No matter in school or in society, everyone will inevitably touch or use papers, which is of great significance to all educators and the improvement of human understanding as a whole. So how to write a general paper? The following is the outline of NC paper I collected for you, for reference only, I hope it will help you.
Abstract: China began to develop numerical control technology from 1958, and a certain scale system has been established at present. Up to now, the numerical control market in China is mostly occupied by foreign numerical control systems. This paper mainly discusses how domestic low-cost CNC machine tools, high-speed and high-efficiency CNC machine tools and heavy CNC machine tools occupy the domestic market.
Keywords: domestic CNC machine tools; Low-cost, high-speed and heavy-duty CNC machine tools; After-sales guarantee mechanism
Since 1958, China began to study numerical control technology, and established an industrial system with middle and low-grade numerical control machine tools as the mainstay. The ultimate success of NC industrialization will be reflected in the national industrialization and market share of NC machine tools. Up to now, China's numerical control market is mostly occupied by foreign numerical control systems, such as Japanese FANUC system, German Siemens system and other well-known foreign brands occupy a large market in China, while domestic systems are ignored for various reasons.
Numerical control technology and equipment are the important foundation of manufacturing modernization. Whether this foundation is solid or not will directly affect a country's economic development and comprehensive national strength, which is related to a country's strategic position. Therefore, we must quickly recover lost ground in the domestic market and make steady progress in the international market in order to win the domestic CNC machine tool market. The following is a brief discussion on the development of low-cost CNC machine tools, high-speed and efficient CNC machine tools and heavy CNC machine tools.
First, vigorously develop low-cost CNC machine tools.
Low-cost CNC machine tool is a popular CNC machine tool with the function of meeting the requirements of users for small batch and multi-variety production (no functional waste), with moderate technical indicators, good reliability and low price, which can be accepted by small and medium-sized enterprises. This kind of machine tool has become one of the development trends of CNC machine tools in the international market, and it is also a product that many domestic users yearn for. It is more suitable for China's national conditions and has a broad market prospect. However, if we develop low-priced machine tools with foreign numerical control systems (including servo components) according to the traditional thinking, it is difficult to reduce the price to a level acceptable to the majority of users. Therefore, adopting the new integrated domestic data system proposed in this paper will be the most promising way to develop high-performance and low-cost CNC machine tools. As long as there is a certain batch, the price of popular CNC lathes in China can be controlled within 6.5438+10,000 yuan, the three-coordinate CNC milling machine can be controlled around150,000 yuan, and the machining center can be controlled around 20,000 yuan. Domestic CNC machine tools at this price will have strong competitiveness.
Second, speed up the development of high-speed CNC machine tools.
High speed and high efficiency is another major trend in the development of CNC machine tools. There are several technical ways to develop high-speed and efficient CNC machine tools:
(1) By increasing the cutting speed and feed speed, the production efficiency can be doubled, and the machining quality and precision of parts surface can be effectively improved. Moreover, this method can also solve the efficient machining problems of some special materials (such as aluminum-titanium alloy, die steel and hardened steel) and parts with special shapes (such as complex thin-walled parts) that are difficult to solve in conventional machining.
(2) reducing the installation times of workpieces through process combination,
This can effectively shorten the processing and clamping time. If the five-face five-axis machining center and vertical lathe are combined into a universal machining center, most (or all) machining tasks of parts can be completed by clamping at one time.
(3) By adopting high-speed and high-precision circumferential milling, new machining methods such as spiral trajectory interpolation and direct tapping without drilling bottom hole can be completed, which can greatly reduce the number of tool changes and improve machining efficiency.
(4) Develop the intelligent positioning processing function of CNC machine tools, eliminate the dependence on precision fixture and manual alignment, and effectively shorten the preparation time for single piece and small batch processing.
