JPH0631428A - Control method for casting parameter of die-cast machine - Google Patents

Abstract

PURPOSE: To enable the judgement on whether a cast product is to reject or not before machining by detecting components, temp. and pressure of gas during a process for pouring molten metal into a mold, comparing with the referential data and deciding whether the quality of the cast product is good or not based on the differences. CONSTITUTION: The components, temp. and pressure of the gas, are detected during the process pouring the molten metal into the mold with sensor type measuring instruments connected with a mold cavity part and a casting chamber. The measured data are compared with the predecided referential data, and it is decided whether the quality of the cast product is good or not based on the compared difference and also, the related parameters, e.g. releasing agent, molten metal pouring height, casting speed, casting pressure, press-in plunger speed, press-in plunger additional pressure, opening/closing movement of an exhaust valve in the mold cavity, etc. are controlled and adjusted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of controlling casting parameters of a die casting machine.

[0002]

BACKGROUND OF THE INVENTION Machine control of die casting machines is known from Ernst Brunhuber, "Practice of Die Casting Metal Making", Third Edition, 1980, page 82 et seq. In this case, the properties of the casting are determined by many individual parameters. These parameters are known from Friedrich Klein, "Automatic Casting Process Control During Die Casting," foundry 68 (1981) 18, page 531 et seq. For example, as described in Klein, page 531, last column, right column, last paragraph, page 532, left column, first paragraph, 12 casting parameters are important control values for the casting process for controlling or adjusting the casting process. used.

The article by Brunn Huber, mentioned at the outset, pages 86, first and second paragraphs, pages 348, 349, deals mainly with the problem of blowholes or bubbles.
Bubbles in the metal, i.e. in the casting, are to some extent inevitable. In this case, as far as the air and the release agent gas are mixed, the pores of the outside and the inside are different. The external pores include air bubbles on the casting surface that appear as a distinct bulge of the casting skin. The bubbles are generated as soon as the corresponding casting profile is removed from the wall of the mold, ie partially before the casting is over. At this time, bubbles on the surface of the cast product may burst. As a solution to so-called external porosity, an extension of the solidification stage is carried out, as described in the literature, in order to cool the casting more strongly and increase its strength. Further, strengthening the mold cooling is also effective. However, in this case the risk of scratch formation must be noted.
Therefore, the literature suggests to avoid bubble formation itself and to consider that a less disturbed metal flow is maintained in the casting chamber until it is poured into the mold cavity. Also, checking and improving the exhaust of the mold has been proposed as an effective solution for reducing bubbles.

The so-called internal pores further include internal bubbles and blowholes, and the internal pores are due to the same criteria as described above, and the general avoidance or reduction of the bubbles is also suggested. . As a solution to this, page 351 of the Brunhuber article, selects a higher amount of hot water to be injected into the casting chamber before the plunger is started and the metal in the casting chamber should be stored as turbulently as possible. Is suggested. Furthermore, a sufficient and effective evacuation of the mold is also suggested. The connection of the known multistage device also causes a high recompression, ie the compression of the internal air. It is suggested to examine the amount, range and frequency of release agent application only if the cause of the bubbles or blowholes is the gas originating from the release agent. Further, in the case of an automatic spraying device, the spraying amount and order can be selected in advance.

As a result, it is known that a considerable amount of gas is generated during casting as the casting process progresses. Depending on the casting process or the cast metal used, a certain proportion of the gaseous constituents results in workpieces which are less than perfect or have to be discarded. The generated gas components are mainly: -hydrogen dissolved or physically mixed in the melt, -CO, CO ₂ due to the mold release agent of the press-fit plunger and the mold release agent decomposed during the casting process. , Cx Hy, and the airborne compounds and other gases such as N ₂ and O ₂ contained in the mold cavity during the casting process.

[0006]

In the case of known casting process control systems, the starting point is the presence of bubbles or blowholes. For this reason, the amount of air or gas must be reduced by the method or procedure described above. However, these methods or measures have the disadvantage that the amount of air or gas entrainment is not precisely known and that the counter-measures mentioned above can only be taken based on the result, ie the quality of the workpiece. There is.

It is an object of the present invention to provide a method of controlling casting parameters which improves the quality of the cast workpiece by more accurately grasping the bubbles or blowholes, ie reducing the reject rate. .

