 27 described above. Then, the spray agent is spray-applied toward the mold cavity surface at a required spray flow rate by the illustrated spray piping, and the spray agent around the spraying unit 200 is sprayed so that the spray agent during spraying does not contaminate the surrounding work environment. Is provided with a hood 40.

On the other hand, the control device 300 which controls the operation of the spray device 200 stores the spray control device 310 which controls the operation of the spray device 200 and the database accumulated in the preliminary experiment, and is provided with given conditions (the mold initial temperature, Based on an operation command of the sequencer 330, a personal computer 320 having a comparison calculation function for searching an optimum spray condition from a database for a die shape, etc., a sequencer 330 controlling sequential activation of the spray device 200, A valve 340 and a die-casting machine operation panel 350 for disconnecting the supply of the spray agent L and the compressed air.
And so on. And personal computer 3
The optimum spraying condition selected in 20, that is, the condition that the coating film of the spraying agent to be applied is uniform and the thermal stress generated as a result of the cooling action of the mold surface by the spray injection does not become excessive. Yes, and consists of the following three control elements. Spray distance (adjusted by hydraulic cylinder 24) Spray flow rate (adjusted by valve 340) Spray nozzle moving speed These three control elements are transmitted to the spray control device 310, and the hydraulic cylinder 2 that controls the operation of the spray device 200.
4, an operation command is transmitted to the hydraulic cylinder 28 and the motor 27, the hydraulic cylinders 24 and 28 are operated via the hydraulic unit 30, and the operation stop of the motor 27 is controlled by an electric signal. The spray nozzle moving speed means, for example, the swirl speed and swivel angle of the spray nozzle 20a operated by the motor 27, and the ascending / descending speed of the spray nozzle 20a by the hydraulic cylinder 28.

The spray device 200 of FIG. 1 is an embodiment in which the conventional type of orthogonal two-axis direction movement and the swiveling around the vertical axis are combined, but the operating form is not limited to this, It may be of any type. FIG.
Shows another embodiment in which a multi-joint type spray robot 200A is adopted in place of the spray device 200. The spray robot 200A includes a rotary seat 210 that is swiveled around a vertical axis by a motor 210a, and a first arm 220 and a second arm 23 that are pin-joined to the rotary seat 210 by a horizontal axis.
0, the motor 240 pin-joined to the lower end of the second arm 230, the vertical shaft 250 connected to the motor 240 and rotatable about the vertical axis, and the spray head 260 connected to the lower end.
The spray head 260 has a pair of left and right spray nozzles (also referred to as a spray gun) 260a facing the surface of the mold.

Then, as in FIG. 1, the robot controller 310A, the personal computer 320, the sequencer 330, the valve 340, and the die casting machine operation panel 350.
Etc., and operates similarly to the embodiment of FIG.

The operation of the spray device 200 and the spray robot 200A shown in FIGS. 1 and 2 configured as described above will be described. Prior to actual operation, preliminary experiments are conducted to understand the state of coating film formation when spray agent is sprayed on the die surface and the state of thermal stress generated on the die surface. In the preliminary experiment, a large number of combinations of spray experiments were performed in which the spray conditions such as spray flow rate, spray distance, spray nozzle moving speed, etc. were variously changed for a given mold shape and mold cavity surface initial temperature. The database is constructed by accumulating a large number of data obtained by measuring the film thickness distribution of the coating film and measuring the thermal stress distribution generated on the mold surface (actually an estimate). Input to the personal computer 320.

Among the measurements in the preliminary experiments, the surface temperature of the mold is directly measured by a contact type temperature sensor or non-contact by using an infrared radiation thermometer. The thickness of the coating film is measured by using a contact type roughness meter to measure the level difference generated by cutting the coating film partially. Since the thermal stress cannot be measured directly, the thermal stress distribution should be estimated by the CAE analysis program using the finite element method based on the temperature distribution on the mold surface measured by the infrared radiation thermometer. ing.

FIG. 3 is an explanatory diagram of a procedure for constructing a database from the measurement results in the preliminary experiment. When it is explained based on this, as described above, the experimental results of various combinations are sent to the personal computer 320. Input, spray agent (release agent) coating thickness, mold surface initial temperature, spray flow rate, spray moving speed, spray distance,
Relationship with spray injection angle The relationship between the mold surface temperature change (thermal stress change) and the mold surface initial temperature, spray flow rate, spray moving speed, spray distance, and spray injection angle is described by the internal computer 320. Are analyzed and stored by commercially available programs or software or programs created by themselves.

That is, the spray film thickness (for example, 20 μm) determined for each die cast product and the thermal fatigue strength (for example, 54 kg / mm ² ) determined for the die material are the constraint conditions for determining the spray conditions. Generally, spraying is repeated several times on the mold. Therefore, in order to shorten the cycle time, it is sufficient to spray a large amount of spraying agent at one time, but on the other hand, the thermal stress becomes excessive and the die life is shortened, which is not desirable. Therefore,
Set the spray conditions so that the thermal stress is within the allowable limit and the cycle time is as short as possible. Since there are many parameters for setting the spray condition, it is difficult for the operator's experience and intuition to cope with the setting, and therefore the personal computer 320 makes the determination instead in the present invention. In this case, an idea such as an expert system is introduced into the inference system to be adopted to obtain the optimum spray condition.

