CNC Machine tool programming refers to the process of writing the NC machining content of the workpiece and its routing route with CNC instructions into a CNC machining program that meets the quality requirements of the workpiece. Learning CNC machine tool programming should write CNC machining program, but to write a CNC machining program that meets the quality requirements of the workpiece is not a course of "CNC Machine Programming". It requires close cooperation with other courses in the CNC professional course group.
These courses include both process theory and machine tool training. The process theory consists of two courses, "Traditional Manufacturing Technology" and "CNC Machining Process". "Traditional Manufacturing Technology" includes the theoretical knowledge of tool cutting theory, tooling design theory, process development and process size calculation required for CNC machining. "CNC machining process" includes CNC machining process design, CNC turning machining process, CNC milling machining process, and machining. Central processing technology and CNC wire cutting processing technology.
Using the theory in "Traditional Manufacturing Technology" to select the tool, tooling, equipment, cutting amount according to the requirements of the workpiece, formulate the processing technology. Using the numerical control machining technology theory, the contents of the NC machining of the workpiece can be determined, and the NC machining process and the path of the workpiece can be determined. Handle the connection between CNC machining process and common machining process.
According to the developed CNC machining process and the route of the cutter, the NC programmers use the CNC instructions to write the NC machining program. The machine tool training includes the milling and milling training including the milling and milling training and the milling and milling training and the CNC machine programming training. The practice of turning and milling knows the practical basis for the course of “Traditional Manufacturing Technologyâ€, and the theory of “Traditional Manufacturing Technology†is applied to the intensive training of turning and milling, so that students can finally complete the machining process of the workpiece according to the part drawing and complete the workpiece. The milling and milling content meets the workpiece quality requirements. The knowledge and skills learned in the milling and milling training provide the process parameters that can be used for CNC machine programming. It provides practical experience for CNC machine tool programming training, and finally enables students to prepare according to the parts drawing. CNC machining process and CNC machining program, processing qualified workpieces, reaching the teaching goal of CNC machine tool programming.
It can be seen that students can successfully write the procedures that meet the quality requirements of the workpieces by successfully inheriting the process theory learned in the "Traditional Manufacturing Technology" and "CNC Plus Process" courses and the machine tool operation experience and process parameters accumulated in the milling and milling training. In this sense, it is necessary to reform the course of "CNC Machine Programming" in both process training and CNC machine tool operation.
Second, the process training beginners CNC machine programming students' mystery and curiosity about the NC machining program make them pay too much attention to the CNC instructions, and neglect the preparation of the workpiece before processing and the processing order of the workpiece and its path, so it is necessary to guide the students Focus on the clamping of the workpiece, the preparation of the tool and the machining route of the workpiece before programming.
"A workpiece clamping CNC machining is used for multi-variety small batch production. The fixtures used in CNC machine tools are mainly general-purpose fixtures, such as three-claw self-centering chucks for CNC lathes, flat-end pliers for CNC milling machines and process platens. The numerical control vehicle adopts the cylindrical surface positioning of the workpiece. The CNC milling adopts one-two-hole positioning of the workpiece. The workpiece is often clamped by hydraulic, electric and other automatic clamping devices to ensure the clamping accuracy. Students should pay attention to these characteristics of CNC machine tool workpiece clamping when selecting the workpiece clamping method.
The second tool is prepared to use new tool materials as much as possible to increase the amount of cutting. CNC lathe finishing is continuous processing. It is necessary to check whether the tool knives and the machined surface of the workpiece interfere with the machining plane and convex contour surface of the CNC milling machine. Large diameter milling cutters should be used as much as possible. When machining concave contour surfaces and cavities, Note that the tool radius and end edge fillet are compatible with the workpiece.
The processing sequence of the CNC machining machine workpieces of the three machining sequences and the cutting path must comply with the basic principles of “reference first, first coarse, fine first, first primary and second backwardâ€, and then further develop the process route and process of the workpiece. However, unlike ordinary machine tools, CNC machining personnel need to determine the path of the tool. Infeed and retract are subject to the shortest route principle.
