Meaning
Dimensional distance separating the tool electrode from the workpiece during the electrical discharge machining of plastic injection moulds. It governs the accuracy of the metal removal and stops applying once the final cavity dimensions are achieved.
Discharge Accuracy
Precise control of this space ensures that the electrical arc removes the correct amount of steel from the mould cavity. If the electrode spark gap is too small, the risk of short circuiting increases and slows down the machining process. A larger gap allows for faster material removal but reduces the fine detail.
Constant flushing with dielectric fluid maintains the integrity of the spark.
Finish Quality
Smaller distances between the surfaces produce a smoother texture on the tool steel. The moulder chooses the gap setting based on whether the final part needs a rough matte look or a polished gloss. Proper adjustment prevents the formation of pits or irregular burnt patches in the metal.
The final texture on the steel is duplicated exactly on every plastic part produced.
Tool Wear
Erosion of the electrode occurs naturally as the spark jumps across the gap to the workpiece. Monitoring this wear is necessary to maintain the dimensional integrity of the mould over a long production run. Compensation for the narrowing electrode ensures that the final cavity matches the original design.
