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Development of For Wire Electrical Discharge Machining (WEDM)-Project

Abstract:

This paper gives an overview of setting up a rotary axis to the existing WEDM machine to investigate the machining parameters in WEDG of harder materials.

There are a number of hybrid machining processes (HMPs) seeking the combined advantage of EDM and other machining techniques. One such combination is wire electrical discharge grinding (WEDG), which is commonly used for micro-machining of fine and hard rods. WEDG employs a single wire guide to confine the wire tension within the discharge area between the rod and the front edge of the wire and also to minimize the wire vibration. Other advantages of WEDG include the ability to machine hard- to- machine materials with large aspect ratio.

INTRODUCTION

The electrical discharge machining (EDM) is a thermoelectric process that erodes workpiece material by a series of discrete electrical sparks between the workpiece and electrode. Unlike traditional cutting and grinding processes which rely on a much harder tool or abrasive material to remove the softer work material, the EDM process utilizes electrical sparks or thermal energy to erode the unwanted workmaterial and generate the desired shape.

Development of For Wire Electrical Discharge Machining (WEDM)

These sparks generate craters and recast layer on the surface of the EDM workpiece. Wire Electrical Discharge Machining (WEDM) is a widely accepted non- traditional material removal process used to manufacture components with intricate shapes and profiles. However WEDM utilizes a continuously travelling wire electrode made of thin copper, brass or zinc coated brass or copper of diameter 0.05- 0.3mm, which is capable of achieving very small corner radii. During the WEDM process the hardness and strength of the work materials are no longer the dominating factors that affect the tool wear and hinder the machining efficiency.

This makes EDM particularly suitable for machining hard, difficult- to- machine materials, such as the metal- matrix composited (MMC), Titanium, Tungsten, Zirconium, Molybdenum which are widely used in aerospace, nuclear, and automotive industries. Without WEDM the fabrication of precision workpieces reqiured many hour of manual grinding and polishing. Grinding with WEDM is one of the emerging areas developed to generate cylindrical form on hard and difficult to machine materials by adding a rotary axis to WEDM.

MAJOR COMPONENTS

The DC pulse generatoris responsible for supplying pulses at a certain voltage and current for specific amount of time.

Work-piece

All the conductive material can be worked by WEDM.

Tool Wire

The WEDM wire is the tool that determines the shape of the cavity to be produce.

Dielectric fluid

The WEDM setup consists of tank in which the dielectric fluid is filled. Electrode & work piece submersed into the dielectric fluid.

Servo system

The servo system is commanded by signals from gap voltage sensor system in the power supply and control the feed of electrode and work piece to precisely match the rate of material removal.

Power supply

The power supply is an important part of any EDM system. It transform the alternating current from the main utility supply into the pulse direct current (DC) required to produce the spark discharge at the machining gap.

SOFTWARE

Low cost, home and small business CNCs require at least one software package to operate. This is the basic package which allows the user to open a graphics file and command the system to machine the part.

The hand-made software is developed in the visual basic 6.0.

VISUAL BASIC 6.0

It is a very easy programming language to learn. The code looks a lot like English Language. Different software companies produced different versions of BASIC, such as Microsoft QBASIC, QUICKBASIC, GWBASIC, and IBM BASICA and so on. However, people prefer to use Microsoft Visual Basic today, as it is a well-developed programming language and supporting resources are available everywhere. Now, there are many versions of VB exist in the market, the most popular one and still widely used by many VB programmers is none other than Visual Basic 6.