JPS5882629A - Electric discharge machining device - Google Patents

Abstract

PURPOSE:To have an electric discharge machining with good processing performance and without risk of fires, by preparing a noncombustible processing liquid from a mixture of saccharoid solution and glycol and using an electrode made of graphite. CONSTITUTION:This electric discharge machining device makes processing of a work with an electrode, which is installed facing the work with a certain gap reserved, in which a non-combustible processing liquid is fed for occurrence of electric discharge phenomenon. As this non-combustible processing liquid is used a saccharoid solution in order to enhance the processing performance and eliminate risk of fires. The saccharoid solution is mixed with glycol and the electrode is made of graphite. As this saccharoid component is used for example saccharose (SR) and as the glycol, polyethylene glycol (PEG).

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electric discharge machining apparatus, particularly to an electric discharge machining apparatus that processes a workpiece using a nonflammable machining fluid.

Electrical discharge machining is a machining method in which an electrode and a workpiece are opposed to each other through a gap, and a discharge phenomenon is caused while supplying machining liquid to the gap to machine the workpiece. And conventionally 1. In carving electrical discharge machining, kerosene 9 is used as a machining fluid.
In addition, in the wire-cutting process, a material with a high specific resistance of water was used as a machining fluid.

However, when kerosene oil is used as the machining fluid, the kerosene oil vaporizes and evaporates due to the heat in the machining gap between the electrode and the workpiece during electrical discharge machining, resulting in discharge sparks and arc columns generated during electrical discharge machining. However, there was a drawback that the vaporized kerosene oil gas could ignite, resulting in a high risk of fire. In addition, Figure 1 shows the region of high arc discharge when using Kepsi oil as the machining fluid and graphite material as the electrode, in relation to the pulse during machining and the average machining current. The shaded area in the figure is the area where arc discharges occur frequently. Further, due to the risk of fire mentioned above, electric discharge machining using a large current is impossible, and automatic unmanned machining and unmanned machining at night are also impossible.

In addition, since kerosene oil 4: #i has such a danger,
Companies that handle kerosene oil are regulated by the Fire Service Act.

Therefore, in order to prevent fires during processing, nonflammable processing fluids are used as processing fluids. Nonflammable processing fluids include water, an aqueous solution of a single organic substance, and an emulsion of a single mineral oil and water. be.

However, when these non-flammable machining fluids are used for die-sinking electrical discharge machining, some of the fluids are superior in terms of processing speed, but inferior in terms of electrode wear and machining accuracy, compared to kerosene oil. ),
Other machining fluids have 5 drawbacks, such as for electric discharge machining (for electric current s = 6), and when these non-flammable machining fluids are used for wire-cut electrical discharge machining, they are said to be affected by kinematic viscosity. There were drawbacks. Therefore, conventionally, only round, non-flammable machining fluids with increased specific resistance have been used for wire-cut electrical discharge machining.

As mentioned above, conventionally, when kerosene oil is used as a machining fluid, there is a risk of fire outbreak, and when a nonflammable machining fluid is used as a machining fluid, compared to kerosene oil, There was a drawback that processing characteristics such as processing speed were inferior.

The present invention has been made in view of the above-mentioned conventional problems, and its purpose is to provide an electrical discharge machining apparatus that uses a nonflammable machining fluid that has good machining characteristics and is free from the risk of fire.

In order to achieve the above object, the present invention makes a workpiece and an electrode face each other through a gap, and processes the workpiece by causing an electric discharge phenomenon while supplying a nonflammable machining liquid to the gap. The electrical discharge machining apparatus is characterized by using a saccharide solution as a nonflammable machining fluid, mixing glycol with the saccharide solution, and using a graphite material as an electrode.

Hereinafter, preferred embodiments of the present invention will be explained based on the drawings.

In the present invention, a saccharide solution is used as a rounding and non-flammable processing liquid that improves processing characteristics and eliminates the risk of fire, glycol is mixed with the saccharide solution, and a graphite material is used as an electrode.

Then, we were able to obtain the processing characteristics described below. In the following examples, for example, sucrose (=JR) was used as the saccharide, and polyethylene glycol (=JR) was used as the glycol. PIG) is used.

