The Study of WEDM Finishing Process on Thick Workpiece
Date Issued
2015
Date
2015
Author(s)
Lai, Yan-Bo
Abstract
Wire electrical discharge machining (Wire-EDM) is an essential material removal process in precision components and die or aerospace materials.When Wire-EDM machined thick workpiece,several finishing process was needed to reach the surface roughness and dimensional accuracy that we required. This study focused on the influence of electrical parameters (pulse on time,pulse off tome,servo voltage),wire parameters(wire tension,wire feed rate) and flushing parameters(flushing rate,flushing types) on surface roughness,material remove rate and drum shape error on the thick workpiece in finishing process.And for the drum shape error, probing into the relationships between discharge location distribution and short circuit frequency. The experiment results showed, when pulse on time increases ,the surface roughness is rougher and the drum shape error larger, but the material remove rate becomes higher.The influence of surface roughness isn’t obvious when pulse off time increases,but the drum shape error and the material remove rate become decreased. In the servo voltage part ,It is effective to reduce the surface roughness,material remove rate and drum shape error, when servo voltage is increased.In the wire parameters part,the change of the wire feed rate doesn’t significantly effect on the surface roughness and material remove rate. However, if the wire feed rate is too slow, there will exist some wire consumption error on the machined part.When the wire tension enhances,It limited impacts on the surface roughness,decreased the material remove rate,and a better cross-section straightness.In the flushing parameters part, when flushing pressure is increased, It doesn’t significantly effect on the surface roughness,but it increases the material removal rate and drum shape error. While at the same flow rate but different flushing types, it doesn’t significantly effect on the surface roughness, the material remove rate and the drum shape error. In the discharge distribution part, discharge location mainly concentrated in the upper and lower workpiece.When the short circuit frequency increases,the drum shape error converts convex to concave.
Subjects
roughness, material remove rate,drum shape error,discharge distribution,short circuit frequency
Type
thesis
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