The big processing attribute of the vertical machining center is that the consistency of the batch size of the workpiece is very high. We know that the traditional processing of the original workpiece must go through the clamping process from one process to another process. This process is manual It is difficult to achieve the same processing size of each part. Of course, this does not mean that the workpiece is out of tolerance. As long as the workpiece is within the tolerance band of the workpiece, it is qualified. This means that the size of some workpieces may be in a large difference. The cnc machining parts is in the middle difference, and some workpieces may be in the small difference. It is difficult to guarantee the dimensional consistency of the workpiece.

Therefore, at this stage, the utilization rate of vertical machining centers is high in small and medium-sized processing enterprises. Of course, vertical machining centers are also cost-effective machine tools among CNC machine tools. They have high machining efficiency and high machining accuracy. These two aspects also solve the problem of maintaining workpieces. The problem of size consistency. Of course, if the numerical control parameters are set improperly or the operation is improper, the vertical machining center will sometimes appear out of tolerance in the actual machining.

The machining accuracy of the vertical machining center is out of tolerance mainly as follows: high surface roughness value of the inner hole processing, the reamed inner hole is not round, the reamed hole position accuracy is out of tolerance, the inner surface of the hole has obvious edge and reaming The center line of the rear hole is not straight, the hole diameter increases, the hole diameter decreases, etc.

• 1. Reasons for the high surface roughness value of the inner hole: The surface roughness of the inner hole processed by the vertical machining center is high, and there are many reasons, which may be due to the high cutting speed, inappropriate cutting fluid selection, and excessive reamer entering angle Large, too large reaming allowance, uneven or too small reaming allowance, not sharp cutting edge, too wide reaming cutting edge band, poor chip evacuation during reaming, excessive wear of the reamer, and possibly optional Reasons such as the mismatch of milling tools and parts materials.
• 2. Reasons for the increase of the processing aperture: The gradual increase of the aperture during the vertical machining center may be caused by: the design value of the outer diameter of the reamer is too large or the reamer edge has burrs, the cutting speed is too high, the feed amount is improper or The machining allowance is too large, the main deflection angle of the reamer is too large, the reamer is bent, the edge of the reamer is adhered to the edge of the reamer, the edge swing of the reamer is out of tolerance during sharpening, the cutting fluid selection is inappropriate, and it may be CNC The problem of the machine tool itself, the bending of the spindle or the loose or damaged spindle bearing, may also cause the above problems.
• 3. Reasons for the position accuracy of the reamed hole is out of tolerance: It may be caused by the wear of the guide sleeve of the vertical machining center, the bottom end of the guide sleeve is too far from the workpiece, the length of the guide sleeve is short, the accuracy is poor, and the spindle bearing is loose.