The temperature change in consideration of the degree of influence of each of the above variables (mold surface initial temperature, spray flow rate, spray moving speed, spray distance, spray injection angle) on the coating thickness, thermal stress, cycle time, etc. (That is, thermal stress change), the coating film thickness and each variable are made into a function and stored.

Next, the function information of the database thus obtained is modified in consideration of the user information, the know-how in the production technology and the knowledge database, or the learning function is added to make it more realistic. After refining (improving) to the used one, use it in actual operation. In actual operation, since the mold surface temperature condition is different for each shot together with the mold shape, that is, the shape of the molded product, the mold surface temperature is measured immediately before the shot and is input to the personal computer 320 together with the mold shape information. Then, the personal computer 320 finds the optimum spray condition most suitable for this condition by the given program, and performs the CRT.
While displaying the output on the screen, the spray control device 310
Alternatively, an operation command is transmitted to the robot controller 310A. As described above, the spray device 200 and the spray robot 200A perform the spray work at the desired optimum spray flow rate, spray moving speed, spray distance, and spray injection angle.

In actual operation, in consideration of the fact that the mold surface initial temperature differs from shot to shot, the personal computer 3 sets the mold surface initial temperature together with the mold shape.
20. On the other hand, the personal computer 320 selects a spray having a small adhesion unevenness (uniform film thickness state) and a relatively small thermal stress from a large number of data in the database according to a given inference system. Search and output the condition. In this way, the optimum spray conditions (spray distance, spray flow rate, spray nozzle moving speed) that match the shape and temperature of the obtained mold are found, and the spray device 200 or the spray robot 200A is operated to perform spraying. By carrying out the work, a uniform coating film is formed and damages such as hair cracks on the mold surface due to thermal stress (tensile stress) are prevented.

As described above, in the present invention,
In the spray method of the die casting machine that sprays the spray agent onto the die cavity surface of the die casting machine, the spray flow rate, spray distance, spray nozzle moving speed, etc. are given in advance for a given die shape and die cavity surface initial temperature. Preliminary experiments were conducted with various combinations obtained by changing the spray conditions consisting of, and the film thickness of the spray coating, the temperature change of the mold and the thermal stress generated on the mold surface were measured and accumulated in the database. For the mold shape and mold cavity surface initial temperature to be used for the shot, the optimum spray conditions with which a uniform film thickness is formed, and the mold thermal stress is small, are stored in the database of the preliminary experiment. Since the spray agent is sprayed on the mold cavity surface according to the optimum spray conditions,
It is possible to form a spray coating film having a uniform film thickness and prevent the occurrence of excessive thermal stress on the die surface.

[0019]

As described above, according to the present invention, a spray coating film having a uniform film thickness can be stably formed, and the life of the mold can be extended. It is possible to improve and produce a good molded product continuously and stably.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a die casting machine according to an embodiment of the present invention.

FIG. 2 is an overall configuration diagram of a die casting machine showing another embodiment of the present invention.

FIG. 3 is an explanatory diagram of a creation procedure for constructing a database from preliminary experiment results according to an example of the present invention.

FIG. 4 is a schematic configuration diagram of a conventional spray device.

[Explanation of symbols]

 1 Tank 2 Compressed Air Source (Compressor) 3 Filter 4 Solenoid Valve 5 Flow Control Valve 6 Compressed Air Source (Compressor) 7 Solenoid Valve 8 Piping 9 Hydraulic Cylinder 10 Spray Device 11 Platen 11A Fixed Platen 11B Movable Platen 12 Mold 12A Fixed Mold 12B Movable mold 20 Spray head 20a Spray nozzle (spray gun) 22 Stand 24 Hydraulic cylinder 24a Piston rod 26 Spray body 27 Motor 28 Hydraulic cylinder 28a Vertical axis 30 Hydraulic unit 40 Hood 100 Die casting machine 200 Spray device 200A Spray robot 210 Rotating seat 210a Motor 220 First arm 230 Second arm 240 Motor 250 Vertical axis 260 Spray head 260a Spray nozzle (spray gun) 300 Control device 3 0 spray controller 320 personal computer (PC) 330 sequencer 340 valve 350 die casting machine operating panel

Claims (3)

[Claims] 1. A spray method of a die casting machine for spraying a spray agent onto a die cavity surface of a die casting machine, wherein a spray flow rate, a spray distance, and a predetermined die shape or a die cavity surface initial temperature are given in advance. Preliminary experiments were carried out with various combinations obtained by changing spray conditions such as spray nozzle movement speed, and the film thickness of the spray coating, the mold temperature change, and the thermal stress generated on the mold surface were measured. Preliminary experiments were conducted on the optimum spray conditions, which are integrated in the database, form a uniform film thickness with respect to the mold shape and mold cavity surface initial temperature used for the shot, and have a small mold thermal stress. Of the die-casting machine that sprays the spray agent onto the mold cavity surface under the optimum spray conditions by selecting from the information in the database of How to spray. 2. The method for spraying a die casting machine according to claim 1, wherein the film thickness is measured by measuring the step difference obtained by partially cutting the coating film with a contact type roughness meter. 3. The spray method for a die casting machine according to claim 1, wherein the thermal stress generated on the mold surface is calculated by a CAE analysis method based on the measured value of the mold temperature change.