Yearly Archive March 11, 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.


CNC machining surface treatment process!

In the field of precision CNC machining, surface treatment technology is needed for machined parts with high requirements for strength and toughness. Let’s take a look at the surface treatment process of CNC machining:

  1. In the hardware mold industry, the process polishing technology of mold accessories processed by CNC is a very important link, and it is also an important process in the process of workpiece processing. The machining surface treatment process of precision mechanical parts is very important in the machining process. It is worth reminding that the mold surface polishing treatment of precision parts is not only affected by the process and polishing equipment, but also affected by the specularity of part materials. This has not been paid enough attention in the current machining, which also shows that, The polishing process itself is affected by the material.
  2. Precision CNC machining. At present, the machining technology to improve the surface performance of precision parts is constantly innovated and upgraded, but the most widely used in precision CNC parts machining are mainly hardening film deposition, nitriding and carburizing technology. Because nitriding technology can obtain a high level of surface properties, and the process of nitriding technology is very consistent with the quenching process of steel in precision parts.
  3. Details of surface treatment. The nitriding temperature is very low, so there is no need for fierce cooling process after nitriding technology treatment, so the deformation of precision machined parts will be very small. Therefore, nitriding technology is also one of the early technologies used to strengthen surface properties in the processing of precision mechanical parts, and it is also widely used at present.

The above is about the surface treatment process of CNC machining.


Steps of CNC precision machining

What is the order of CNC machining? For precision part processing, it must be based on the structure of the part, the condition of the blank, and the requirements of positioning and clamping. The key point is that the rigidity of the workpiece will not be damaged. There are the following points:

1、 The familiar understanding of precision parts processing technology can be divided into several points:

  1. How to handle the previous process will not affect the positioning and clamping of the next process. The middle cross section has a general fine part processing process.
  2. First stop the adding process of the inner cavity, and then stop the shape processing process.
  3. It is better to use the same positioning and clamping method or the same tool to stop the process, so as to reduce the number of repeated positioning, tool change and the number of moving pressing plates. Dongguan machining factory method.
  4. In multiple processes stopped in the same device, the process of damaging the workpiece stiffness shall be arranged first.

2、 The precision machining process of all parts can be completed by using the same tool sequence. Using other tools can successfully complete other parts. This can reduce the number of tool changes, shorten the dead time and reduce unnecessary positioning errors.

3、 Sorting method of processing parts: for parts with a large amount of processing content, according to their structural characteristics, the processing parts can be partially red, such as internal shape, shape, surface or plane. Common machining plane, locating surface and post machining hole; First deal with simple geometry, and then deal with complex geometry; Firstly, the parts with low precision shall be processed, and the parts with high precision shall be processed.

The above is the steps of precision CNC machining.