Gap tracking actually refers to frequency conversion speed. The principle of frequency conversion is as follows: a sampling voltage is obtained from the discharge gap, and this voltage controls an oscillator whose frequency changes almost linearly with the voltage. The pulses output by the oscillator directly serve as the controller's calculation and feed start/stop signals, thus achieving control of the feed speed by the gap voltage. The so-called tracking tightness usually refers to artificially changing the amplitude range of the sampling voltage supplied to the oscillator. The most fundamental principle of tracking adjustment is to obtain stable processing; as long as it is stable, speed and surface finish are guaranteed. Because the automatic control range of the frequency conversion circuit is very large, under normal circumstances, the location of the frequency conversion adjustment on the panel is not very important; processing can be carried out anywhere. However, in certain specific situations, cutting efficiency and quality are still significantly related to the high speed of frequency conversion.
The speed adjustment method is as follows: After selecting the pulse width, pulse interval, and the number of transistors, observe the voltmeter and ammeter of the pulse source. Adjusting the frequency converter speed will cause the meter readings to fluctuate within a certain range. In the range with lower current, the adjustment will be more sensitive. Adjusting towards faster speeds will result in a period of sluggishness. Placing it at the boundary between sluggishness and sensitivity is more suitable. In other words, when it is adjusted to a position where it is no longer sensitive enough but can still process normally, it should be slightly adjusted back.
This refers to ordinary materials of normal thickness. For special materials or ultra-thick processing, frequency conversion adjustments should be tailored accordingly. For example, for materials with low conductivity, in addition to increasing the amplitude of the high-frequency source, the sampling starting voltage should be increased, and the tracking should be loosened. For processing of large thicknesses, the frequency conversion speed should also be slightly slower, even if some no-load pulses occur, to allow sufficient time for cleaning gaps and insulation recovery. Excessive tracking will, to some extent, reduce the discharge gap and make the black and white stripes on the plating lighter, but this only results in a lighter color; the smoothness is not improved. This is because pitting and commutation stripes are the same, only more prone to short circuits. If the wire is loose or the tension is uneven, causing overfeeding followed by prolonged short circuits, both smoothness and efficiency will be lost.
The tracking gap directly affects the machining performance of wire EDM machines. If the tracking gap is too small, short circuits and streaks can easily occur during cutting. If the tracking gap is too loose, tracking will be incomplete, leading to unstable cutting. In short, adjusting the tracking gap properly is crucial during wire EDM cutting. Currently, Baoma CNC's BMXP control system, for machining at standard heights, automatically adjusts the tracking based on the cutting situation when VF is selected as "0," achieving intelligent operation.
