(2) The processing size is unqualified
After cutting, the actual measured size exceeds the tolerance range of the required size of the pattern, and the size is too large or too small. In this case, it is generally possible to precisely control the machining size by correcting the program offset. For example, when cutting a punch, the program offset can be reduced when the size is too large. It should be noted that this adjustment is based on the inherent accuracy and stability of the machine itself, and the machine is in good maintenance. At the same time, the influence of environmental factors on precision machining is also very large. The indoor temperature should reach 21±2°C, the humidity should be 40-80%, and there should be no direct sunlight or airflow.
(3) Taper phenomenon
The wire cutting speed of the slow wire cutting process is slow, and the wire is lost in the main cutting process. Although the electrode wire for the wire cutting process is used once, the wire loss is inevitably present. Therefore, the slitting feature is wide and narrow, which is the main reason for the slight taper phenomenon in the processing of the mold parts. When the punch is cut, the upper end of the part is small, the lower end is large, and a certain taper is exhibited, and the dimensional error is about 6 μm.
Obviously, this problem can be solved by appropriately increasing the wire speed of the machine tool. However, this method will increase the processing cost. In actual production, the taper compensation function can be used in programming, that is, a small taper is added to the straight body part to correct the difference in accuracy. In addition, it is possible to appropriately increase the tension of the wire, and at the same time, it is necessary to confirm that the wire is subjected to accurate vertical alignment, and the upper and lower nozzles are intact without damage, and the low-pressure flushing flow during the trimming is correctly adjusted.