JPH0482619A - Processing fluid circulating method for electric discharge machine - Google Patents

Abstract

PURPOSE:To prevent processing fluid containing impurites from over-flowing out of a waste water tank by providing a flow rate control means which controls the valve opening of a flow rate adjusting valve based on detected signals from a fluid quantity detection device, and thereby keeping the fluid quantity of the waste water tank appropriate, which is in a processing fluid treating tank. CONSTITUTION:The quantity of processing fluid within a waste water tank 8 in a processing fluid treating tank 3 is detected by a detection device 10, the detected signal is sent to a flow rate control means 11. The flow rate control means 11 controls the opening of a flow rate adjusting valve 13 provided at the inlet side of the waste water tank 8 based on the signal. With this constitution, the flow rate of processing fluid flowing into the waste water tank 8 is thereby adjusted, and the quantity of fluid within the waste water tank 8 is therefore kept appropriate.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a machining fluid circulation system for an electrical discharge machine used for electrical discharge machining of a workpiece, and particularly to a machining fluid circulation system for controlling the amount of machining fluid in a machining fluid treatment tank. This article relates to a machining fluid circulation system for a machining machine.

[Conventional technology]

An electrical discharge machine uses machining fluid when machining a workpiece. The machining fluid used for machining flows from the machining fluid tank into the machining fluid treatment tank, and after impurities in the machining fluid are removed, it is used for machining again.

[Problem to be solved by the invention]

However, in conventional electrical discharge machines, when machining fluid flows from the machining fluid tank to the sewage tank in the machining fluid treatment tank, the difference in head between the two types is used to allow the machining fluid to flow naturally. . For this reason, a large amount of machining fluid flows in from the machining fluid tank,
When the flow rate from the sewage tank decreases, there is a problem in that the processing fluid overflows from the sewage tank and the processing fluid containing impurities flows into the adjacent clear water tank.

The present invention has been made in view of these points, and it is an object of the present invention to provide a machining fluid circulation system for an electric discharge machine that prevents machining fluid containing impurities from overflowing from a sewage tank.

Electrical discharge machining characterized by having a flow rate control valve that adjusts the flow rate of the two liquids, and a flow rate control means that controls the valve opening of the flow rate control valve based on a detection signal from the liquid amount detection device. A machining fluid circulation system of the machine is provided.

[Effect]

The liquid amount detection device detects the amount of machining liquid in the sewage tank of the machining liquid treatment tank, and sends the detection signal to the flow rate control means. The flow rate control means controls the opening degree of a flow rate regulating valve provided on the inlet side of the sewage tank based on the signal. Therefore, the flow rate of the machining liquid flowing into the sewage tank is adjusted, and the amount of liquid in the sewage tank is maintained at an appropriate level.

[Failure to solve the problem]

In order to solve the above problems, the present invention provides a machining fluid circulation system for an electrical discharge machine that performs machining by circulating machining fluid.
A liquid amount detection device for detecting the amount of machining fluid in a sewage tank of a machining fluid treatment tank, and a liquid amount detection device that is provided on the inlet side of the sewage tank and flows into the sewage tank [Example] Hereinafter, one embodiment of the present invention will be explained based on the drawings.

FIG. 1 is a diagram schematically showing the structure of a machining fluid circulation system of an electric discharge machine according to the present invention. 1 in the figure is a wire-cut electric discharge machine.

The wire-cut electric discharge machine 1 includes a machine main body 2, a machining fluid treatment tank 3, and a numerical control device (CNC) 4.

The processing machine main body 2 is connected to a CNC 4 and processes a workpiece (not shown) based on command signals from the CNC 4. The processing machine main body 2 has a nozzle 5 and a processing liquid tank 6. The nozzle 5 injects machining liquid into the machining gap of the workpiece. A machining fluid used for machining a workpiece flows into the machining fluid tank 6 .

The machining fluid treatment tank 3 includes a fresh water tank 7, a dirty water tank 8, and a filter 9. Impurities such as processing waste are removed from the processing liquid by the filter 9, and the processing liquid is always kept clean. Further, an appropriate amount of the machining fluid in the machining fluid treatment tank 3 is passed through an ion exchanger (not shown) so that the specific resistance thereof is kept constant.

The sewage tank 8 is provided with a liquid level detection device (for example, a float switch) 10, which detects the height H of the liquid in the sewage tank 8.
The detection signal is sent to a PMC (programmable machine controller) 11 built in the CNC 4.

A flow rate control valve 13 is provided in the machining fluid passage 12a between the machining fluid tank 6 and the wastewater tank 8. The flow rate control valve 13 is PM
C11, the valve opening degree is controlled according to a command signal from PMCII, and the flow rate of the machining fluid flowing into the sewage tank 8 is adjusted.