Under the realistic conditions of our country, if we follow the traditional thinking, it is difficult to realize the above-mentioned ways. We must base ourselves on the national conditions, combine the reality, be brave in innovation and boldly explore new ways. Considering that the general structure of conventional CNC machine tools basically adopts the scheme that the workpiece and the tool move together along their respective guide rails, on the one hand, it is difficult for moving parts to obtain higher feed speed because of the lack of rigidity of the transmission link of the machine tool and the large friction resistance in the guide rails; On the other hand, because the total mass of workpiece, fixture and worktable is relatively large, it is difficult to obtain high acceleration. In addition, the traditional machine tool structure is series open chain structure, with many parts and complicated structure. Because of the connection gap between the cantilever part and the connecting rod, it is difficult to obtain higher overall stiffness, so it is difficult to adapt to the special requirements of high-speed and efficient machining. Therefore, in the development of domestic high-speed and high-efficiency CNC machine tools, a new structure suitable for high-speed and high-efficiency machining centers can be adopted, that is, the workpiece is fixed, the parallel short chain composed of linear motors directly drives the spindle and the cutter to move, and the combination of high-speed and high-precision transmission and high-rigidity support. The high-speed and high-efficiency CNC machine tool with this structure not only has high speed and stiffness, but also can achieve higher machining accuracy and quality than the conventional machine tool if it is properly handled in transmission and control. But also has obvious advantages of simple mechanical structure, high standardization degree of parts, low manufacturing cost, easy economic mass production and the like. Therefore, the development of high-speed and efficient CNC machine tools along this line of thinking will be a road that conforms to the national conditions and is easy to succeed.
Third, break through the design and manufacturing technology of heavy CNC machine tools.
Heavy CNC machine tools (especially multi-coordinate heavy CNC machine tools) are important key equipment in national economy and national defense production and belong to strategic materials. Really advanced heavy CNC machine tools can't be sold to us abroad. Therefore, we must rely on our own strength to solve the problems in the development of CNC products in China in the next century. The development of heavy CNC machine tools must have a solid foundation. In the process of localization of CNC machine tools, we should constantly sum up experience, strengthen the research on basic technologies and key technologies, give full play to the advantages of combining domestic and Industry-University-Research, and make joint efforts with various departments to make breakthrough progress in a short time.
Fourth, establish a strong after-sales guarantee mechanism.
As typical high-tech products, CNC system and CNC machine tools are very important for users' technical support and service. Besides reliability, another big problem is the lack of strong technical support and services. Users spend a lot of money to buy CNC machine tools or CNC systems, but once there is a problem, it is called daily failure, and the ground is invalid. Even if the manufacturer agrees, the maintenance personnel can not be in place in time, and the technical level of maintenance personnel is uneven. In this era of efficiency, such after-sales service is not feasible. Who will dare to buy our products at this rate? Therefore, technical support and service to users should become our important daily work, so that we can further advance in the market and have a strong rear as a guarantee. Therefore, in order to win the overall market competition of CNC products, we must establish a strong after-sales service foundation with technical support and service as the core.
According to the requirements of NC machining simulation software, NC machining teaching and training, frequent accidents, serious machine tool wear and high cost, this paper discusses the principle, function and function of NC machining simulation system, and how to effectively use NC machining simulation system software to train students and trainees in the basic operation of NC machine tools, so as to achieve more, faster, better and cheaper purposes.
Key words: CNC machine tools, CNC machining, virtual reality, simulation system.
introduce
With the rapid development of higher vocational education in China and the wide application of CNC machining technology in machinery manufacturing, the professional training of a large number of CNC machine tool operators has become an urgent and thorny issue. In the traditional operation training, the effective training of programming and operation of CNC machine tools must be carried out on real machine tools. However, with the increasing number of students, the limited number of machine tools makes it difficult to ensure that every student has enough time to operate on the computer. At the same time, it is dangerous and unsafe for students to operate on real machine tools. Misoperation in training often leads to the damage of instruments and knives, and even leads to personal injury accidents, which increases the training cost. Therefore, the traditional training method of machine tool operation is inefficient, the workload of teachers is heavy and the training cost is high, so it needs to be replaced by newer methods.
1, virtual reality technology
Virtual Reality, English name is Virtual Reality, referred to as VR technology. This term was put forward by jaron lanier, the founder of American VPL company, in the early 1980s. Also called mental technology or artificial environment. As a cutting-edge technology, virtual reality combines the latest development achievements of computer graphics technology, computer simulation technology, artificial intelligence, sensing technology, display technology, network parallel processing and other technologies. It is a high-tech simulation system generated by computer. It originated from the combat simulation system of the US military, and gradually attracted attention from all walks of life in the early 1990s, and was further developed in the commercial field. The characteristic of this technology is that an artificial virtual environment is generated by a computer, which is a three-dimensional digital model composed of computer graphics, and compiled into a computer to generate an artificial environment with visual perception as the main part, including hearing and touch, which makes people feel immersive visually, and can directly observe, operate, touch and detect the internal changes of the surrounding environment and things, and interact with them, thus,
Virtual reality is the product of the combination of computer technology and thinking science, and its appearance has opened up a new way for human beings to understand the world. The biggest feature of virtual reality is that users can interact with the virtual environment in a natural way, which changes the past mode that human beings can only understand the environment indirectly except for personal experience, thus effectively expanding the cognitive means and fields. In addition, virtual reality is not only a demonstration medium, but also a design tool. It creates a humanized multidimensional information space in the form of vision, which provides favorable support for us to create and experience the virtual world. Virtual reality technology plays an important role in simulation and training in military and aerospace fields with its real-time three-dimensional spatial representation, interactive operating environment and immersive feeling. In recent years, with the development of computer software and hardware technology and people's increasing awareness of its important role, virtual technology has been developed to varying degrees in all walks of life, and has increasingly shown broad application prospects.
