Research on CAD/CAM System of CNC Punch

Abstract: The advantages of turret type CNC punch press with its fast and high-precision flexible punching processing system and numerical control programming simulation technology for accurate prediction of products have been widely used in recent years.
The advantages of the turret type CNC punch press with its fast and high-precision flexible punching processing system and numerical control programming simulation technology for accurate prediction of products have been widely used in recent years. It is especially suitable for small and medium batch production of multi-variety, high precision and complex parts.

The turret type CNC punching machine is multi-station, and the holes of various shapes are processed by changing the machining trajectory and replacing the punch when processing the sheet. It is mainly used in the processing equipment panel, electrical component mounting board and various hole processing of different sizes and shapes on the cabinet.

For example, my existing AMADA company's PEGA-345 CNC punching machine can install 58 kinds of punches on the turntable. Simply change the punch and just rotate the turntable. It can be seen that the main workload of CNC machining is mainly the problem of programming code.

1 programming analysis

1. According to foreign statistics, when programming manually, the ratio of the programming time of one part to the actual machining time of CNC machine tool is about 30:1, and 20%~30% of the reason why the CNC machine can not be started is due to the preparation of the machining program. No reason. For example, there are 18 kinds of heat conduction plates of a certain product in our company. It takes at least one day for each part to process drawings, calculate various coordinate data, and manual programming, and the actual processing time only takes 3 min to 5 min.

1. 2 CNC milling machines, machining centers, etc. have a relatively complete CAD / CAM system as a platform, can automatically generate CNC code. However, for CNC punching machines like AMADA, there is only a simple CNC encoding program support, and most of them are based on the MS-DOS system. The code is mainly written by the technicians step by step, even before writing. The coordinate calculation of the series. Not only is programming inefficient and error prone.

For example, our 1995 random bed software is AMADA-1E simple manual programming software.

Its operating mode is shown in Figure 1.

Because it is in a manual drawing expansion diagram, calculating various data, and manually inputting the state, the programming efficiency is very low; in addition, the file management system is limited, and it is not convenient to store, manage, and query program files.

In particular, our military and civilian production tasks have a large workload and a wide variety. If we do not establish a database of program files, there will be a lot of unnecessary duplication of work.

1. 3 The existence of this situation severely restricts the needs of our military and civilian production tasks, in order to further improve processing efficiency, shorten processing cycle, improve processing accuracy, and enable advanced equipment to better serve scientific research and production. The CNC punch programming software on the market fully researched, analyzed and demonstrated that the AMADA-1E programming system was upgraded to the AMADA-2D programming system in 2002.

Its operating mode is shown in Figure 2.

It has the following advantages: (1) The machining program can be automatically generated by drawing the development map; (2) The programming efficiency is greatly improved by avoiding repeated drawing of the part development drawing, manually calculating various machining data, and manually writing the machining program; 3) The file management system is relatively powerful, which is convenient for storing, managing, and querying program files. It is especially suitable for the situation that our military production tasks have a large workload and a wide variety, avoiding duplication of work.

2 auxiliary programming analysis

2. 1 Although the AMADA-2D programming system has made great progress compared to the AMADA-1E software, it still has many defects that cannot meet the actual production needs.

2. 1. 1 AMADA - 2D programming system is a stand-alone programming system. In the case of multiple technicians, a "serial" programming system is formed, which still limits programming efficiency to a large extent.

2. 1. 2 For the AMADA - 2D programming system, the main job of programming is how to generate 2D CAD plane development maps well.

According to the test, the time to draw a 2D planar development map is as much as 3/4 of the total programming time. For its CAM post processing, the relative occupation time is much shorter.

The AMADA - 2D programming system is, after all, a programming software with limited CAD drawing capabilities and is unfamiliar to the average engineering staff.

2. 2 In order to solve the shortcomings of the AMADA-2D programming system, after long-term programming practice, I found that the AMADA-2D programming system can exchange data with other applications through the DXF (Drawing Exchange File) format.

As a CAD software platform, AU TOCAD has the characteristics of user-friendly interface, powerful drawing and easy to grasp, and is very popular among engineers and technicians.

Since the accuracy of CAD itself can reach 0. 000 1 mm, high-precision CAD graphics ensure high precision of parts. I have combined AUTOCAD with the AMADA-2D programming system to build a programming system as shown in Figure 3, which greatly improves programming efficiency and program accuracy.

2. 2. 1 Parallel system of CAD graphics

Not only can programmers draw CAD drawings in parallel, but they can also take advantage of the CAD drawings of the process and design, as shown in Figure 3. Since the development of the unfolded graph comes from multiple channels and multiple links, a "parallel" system of CAD graphics is formed, which greatly improves the programming efficiency and correctness.

2. 2. 2 Fully apply AU TOCAD's powerful drawing function

With AUTOCAD's powerful drawing capabilities, manual placement of special small parts can be achieved, saving material and processing time. Although the AMDAD-2D programming system has a typographic function, the layout function for special parts does not meet the needs of the field. If you can combine it with the AUTOCAD system, you can easily realize the functions that AMDAD-2D cannot achieve by using a series of cutting, copying, symmetry, and array operations of AUTOCAD.

