Analysis of the Causes of Wire Breakage in Medium-Wire EDM

Wire EDM By utilizing a continuously moving metallic molybdenum wire and applying sustained pulsed spark discharges between the wire and the workpiece, the temperature in localized micro‑regions is raised to tens of thousands of degrees, causing the metal at that location to melt or even vaporize. Under the action of the resulting explosive force, the molten material is ejected into a liquid medium, where it is carried away, leaving a minute pit on the part’s surface. Repeating this process enables the part to be cut and shaped by the wire.

During wire EDM machining, the molybdenum wire often breaks due to various factors, leading not only to process interruptions but, in severe cases, to complete scrap. It is therefore essential to analyze the root causes of wire breakage and implement targeted measures to address them. Typically, the wire may snap from excessive tensile stress; however, more commonly, it fails due to wire slack, improper parameter settings, or component‑related issues that bring the workpiece and electrode too close, resulting in arcing and burnout.

Workpieces that have not had their residual stresses adequately relieved may crack and sever the molybdenum wire mid‑process, or they may burn out due to excessive spacing caused by deformation. They can also be pinched or chipped off as a result of deformation. Without clamping devices, positional shifts during machining can trigger arcing and wire breakage, or the wire may snap under the influence of its own weight and deformation.

Wire EDM The voltage and pulse width should be set to facilitate chip removal; poor chip evacuation can lead to material buildup, resulting in localized discharges and arcing. When cutting thicker materials, it is advisable to reduce the cutting speed, increase the pulse interval, and slightly lower the no-load voltage to decrease the peak current, thereby giving the molten metal particles sufficient time to be expelled. Excessively high cutting speeds can easily trigger arcing and concentrated discharges.

When starting the cutting process, check for non-conductive materials that could prevent proper cutting and cause the wire electrode to snap. If the flushing pressure is too high, it may deflect the wire electrode and trigger arcing; if it’s too low, chip removal will be inadequate, leading to poor discharge conditions and wire breakage. In the absence of working fluid, the wire will burn through directly.

Wire EDM The guide wheel directs the wire electrode’s path; if it rolls poorly and vibrates, this can compromise machining stability and even lead to wire breakage. An improperly chosen wire‑feeding trajectory may cause workpiece deformation, clamp the wire, or result in direct burnout and breakage. For thick‑walled workpieces, chip removal is challenging, necessitating a moderate reduction in feed rate and enhanced chip evacuation to ensure adequate flushing by the working fluid and timely removal of debris. Similarly, for thin‑walled parts, an excessively high feed rate can easily trigger frequent short circuits and subsequent wire burnout.

In actual machining, the occurrence of wire breakage is far more complex and multifaceted than the factors listed above. This underscores that, to ensure a smooth and stable wire‑cutting process, it is essential to thoroughly assess all potential causes that may affect quality or even lead to wire breakage, and to implement appropriate countermeasures to eliminate them. Only by identifying the root cause of malfunctions can targeted solutions be applied, thereby enhancing the quality and stability of the machining process, extending the service life of the wire electrode, and improving its overall efficiency.

Dongguan Fulin Machine Co., Ltd. specializes in wire EDM, high-precision grinding, slow-wire EDM, mechanical parts, multi-axis machining, CNC machining, five-axis machining, precision parts, non-standard parts, and general machining. The company boasts state-of-the-art production equipment and is equipped with advanced inspection tools, such as coordinate measuring machines, microscopes, projectors, hardness testers, 3D measuring devices, and Swiss height gauges, ensuring the production and processing of high-precision products to meet customer requirements. To date, we have maintained successful long-term collaborations with numerous related enterprises, and our product quality has consistently earned customers’ recognition and praise. Our unwavering commitment is to put people first, excel through quality, foster unity and progress, and pursue continuous innovation—satisfying our customers by delivering superior quality, honoring precise delivery schedules, providing exceptional service, and ensuring customer satisfaction through systematic management.