![<?echo $_SERVER['SERVER_NAME'];?>](/template/twentyseventeen/skin/images/header.jpg)
At present, more and more complex parts in the world are being processed by composite machine tools. The composite processing machine highlights that most or all of the machining operations of the workpiece are completed in a single installation, so as to reduce the number of machine tools and fixtures, improve the accuracy of workpiece processing, shorten the processing cycle, and save the work area. In compound machining, the tool and machine tool are always complementary and inseparable.
In this column, the reporter invited Mr. Liu Jinshi, Minister of Technology of Little Giant Machine Tool Co., Ltd., Dr. Wang Yongguo, Automotive Industry Manager of Nanjing Lanzhi Metal Processing Technology Co., Ltd., and Mr. Zhang Tao, Minister of Machinery and Tools of Kyocera (Tianjin) Trading Company, Shanghai Branch. , They discussed their respective viewpoints on the technical application and development trend of composite processing machine tools and tools.
Technical requirements and processing advantages
Mr. Liu Jinshi: Compared with ordinary machine tools, compound machine tools can perform complex machining processes such as turning, milling, drilling, boring, grinding and gear machining. They can also perform cross-category machining such as stamping, laser quenching and metal machining. Sintering and so on. Because the multi-tasking machine tool can integrate multiple processes and multiple processes on a single device, parts can be completely or mostly processed after a single clamping, which not only reduces the number of parts and many auxiliary tools. Non-processing time improves production efficiency. At the same time, one-time mounting of parts reduces man-made errors and improves the machining accuracy of the entire part. For the entire production environment, due to the improvement of the compound capabilities of the equipment, the number of equipment required for parts processing and the floor space of the production plant are reduced, labor costs and investment in fixed assets are reduced, production costs are reduced, and more important It simplifies the production management process, improves the degree of flexibility and automation in the production department, and improves the ability of the entire company to respond to market changes.
Dr. Wang Yongguo: Composite machining is generally used in the following two aspects: First, parts require high processing efficiency; in order to improve processing efficiency, multiple processes are compounded together; on the other hand, two or more processing surfaces There are strict requirements for positional accuracy such as coaxiality, and in order to achieve this accuracy, the relevant two or more machining surfaces are compounded and processed together.
Composite machining places higher requirements on the process system consisting of machine tools, tools, fixtures, and workpieces. First of all, when multiple processes are combined together, it is necessary to consider whether the power and accuracy of the machine tool are appropriate. If the power of the machine tool is not enough or the accuracy of the machine tool is not high enough, it is not suitable for compound machining. Secondly, it is more difficult to design and manufacture the tool for complex machining. It is necessary to fully consider the interference problems during tool processing, the strength of the tool, and the problem of ensuring the flow of the internal coolant. In addition, if the tool that processes a machined surface has a problem, the entire composite tool will reach the end of its life. Therefore, higher requirements are also placed on the design and manufacture of the tool. The fixture design of composite machining must fully consider the force conditions of the entire machining process; the composite machining process requires a uniform internal structure and stable mechanical performance. Finally, composite machining should be done as much as possible between roughing or finishing.
Figure 2 Aluminum Alloy Parts
Mr. Zhang Tao: At the same time, the tools for compound machining centers with turning and milling functions are more prominent than conventional tools in terms of low resistance and high efficiency. In response to this demand, Kyocera has developed the world's leading high-efficiency, low-resistance, serialized end mills (MEC, MECX), which have lower cutting resistance and cutting edges than conventional end mills. Many features such as multiple feeds and high feed rates enable efficient processing.
Common problems and solutions
Mr. Liu Jinshi: From the machine tool point of view, the common problem encountered in the composite machining of parts is to blindly and greatly expand the equipment's compound processing ability, but this is always limited in the actual processing. It must be influenced by many factors such as realizability, machine economy and social supporting environment.
Figure 3 Combined PCD tool
CNC compound machine tools are not formed by simple superposition of various single machine tools that realize different processes, but are composed of newly developed basic technology modules with composite processing requirements, such as: automatic tool magazine modules that accommodate various types of tools. The spindle module for cutting that can use various tools; the B-axis function module that makes the spindle oscillating and the module that has the space to move capability, etc. Therefore, to solve the above problem, to better develop the composite machining technology, it is necessary to The use of new processes, new concepts, and the development of new types of composite processing modules can be solved.
