Wire EDM in Taiwan: Precision Insights into the Metal Industry

In the metalworking industry, electrical discharge machining (EDM) is also known as wire-cut EDM, spark machining, spark eroding, burning, die sinking, wire burning, or wire erosion. This is a manufacturing process that uses electrical discharges that cause sparks to form the desired shape of the workpiece, so it is also called sparking machining in Mandarin.

 

What Is a Wire EDM Process?

During processing, unwanted materials are removed from the workpiece through a series of rapidly recurring currents. In these components, one electrode is called a tool electrode, and the other electrode is called a workpiece electrode. There will be no surface contact between the tool and the workpiece during the entire machining process.

 

A Brief History of Wire-cut EDM

Today, there are many types of EDM. In this section, we will discuss a type widely used in the manufacture of household appliances, filters, electronic consumables, and other smaller-sized workpieces. Providing such a process is a must for manufacturing a wide range of products today, wire EDM is vital not only to the Western world but to the East. Taiwan is a country experienced in the metalworking and manufacturing industry. There are firms in Taiwan that dedicate to the design and building of wire EDM machines so that Taiwan has the capacity to handle the demand and even take the lead in this very field over decades in Asia. 

Wire-cut types of EDM machines were developed in the late 1960s, the purpose is to use hardened steel as materials to make tools and molds. The earliest numerical control (NC) machine tools were extended from a perforated vertical milling machine. In the late 1960s, the Soviet Union manufactured the first commercial CNC machine tool in Russia. It was a wire-cut electric discharge machine. During this period, the aviation, military, defense, and automotive industries were progressing in a positive direction. David H. Dulebohn's group developed machine tools for milling and grinding at Andrew Engineering Company in the 1960s.

Later, master drawings were produced by a computer numerical control (CNC) plotter to improve accuracy and repeatability. In the early 1970s, the production of wire cut EDM using CNC plotters and optical line follower technology. Dulebohn later used this CNC plotter, which was programmed and could directly control the operation of the EDM. The first CNC EDM machine was therefore produced in 1976.

 

Commercial Applications of EDM

Due to technological progress, in recent decades, the functions and applications of commercial wire EDM have been greatly improved. In addition, the feeding speed of the EDM is increased, and the finish of the machined surface can be well controlled.

 

Die-sink EDM

Another EDM process is die-sinking EDM. Its history can be traced back to the end of the Second World War in 1943. Two Russian scientists (B. R. Lazarenko and N. I. Lazarenko) were instructed to study methods to prevent sparking effects from corroding tungsten electrical contacts.

Although they failed to complete this task, their efforts contributed to this technology. At that time, they did find that when the electrodes were under certain environmental conditions, the corrosion could be controlled more accurately, which greatly inspired subsequent research.

The results of these studies prompted them to invent an electrical discharge machining method for processing hard materials such as tungsten. The name of the Lazarenko machine is called R-C machine, which means the resistance-capacitance circuit of electrode charging.

 

EDM Machine Progress Worldwide

In addition, there is an American research team composed of Harold Stark, Victor Harding, and Jack Beaver. They have successfully developed an EDM machine for removing broken end drills and taps on aluminum castings.

This increased the machining capacity of the wire EDM machines. Together with the accuracy improvement, the overall accuracy of the wire EDM machines is elevated ever since.

The American team initially used feeble electric-etching tools for the machine, but the results were not very ideal, so they later changed to this method. After that, Stark, Harding, and Beaver's machines were able to generate 60 sparks per second, which was a technological breakthrough at the time.

Later, machines based on this design used vacuum tube circuits, which enabled thousands of sparks per second, which greatly increased the cutting speed, and had great potential and productivity. This marks the great leap in the wire EDM machine development since wire EDM machines were used to be more like in the developmental stage then, but later the wire EDM was adopted officially in the industry.

 

EDM Today

Today, wire EDM and the relevant technology are very common metal cutting technologies that people have used to cut hard and complex materials. It is most widely used in the mold manufacturing and tool manufacturing industries.

In addition, it has become a common method for producing prototypes and parts, especially in the aerospace, automotive, and electronics industries with a small but diverse production model.