JPS5916896B2 - Hodenkakoueki - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in machining fluid for electrical discharge machines, that is, electrical discharge machining fluid.

Oil, water, emulsified oil, etc.5 have been used as conventional electrical discharge machining fluids, but when oil is used, the risk of fire increases as the machining current increases, and the surface of the workpiece may become carburized. formation of layers, high viscosity and difficulty in handling;
Problems such as these have been pointed out, and when water is used as an electrical discharge machining fluid, the machining speed/0 is low, rust appears on the machine and the workpiece, and emulsified oil is used as an electrical discharge machining fluid. In each case, the drawbacks of high costs were pointed out.

The present invention provides an electric discharge machining fluid that has a high machining speed '5, ease of handling, low cost, and does not cause problems of rusting or carburized layer formation during electric discharge machining. .

The electrical discharge machining fluid of this invention is an aqueous solution i0 containing 1 to 10% by weight of silicone oil and a small amount of surfactant.

Silicone oil is generally a polymer compound having the structural formula '5; however, in the present invention, silicone oils having a structure other than the above can also be widely used. For example, a phenyl group is used as a moiety instead of a methyl group.
〇'0 Also used are silicone oils with the structural formula O-Si-O-Si-O 1, O-width, which has been introduced as an alkyl group, and with the structural formula △0-△i-0-▲i-0▗, which has introduced an alkyl group. can.

Also, a wide range of known surfactants can be used to emulsify and disperse silicone oil in water, such as polyoxyethylene alkyl phenol, alkyl sulfonate, polyoxyethylene sorbitan alkylate, polyoxyethylene alkyl ether, palmitic acid, and the like.

An electrical discharge machining fluid in which silicone oil is emulsified and dispersed in water with a small amount of surfactant has a significantly higher machining speed than an electrical discharge machining fluid that is simply water.

The drawing shows the relationship between the concentration of silicone oil in the electrical discharge machining fluid and the machining speed. According to the diagram, when the silicone oil concentration is around 1% by weight, the machining speed is remarkable compared to water, and when the concentration of silicone oil is around 3% by weight, the machining speed is remarkable. It can be seen that this shows the highest machining speed. However, setting the concentration to more than 10% by weight is uneconomical as it is an unnecessarily high concentration even considering the wear and tear during a long working period. Therefore, in this invention, the concentration of silicone oil in the electrical discharge machining fluid is limited to a range of 1 to 10% by weight. Why does emulsification and dispersion of silicone oil increase processing speed?
The reason is as follows.

In other words, when plain water is used as the electrical discharge machining fluid, the machining debris melted by the electrical discharge solidifies on the surface of the workpiece.
Since it is necessary to rework this, the discharge efficiency will inevitably drop significantly, but when electrical discharge machining is performed in an aqueous solution emulsified with silicone oil, an oil film and a silicic acid film will form on the surface of the workpiece. Since the molten processing waste is formed by adsorption and solidification is prevented, there is no power loss and the processing speed is increased. The effects of this invention are remarkable not only when compared to water but also when compared to an aqueous solution made by emulsifying mineral oil. Shows processing speeds comparable to emulsified aqueous solutions. The main reason why the machining speed of the electric discharge machining fluid of the present invention is excellent and high is that, in addition to the oil film alone, the heat resistance and insulation properties of silicic acid exhibit appropriate effects.

Next, looking at effects other than machining speed, when the electrical discharge machining fluid of the present invention is used, rust is less likely to occur on the machining machine or the workpiece.

To be more precise, if the concentration of silicone oil exceeds 3% by weight, no rust will be observed on the workpiece for at least 4 to 5 minutes, but if the concentration of silicone oil is less than 3% by weight, rust will occur. In such a case, it is desirable to appropriately add a commercially available rust preventive agent to the electrical discharge machining fluid. On the other hand, from an economic point of view, silicone oil itself cannot be said to be a cheap substance compared to mineral oils, etc., but as mentioned above, it has the advantage of significantly higher electrical discharge machining speed, so it can shorten the process and reduce costs. The economic benefits of savings are significant.

