JPS62251012A - Electric discharge machining fluid - Google Patents

Abstract

PURPOSE:To aim at rustproofing and anticorrosion as well as to keep off any loading in a filter attributable to a microorgamism, and solve various hindrances, by using D-sorbitol and triethanolamine for an electric discharge machining fluid as an effective component. CONSTITUTION:Triethanolamine and D-sorbitol are mised in a base solution of pure water or the like so as to cause content in the former to become 0.001-0.1 wt% and content in the latter to become 0.01-30 wt% respectively, setting this mixture down to a machining fluid. This D-sorbitol restrains sudden oxidation on a machining surface due to electric discharge machining and oxida tion of the whole workpiece caused by dissolved oxygen contained in the machin ing fluid, prevening rust from gathering. With coexistence of the triethanolamine and the D-sorbitol, a synergetic action for anticorrosion is secured and, what is more, generation of a microorganism in the machining fluid is kept back.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to electrical discharge machining fluid, which has particularly excellent antirust and anticorrosion effects, and is free from various problems such as filter clogging caused by microorganisms. This invention relates to an electrical discharge machining fluid useful for electrical discharge machining for wire cutting.

[Conventional technology] Wire-cut electric discharge machining involves a small distance between the workpiece and the
A wire-shaped electrode is installed, and the workpiece is moved while spraying machining fluid. When the workpiece reaches the desired location, it is intermittently discharged, and the heat is used to move the workpiece. As it softens and melts locally, part of the machining fluid rapidly evaporates and vaporizes in the discharge column, and the strong pressure blows off the melted part, simultaneously cooling the fine powder of the workpiece and discharging it out of the system. It is. Unlike the die-sinking method, in which the workpiece is machined while immersed in the machining fluid, wire-cut electric discharge machining uses the machining fluid to be sprayed locally onto the workpiece in the atmosphere, so the drying process caused by the workpiece fluid is prevented. The wet state is often repeated.

Conventionally, hydrocarbon oil has been used as the electrical discharge machining fluid, but due to the problem of ignition, pure water-based nonflammable machining fluids have become mainstream in recent years.

Normally, this machining fluid is reused after being discharged and the SS component is removed by filtration. After removing soluble impurities in the liquid, it is reused (usually, the electrical conductivity of the processing liquid is 10 to 100 I).
It is said to be about LS/cm. ). This is because if the electrical conductivity of the machining fluid increases, electrical discharge machining with good machining accuracy cannot be expected, and the electrical conductivity of the machining fluid is adjusted by the ion exchange treatment.

By the way, in wire-cut electrical discharge machining, the workpiece is exposed to a severe corrosive environment in which the workpiece is repeatedly wetted by the machining fluid as described above.Moreover, in this method, narrow groove-like gaps are formed, making the machining difficult. Machining chips such as chips from the workpiece, electrodes, wires, etc. that are sometimes generated tend to adhere (remain). However, once the processed chip is attached,
An oxygen concentration cell is formed there, and the workpiece, especially metal workpieces such as steel, is extremely susceptible to rust. Zero rusting not only deteriorates the appearance of the workpiece, but also reduces machining accuracy. This causes many problems such as inhibiting high-order processing for finishing.

For this reason, it has traditionally been used to prevent rust on workpieces.

A machining fluid in which a rust preventive agent is added to pure water is used, and it has been proposed to add known ionic rust preventive agents such as nitrites and phosphates (Japanese Unexamined Patent Publication No. 51-147096). However, the ionic rust inhibitor pine increases the electrical conductivity of the machining fluid, reducing machining accuracy and requiring the ion exchange resin tower to be operated constantly, which reduces the rust inhibitor concentration in the machining fluid. This is extremely uneconomical in terms of deterioration, shortening of the life of the ion exchange resin, and other operating costs of the resin tower.

For this reason, examples of nonionic rust preventive agents that can exhibit a rust preventive effect without changing the resistivity of the machining fluid include reducing sugar (Japanese Patent Application Laid-Open No. 107843/1983), reducing sugar alcohol ( JP-A-54-125599) and the like have been proposed.

[Problems to be Solved by the Invention] However, none of the conventional rust preventives provides a sufficiently satisfactory effect. Among the above-mentioned conventional rust inhibitors, reducing sugars are relatively preferable, but in order to prevent rusting of the workpiece to which processed chips are attached during processing using reducing sugars alone, it is necessary to add a large amount. Become. In this case, new problems arise such as the area around the processing machine becoming sticky due to splashes of the processing fluid containing a high concentration of nonionic rust preventives such as sugars.

In addition, reducing sugars, reducing sugar alcohols, and the like are substances that are easily decomposed by microorganisms in processing fluids, and therefore cause microbial development and proliferation. As a result, not only does the concentration of the rust preventive agent decrease due to microbial decomposition, but the generated microbial flocs clog the filter and the ion exchange resin column, resulting in a decrease in ion exchange performance and the formation of dirt in the processing liquid tank. There was a problem in that it caused secondary problems.

[Means for Solving the Problems] The present invention solves the above-mentioned conventional problems, exhibits extremely excellent rust and corrosion prevention effects over a long period of time with a low concentration of nonionic rust inhibitors, and furthermore provides anti-corrosion effects caused by microorganisms. The object of the present invention is to provide an electrical discharge machining fluid that does not cause any damage, and the electrical discharge machining fluid is characterized by containing D-sorbitol and triethanolamine as active ingredients.