Mr. Zhang Tao: Due to the special nature of the compound processing, premature wear of the tool may occur. This requires that the tool product must have strong toughness, good wear resistance, large feed, heavy cutting, and hardness. Material cutting. In addition, the tool products should also have good accuracy and stability, be able to adapt to high-speed cutting environments, and have a good chip breaking structure.
Figure 4 Engine cast iron cylinder block
Most of the problems that occur in the tooling of composite machining can be solved by considering the factors such as machine tools, tools, fixtures, and workpieces when designing the tooling plan and designing and manufacturing the tool.
Dr. Wang Yongguo: In the composite machining of parts, the most common is that the cutting edge of one or several machining surfaces of the compound machining tool wears or breaks to reach the service life. This is mainly due to the poor design of the tool or the workpiece material. Inhomogeneities, etc., re-improvement of the design or the requirement to improve the quality of the blank can solve this type of problem. In addition, the poor quality of the processed surface may also be affected by poor chip evacuation. This is mainly due to the unreasonable design of the flutes and the insufficient flow of the coolant. The problem can be solved by improving both aspects. In addition, sometimes the tool strength is not enough to cause instability in the process.
First of all, we must develop tool materials that can be used for various types of materials to be cut. At the same time, we must design a chip-breaker shape that can achieve good chip-removal processing, and develop tools that ensure high feed rates and high-precision machining.
Product Technology Highlights
Mr. Liu Jinshi: The performance of the turning and milling and compound machining center of Little Giant Machine Tool Co., Ltd. is outstanding in terms of power output, automation and intelligence. The QTN250MS (see Fig. 8) of the milling and turning machining center of our company is equipped with a built-in electric spindle. The spindle motor and the spindle are integrated, and no belt drive or coupling is required. The spindle itself is a spindle motor and can realize high speed. And high-precision positioning and interpolation to improve the composite processing capabilities. QTN250MS power milling spindle is provided by AC servo spindle motor, and the peak power can reach 5.5kW, which is equivalent to the power of a small machining center spindle. It can use the 50mm diameter face milling cutter, and each cutter seat can be equipped with power tools. This power and tool capability have a wide range of processing and improve the ability of the parts to be composite processed. With the function of the second spindle, the exchange of parts between processes can be performed. After one clamping, complete processing of two processes of a workpiece can be completed, which not only improves the processing efficiency, but also because the exchange is completed by the machine tool itself, reducing man-made Errors improve the machining accuracy of parts.
Figure 6 multi-function composite tool
In terms of automation and intelligence, our company's full range of CNC lathes are equipped with intelligent electric tailstocks. The electric intelligent tailstock adopts servo motor and screw drive. Through the stability mechanism and the control of the current loop of the servo motor, the thrust value set by the program is realized, and an ultra-fast thrust setting of the machined parts of any length can be realized. The entire process is performed automatically by the program without manual intervention. The CNC system automatically judges the length of the part and adjusts the thrust value set by the program. During the machining of the part, the magnitude of the thrust can be changed at any time. For example, when starting the cutting, the blank is generally removed more than the rough machining of the structure. In this case, a large thrust value such as 2KN can be set in the program, along with the blank The weakening of the local or overall rigidity can be appropriately set by the program to reduce the thrust value such as 1.8KN, 1.6KN, 1.2KN... This can effectively reduce the deformation caused by the excessive thrust, as much as possible to improve the precision of the parts. Precision.
Dr. Wang Yongguo: Our company has strong technical advantages in compound machining tools. Taking the machining of the aluminum alloy part (AlSi9) shown in Fig. 2 as an example, each of the coaxial processing surfaces can be directly machined with the combined PCD tool shown in Fig. 3 at a rotational speed of 4 000 r/min without rough machining. Give 800mm/min). On the one hand, the cutting efficiency is very high (cutting time only takes about 10s), on the other hand, the concentricity of each inner hole surface is very high (less than 0.003mm); at the same time, the surface roughness of each inner hole surface can reach the mirror surface. This type of composite tool is currently only designed and manufactured by a few tool companies.
