This paper discusses the function and market demand of CNC tool grinding machine, the technical characteristics, structural form, key technology and important supporting parts of CNC tool grinding, and introduces the typical models of foreign CNC tool grinding, and proposes to accelerate the development of domestic CNC tool grinding.
First, the market demand is broad
In today's world, China has become the world's largest equipment manufacturing country. According to reports, in 2013, the output value of China's equipment manufacturing industry exceeded 20 trillion yuan, 2.2 times that of 2008, accounting for about one-third of the global equipment manufacturing output ratio, ranking first in the world. Among them, the output of power generation equipment is 120 million kilowatts, accounting for 60% of the world; the completion of shipbuilding is 45.34 million deadweight tons, accounting for 41% of the world; the output of automobiles is 22.12 million, accounting for 25% of the world; the output of machine tools is 960,000, accounting for 38% of the world. . In addition, the annual output of washing machines, refrigerators, motorcycles, air conditioners, televisions, mobile phones, etc. are among the highest in the world. The machine tool is the working machine of the equipment manufacturing industry. From 2002 to 2013, China has become the world's largest machine tool* consumer in 12 years, and the machine tool consumption accounts for 40%-45% of the total global machine tool consumption.
It goes without saying that China is also a major consumer of CNC tool grinding machines in the world. It is reported that in 2013, China's CNC tool grinding machine consumption was 33 billion yuan, of which the imported CNC tool grinding machine was 11.5 billion yuan; the proportion of domestically produced tools (CNC tools) has risen from 15% in the early 11th Five-Year Plan to 25%. Showing a good posture, but the development potential is still huge. According to the relevant information of the tool industry,
The rapid increase in the demand for CNC tool grinding machines in China has promoted the huge market potential of the CNC tool grinding machine industry. At present, CNC tool grinding machines mainly rely on imports. It is reported that the number of 4-5 axis CNC tool grinding machines imported by major tool manufacturing enterprises in China has reached more than 100 sets, and some medium-sized tool manufacturers have also imported dozens of such machine tools.
Second, BT-150D CNC tool grinder Characteristics
The modern CNC tool grinding and assembly of CNC machining technology is mainly reflected in:
1. Precision
High precision is the embodiment of tool quality, which is directly reflected in the production quality of machined parts. Due to the high precision requirements of modern CNC tools, the corresponding five-axis CNC tool grinding has the precision of precision machine tools. The machining accuracy of the foreign five-axis CNC tool grinding reaches 2μ, so the machine structure is optimized and designed with functional components, which have good static, dynamic and thermal performance.
2. High speed
The numerical control tool processing form is mainly high-speed, high-precision forming grinding. The application of super-hard material grinding tools such as diamond grinding tools and CBN grinding tools puts new demands on the high-speed performance of the grinding machine. For example, the grinding wheel shaft generally adopts an electric spindle, and the rotating speed exceeds 10000r/min. The machine is required to have excellent electromechanical coupling, servo optimization, and high acceleration performance. The application of direct drive components such as electric spindles, torque motors, and linear motors has become a new bright spot in the high-speed performance of foreign five-axis CNC tool grinding.
3. Compound
Multi-axis linkage control and multi-process composite grinding are one of the main technical features of the five-axis CNC tool grinding. The five-axis CNC tool grinding can realize the complete grinding of complex profiles and composite tools in one loading. Because superhard materials such as polycrystalline diamond (PCD) and polycrystalline cubic boron nitride (PNCB) are used in CNC tools, it is not enough to grind such CNC tools with diamond wheels. Under the impetus of scientific and technological advancement, the technology of applying EDM and laser machining of CNC tools has emerged as the times require. At present, 5-axis CNC tool grinding is used for rotating EDM of polycrystalline diamond. The integrated grinding wheel is ground on the same tool grinding machine. It can be used for the double spindle and single spindle models with the electrode and grinding wheel replacement device. It is mainly used for metal and wood. The processing of polycrystalline diamond tools in the processing industries such as ceramics and plastics indicates that composite machine tools using EDM and grinding wheel grinding in combination with PCD tools have also matured. Special processing and compound processing have become an important development direction of CNC tool grinding.
4. Intelligence
The five-axis CNC tool grinding is one of the concentrated models of intelligent technology applications. The foreign advanced five-axis CNC tool grinding equipment is equipped with a laser probe, grinding wheel probe, sonar sensor, CCD camera, etc. Its models generally have machine state monitoring and optimization, automatic compensation of dynamic and thermal states, anti-collision function, tool processing. In the machine inspection, the grinding wheel automatically repairs the calibration and dynamic balance functions on the line, which improves the intelligent level of tool grinding.