FIG. 2 shows the magnification of the machining speed (g/=+) when the peak current p is changed for various machining fluids. In Fig. 2, as the machining fluid, 20
% of nuts, callos and 20 pieces of polyethylene glycol〒A
-, an aqueous solution containing 100% kerosene oil, 40% sucrose, and an aqueous solution containing 4OS polyethylene glycol (average molecular weight 600).
seeds are used. Note that graphite material is used as the electrode.

Moreover, FIG. 3 shows an aqueous solution containing 20% of Sutsuka rose and 20% of polyethylene glycol, and 40% of polyethylene glycol. The electrode volume consumption ratio (-) is shown when the waxes of saccharose and polyethylene glycol are changed for a saccharose aqueous solution and a 40% polyethylene glycol aqueous solution. Note that graphite material is used as the electrode.

From the above figures 2 and 3, it is understood that the processing characteristics improved by the non-flammable processing fluid of the example. That is, by using graphite material as the electrode and an aqueous solution containing saccharose and polyethylene glycol f as the nonflammable machining fluid, the machining speed is more than twice that of kerosene oil, and the electrode volume consumption is The value is equivalent compared to other solutions.

In addition, Fig. 4 shows the magnification of machining speed (g/I1m) when the peak current p is changed for various machining fluids, and Fig. 5 shows the The electrode weight consumption ratio is shown. As various machining fluids 2, machining fluids similar to those shown in FIG. 2 are used.

In addition, in FIG. 2.3, graphite material is used as the electrode, but in FIG. 4.5, copper is used as the electrode.

From the above figures 4' and 5, it is understood that the machining characteristics are improved by the non-flammable machining fluid. That is, using copper as an electrode,
By using an aqueous solution containing saccharose and polyethylene glycol as a nonflammable processing fluid, the processing speed is inferior to that of kerosene oil, but compared to a single organic substance aqueous solution, that is, a saccharose aqueous solution and a polyethylene glycol aqueous solution. It is fast and the electrode weight consumption is comparable compared to other solutions.

Next, an experiment was conducted to investigate the relationship between concentration, kinematic viscosity, average molecular weight, and processing speed in nonflammable processing fluids.

Figure 6 shows the results when the concentration of the solutions was changed for three types: 40% polyethylene glycol (average molecular weight 1000) aqueous solution, 40% polyethylene glycol (average molecular weight 60o) aqueous solution, and 40% saccharose aqueous solution. The kinematic viscosity is shown, and FIG. 7 shows the average molecular weight in the solution when the concentration of the solution is changed for the same three types of aqueous solutions as shown in FIG. 6. Furthermore, Fig. 8 shows the permeability (g/m) when the concentration is changed for a 40-inch saccharose aqueous solution. FIG. 9 shows an aqueous solution containing 20% saccharose and 20% polyethylene glycol, a 40% saccharose aqueous solution, and 40% polyethylene glycol (average molecular weight 600).
The processing speed & (g/■) is shown when the mixing ratio in the solution is changed and the average molecular weight in the solution is changed. 'In addition, in Fig. 8.9, steel is used as the electrode.

From the above Figure 6.7.8.9, the following can be understood. That is, in Figure 6'', when we experimented with the difference in processing speed with respect to the average molecular weight of three types of aqueous solutions while keeping the kinematic viscosity at a constant value, the processing speed was faster for #1, which had a larger average molecular weight in the solution. In Figure 8, when the processing speed was measured by changing the concentration of saccharose, the amount of organic matter in the solution was large, the kinematic viscosity was high, and the average molecular weight was high;
The lower the amount of water in the liquid, the faster the processing speed. Therefore, in order to obtain a practical nonflammable machining fluid, the kinematic viscosity should be reduced to 6.
Centistoke (CSt) or less is set so that the average molecular weight, the amount of water in the liquid, and the amount of organic matter are suitable for processing. According to various experiments, it has 10 to sob of sugar (for example, saccharose) and 10 to sob of glycol, and the total amount of sugar and glycol is 6.
091 or less, and further has a kinematic viscosity of 6 centistokes (
It was recognized that a nonflammable machining fluid having a temperature of C8t) or less is desirable for machining.

