I. Background and Construction Experience of the Course "Numerical Programming and Operation" 1. Background: The application of CNC technology was established in 2003 by our institute. At the beginning of the professional setting, according to the professional construction plan, "CNC programming and operation" is taken as a main professional course of numerical control technology application. The "CNC Machine Tool Programming and Operation" course is a core professional course for numerical control technology, mechatronics and other related majors. It is one of the key courses to master the operation of CNC machine tools. How to let high-level students master the abstract programming theory and learn the numerical control operation skills is our main goal of this course reform.

2. The course of "CNC Programming and Operation" has experienced three stages in our hospital: (1) The teaching of the theory-based classroom has been started in 2003, and in 2006, it started for the teaching of NC programming and operation courses. At that stage, we learned and communicated with the masters of the first-line work with rich CNC programming experience and practical experience in Lu'an Machine Tool Plant. Taking the FANUC system production machine as a reference, and referring to the programming specification of the typical CNC system, we wrote the theory. Teaching-oriented numerical control programming lectures, we have carried out the practical teaching of the curriculum through the joint with the school-run factory, and achieved certain results.

(2) The teaching stage of the combination of theoretical teaching and numerical control simulation training From 2006 to 2008, due to the limitations of the conditions, in order to enhance students' practical ability and overcome the limitation of the number of machine tools, we installed Yulong CNC simulation training software. In practice, it solves the problems of many students and few machine tools, and is convenient for students to master the skills of numerical control programming.

(3) In terms of practical teaching, with the continuous investment of the college, it has gradually shifted from theoretical teaching to practical teaching. Since 2008, due to the development of the college and the improvement of teaching conditions, the investment in hardware has been continuously increased. The CNC machining workshop is mainly based on the current popular wide number. There are more than 10 CNC cars and milling machines, and there are CNC machining simulation training rooms, which basically meet the needs of CNC training.

Second, "CNC Programming and Operation" course construction problems Currently, although we have achieved some achievements in the "CNC Programming and Operation" course construction, but still very backward in practice. Reflected in the teaching methods and methods, there are the following problems: (1) Separation of teaching and learning At present, we have a total of 120 hours of theoretical and practical lessons in the course arrangement of "Numerical Programming and Operation" (30+30+ 60), of which 30 hours are theoretical, another 30 hours are simulation operations, and 60 hours are CNC internships. In the 4th class of the week, 2 class hours is the theory, and 2 class hours are the simulation operations in the computer room. In this way, the theoretical teaching in the classroom and the simulation operation in the computer room are separated in time and space, and teaching and learning are disconnected from each other. If you can't do the theory and practice, the teaching effect is not ideal.

(2) Separation of learning and doing The numerical control operation performed by the students in the simulation training room is only a simulated exercise, which is far from the actual machine tool operation. After the simulation exercise, we cannot go to the training center immediately. The verification of the actual operation, the workshop of the simulation exercise and the workshop of the actual operation are also separated in time and space, which leads to the disconnection between learning and doing. When the CNC internship is suspended for 2 weeks, what you have learned in the machine room will have to start again on the actual machine. In addition, in the arrangement of the internship time, due to the small number of machine tools and the number of internships, it is impossible to arrange many students for internships at the same time.

Due to these problems, we can see from the performance and achievements of our students in the CNC skills competition in the province, the gap is still great compared with the province's first-class high-level job. Therefore, this requires us to make bold reforms, break the rules, and strive to pass reforms so that our students have a qualitative leap in their core competencies.

Third, how the teaching reform program allows students to achieve better learning results in the teaching plan (120 hours), for which we design a new teaching reform of teaching, learning and doing a high degree of integration of teaching, learning and doing. : We have carefully designed the venues, class schedules, requirements for teachers and teaching content. The specifics are as follows: 1. The venue is in the CNC training center, CNC lathes and CNC milling machines, and at the same time, in the center, Learn and do one classroom, can accommodate 50 people (one class), 50 computers in the classroom, 50 pieces of genuine CNC simulation software, and a set of projection equipment.

2. The time will be 30+30+60 for a total of 120 hours, and the integration will be concentrated in one month.

3. Teachers are required to be "double-type" teachers, should have the following teaching skills: 1 skilled CNC technology and programming skills; 2 skilled CNC car, milling operation skills; 3 proficient in CNC simulation software.