The value of virtual reality technology in transforming traditional industries lies in: it can reduce the cost and avoid the risk of new product development when used in product design and manufacturing; Used for product demonstration, which can attract customers and win orders through multimedia effects; For training, "virtual equipment" can be used to improve the operating proficiency of employees. Virtual reality technology will have a revolutionary impact on many traditional industries and industries.
2. NC machining simulation system
With the development of virtual reality technology and computer technology, a computer simulation processing system has emerged, which can simulate the actual machine tool processing environment and its working state. It is a simulation software that applies virtual reality technology to the training of NC machining operation skills. Using computer simulation training system to study and train can not only improve the theory and operation level of trainees quickly, but also be very safe and reliable with low training cost.
At present, some colleges and universities in China have applied computer simulation to the teaching of NC operation talents, and various NC machining simulation teaching systems have also appeared one after another, such as Shanghai Yulong, Beijing Fick, Nanjing Aerospace, Guangzhou Super Soft, Wuhan Honeysuckle and other different NC machining simulation software. The above-mentioned teaching system can run independently on a stand-alone system or online. Independent operation is a machine tool model mode, and its training facilities only need a microcomputer. The simulation operation of NC machine tool is carried out on the simulation panel displayed on the display screen, and the cutting process of parts is demonstrated by the machine tool model through three-dimensional animation. Practice has proved that this method is very economical and effective for preliminary training. On-line operation is the working mode of machine tools. In this way, the teaching system will be connected with the actual machine tool, and the cutting process of parts will be realized by hardware. At this time, except that the operator operates with the analog panel, the other is the same as the real situation of the actual machine tool. That is, the simulation of the real scene is generated by using special software and hardware such as computers, and the operator experiences a feeling close to the real scene through interaction with the simulated scene. Therefore, this method can further improve the practical operation skills of operators.
The core of NC simulation system is virtual NC machine tool, which is an important execution unit in virtual manufacturing technology. It not only provides manufacturability analysis for product design in NC machining process, but also provides perfect learning methods and learning environment for students in NC system learning and training. The NC simulation system completely simulates the machining process of real parts, can check whether all kinds of NC instructions are correct, can provide the same operation panel as the real machine tool, and has various functions such as debugging, editing, modifying and tracking execution.
3. Construction of virtual NC machine tool platform
Virtual CNC machine tools generally realize the above functions through the following construction platforms:
(1) CNC interpretation platform. The numerical control interpretation platform includes numerical control interpreter and numerical control checker. The task allocation database receives the NC code from the task scheduling and translates it into the motion information of the parts and tools of the virtual machine tool, and simulates the response of the machine tool through the calculation module. The NC interpreter can be freely configured to simulate the CNC controller of any CNC machine tool.
(2) CNC verification machine. You can verify whether the syntax of the NC code is correct.
(3) Tool library. The tool library should include all the tools required by a CNC machine tool, and the tool number in the tool library can be freely configured to simulate the tool changing form and cutting requirements of any CNC machine tool.
(4) Simulation platform. The simulation platform includes tool path simulation, cutting force simulation, machining accuracy simulation, three-dimensional animation simulation and statistical analysis of machining hours. Simulation platform is the core technology of virtual NC machine tool. The operator can simulate the movement and cutting process of the machine tool in the virtual environment, and obtain relevant machining data from it. For example, the displacement of feed shaft, tool changing state, spindle speed, acceleration, feed speed, processing time, etc. Through the simulation of machining process, we can understand the machinability of the designed workpiece, verify the correctness of NC code, evaluate and optimize the machining process, and optimize it by modifying NC code online.
(5) Computing platform. Using the computing platform to complete various calculations in the virtual NC machine tool, such as calculating the new geometric shape of the machined part according to the NC code, and calculating the compensation amount and thermal compensation amount of the tool according to the material, running time, material characteristics of the part and characteristics of the lubricating medium. These calculation results are necessary for machining scheme evaluation and manufacturability analysis of virtual NC machine tools in virtual manufacturing process.