Fig. 7 Composite machining tool HSK
Figure 4 shows a foreign company's engine cast iron cylinder block, Figure 4 is a composite tool that can be processed in the process can be processed simultaneously three diameters of the inner hole surface, a 15 ° chamfered surface and a 45 ° chamfered surface. Because the long diameter of the tool is relatively large, the concentricity and surface roughness of the three inner hole surfaces are required to be high. Therefore, a compound tool with a blade and an adjustable blade is used. Since the cylinder material is cast iron, coated cemented carbide or CBN inserts can be used according to requirements such as efficiency, and the guide bars can be cemented carbide CBN or multilayer materials. The actual use of the effect is very good, fully meet the precision requirements of the parts. This type of tool represents the highest level of hole machining, and requires very high design and manufacturing of the tool. At the same time, it has strict requirements on the type, concentration, and pressure of the cutting fluid.
Mr. Zhang Tao: Our company mainly focuses on the specific requirements for the spindle work of machine tool equipment, and develops various turning tools suitable for spindle head installation. In addition, the company is also actively developing special composite cutting tools adapted to modern production conditions to expand the types of composite cutting tool products. In the application field, we can meet the needs of more customers and strive to use a single tool to complete the various processes that originally required the use of multiple tools to achieve multi-function. Compound machining tool HSK is shown in Fig. 7.
Composite machining tool/machine tool selection
Mr. Liu Jinshi: The increase in the performance of a single piece of equipment has contributed very little to the increase of production efficiency. Only the transformation of the manufacturing mode and management model of the entire plant can make the production efficiency improve dramatically. Therefore, the use of composite processing equipment must take into account the entire plant environment and match the production pattern of the entire plant. The devices used in advanced digital manufacturing plants are highly compounded and highly automated devices that can correspond to production management models. If there are only partially compounded equipment in the factory and the others are ordinary equipment, then the increase in production efficiency of this factory will be greatly reduced because the management model may not be improved to a higher level because of differences in equipment. Therefore, the choice of the compounding machine should be integrated with the equipment and the management environment in the factory. Generally, the higher the degree of compounding, the more advanced the production management mode corresponding to the production equipment.
Fig. 8 QTM250MS Milling and Milling Machining Center
Dr. Wang Yongguo: Composite cutters can indeed improve machining efficiency and accuracy of parts, but not all composite cutters are suitable for all applications. Only when machine tools, knives, fixtures, and workpieces meet the requirements of a certain process system, but also when the production efficiency and accuracy of the parts have higher requirements, the composite cutter can exert its advantages. In addition, due to the high technical content and high price of the composite tool, there are high requirements for the use conditions of the tool. Therefore, it must be fully considered when selecting whether to use the compound tool. It is better that experts in the compound tool demonstrate the machining scheme together. .
Mr. Zhang Tao: In lathe-based composite machining, we should focus on selecting widely usable tool materials with good versatility, and try to match chipbreaker shapes with a wide range of chip removal that can perform good chip processing; Based on composite machining, it should be focused on selecting tools that can achieve both low cutting resistance and high efficiency machining.
Technical trends
Mr. Liu Jinshi: The technology integration and technology compounding of the composite machining technology is one of the most active development trends of CNC machine tools. Currently, it has evolved from machining composites to non-machining compounding, and has developed into parts manufacturing and management information and application software. Compatible, the purpose is to realize the complete processing of the complex shaped parts and the intensive management of the production process, and to increase the flexibility and manufacturing efficiency of the entire production system. With the integration of composite technology and information technology, manufacturing plants are entering a new era, namely the era of digital flexible manufacturing.
Dr. Wang Yongguo: The application of composite processing in the automotive industry will become more and more extensive. This is determined by the characteristics of the manufacturing of automotive parts represented by engines and transmissions. On the one hand, the automotive industry is mass-produced and has high requirements on efficiency. The precision requirements for parts in the automotive industry are much higher than traditional manufacturing; on the other hand, the automotive industry currently uses a large number of high-precision machining centers for composite tools. Use created the conditions. In addition, composite tools are widely used in other industries where productivity and precision of machining are required.
Mr. Zhang Tao: The composite processing technology belongs to the already mature technology, and its application will be continuously deepened. Composite machining will not only be applied to the relatively common "turn-milling center" at present, but will also process some box-type parts, crankshafts, and other workpieces with complex structures and difficult machining. With the development of industry and technology, we It is believed that this technology will extend to many aspects such as gear machining and plastic processing.