In addition, when using this invention, it exhibits effects that cannot be seen with oil-based electrical discharge machining fluids, such as no risk of fire during use, no problems with carburized layer formation, and low viscosity and ease of handling. Ru.

Next, embodiments of this invention will be described, but prior to that,
Regarding the formulation example of machining stock solution used for preparing electrical discharge machining fluid,
Some of them are shown in the table.

Example 1 Preparation of 0 electric discharge machining fluid: From the machining stock solution of Formulation Example 1, the concentration of silicone oil was 3% by weight.
An electrical discharge machining fluid was prepared, and electrical discharge machining was performed using this fluid in the following manner.

For comparison, electrical discharge machining was performed in the same manner using tap water and an aqueous solution of mineral oil emulsified with a surfactant as electrical discharge machining fluids.

o Electric discharge machine: No-load voltage 48V, continuous rated current 500
A independent oscillation type pulse power supply (single-phase full-wave rectification), outer diameter 18
mm, equipped with a graphite cylindrical electrode with an inner diameter of 10 mm.

O operation: Feed was carried out manually, and the electrode was brought close to the workpiece while looking at the ammeter, and when a short circuit occurred, the electrode was moved away, and when no discharge occurred, it was brought closer.

The electrical discharge machining fluid was supplied to the gap between the electrode and the workpiece through the inner hole of the cylindrical electrode, carbon steel was used as the workpiece, the electrode was negative, the carbon steel was positive, and the machining current was 300 A for 1 minute. processed.

O Result: When using the electric discharge machining fluid of this invention, the machining speed is 457/
Mm was obtained, and no rust was observed on the surface of the workpiece.

In addition, when tap water is used as the electrical discharge machining fluid, 207
/Mm, and in the case of an aqueous solution emulsified with mineral oil, the processing speed remained at 357/7ft1n.

Example 2 An electrical discharge machining fluid having a silicone oil concentration of 1% by weight was prepared from the machining stock solution of the formulation example, and electrical discharge machining was performed according to the same procedure as in Example 1.

As a result, a machining speed of 437/Mul could be obtained, and no rust occurred on the surface of the workpiece.

Note that when tap water was used as the electrical discharge machining fluid, the machining speed was 20y/TIW, and when an aqueous solution emulsified with mineral oil was used, the machining speed was only 357/Mml. Example 3 An electric discharge machining fluid containing 2.5% by weight of silicone oil and 0.3% by weight of sodium nitrite was prepared from the machining stock solution of the formulation example, and the same procedure as in Example 1 was followed. , electrical discharge machining was performed.

As a result, it was possible to obtain a processing speed of 467/Mm,
No rust was observed on the surface of the workpiece.

The processing speeds of tap water and mineral oil emulsified aqueous solution as comparative examples are 207/Mm and 357/Mm, respectively. Example 4 An electrical discharge machining fluid with a silicone oil concentration of 5% by weight was prepared from the machining stock solution of the formulation example, and electrical discharge machining was performed in the same manner as in Example 1. As a result, a machining speed of 457/Mm was obtained, and the workpiece There was no rust on the surface either.

As a comparative example, tap water and an emulsified aqueous solution of mineral oil were used as electrical discharge machining fluids, and the results were 207/
7njt1357/Mi.

As is clear from the above, the electric discharge machining fluid of the present invention is made by emulsifying and dispersing 1 to 10% by weight of silicone oil in water using a surfactant, and not only can a significantly higher machining speed be obtained, but it is also less likely to rust. It has important practical effects, such as being economical, safe, and easy to handle.

[Brief explanation of the drawing]

The drawing is a diagram showing the relationship between electrical discharge machining speed and the concentration of silicone oil in an aqueous solution, and shows one of the important effects of the present invention.

Claims (1)

[Claims] 1. Electrical discharge machining fluid made by adding 1 to 10% by weight of silicone oil and a small amount of surfactant to water.