(6) Design and development platform. Virtual CNC machine tool design platform is an object-oriented CNC software library and its development environment. Through the research on standardization and normalization of numerical control software and data exchange with other CAD/CAM software, typical parts are packaged and reusable software with stable and universal interface is designed.
(7) Operating operating platform and monitoring platform. The operation of real machine tools is completely realized in virtual environment, and users can fully feel the running characteristics of real machine tools. Based on these, we can use monitoring software and hardware to control simple machine tools, increase the realism of virtual CNC machine tools, and carry out experimental cutting of typical parts, so that users can feel immersive. Especially in the process of NC teaching and training, beginners need a lot of programming exercises and practical debugging. It is obviously unreasonable and difficult to test NC machining program by trial cutting method. If the simulation technology is adopted, these problems can be easily solved, and human error or unreasonable process in programming can be avoided, resulting in workpiece scrapping.
4. The function of numerical control simulation system and its application in teaching.
Virtual NC machine tool is actually the model of NC machine tool in virtual environment. Compared with real machine tools, virtual CNC machine tools have the following functions and characteristics:
The structure of virtual NC machine tool is exactly the same as that of real machine tool. Virtual CNC machine tools can imitate any function of real machine tools, and will not distort or lose some structures and information because of some approximate substitution. It has exactly the same interface style and corresponding functions as real machine tools, such as real-time interactive operation of dynamic rotation, scaling, movement and other functions, thus providing guarantee for students' learning and training.
Whole process simulation of machine tool operation. Simulate the whole process of machine tool operation: blank definition, workpiece clamping, platen installation, benchmark tool alignment, tool installation and manual operation of machine tool.
A rich and varied tool library. The system adopts a database of tool materials and characteristic parameters managed by database, including hundreds of turning tools and milling cutters with different materials, types and shapes, and also supports users to define tools and related characteristic parameters.
Comprehensive collision detection. Real-time collision detection in manual and automatic machining modes, including the collision between tool and fixture, pressure plate, tool and machine tool when the travel is out of bounds and the tool rest and workpiece are not rotating. There will be an alarm or prompt when there is an error, so as to prevent misoperation.
Powerful measuring function. It can measure the roughness of parts according to the cutting parameters of tools, and can automatically and intelligently measure the workpieces processed on simulation software.
Have perfect graphics and standard data interface. Users can not only run the virtual machine tool in the real environment, but also observe its various operating parameters, and can directly call other CNC programs generated by CAD/CAM software, such as UG, Pro/E, Mastercam, etc. , enter the processing.
Practical and flexible examination system. It can be used for remote network learning, homework, examination and other functions, and realize the functions of saving answer sheets, automatic grading, query and analysis of results, and easily realize paperless examination and evaluation.
The powerful network function of virtual NC machine tool can realize distance education. It not only has the teaching function of two-way interaction on LAN, but also has the distance teaching function of two-way interaction based on Internet. Data transmission can be carried out by satellite and broadband (ADSL, ISDN, cable, etc.). ) or narrowband Internet (56K modem). This makes distance education worthy of the name, and it represents the development direction of future education.
5. Concluding remarks
In view of the outstanding function of virtual CNC machine tools, and the increasing number of students taking part in CNC teaching courses and internships in colleges and universities, CNC machine tools are characterized by precision and high cost. It is undoubtedly wise to introduce CNC machining simulation system software into teaching and use it for CNC machine tool programming and operation training. This can not only avoid damaging the expensive CNC machine tools due to misoperation, but also make the operators have a sense of presence and realism in the process of operating the simulated CNC machine tools. At the same time, because of its low cost, it can be equipped with a large number of terminals, which completely solves the problem of insufficient number of CNC machine tools, so that every student has enough practice opportunities, so that students can be familiar with and understand the working process of CNC machining faster and master the operation methods of various CNC machine tools. Its greater advantage is to achieve the same training effect while minimizing the handling error rate and accident rate.
Judging from the application effect of our college, the introduction of numerical control simulation system makes the classroom teaching of students learning numerical control programming theory more vivid and concrete, improves students' learning interest and obviously improves the teaching effect. When learning the actual operation, because there is no safety problem in the simulation software, students can study and practice boldly and independently, and can self-test the geometric accuracy of the machined parts, which greatly improves and strengthens the cultivation of students' machine tool operation ability. At the same time, the system can also reduce the work intensity of teachers, reduce the consumption of workpiece materials and energy, and save the training cost of practical links, with remarkable results. I believe that in the near future, it will become an indispensable and important means in NC teaching.
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