2. 2. 3 Make full use of the designed CAD graphic files

Take the heat conduction board of a certain product of our company as an example: in the previous manual programming mode, the time for writing a machining program is about one day, and it is easy to make mistakes. For example, using the AMADA-2D programming system, the programmer will re-process the positioning map. The CAD drawing is generated, the drawing time is about 1 h to 2 h, and the time for generating the program is about 30 min, the efficiency is not high, and it is difficult to ensure the processing accuracy. If you can fully integrate the designed CAD graphics with the AMADA - 2D programming system, with the designed CAD graphics, you can complete the programming in less than 1 h, achieving twice the result with half the effort.

2. 2. 4 Drawing an expanded view of a box-like part using AUTOCAD

The most important task of NC programming of box parts is how to generate a two-dimensional plane development map quickly and accurately. The traditional process flow is shown in Figure 4.

In the above-mentioned links, on the one hand, since it is difficult to draw the part graphics and the unfolded drawings strictly in the open CAPP, the craftsman generally provides only the unfolding schematic diagram of the parts, and the CAD development drawing for the numerical control programming. It must be a strict, scaled CAD drawing. On the other hand, because the open CAPP and AUTOCAD can not realize the true data sharing and graphics exchange, there is not only a large amount of unnecessary and repeated labor of the technicians and CNC programmers, but also the various links are not very good. The process of checking makes the probability of error increase exponentially.

Make full use of my existing office automation to enable design, process, and CNC programmers to truly share data. Not only will there be a big improvement in programming efficiency, but the mutual inspection of each link can also enable the design, process and programmer errors to be discovered and corrected in time, as shown in Figure 5.

In short, only the AMADA-2D programming system can be fully and effectively combined with AUTOCAD. With the advanced and powerful CAD platform of AUTOCAD, the advanced and reasonable CAM functions of the AMADA-2D programming system can be used to quickly and accurately program CNC machining programs and advanced equipment. In order to better play a role and better serve scientific research and production.

3 programming examples

3. 1 Programming of a product heat-conducting plate

Through the local area network, the designed CAD graphics are called, the useful entity information is extracted, and the data exchange with the AMADA-2D programming system through the DXF file is completed, and the NC program is compiled quickly and accurately.

The realization of this programming method not only improves the processing efficiency, but also greatly reduces the probability of error in each link. Improve efficiency and ensure machining accuracy and accuracy. The heat-conducting plates of various products of our company not only have many production tasks, but also have tight cycle requirements. The application of this programming method not only guarantees the production cycle, but also ensures that one test of the heat conducting plate is qualified. In the past two years, hundreds of designs of CNC programs for the heat transfer plates of our various products have been completed.

3. 2 Reasonable layout of small parts

Although the AMADA - 2D programming system has a nesting function, for some special shapes, if you use the layout function of the AMADA - 2D programming system, it is far from meeting the needs of the production site.

Simply using the nesting function of the AMADA - 2D programming system, only 12 parts can be machined on a (500 mm × 240 mm) sheet, as shown in Figure 6.

First, use AUTOCAD's series of operations such as cutting, copying, symmetry, and rotation to properly align the two parts. The AMADA - 2D programming system is used to generate the machining program, and the 18 parts can be machined on the (500 mm × 240 mm) sheet, as shown in Figure 7.

After reasonable arranging, it not only improves the utilization rate of materials, but also reduces the processing time of single parts, improving the service life and processing efficiency of the mold.

In fact, the reasonable layout of small parts should be analyzed according to the characteristics of the parts. Sometimes it is more reasonable to rotate the part in AUTOCAD at a certain angle and then apply the AMADA - 2D generation program. As shown in Figure 8.

3. 3 AU TOCAD auxiliary expansion of box parts

Through my existing LAN, the CAD view of the design is called as shown in Figure 9. In AUTOCAD, select a view as the datum of the unfolded view as shown in Figure 10, through a series of cut, copy, symmetry, and rotation. When the command is operated, the craftsman can not only easily draw out the CAD drawing of the part, but in the process, the craftsman has a more detailed inspection process on the designed graphic, so that the negligence of the design can be found and given in the first time. correct. Before programming the part development drawing of the application process, the programmer can re-calibrate the part drawing and the part development drawing, so that the design and process errors are found early, and the qualification and production cycle of the part are guaranteed. The numerical control program of this part generated by this method is processed by the CNC punching machine, and the parts are qualified once.

This paper mainly focuses on the research of AMDAD - 2D programming system. It points out that only the AMDAD - 2D programming system can be fully and effectively combined with AU TOCAD. With the advanced and powerful CAD platform of AU TOCAD, the advanced and reasonable CAM function of AMADA - 2D programming system can be used. Quickly and accurately prepare CNC machining programs to better serve scientific research and production.

However, for some parts given in the coordinate data format, sometimes the AMADA-1E manual programming software is convenient. Sometimes even the WINDOWS WordPad program is more convenient, because the text file is edited and the tablet is operated more. For convenience and speed. The programmer should treat the specific situation and specific conditions and use the software resources reasonably.

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