[0008]

In order to achieve the above object, the present invention was developed from a conventional casting process control and control method, in which at least the amount of gas and its temperature are mainly determined according to the type of gas. It is equipped with a unique measuring device that detects each individually. In this case, a sensor may be provided, which projects into the mold cavity, which sensor detects and evaluates the temperature during the mold pouring process, the composition of the gas and optionally the pressure as measured data. The resulting measurement signal indicates whether the cast part is suitable for its application or, if it cannot be used, should be directly disposed of without further processing required for the application. I can judge.

[0009]

Example: The detection of the measurement data is carried out via a sensor installed in the mold cavity, in which case the measurement data is effectively compared with a preset reference data, so that the casting difference results from the found difference. The quality of the work piece is judged.

The measured data are continuously detected during the pouring process and can be evaluated immediately. It is also possible to set the time when the measured data is detected and compared with the reference data, for example, immediately before the end of pouring. The sensor, mainly for gas metering, can be fixed in the mold cavity of the casting mold and / or the casting chamber.

In order to control the release agent gas generated by the release agent, the control and adjustment of the release agent amount based on the evaluation of the measurement signal is performed for the casting mold and the press-fitting plunger. It can be carried out directly or mainly in the next casting step. In addition, other casting parameters such as the press-fitting speed and the press-fitting pressure of the press-fitting plunger are controlled and adjusted, mainly by evaluating the measured signals relating to the interaction of the gas constituents and the gas pressure and temperature. Since this can be done during the current casting process or for the next casting process, the adverse effects of the gases generated during the casting process are taken into account. Furthermore, this direct detection of the gaseous constituents can be corrected, for example during the casting process, by a higher additional pressure or by a controlled injection plunger speed.

In order to achieve a more optimal exhaust from the mold, the gas constituents and the associated parameters, mainly temperature and pressure, are detected and the exhaust valve in the mold cavity is opened and closed. In this case, a temperature sensor is mainly provided, and this temperature sensor detects the state of the mixed gas like the pressure sensor.

The known casting process control is therefore easily optimized by the method according to the invention, in which case known treatments can be reliably associated. This is shown in pages 531 and 532 of the Klein document mentioned at the outset. In this case, currently commercially available sensors are used according to the type of gas for measuring the gas content and mainly for quantifying the gas constituents. Moreover, conventional sensors for pressure and temperature detection can be used.

Since such a sensor is used to control an automobile catalyst and is designed to withstand the melt,
It can be mounted directly in or on the surface of the mold cavity. The non-melt resistant sensor must be located in a separate casting chamber and shut off from the melt inflow by a valve. These valves are known in the casting mold evacuation art.

[0015]

As described above, according to the present invention, the amount of bubbles in a cast workpiece is detected by a sensor, compared with a predetermined value, and the quality of the workpiece is judged based on the result. It becomes possible to immediately determine whether or not to dispose without further processing.

Claims (9)

[Claims] 1. A method of controlling casting parameters of a die casting machine such as detecting various casting parameters during a casting process and adjusting them according to reference values, and mainly controlling an automatic casting process during casting. By means of a sensor-type measuring instrument connected to the mold cavity and / or the casting chamber, the composition of the gas and the associated gas temperature and / or
Alternatively, gas pressure is detected during the mold pouring process, the measured data detected is compared with predetermined reference data, and the resulting difference determines the quality of the cast product and the associated casting parameters. A method characterized in that the readjustment is performed. 2. The method according to claim 1, wherein the amount of gas is detected for each type of gas. 3. The method according to claim 1, characterized in that the measurement data is continuously detected during the whole cycle of the mold pouring step. 4. The method according to claim 1, wherein the measurement data is detected at a predetermined time point immediately before the end of the casting of the mold. 5. The measurement data is used to control and adjust the amount of the mold release agent of the mold and the press-fitting plunger, and the measurement data is used to achieve a non-defective product in the next casting step. The method according to any one of 1 to 4. 6. The measured data is mainly the pouring height of the casting chamber,
6. Use according to any of claims 1 to 5, characterized in that it is used for controlling and adjusting casting parameters such as casting speed and casting pressure, evaluated during the current casting process or for the next casting process. the method of. 7. The method according to claim 6, characterized in that the press-fitting plunger speed and / or the press-fitting plunger add-on pressure are controlled by the measured data relating to the gas constituents. 8. The method according to claim 1, wherein the measured data regarding the gas component is used for controlling and adjusting the opening / closing operation of the exhaust valve of the mold cavity. 9. The measurement data are used for controlling and adjusting the opening and closing operation and are detected by a temperature sensor and / or a pressure sensor.
The method described in any one of.