Analysis of the factors affecting the quality of CNC machining
February 14, 2023
Abstract: The proportion of free-form surfaces in automotive molds has been increasing and the quality requirements of products have been continuously improved. Both of them have put forward higher requirements on the manufacturing precision of curved surfaces. Through the summary of the experience of CNC machining of molds, the related factors affecting the quality of CNC machining are analyzed. From the aspects of machine tools, tool holders, tools, machining processes, software and cutting parameters, the measures taken to improve the quality of CNC machining are introduced.
Key words: molding company; mold; processing quality; process; software
Chengdu Aerospace Molding Co., Ltd. is a specialized company engaged in the manufacture of molds and automotive interior and exterior parts. The company has a high-quality research and development and design team, connecting more than 60 workstations with the most advanced software in the world, with CAD /CAM/CAE technology and dozens of CNC machining equipment and CNC injection molding equipment form a world-class product development system and strong mold manufacturing and injection molding capabilities. Since the introduction of CNC machining center, the company has been using CNC equipment for nearly 20 years. It is deeply understood that the development of mold manufacturing has become more and more inseparable from CNC equipment at present. CNC machining is highly accurate, high quality and high. Speed, high automation direction! CNC machining has become an indispensable process for mold making, and it will become more and more important. The number of CNC equipment and the advanced degree of CNC equipment have become one of the key factors for a mold manufacturing enterprise to win the market and win competition.
In the modern mold manufacturing industry, the design of the cavity profile is becoming more and more complicated, especially the proportion of the free-form surface in the automobile mold is increasing and the product quality requirements are continuously improved, which puts higher requirements on the manufacturing precision of the surface. Therefore, the accuracy of the mold manufacturing process system, the accuracy of the CNC system, and the CAM technology of the mold manufacturing all have an impact on the surface quality. The molds containing free-form surfaces are basically automatically programmed by various CAM software and processed by CNC machine tools.
Most of the CNC machining centers of the molding company have a long service life. Although there are strict CNC machine operating specifications and good machine maintenance, its own precision loss is inevitable. In order to control the processing quality of the products, we regularly inspect and repair the CNC equipment, clarify the processing accuracy of each equipment, and clarify the processing tasks of each equipment. Strictly distinguish between rough and fine machining equipment, because rough machining pursues high speed, high removal rate, low machining accuracy, and the precision damage of equipment during roughing is the most serious, so we will use the service life. The equipment with the longest precision is designated as a special roughing equipment. The new equipment and the equipment with high precision are designated as finishing equipments. The reasonable matching of existing equipment resources and clear division of labor have been achieved, and the impact of machine tools on processing quality has been reduced. The lowest, while protecting the expensive CNC equipment, extending the life of the equipment. When our machine tools cannot be changed, the influence of the tool holders and tools associated with the machine tool on the quality of CNC machining has become prominent. In any rotary tooling system, the coupling of the spindle to the collet (or combination thereof) is the true cornerstone of tooling performance! The interface between our company's common tool holder and machine tool has BT handle and HSK handle. The taper shank of the BT handle and the machine tool spindle has a taper of 7:24. This type of shank is only suitable for traditional low speed machining because the BT shank and the main shaft are only tapered. When the speed is too high, due to the centrifugal force Will increase the taper clearance, which will affect the quality of CNC machining. When the maximum speed of the machine reaches 15000 rpm, it is usually necessary to adopt the HSK type shank. The HSK arbor is over-positioned and provides standard connection with the machine tool. Under the tension of the machine tool, the short cone and end face of the arbor are closely matched with the machine tool. .
Stand Dragon Industrial Co., Ltd.
