Monthly Archive February 25, 2022

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.


Reasons affecting CNC machining accuracy

In the field of machining industry, what are the reasons for the influence of CNC machining accuracy? Let’s look at the following reasons:

  1. The first is the error of position influence: it usually refers to the change or deviation degree of the mutual position of the actual surface, axis or symmetrical surface of the machined part relative to its ideal position, such as perpendicularity, position, symmetry, etc.
  2. Machine tool error: the self error of the machine tool usually refers to the dead angle error. The main causes of position error are the machining error caused by the gap and elastic deformation caused by the transmission in the machining process of machine tool parts, and the position error caused by the friction force that the tool head needs to overcome in the machining process. In the open-loop system, the position accuracy is greatly affected, while in the closed-loop servo system, the position accuracy mainly depends on the displacement detection.
  3. Geometric error: machining accuracy error caused by geometric error of CNC machining. In the process of CNC machining, due to the influence of external factors such as external force and heat generated in machining, the geometric accuracy of machine tool is affected, and the geometric deformation of parts processed on machine tool will lead to geometric error. According to the research, there are two main reasons for the geometric error of NC machine tools: internal factors and external factors. The internal factors causing the geometric error of the machine tool refer to the geometric error caused by the factors of the machine tool itself, such as the levelness of the machine tool workbench, the levelness and straightness of the machine tool guide rail, the geometric accuracy of the machine tool and fixture, etc. External factors mainly refer to the geometric errors caused by the influence of external environment and thermal deformation in the machining process. For example, the geometric error caused by the thermal expansion and deformation of tools or parts in the cutting process will affect the machining accuracy of machine tools and parts.
  4. Cumulative error: from the long-term data analysis and actual operation of part processing, it can be seen that the machining accuracy error caused by the positioning of CNC machining machine tool. The positioning of machine tool has a great influence on the machining accuracy of NC machine tool. In terms of structure, the machining error of NC machine tool is mainly caused by positioning accuracy, and the feed system of machine tool is the main link affecting positioning accuracy. The feed system of NC machine tool is usually composed of mechanical transmission system and electrical control system. In the structural design, the positioning accuracy is related to the mechanical transmission system. In the closed-loop system, the CNC machine tool can usually prevent the position deviation of the main components in the feed system (such as ball screw and other components) through the positioning detection device. However, for the open-loop system, due to many influencing factors and complex conditions, it is impossible to carry out positioning monitoring, so the machining accuracy of NC machine tool is greatly affected.

The above explanation is the reason why Dongguan CNC machining accuracy is affected. I hope it will be helpful to you after reading it.

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