5. Application software
“Half is hardware and half is software.” This is the basic feature of five-axis CNC tool grinding CNC tools. Without the support of CNC tool grinding software, it is impossible to process a variety of CNC tool products with various forms and forms. General grinding software includes machining standard tool modules and non-standard tool modules. The operator can apply the database or set the tool geometry parameters to form a 3D graphics simulation machining program. For the grinding of complex-shaped tools such as tapered ball end mills, foreign companies with strong strength can process them, because the machining of such tools requires high-precision multi-axis linkage CNC tool grinding machines and high-precision machining data calculations. Cutting software. It can be seen that the five-axis CNC tool grinding is one of the most complete CNC machine tools for software development and application.
6. Automation
The robot is widely used in CNC tool grinding machines, which successfully solves the problems of automatic exchange of grinding wheels and automatic loading and unloading of workpieces, thus greatly improving the processing efficiency, precision, and consistency of the numerical control tool grinding machine. The organic fusion of industrial robots and CNC tool grinding forms an automated grinding center (FMC).
In summary, the modern five-axis CNC tool grinding combines advanced manufacturing technology into one, becoming the carrier of contemporary high-tech integrated application. In addition, the five-axis CNC tool grinding can be used for precision machining of special parts such as medical parts, IT and aerospace. It is foreseeable that the five-axis CNC tool grinding, which is hailed as the “elf”, will play an increasingly important role in modern manufacturing.
Third. The structural form of the CNC tool grinding machine
CNC tool grinding mainly grinds complex CNC tools. In order to achieve grinding of complex surfaces, X, Y, Z, A or (B), C-- five-axis linkage is required for machine tool processing. The machine tool generally consists of a main moving part (grinding wheel), a feed moving part, an auxiliary port, a column, a stand, and the like. The layout structure of the five-axis CNC tool grinding moving parts is various, and it is divided into two types according to the main axis of the workpiece. Several types of machine tool structures commonly used at home and abroad are introduced.
1. The vertical layout of the machined part
The main axis of the workpiece of the machine tool is vertically arranged to realize 5-axis linkage:
X---Workpiece table lateral movement
Y----Workpiece table longitudinal movement
Z----The grinding head axis moves vertically up and down
A---Workpiece spindle rotation angle 360 degrees
B---grinding shaft rotation
C----Workpiece table horizontal swing
Based on this layout, the grinding wheel can be approached to the workpiece at any angle from the front, the back, the left, and the right, achieving 5-axis linkage, and the workpiece can be fully ground in one setup. This grinding method is flexible and efficient, eliminates the influence of the center of gravity of the workpiece, and has high machining accuracy.
2. Horizontal layout of the workpiece axis, workpiece work table realizes A, C axis rotation
The axis of the workpiece is horizontally arranged, the workpiece table has an X-axis, and the A and C axes are rotated; the spindle of the grinding wheel moves up and down and left and right to realize the Y and Z axis movement. The column can adopt the integral gantry type, the beam slides up and down the column, and the grinding wheel shaft slides on the left and right sides of the beam. The combined structure is compact and the rigidity is superior. The axis of the grinding wheel moves smoothly, the workpiece is in the same horizontal plane and the movement is stable, and the operation is convenient.
3. The horizontal axis of the workpiece is laid, the A-axis of the workpiece table rotates, and the B-axis of the grinding wheel spindle rotates.
The workpiece axis is horizontally arranged, the workpiece table has X-axis, Z-axis, and A-axis, and the grinding wheel spindle has Y-axis and B axis. This combination is flexible, compact and efficient.
4. Horizontal layout of the workpiece axis, C-axis rotation of the grinding wheel spindle
The horizontal axis of the workpiece is laid, the workpiece table has X, Y, Z, A-axis, and the grinding wheel spindle has C axis. This combination increases the C-axis stiffness and the running stability of the grinding wheel and improves the grinding wheel movement accuracy. The grinding wheel replacement is very advantageous; the workpiece table has more movement coordinates and a compact structure.
Fourth, key technologies and important supporting parts
1. Key technology
The five-axis linkage CNC tool grinding involves the following key technologies:
(1) Finite element analysis and machine optimization design techniques for high-rigidity bed, column and main structural parts of precision machine tools for precision grinding;
(2) High-speed electric spindle (grinding head) structure optimization and lubrication and cooling technology;
(3) Virtual online dynamic balancing, detection and finishing technology for high-speed electric spindle grinding wheel;
(4) Rotary shaft-A/B/C structure design and high-precision motion technology;
(5) Linear axis-X/Y/Z design and repeat positioning accuracy control technology;
(6) Five-axis linkage tool processing program preparation and system software application technology;
(7) Automatic tool measurement and positioning system technology;
(8) Injection of high-speed grinding coolant and filtration and cooling technology of high-pressure and large-flow cutting fluid;
(9) Final assembly and commissioning technology of five-axis linkage CNC tool grinding machine.