In general, CNC lathe processing shaft parts, axial cutting, radial feeding, cycle cutting margin CNC lathe processing roulette parts, radial cutting, axial feeding, cycle cutting margin. For CNC milling machines, choose the correct milling method. Do not stop the tool at the contour of the workpiece to avoid leaving tool marks. Students need to determine the programming trajectory according to the above principles before programming. Four-cutting student programming, due to the lack of CNC machining experience, can not determine the amount of cutting. In teaching, I use two methods. One is to let students use the cutting machine experience data used in the ordinary machine tool internship. The second is to check the relevant process manual to determine.
Third, the CNC machine tool operating enterprises to train the CNC machine tool programmers, is to let the students in the CNC machine tool, while learning the CNC machine tool programming knowledge, while under the guidance of the master, the CNC machine tool. In other words, the enterprise adopts a teaching mode in which professional theory and practice are integrated. Practice has shown that after half a year of study, students can get a job. This teaching model should also be adopted as a vocational college that trains skilled personnel.
However, due to the high price and the small number of numerical control equipment, the number of students using numerical control equipment is large, and the number of numerical control training teachers is insufficient. Therefore, it is very difficult for vocational schools to adopt this skill training mode of enterprises. As a full-time teacher of "CNC Machine Tool Programming", I have made some explorations in adopting this teaching mode. I have increased the teaching content of CNC machine tool operation. I expanded the machine tool operation contents in the relevant chapters of the "CNC Machine Tool Programming" textbook into chapters. , mainly to enrich the content of the machine operation process.
Second, the use of computer projection and numerical control simulation software for teaching on the blackboard is unable to teach the operation of CNC machine tools, for this application for computer projection and computer teaching. Using computer projection to teach machine tool panels and machine tool operation students use CNC simulation software to operate on a computer, which is equivalent to operating on a CNC machine tool, which can realize the whole process of CNC machine tool operation, and students are very interested.
Third, increase the numerical control machine tool experimental teaching CNC machine tool simulation software is like a kind of game software for students, students will soon be able to manipulate the CNC machine tool specified by the teacher, but this is still far from the real control of CNC machine tools. .
For example, the workpiece clamping, tool setting, tool change, etc., in the simulation software is only a few related buttons, but in the actual CNC machine tool operation, the workpiece clamping involves the correct position of the workpiece. Is it necessary to find the instrument to correct the clamping force? Is it appropriate to clean the burrs left by the plane of the workpiece before the knife? The real edge of the workpiece is the tool to remove the shank and remove the tool. Find new tool holders to match the changed tools, etc., so students need to operate on real CNC machines.
Since the school's CNC machine tools already have other classes of students in the training, so by arranging experimental teaching, let the students operate on the CNC machine tools, feel the difference with the simulation software, and can also operate and program with other class students. Communication makes students have a great leap in machine programming and operation.
Fourth, part of the course content is based on "task-driven"
Using numerical control simulation software, students are required to program on the software. This requires the content of the course to be "task-driven", so that students can complete specific programming tasks in the numerical simulation software practice class. According to the requirements of "Task" and the nature of "CNC Programming" course, it is suitable to use "task-driven" content to design two tasks: "CNC lathe programming" and "CNC milling machine programming", corresponding to CNC lathe operators and CNC milling machines. Operator two positions. These two tasks are broken down into several subtasks according to the machining surface of the workpiece.
Each subtask is actually the content of NC programming training. Putting the NC programming training content into the teaching of CNC machine tool programming course, it is to make the combination of programming theory and programming training to realize the integration of professional theory and practice. Teaching mode. "Task Driven"
The tasks used are mainly CNC lathe programming tasks, outer contours, end face and step programming contour cones, chamfered programming slots and programmed outer contours of the programmed outer contours. The cavity is programmed to program the rough and finish of the workpiece with the inner and outer contours. CNC milling machine programming shape milling programming face milling programming groove programming hole system programming 'mirror function programming rotation function programming milling surface integrated programming.
V. Conclusion The teaching reform program was piloted in the numerical control college class of our college. The numerical control programming ability and the numerical control machine tool operation ability of the class students who adopted the program were significantly improved compared with the class that did not adopt the program. The reform results were obtained by the department leaders and The approval of the training master.
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