Effect of discharge accumulation on wire breakage in WEDM process

In recent years, WEDM has been adopted in precision machining as an important alternative machining method because of its greater flexibility and lower wear cost compared with traditional machining, whereas wire breakage during WEDM is an unignorable problem that influences the machining quality and efficiency. Therefore, it has been a research topic of considerable interest. This work focuses on exploring the reason for the wire breakage. Firstly, by observing the wire after discharges and using the finite element method, a complete thermal model considering both latent heat and flushing efficiency was built. With this model, the simulation of the crater on the wire was finished. Then based on the result gotten from the simulation and experiment, the heat partition ratio to the wire was found as 46.74% by inverse fitting. After that, a wire breakage experiment was done and through locating the position of 50 discharges before wire breakage it is found that 34% of discharges were located within a range of 2 mm, and the minimum area in the wire cross-section only remained 41.88% compared with the original wire. This kind of decrease in the cross-section area made the stress higher than the UTS of the wire and caused the wire breakage. The findings of this work allow for a more in-depth understanding of the effect of discharge accumulation on wire breakage.

Automated summary

In recent years, WEDM has become an important alternative machining method in precision machining due to its greater flexibility and lower wear cost compared to traditional machining. However, wire breakage during WEDM is a significant problem that affects machining quality and efficiency. This work focuses on investigating the causes of wire breakage, using observation, simulation, and experiments. The findings provide a better understanding of the impact of discharge accumulation on wire breakage.