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How to ensure the machining accuracy of CNC mold parts

2021-05-22

How to ensure the machining accuracy of CNC mold parts

Machining center in the process of processing the mold, the precision and surface processing quality requirements are getting higher and higher, in order to ensure the mold processing quality, we should be the choice of the machine tool, the choice of the handle, the choice of the cutting tool, processing scheme, program generation, operator requirements and other aspects to consider.


1. Selection of high precision and high speed machining center

With the improvement of product design requirements and the development of high-speed and high-precision machining technology, the quality of numerical control machining of the die has been greatly improved, the processing speed of the die has been greatly improved, the processing process has been reduced, the production cycle and The Times of clamping of the die have been shortened, and sometimes the time-consuming flocksmith repair work can be eliminated.High-speed and high-precision machining of die and mould has gradually become one of the important contents of technological transformation of die and mould production enterprises. High-speed CNC machining center has become inevitable to replace the traditional low-speed machining, and the development of die and mould manufacturing technology will also bring us more abundant product experience.

2. The use of appropriate tool handle structure

The use of high speed and high precision machining center will also drive the renewal of related process equipment.In particular, the influence of the tool on the quality of NC machining and the tool handle will become prominent.In the rotary tool machining system, the collet and the machine tool (or its combination) are closely connected to ensure the realization of the tool machining performance.Generally, there are two types of interfaces between the commonly used machine tools and the tool holder: HSK hollow tool holder and BT tool holder.Machine tool spindle and BT shank taper shank interface for 24:7, the traditional low speed processing is suitable for the use of this tool shank connection, because BT shank and machine tool spindle is only with the taper, under the action of high speed centrifugal force will make the taper with clearance increases, thereby affecting the quality of CNC processing.Generally, when the spindle speed exceeds 16000 RPM, we will need to adopt HSK hollow handle. HSK tool bar positioning structure is over-positioning, providing standard connection with the machine tool. Under the pull force of the machine tool, the short cone and end face of the tool bar can be closely matched with the machine tool.

3. Choose the right tool for processing

Reasonable use and selection of tool will be an important factor affecting the quality of NC machining.Cemented carbide tools are more and more widely used. Coated cemented carbide will replace most blade steel tools in high speed machining, including reamer, ball cutter, boring cutter and other simple tools. Coated cemented carbide will play an important role in high speed machining tool materials, and will be used in most of the conventional processing fields.

Usually we know that in rough machining we will choose a large diameter tool for processing, in order to save costs and reduce the difficulty of tool manufacturing, we will use the machine clamp-type carbide blade, try to make rough processing chip more;In the semi-finish machining, the insert tool with high speed and high feed is used to make the semi-finish machining faster.In the finishing process as far as possible to use the high precision round head mirror blade on the carbide tool bar to ensure the strength of the tool and the tool bar, so that the machining accuracy can be maintained at the same time to save the expensive cost of choosing the overall alloy tool.We also need to pay attention to finish machining parts in processing on the profile radius must be greater than or equal to the radius of the cutter, selects the radius is less than the corner radius of the cutting tool or diagonal lines in the form of circular arc interpolation interpolation method for processing, so that you can avoid using linear interpolation and cut occurred, ensure the quality of the mould finishing.

4. Numerical control process plan

In high speed and high precision machining, the importance of numerical control process design has been mentioned higher status, must control the whole process of processing, any error will have a serious impact on the quality of the mold, so the process plan will play a decisive role in the processing quality.Numerical control machining process design can be considered by the parts of the blank to parts processing and forming between a system of state control of the process scheme.Good process plan in the whole design process is more difficult, need to go through continuous practice summary and modification to get, in the design process to consider a large number of information, the relationship between the information is extremely complex, which must be guaranteed through the actual work experience of the programmer.Therefore, the quality of process design mainly depends on the experience and level of technical personnel.

5. A CAM software

A good software also can improve the machining quality and efficiency of the mold, such as UG and PM are good mould processing software, especially the two kinds of different processing strategy, rich and practical software programming in nc milling programming, car, wedm programming has been widely used, complement each other to make the quality and efficiency of nc machining obtained the very big enhancement.

Software it is just a tool, an excellent programming personnel have a wealth of on-site mechanical processing experience and theoretical knowledge, at the same time master the software function of numerical control program designers, talent is the decisive factor in the mold numerical control processing, the quality and efficiency of numerical control processing plays a key role.To establish a perfect training system for programmers.First of all, the designer should first practice for a period of time in the position of CNC operation, after strict operation examination, can carry out the design and training of CNC program.In order to ensure the quality of NC machining, it is necessary to have a good NC program.

6. Operator

Machining center operators are the executors of CNC machining, and their control over the quality of CNC machining is also obvious.They in the process of the implementation of processing tasks on the machine tool, handle, cutting tools, processing technology, software and cutting parameters of the real-time state of the most understanding, their various operations on CNC machining the most direct impact, so the processing center operator's skills and responsibility is also to improve the quality of CNC machining key factors!


Summary: Although the machining center and other hardware equipment is very critical, but the talent is the decisive factor affecting the quality of CNC machining, because the professional ethics of programmers and machine tool operators, skill level, job responsibility to determine the effectiveness of a variety of advanced equipment can play a large role.We must pay attention to each link of processing, especially the human elements, in order to make the CNC machining center mold processing more and more widely