JPS59129628A - Electrode wire for wire cut electro-discharge machining and its manufacture - Google Patents

Abstract

PURPOSE:To obtain an electrode wire excellent in the titled machining property and hardly adheres to a work, by covering a core material comprising a steel wire with an Al/Li/Zn/Mg alloy. CONSTITUTION:A steel wire is used as a core material of an electrode wire for electro-discharge machining, and is covered with a layer comprising an Al/Li/Zn/Mg alloy consisting of 0.005-3wt% Li, 2wt% Zn and/or Mg and 50wt% or more Al by hot dipping. As the outer layer contains Li, the present electrode wire is improved in discharge property and is hardly broken. The outer layer is improved in adhesion in the hot dipping. When ceramics are machined using the present electrode wire, it would hardly adhere to the work.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field The present invention relates to a composite wire suitable as an electrode wire for wire-cut electric discharge machining and a method for manufacturing the same.

(B) Background technology The wire-cut electrical discharge machining method is a process in which an electric discharge is generated between a workpiece and a linear machining electrode (hereinafter referred to as an electrode wire), and the electrode wire and the workpiece are moved relative to each other. This is a method that has been used in the past to cut the workpiece into a desired shape.

In this wire cut electrical discharge machining method, a long wire with a diameter of 0.05 to 0.25 Bφ is usually prepared as a linear electrode wire, and new wires are sequentially supplied to the electrical discharge machining part. .

In the electric discharge machining method, the quality of the electrode wire used has a direct and significant effect on the machining speed, machining accuracy, and surface quality of the workpiece surface, so there is a strong demand for the use of suitable materials. ing.

In general, the requirements for this electrode wire are: (1) Machining speed: Generally, the machining speed is not necessarily high in the wire cut electric discharge machining method, so it is possible to increase the machining speed even a little.

(2) Dimensional accuracy and surface texture of workpiece: Good dimensional accuracy,
It can also be processed without causing surface roughness.

(3) Workability: If the electrode wire breaks during cutting work, workability will be significantly impaired, so the occurrence of breakage during this work should be low.

(4) Price: As mentioned above, the electrode wire is a consumable item, so it should be inexpensive.

etc. are listed.

To further explain the above requirements for the electrode wire, the machining speed can be increased if a sufficiently stable electrical discharge is generated between the electrode wire and the workpiece, but conventionally the machining speed cannot be increased. Electrode wires that can be used often cause roughness on the surface of the workpiece.

In addition, in order to obtain the dimensional accuracy of the workpiece, it is necessary to maintain the dimensional accuracy of the diameter of the electrode wire and to apply sufficient tension to the electrode wire. It requires something difficult.

Next, regarding surface properties such as surface roughness, it is necessary to generate a uniform and stable electric discharge, and conventional machining speed and dimensional accuracy,
Since it has been difficult to satisfy both of the processed surface conditions, it is particularly desired to develop an electrode wire that satisfies both of these points.

In addition, wire breaks during cutting are caused by short circuits between the electrode wire and the workpiece, uneven discharge, and applied tension.
From this point of view, the electrode wire itself is required to have dimensional accuracy, stable discharge performance, and high tensile strength.

Furthermore, it is necessary that the raw materials are inexpensive so as not to increase the price, and that the material has good wire drawability into thin wires with a diameter of 0.05 to 0.25 Bφ as electrodes for electrical discharge machining.

Conventionally, copper wire, brass wire (Cu-30%Zn), tungsten wire, etc. have been used as electrode wires for wire-cut electrical discharge machining, but these do not necessarily meet the above requirements in the following points. I wasn't satisfied.

That is, copper wire has drawbacks such as not having very high strength, being easily broken, and being generally inferior to brass wire in terms of processing speed.

In addition, although brass wire has improved processing speed over copper wire, it is still not sufficient, and the dimensional accuracy and surface condition of the workpiece are not necessarily good, and in addition, it is not always sufficient in terms of workability. It has drawbacks such as being unable to speak.

Furthermore, tungsten wire is difficult to draw, and while the material is expensive, it does not have very good electrical discharge machinability.

Furthermore, recently, composite wires such as copper wires coated with zinc or zinc alloy (hereinafter simply referred to as zinc) have been studied.

Zinc-coated copper wire has extremely stable electrical discharge and has the excellent feature of increasing machining speed without roughening the surface of the workpiece. However, as mentioned above, copper wire Since the tensile strength is low, a material with higher tensile strength is required for the core material of zinc-coated composite wire. On the other hand, with zinc-coated composite wires, if the underlying core material is exposed due to scattering or evaporation of the zinc layer, the discharge becomes unstable, so it is necessary to thicken the zinc layer and increase the strength of the core material mentioned above. Therefore, there are difficult problems in manufacturing. In order to improve the tensile strength of the composite wire, an electrode wire has been proposed in which a steel wire is used as the core material and Zn 4 or A4 is coated as the outer layer. However, when Zn coating is hot-dip plated, intermetallic compounds are generated, causing problems in wire drawability, and in the case of AA, uniform adhesion is difficult. If electroplating is used, a good coating can be obtained, but it is expensive and is not practical as an electrode wire, which is a consumable material. Furthermore, with these composite wires, the machining speed may decrease when machining tool steel, and with ceramics such as BN, coating Zn or AA may adhere, making the discharge unstable.

(C) Disclosure of the Invention The present invention has been made to solve the above-mentioned problems, and uses a steel wire as a core material and contains 0.005 to 3% by weight of Li by hot-dip plating on the surface of the steel wire. A1 alloy layer containing 150% by weight or more of A1 or Mg and/or in addition to the above Li.
Alternatively, it is characterized by forming an alloy layer of 50% by weight of Al containing a total amount of 2% by weight of Zn, and its manufacturing method is a hot-dip plating method.

Containing Li in the coating layer is essential, and a content in the range of 0.005 to 3% by weight has the effect of improving discharge characteristics, particularly preventing disconnection due to short circuits, and further improves the adhesion of hot-dip plating. If A1 is less than 50% by weight, adhesion is likely to occur during ceramic processing. Moreover, when Mg and/or Zn is less than 2%, the speed in machining tool steel etc. decreases.

Next, the present invention will be explained in detail with reference to Examples.

Example A1 alloy coated wire-cut electric discharge machining wires having various compositions shown in Table 1 were passed through the melt bath of each coated alloy at a bath temperature of about 680"C after the steel was pretreated with hydrochloric acid. A, 12 alloy was coated.

This was wire-drawn to produce electrode wires of predetermined dimensions.

Table 2 shows the results of these wire cut electrical discharge machining tests. The workpiece is a sintered body of tool steel 3KD-11 and poron nitride (BN).

As shown in Table 2, it can be seen that the products of the present invention are superior to conventional products and comparative products as electrode wires for electrical discharge machining.

Claims (2)

[Claims] (1) The core material is a steel wire, and the outer layer is an A1 alloy coating layer containing 0.005 to 3% by weight of Li or further containing 2% by weight or more of Mg and/or Zn in total and containing 50% by weight or more of A1. An electrode wire for wire cut electrical discharge machining, characterized by the following. (2) Passing the steel wire through an A1 alloy molten bath containing 50% by weight or more of A and 0.005 to 3% by weight of Li, or further containing 2% by weight or more of Mg and/or Zn in total A method for producing an electrode wire for wire-cut electric discharge machining of a wire-cut wire having a core material made of steel and an outer layer made of an A1 alloy coating layer.