Deformation Analysis For the processing Of Die Block In Lower Speed Wire Cutting

Due to the high precision requirements of the workpiece processed by the lower speed wire cutting, in addition to the use of high-quality EDM Parts such as wire guides, power feed contacts, nozzles, rollers, etc., if the processing technology is a little negligent, it will also cause the workpiece to be scrapped. At the same time, it will also have a negative impact on the manufacturing cost and processing cycle of the mold.

1. Before the wire cutting process, the die block has been subjected to cold processing and hot processing, and a large residual stress has been generated inside. The residual stress is a relatively balanced stress system. When a large amount of waste is removed by wire cutting, the stress is released as the balance is destroyed. Therefore, during the wire cutting process, with the effect of the original internal stress and the influence of the processing thermal stress generated by the electric spark discharge, the die block will produce non-directional and irregular deformation, resulting in uneven thickness of the subsequent cutting, which seriously affects the processing quality and processing accuracy.

The longer the processing time, the greater consumption of EDM brass wire, ion exchange resin, EDM filter, etc., which increases the manufacturing cost of the die block. What’s more, the machine tool will be slightly out of shape with the extension of processing time and temperature fluctuations.

2. Therefore, based on years of production experience, if the machining accuracy allows, the die block can be cut in the following way: in the first cutting, all the inner holes can be processed at one time, then take out the waste. Then the 2, 3 and 4 cuts of each inner hole are combined together (that is, after the 2nd cut of hole a, the EDM brass wire will not be displaced or cut, and then the 3rd and 4th times will be processed, and then: b inner hole→c inner hole...→n inner hole). After the cutting is completed, the aperture and relative size basically will meet the requirements.

3. If the displacement between the inner holes, threading the EDM brass wire, cutting the EDM brass wire, filling the processing tank with water, and draining the processing liquid tank are all calculated as 1 minute, then when this cutting method is used to machine a die block with 100 inner holes, it will save about 9h of processing time each time, after cutting 4 times, it will save about 30H. In this way, for the lower speed wire-cutting machine tool with more expensive EDM Parts, it not only improves the production efficiency, but also reduces the consumption of EDM Parts, in other words it reduces the manufacturing cost of the die block.

4. This cutting method can make each inner hole have enough time to release the internal stress after being processed for the first time, and can minimize the mutual influence and micro-deformation of each inner hole due to different processing sequences, and better guarantee the processing dimensional accuracy of the die block.