Precision electrical discharge machining uses multi-ele […]
Precision electrical discharge machining uses multi-electrode machining technology. According to the different characteristics of the discharge gap of the machining part in rough, semi-finish and finish machining, several electrodes with corresponding size scaling are used to complete the rough, semi-finish and finish machining of a cavity. First, a large amount of metal is etched away with the rough machining electrode, then the semi-finished electrode is changed to complete the transition from rough machining to finishing, and finally the finishing electrode is used for final finishing. The final finishing should also use multiple electrodes to compensate for the electrode losses.
In general precision processing, the size scaling of the electrode is 0.03-0.1mm/single side. In the processing, multi-segment processing conditions are used to smooth the side and bottom sections by shaking. Because of the small amount of shaking, it still has a high copy accuracy, and the shaking process makes the discharge more stable, and can obtain a more uniform surface roughness on the side and bottom, which is widely used. In precision machining, multiple electrodes need to be replaced. As long as the repeated positioning accuracy is guaranteed, a satisfactory technological effect can be achieved.
Method for guaranteeing positioning precision of precision machining
Precision electric discharge machining In order to ensure extremely high repeat positioning accuracy without reducing processing efficiency, a quick clamping positioning system is used, such as the 3R rapid clamping fixture of GF Machining Solutions Group. When using this type of fixture, as long as the accuracy is adjusted before the matching, the highest repeatable positioning accuracy during processing can reach ±2μm, and the electrode and the workpiece can be quickly changed. Before processing, use the centering reference ball tool and use the CNC The automatic centring function of the spark machine completes the positioning of the spindle chuck and the zero point of the workpiece center. It is very convenient to take off the workpiece for size measurement during processing and then continue processing.
The method of dividing the reference ball can ensure high-precision repeated positioning, and the contact area between the reference ball and the workpiece is one point during the dividing, which can avoid the influence of positioning accuracy due to the presence of fine debris. Both the precision-machined positioning electrode and the workpiece must have a clear positioning reference, and the electrode takes the center point of its reference, so that the error of the electrode size can be evenly distributed. The workpiece can take the reference single surface or the reference center according to the situation. The reference surface used to touch the edge must be smooth and flat, especially important in depth positioning, so that the positioning accuracy error can be controlled to a minimum.