(10) Automation technology such as industrial robot application
2. Important matching parts
(1) CNC system
High-performance five-axis CNC tool grinding requires a CNC system with the following features: open architecture; high-precision nano-interpolation and motion control; networked digital system architecture; surface machining performance; easy CNC programming and debugging. The numerical control system should have multi-axis and multi-channel control; it has high-speed, high-precision motion performance; digital bus communication; intelligent functions such as dynamic compensation and servo optimization.
At present, foreign manufacturers generally use the FANUC31i system and the SIEMENS-840D SL system. This type of control system is highly versatile. Now tool grinder manufacturers are keen to develop special CNC systems and tool grinding software, such as ANCA's ANCA system, WALTER's HMC500 and HMC1500/200 systems, and Anton's AGATHON system. This trend indicates that the dedicated system can be used to increase the complexity and processing of the object, and the modular component can increase or decrease the processing function to achieve its sexuality and economy. The CNC programming technology of the tool grinder special system combines various mathematical equation expressions, thus enabling a wide range of interpolation: linear interpolation, circular interpolation, involute interpolation, exponential function interpolation, and spiral interpolation. Complementary, spline function interpolation and other functions can solve high-precision machining of various complex shape tools.
(2) CNC tool grinding software
The tool grinding software for foreign CNC tool grinders can be divided into two categories: one is software developed by a professional tool grinding software company, such as the tool grinding software tool kit-FESSIONAL developed by MTS in Switzerland, Switzerland. The tool grinding software NUMROTOplus developed by NUM; the other is software developed by the tool grinder manufacturer. This kind of grinding software includes not only the tool grinder manufacturer (the well-known tool grinder manufacturer is also well-known). The tool manufacturer's knowledge of tool grinding and machine tool manufacturing has incorporated its long-standing experience in tool manufacturing. Although the tool grinding software introduced by each company differs in functions, intelligence, visualization, etc., it generally has 3D simulation, graphic guidance, parameterized programming functions, open tool grinding expert library, etc., in order to realize numerical control. Tool design and manufacturing.
(3) Features
The main functional components include high-performance electric spindle (grinding head spindle), high-precision ball screw and linear rolling guide, high-precision linear and circular grating, linear motor and torque motor, high-precision rolling bearing, high-precision CNC rotary table, precision static bearing, static pressure rails, etc.
(4) Other matching parts
The cutting fluid system of the machine tool needs to be equipped with a high-pressure, large-flow filter cooling station. The machine tool requires an environmental safety device such as an oil mister and an explosion-proof fire extinguisher.
The intelligent and automatic functions of the machine tool need to configure the workpiece (tool) and the automatic measurement and positioning system of the grinding wheel, the virtual online dynamic balance detection device of the grinding wheel, as well as the grinding wheel library or the automatic grinding wheel converter and the robot, the loading and unloading robot, etc., so as to improve the machine tool intelligence. The level of automation and automation meets the growing demand for CNC tools and high-precision grinding.
Suggestions on accelerating the development of domestic five-axis CNC tool grinding
Overall, the domestic has a gap in processing precision, efficiency, intelligence, automation, CNC and software technology, reliability and amenity compared with foreign advanced level, accelerating the development of domestic 5-axis CNC Tool grinding requires national industrial policy and science and technology policy support, and it requires industry efforts. To this end, the following recommendations are made:
(1) Increase the support of the National Science and Technology Major Project of “CNC Machine Tool and Basic Manufacturing Equipment” for the research, development, demonstration and promotion of five-axis CNC tool grinding.
(2) Focus on improving the technical level, product quality and reliability of the domestic five-axis tool grinding. For the production enterprises, it is recommended to implement the preferential policies of VAT pre-requisition and return according to the sales of five-axis tool grinding and encourage the promotion and application.
(3) Vigorously develop the functional components required for the five-axis CNC tool grinding products, and provide support for the industrial chain for product upgrade and industrialization.
(4) Support key enterprises to implement technological transformation, improve the manufacturing process equipment level and test and detection capability of five-axis CNC tool grinding.
(5) Encourage the leading enterprises as the leading factor, take the market demand as the traction, combine the “production, study and research”, especially strengthen the cooperation between the leading enterprises of tool manufacturing and tool grinding machine manufacturing, and promote the industrialization of scientific and technological achievements.
Promoting the domestic CNC tool grinder to improve the technical level and industrialization, accelerate the development of domestic five-axis CNC tool grinding, to meet the needs of China's manufacturing industry, has become an urgent task for the transformation and upgrading of the machine tool industry. We appeal to powerful enterprises and people with lofty ideals to contribute to the development of domestic five-axis CNC tool grinding.
