In the single-piece CNC machining, the blank is generally processed. Therefore, there will be interference of excess blank amount when the reverse machining is performed, and other tools are needed to meet the requirements. In the actual processing, although the ordinary reverse-side method can meet the requirements, there are problems such as cumbersome operation process, long machine tool occupation time, and inconvenient observation, which greatly affects the processing efficiency and processing precision. This article will introduce the improvement methods of reverse side in CNC machining in detail.

1. Common method for reverse side processing

It is mainly used for the flat vise clamping when processing parts.

  • Straight shank round bar. This method is to clamp the straight shank round rod on the spindle. Suppose the X-axis is divided: the moving spindle is slowly approaching one side of the workpiece. When approaching, use the parallel block to insert the gap between the round bar and the machined surface of the workpiece. When it feels easy to advance, take out the parallel block and continue. Move the spindle and re-plug the parallel block. If it is still easy to plug in or not plug in, move the spindle again, so that it can just be inserted, then return the X axis of the relative coordinates to zero; then move the spindle to the workpiece. On the other side, the same method of operation, the total value of the X-axis is obtained, and the coordinate system is set after moving the spindle to half of the total value (middle of the workpiece). The advantage of this method is that the operation is simple and the required tools are not of high value; the disadvantages are that there are many operation steps, the process is cumbersome, and the precision of the tool is not high.
  • Use a dial gauge to align thecutter. This method is a flexible method of using several accessories of the lever dial gauge to achieve the method. The operation method is as follows: the clamping cap of the lever dial gauge is set on the main shaft, and the dial gauge is attached to the clamping cap.

2. The improvement method of the reverse side

By summarizing the various sub-tools, it is found that the use of the eccentric edge finder is easy to operate, and the accuracy of the sub-center is high, but its characteristic is that the reverse side can not be completed. This is a major shortcoming of the eccentric edge finder. Therefore, after many experiments, the peripheral structure of the eccentric finder can be improved, and the original advantages can be retained, and the range can be extended to complete the reverse side.

Firstly, the outer circle and the inner hole of the fitting are completed on the numerical control lathe, wherein the inner hole is just matched with the edge finder, and the thickness is determined according to the processing condition of the part. Next, the threaded hole on the side is machined on the drill bed. The size of the threaded hole depends on the thickness. When the fitting is completed, it is matched with the edge-finding end of the edge finder, and then the two screws are locked by the side screws.

The improved sub-central method not only ensures the processing accuracy, but also has the advantages of convenient observation and simple and quick operation.