A pump 1 is provided in the machining fluid passage 12b between the dirty water tank 8 and the fresh water tank 7, and in the machining fluid passage 12c between the fresh water tank 7 and the processing machine main body 2.
4.15 is provided.

The machining fluid enters the wastewater tank 8 from the machining fluid tank 6 via the flow M control valve 13, is sent to the filter 9 and the clean water tank 7 by the pump 14, is further pumped up by the pump 15, and is injected from the nozzle 5. Ru.

After the workpiece is processed, the liquid enters the processing liquid tank 6 again and is circulated. Water maintained at a predetermined resistivity by an ion exchanger is used as the processing fluid.

PMCII of the CNC 4 controls the valve opening degree of the flow control valve 13 as described above. That is, PMCII is P
A flow rate control program is executed based on the detection signal from the liquid amount detection device 10 manually input to the MCII, and a command signal is sent to the flow rate control valve 13 to control the valve opening of the flow rate control valve 13. Details will be described later.

Figure 2 shows the height H of the liquid in the sewage tank and the opening degree V of the flow rate control valve.
FIG. When the height H of the liquid in the sewage tank 8 is H1 or more, the flow control valve 13 is throttled to the first valve opening V1, and when it is H2 or more and 1 or less, the flow rate regulating valve 13 is reduced to the normal second valve opening V2.
When it is below H2, the valve is opened and the third valve opening degree is controlled to ■3.

In this way, the valve opening degree V of the flow control valve 13 is controlled in three stages according to the height H of the liquid in the sewage tank 8.

Therefore, the flow rate of the machining liquid flowing into the sewage tank 8 is controlled, and the amount of liquid in the sewage tank 8 is maintained at an appropriate level.

Therefore, processing fluid is prevented from overflowing from the sewage tank 8. Further, processing fluid containing impurities is also prevented from flowing into the fresh water tank 7.

FIG. 3 is a flowchart of the machining fluid circulation system of the electric discharge machine of the present invention. In the figure, the numbers following S indicate steps and numbers.

[S1] It is determined whether the height H of the liquid detected by the liquid level inspection device 10 is greater than or equal to the upper limit value 81. If it is H1 or more, the process goes to S2, and if it is H1 or less, the process goes to S3.

[S2] The flow control valve 13 is throttled to control the first valve opening degree V1.

[S3] It is determined whether the height H of the liquid is less than or equal to the lower limit value H2. If it is less than H2, the process proceeds to S4, and if it is more than H2, the process proceeds to S5.

[S4] The flow control valve 13 is opened and controlled to the third valve opening degree V3.

[S5] The flow control valve 13 is controlled to the normal second valve opening degree V2.

In the above description, the valve opening degree of the flow rate control valve is controlled in three stages, but a configuration in which it is controlled in two stages may also be used. Further, the flow rate regulating valve can also be controlled so that the valve opening degree changes continuously according to the height of the liquid in the sewage tank.

Furthermore, although the above description has been made using a wire-cut electric discharge machine, the present invention can be similarly applied to a die-sinking electric discharge machine.

〔Effect of the invention〕

As explained above, in the present invention, the liquid volume in the sewage tank in the machining fluid treatment tank is maintained at an appropriate level, so it is possible to prevent the machining fluid containing impurities from overflowing from the sewage tank. Further, processing fluid containing impurities is also prevented from flowing into the clean water tank.

[Brief explanation of the drawing]

Fig. 1 is a diagram schematically showing the configuration of the machining fluid circulation system of the electric discharge machine of the present invention, and Fig. 2 is a diagram showing the relationship between the height H of the liquid in the sewage tank and the valve opening degree V of the flow rate control valve. , FIG. 3 is a flowchart of the machining fluid circulation system of the electric discharge machine of the present invention. Sewage tank liquid level detection device MC flow rate control valve

Claims (4)

[Claims] (1) In a machining fluid circulation system of an electric discharge machine that circulates machining fluid to perform machining, a fluid amount detection device that detects the amount of machining fluid in a sewage tank of a machining fluid treatment tank; a flow rate control valve that is provided and that adjusts the flow rate of the machining liquid flowing into the sewage tank; and a flow rate control means that controls the opening degree of the flow rate control valve based on a detection signal from the liquid amount detection device; A machining fluid circulation system for an electrical discharge machine characterized by having the following features. (2) The machining fluid circulation system for an electric discharge machine according to claim 1, wherein the flow rate control means is a programmable machine controller within a numerical control device. (3) A machining fluid circulation system for an electrical discharge machine according to claim 1, wherein the fluid amount detection device is a float switch. (4) The machining fluid circulation system for an electric discharge machine according to claim 1, wherein the opening degree of the flow rate control valve is controlled in three stages.