As described above, according to the present invention, since a nonflammable processing liquid containing a sugar solution mixed with glycol is used and a graphite material is used as an electrode, processing characteristics can be improved. In addition, the mixture of sugars and polyethylene glycol reduces electrode wear and eliminates the high consumption of sugars and the large amount of iron adhering to the stained electrode due to the action of polyethylene glycol, resulting in good results. It will be done.

In the above examples, saccharose was used as the saccharide, but it is also possible to use glycose or fructose instead of saccharose. ) was used instead of polyethylene glycol (average molecular weight 4600), polyethylene glycol (average molecular weight 200 S-1540), dipropylene glycol (DPG), and ethylene glycol (1!i) were used.
G) can also be used, and the same effect as in the above embodiment can be obtained.

Furthermore, the present invention is applicable not only to die-sinker electric discharge machining but also to other electric discharge machining.

As explained above, 1-1 according to the present invention, since a nonflammable processing liquid containing glycol mixed with a sugar solution is used and a graphite material is used as an electrode, there is an advantage that processing characteristics are improved. The kinematic viscosity of the machining fluid can be adjusted to a value suitable for machining, the average molecular weight of the machining fluid can be increased, nonflammability can be maintained, and the water content in the solution can be reduced. can. Moreover, according to the present invention, the processing speed is more than twice that of kerosene oil, faster than that of a single organic substance aqueous solution, and electrode wear can be kept to the same value. . Furthermore, according to the present invention, since the machining gap between the electrode and the workpiece can be maintained in a good condition, it is possible to reduce the occurrence of abnormal discharges and arc columns, and there is a risk of fire due to the characteristics of the non-flammable machining fluid. disappears. Therefore, in electric discharge machining, automatic unmanned machining and unmanned machining at night are possible, and machining productivity can be improved.

[Brief explanation of the drawing]

Figure 1 shows the relationship between the pulse width during machining and the average machining current (an explanatory diagram showing two areas where arc discharge occurs frequently), and Figure 2 shows the machining speed magnification when changing the peak current for various machining fluids. Fig. 3: A graph showing the consumption ratio of Natsuka rose and polyethylene for various machining fluids; Fig. 4: Hiro: The machining speed multiplier when changing the peak current for various machining fluids. Fig. 5 is a graph showing the electrode weight consumption ratio in the case of Fig. 4, Fig. 6 is a graph showing the kinematic viscosity when the concentration of the solution is changed for various processing fluids)7 Figure 7 is a graph showing the average molecular weight when the concentration of the solution is changed for various processing liquids, and Figure 8 is a graph showing the processing speed when the concentration of the solution is changed for the Natsukarose aqueous solution. The graph shown in FIG. 9 is a glass diagram showing the processing speed when the average molecular weight in the solution is changed by changing the mixing ratio in the solution for various processing solutions. 5 J! I Tadaso J#! ! Qi Qi Wisdom - Kaihonshin 484 years of management and training l - Kaoru @ Yun Figure 8 12/l (%) Figure 9 Average distribution amount

Claims (1)

[Claims] (1) A workpiece and an electrode are faced to each other with a gap therebetween,
In an electrical discharge machining device that processes a workpiece by causing an electrical discharge phenomenon while supplying a nonflammable machining fluid into the gap, a sugar solution is used as the nonflammable machining fluid, Gutsuicol is mixed with the sugar solution, and the material is used as an electrode. An electrical discharge machining device characterized by using graphite material. (2. The electrical discharge machining device according to claim (1), characterized in that polyethylene glycol (average molecular weight 200 to 1,540), dipropylene glycol, or ethylene glycol is used as the rubber. (3) An electric discharge machining apparatus according to claim (1) or (2), wherein the nonflammable machining fluid contains 10 to 50 saccharides. (4) Percentage of claim (1) , (2), Matahiro (3)
In the described apparatus, the nonflammable processing liquid contains 60% or less of sugars and glycol in total, and the nonflammable processing liquid
o kinematic viscosity to 6 centistokes (ast) (40°C)
An electric discharge machining device characterized by having the following range.