2 Function and application of MasterCAM software

Figure 1 machined parts drawing

1. Process analysis of parts
Figure 1 shows the processed parts drawing. Before using the MasterCAM software to automatically program the parts for NC machining, firstly, the machining process analysis of the parts is carried out to determine a reasonable machining sequence, while ensuring the surface roughness and machining accuracy of the parts. It is necessary to minimize the number of tool changes, improve the processing efficiency, and fully consider the shape, size and machining accuracy of the parts, as well as the rigidity and deformation of the parts, so as to finish the roughing and then finish the machining; ; Machining other surfaces after machining the datum.
The parts shown in Figure 1 can be finished by turning. The knives used are external turning tools, 5mm wide grooving knives and external thread turning tools. The process flow of the part on the CNC lathe is: contour machining, grooving machining, thread cutting and final cutting.
If the part is programmed with a cycle command, the program includes the following parts: 1) the coordinate system and the specified program of the machining process parameters; 2) the roughing and finishing process of the contour cycle; 3) the grooving cycle machining program; 4) the thread Cyclic machining program; 5) Final truncation machining program.
2. 2.2 Geometric modeling of parts
   The geometric model of the part is built to realize the basis of CNC machining. Any one of the four modules of MasterCAM has the function of 2D or 3D design and has strong (CAD) drawing function. You can use the Design module to model, or you can use the Mill module, Lathe module and Wire module to directly model according to the processing requirements. At the same time, because of the many data conversion files set in the software system, various types of graphic files such as AutoCAD, CADKEY can be used. Graphics on software such as Mi-CAD are converted to use on the MasterCAM system.
   When modeling the part, it is not necessary to draw the model of the whole part. It is only necessary to draw the outline of the machined part. The machining size, geometrical tolerance and fit tolerance can be omitted, which saves modeling time. , can meet the needs of CNC machining; when modeling, should be drawn according to the actual size of the part to ensure the correctness of the calculated tool path coordinates; and different processing steps can be drawn in different layers, With the function of the layer in MasterCAM, when determining the tool path, it is called or hidden to select the contour required for machining. The parts processed in Figure 1 do not need to draw all the parts in the process of modeling and drawing. Just draw the outline of the part, as shown by the thick line in Figure 2.
   

   Figure 2 Outline drawing to be drawn

3. Part machining tool path determination
   After the part is modeled, according to the arrangement of the machining process, select the tool used in the corresponding process, select the machining blank according to the requirements of the part, and correctly select the workpiece coordinate origin, establish the workpiece coordinate system, and determine the relative relationship between the workpiece coordinate system and the machine coordinate system. Dimensions, and various process parameters are set to obtain the tool path for part machining. The MasterCAM system generates the corresponding toolpath process data file NCI, which contains all the set tool motion trajectories and machining information.
   The parts shown in Figure 1 can be set by Mastercam Lathe for various process parameters to obtain the tool path for part machining.
4. Simulated CNC machining of parts
   After the tool machining path is set, the machining simulation function provided by the MasterCAM system can be used to observe the cutting process. It can be used to check whether the setting of the process parameters is reasonable, whether there is interference in the actual machining of the CNC, and whether the operation of the device is correct. Whether the actual part meets the design requirements. At the same time, in the NC simulation processing, the system will give a report on the machining process. This can eliminate the trial cutting process in actual production, which can reduce material consumption and improve production efficiency.
5. Generate NC instruction code and program transmission
   By computer simulation of CNC machining and confirming that it meets the actual machining requirements, MasterCAM's post-processing program can be used to generate NCI files or NC code. The MasterCAM system itself provides more than one hundred post-processing PST programs. For different CNC equipment, the CNC system may not be the same, and the selected post-processing program will be different. For the specific numerical control equipment, the corresponding post-processing program should be selected. After the NC control code generated by the post-processing is properly modified, if it can meet the requirements of the numerical control equipment used, it can be output to the numerical control equipment for CNC machining.