4. The teaching content is arranged in the arrangement of teaching content, based on the principle of project-oriented and based on the processing of parts. Our course content is decomposed into three modules: CNC machining, CNC milling and NC machining. Several simple and complex car and milling examples are selected as different projects, and then each project is analyzed. The process is: Module→Processing project→Parts pattern→Analyze its process→Write CNC program→Verify the program on the simulation software→Process the parts on the machine tool of the training center→Finished product (size inspection): For example, the project 4 in the CNC milling machine of module 2 The specific method is as follows: Item 4: Φ30 hole and the other four holes 4-Φ13H7 hole have been processed, and the contour is processed by milling machine. Take Φ140×16 blank, Φ20 end mill Teaching content: 1 Guide: The NC program is given by the pattern, and the machining process is demonstrated on the simulation software. (About 10-20 minutes) Attachment 1 (FANUC0I) 2 performs process analysis, and introduces relevant knowledge of the machine tools, tools, fixtures, etc. required for the parts.

The specific content is as follows: see Attachment 3 (1 of the basics of CNC milling machine processing technology 2) The basics of CNC milling machine processing technology 3) Coding the parts: Introduce the relevant coding knowledge: The specific content is: see attachment 4 (CNC milling machine Basic programming method) 4 Let students simulate the case in this case. The specific content is as follows: See Attachment 5 ("CNC Programming and Operation" CNC Milling Machine Training Guide) 5 The actual operation of this case is as follows: See Attachment 5 ("CNC Programming and Operation "CNC Milling Machine Training Guide" Attachment 1 to Annex 5 We have specially prepared the corresponding lecture notes for teaching. For example, the basics of CNC milling machine processing technology, the content is: 1 process analysis from the requirements of the figure, the cam curve is composed of several arcs, Φ30 hole is the design basis, and the remaining surfaces including 4-Φ13H7 holes have been Processing.

Therefore, the Φ30 hole and one end face are taken as the main positioning surface, the edge-cutting pin is added in one hole of the coupling hole Φ13, and the nut is pressed on the end surface. Since the hole is the reference for design and positioning, the tool point is selected at the intersection of the center line and the end face of the hole, so that it is easy to determine the relative position of the tool center and the part.

2 The position of the machining adjustment coordinate system in the X and Y directions is set in the middle of the table. In the G53 coordinate system, X=-400, Y=-100.Z coordinates can be determined according to the length of the tool and the height of the fixture and part. The Φ20 end mill is selected, the upper end surface of the part is the Z coordinate zero point, and the position of the point in the G53 coordinate system is Z=-80, and the above three values ​​are set into the G54 machining coordinate system.

3 Mathematical processing The contour of the cam machining is composed of arcs, so as long as the coordinates of the base point are calculated, the program can be programmed. In the machining coordinate system, the coordinates of each point are calculated slightly. According to the calculated value, the cam processing path can be drawn.

4 Write the program and program description of the machining program cam processing.

Fourth, the specific implementation of the program implementation plan: take the car or milling processing project, the first step of programming basic learning, according to the given pattern for process analysis and numerical control programming, let students write a process of processing; the second step by The programmed program is used for simulation exercises. Students need to learn how to use the simulation software, CNC machine tool operation process and method. The third step is to carry out practical training on the machine tool, first processing the plastic parts, and then processing the metal parts.

The first week and the second week completed the machining project, the second and third weeks completed the milling project, and the fourth week completed the car and milling accessories. There is no strict definition of the time schedule within the four weeks, which can be adjusted according to the actual situation of the students.

V. Concluding remarks Through such a numerical control processing project, students are allowed to learn relevant theories according to the drawings, and then the programmed theories, and the programmed programs are verified by simulation software and machine tools. In this way, the students learned the theoretical knowledge of numerical control programming and mastered the operation method of numerical control machining. This kind of reform puts forward relatively high requirements for teachers. Teachers need to understand the theory and skillful operation skills. Let the teacher walk down the stage, walk into the workshop, and let the students walk out of the classroom. Through such an attempt, the students will achieve twice the result with half the effort.

(Finish)

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