The present invention will be explained in detail below.

The electrical discharge machining fluid of the present invention contains D-sorbitol and triethanolamine.

The electrical discharge machining fluid of the present invention can be easily prepared by mixing D-sorbitol and triethanolamine with a base fluid such as pure water, but the machining fluid can be prepared with significantly superior protection by adding these additives at low concentrations. Because it has rust and anti-corrosion effects, it is generally
The concentration of D-sorbitol in the processing liquid is about 0.01 to 30% by weight, and the concentration of triethanolamine is c, o, ooi.
It is preferable to adjust the amount to 0.1% by weight.

[Function] The electrical discharge machining fluid of the present invention exhibits good rust and corrosion prevention effects due to D-sorbitol and triethanolamine, and also prevents damage caused by microorganisms.

In other words, D-sorbitol has the function of preventing rust by suppressing rapid oxidation of the machined surface due to electric discharge during machining and oxidation of the entire workpiece due to dissolved oxygen contained in the machining fluid. There is.

Therefore, the coexistence of a small amount of triethanolamine and D-sorbitol provides a synergistic effect of extremely excellent antirust effect, and it is also possible to obtain a synergistic effect of extremely excellent antirust effect. The presence of ethanolamine suppresses the generation of microorganisms in the processing fluid, and as a result, microbial decomposition of D-sorbitol is prevented, and problems such as filter clogging caused by microorganisms are also prevented.

Conventionally, an electrical discharge machining fluid containing a sugar solution and a rust preventive agent (triethanolamine) is known (Japanese Patent Laid-Open No. 15638/1983).
). The present invention uses D-sorbitol in place of the saccharides in the above-mentioned known examples, but since D-sorbitol has a higher reducing state than saccharides,
Compared to those described above, significantly superior antirust and anticorrosion effects can be obtained.

[Example 1] Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples unless it exceeds the gist thereof.

Examples 1 to 2, Comparative Examples 1 to 5 Steel materials (S55C: 100100 x 250 x 40) were processed using a wire-cut electric discharge machine using a brass wire with a wire diameter of 0.2 mm, and the machining fluid shown in Table 1 was heated to a water pressure of 2 k.
Water was supplied at a rate of g/crn', the material was processed into a U-shape (5 x 80 x 40 mm x 2) at a processing speed of 1 mm/min, and then left for 15 hours.

After standing, it was cut into two pieces each measuring 5 x 80 x 40 mm, and the initial weight (Wi) was measured. Thereafter, each processed product was derusted using hydrochloric acid containing an inhibitor, and then its weight (Wf) was measured. Table 1 shows the average weight difference (Wi-Wf) between the two sheets, the number of general bacteria in the processing fluid, and the rusting state of the processed materials.

W i −W f represents the sum of the amount of deposits on the processed chip and the weight when rust occurs, and the smaller W i −W f represents the less adhesion of the processed chip to the processed surface and the less rust formation. . Incidentally, W i -W f is about 400 g g/c rn'' even when there is no deposit at all in appearance, and a value of 500 to 800 #Lg/Cm' is sufficiently practical.

Example 3, Comparative Example 6.7 Number of general bacteria in the machining fluid and microorganisms in the machining fluid tank of a commonly used wire-cut electric discharge machine when using the machining fluid shown in Table 2 The occurrence situation was investigated and the results are shown in Table 2.

Tables 1 and 2 show that according to the processing fluid of the present invention, by adding a low concentration of chemicals, it is possible to prevent processing chips from adhering to the workpiece and to effectively prevent rusting. It is clear that the generation of microorganisms can be suppressed and disorders caused by microorganisms can be prevented.

Table 1 Table 2 [Effects of the Invention] As detailed above, the electrical discharge machining fluid of the present invention contains D-sorbitol and triethanolamine,
In addition to having excellent rust and corrosion prevention effects, ■ D-sorbitol, the main ingredient, is nonionic.
Since the amount of ionic triethanolamine used is small, there is little increase in the electrical conductivity of the machining fluid, so the load on the ion exchange tower is not significantly increased, and precision machining is possible.

■ The required amount of active ingredient drug can be significantly reduced.

- Therefore, it is possible to prevent the area around the processing machine from becoming sticky due to splashes of processing fluid.

Moreover, since it suppresses the generation of microorganisms, (1) consumption of D-sorbitol due to microbial decomposition is prevented.

■ Microbial disturbances such as a decrease in ion exchange capacity due to filter clogging and ion exchange resin column clogging are prevented.

■ Prevents the generation of sticky substances caused by microorganisms in the processing liquid tank, reducing the work required to clean the tank.

Effects such as these are produced.

Therefore, according to the electrical discharge machining fluid of the present invention, it is possible to perform extremely good machining economically, with high machining accuracy, and with good workability.

Claims (3)

[Claims] (1) An electrical discharge machining fluid characterized by containing D-sorbitol and triethanolamine as active ingredients. (2) The concentration of triethanolamine is 0.001 to 0.
The electrical discharge machining fluid according to claim 1, which is 1% by weight. (3) D-sorbitol concentration is 0.01 to 30% by weight
Claim 1 or 2 characterized in that
The electric discharge machining fluid described in section.