Monthly Archive March 30, 2022

Machining and milling technology of CNC parts

Let’s take a look at CNC machining and milling technology!

  1. Feed line of precision CNC machining and milling plane parts: when milling plane mechanical parts, the side edge of end mill is usually selected for cutting. In order to reduce the tool receiving trace and ensure the appearance quality of parts, the cutting in and cutting out procedures of tools are carefully designed.
  2. In the machining process, when milling the surface, the cutting in and cutting out points of the cutter and milling cutter should cut in and cut out the surface of the part along the extension line of the part summary curve, rather than directly cutting in the part along the normal direction, so as to avoid scratches on the machined surface and ensure the general lubrication of the part.
  3. In the process of precision CNC machining and milling, if the inner generalization curve allows extension, it should be cut in and out along the tangent direction. If the inner generalization curve does not allow extension, the tool can only cut in and out along the normal direction of the inner generalization curve, and the cutting in and cutting out points are selected at the intersection of two or more elements of the generalization of mechanical parts. When a few internal elements are tangent without intersection, in order to avoid leaving a notch at the general corner when the tool compensation is cancelled, the cutting point of the tool should be far away from the corner.

The above is about the skills in the process of precision CNC machining and milling. For the machining of simple and complex precision parts, the CNC milling technology will be different, which can be based on the appropriate machining line.


Precision parameter control of CNC machining

In the machining industry, the accuracy parameters of CNC machining are mainly the level that the specific geometric parameters (specification, shape and position) of CNC parts are consistent with the ideal geometric parameters. Learn the following parameters in detail:

In the process of machining mechanical parts and small batch parts, CNC machining accuracy usually includes three level parameters: specification accuracy, shape accuracy and position accuracy.

  1. Appearance specification parameters of CNC processing

The specific specification of the surface itself or the middle of the surface after machining of CNC parts is consistent with the middle of the ideal part specification. The ideal part processing specification refers to the median value of the specification indicated on the part drawing.

  1. Shape accuracy parameters of CNC machining

The specific shape of the machined surface of CNC parts is consistent with the ideal part surface shape. The ideal part surface shape refers to the definite surface geometry shape.

  1. Precision parameters of machining parts of CNC parts

After machining, the specific parts of each surface of CNC parts are consistent with the parts between the surfaces of ideal parts. The position between the surfaces of ideal parts refers to the certain position between the surfaces.

The above is the accuracy parameter control of CNC machining. For different shapes, shapes, simplicity and complexity, it is necessary to select appropriate machining process parameters to improve CNC machining efficiency and ensure the machining accuracy of parts.


Four key points of CNC precision machining

In order to ensure the quality of precision CNC processing products, the following four key points should be followed in precision CNC processing:

  1. Datum first: that is, the datum plane shall be processed first. In the machining process of precision parts, the appearance as the positioning datum shall be processed first, so as to provide a precision datum for the processing of subsequent processes as soon as possible, so as to reduce the processing error.
  2. Division of processing technology: for the drawing size with high quality requirements for precision machining, multiple processing process routes shall be made, which can generally be divided into three stages: rough machining, semi finishing machining and finishing machining. Mainly to ensure the machining quality of mechanical parts; Conducive to the scientific application of equipment; Facilitate the arrangement of heat treatment process; And facilitate the discovery of blank defects.
  3. Face first and then hole: for precision CNC processing, for parts such as box, support and connecting rod, the plane shall be processed first and then the hole shall be processed. In this way, the plane can locate and process the hole, ensure the position accuracy of the plane and the hole, and bring convenience to the hole processing on the plane and ensure the processing quality.
  4. Finish grinding: the finishing of main surfaces, such as grinding, honing, finish grinding, rolling, etc., should be placed at the end of the process route. The general principle of formulating the process route of precision CNC machining and the formulation of the process specification of precision parts can be roughly divided into two links. The first is to draw up the process route of machining mechanical parts, and then determine the process size, equipment and process equipment, cutting specifications and man hour quota of each process.

The above is a personal understanding of the four key points that need to be followed in precision CNC processing.