With the rapid development of modern industry, cnc machine tools have become the main force in the manufacturing industry. The application of CNC machine tools has become increasingly popular. Advanced manufacturing technology is developing towards a high-level direction of full automation in design, manufacturing and management. The society requires CNC technical talents. Also getting higher and higher. The author combines teaching with MasterCAM software as the core, coupled with numerical control simulation software and numerical control machine tool training mode, to explain numerical control skills training.
1 CNC equipment environment The equipment for CNC training consists of 80 computers, networks, several CNC lathes and machining centers. Configure the corresponding numerical control machine simulation software (self-made) and MasterCAM software on the computer. The computer and the computer and numerical control equipment are connected with a network cable to form a small local area network (as shown). The Cnc Machining program is transmitted to the CNC machine tool through the RS232 interface.
Because the price of numerical control equipment is relatively expensive and the number of sets is small, and the number of students participating in numerical control training is large, only by simulating the operation process of numerical control machine tools through a large number of computer simulations can you observe and modify the processing program. Complicated, for example, manual calculation and programming of curved parts cannot be performed, and CAD/CAM software must be used for automatic generation of processing programs. Master CAM software is one of them. It can enable students not only to design parts, but also to produce and process the designed parts.
2MasterCAM software’s characteristic company developed an application software integrating CAD and CAM functions. In addition to the general CAD drawing function, the software also adds strong curve and surface modeling functions in order to meet the needs of parts processing. In terms of CAM, it has a variety of processing methods such as turning, milling, drilling, wire cutting, etc. MasterCAM provides built-in two-way graphic file interfaces, including STA, IGES, VDA, DXF, CDL, STL and ASC, and has the ability to communicate with The function of processing machine tool communication.
The geometric modeling of the part needs to be generated by CAD drawing (the graphic data shown must be accurate, otherwise the accuracy of the NC programming result will be affected), and the computer will automatically generate the geometric data of the part graphics. According to these geometric data, MasterCAM will receive the processing according to the processing Date: (1) 01-05-21 requires automatic extraction of these data, analysis and judgment and necessary mathematical processing to form suitable data, and the tool path file NCI is converted into NC commands. The NC command is transmitted to the CNC machine tool through the RS232 interface for production processing.
The application of 3MasterCAM software generally carries out numerical control training mainly for the use of numerical control machine tools. For numerical control programming requirements, only manual numerical control programming of simple parts is required and the parts are processed by numerical control machine tools. However, such CNC training is far from being able to meet the processing requirements for the processing of complex parts. It is necessary to convert the complex parts from the DXF file of the ordinary three-dimensional modeling into the tool path file, namely the NCI file, through the MasterCAM software, and then automatically generate the NC command.
Cup-shaped wireframe and surface modeling For example, processing a cup-shaped surface modeling (see). As shown in the figure, it can be seen that there are many transition round corners between the straight lines in the cup-shaped wire frame size figure and the arc is relatively large. During the machining process of the CNC lathe, the flank face of the turning tool is easy to be squeezed and deformed by the arc extrusion. , Thus affecting the processing of dimensional accuracy. At the same time, when manually programming the cup shape, the tangent point between the straight line and the arc is more difficult to locate and calculate, and the positioning calculation is not accurate. It is easy to leave convex lines during processing, which will affect the smoothness and appearance of the processed workpiece. feel. When using a Cnc Milling Machine to process the part, if manual programming is used, not only the calculation amount is large, the program is very easy to make mistakes in the process of processing, and the surface accuracy of the part is extremely low.
If you use the radial function of MasterCAM’s Mill processing to perform milling processing, the above phenomenon can be avoided. First, use the CAD function module in MasterCAM to perform entity drawing of the known wireframe, and draw a two-dimensional cup-shaped wireframe size drawing according to the actual size given by the cup. In three-dimensional coordinates, use the rotate surface command to rotate the two-dimensional cup-shaped wireframe size drawing around a line parallel to the X axis by 180 to generate a cup-shaped surface model. Call the “radial” rough machining function for surface machining in the tool path, and enter the corresponding CNC machine information in the “radial” menu, such as inputting tool parameters (such as tool number, milling cutter size, speed, feed rate, coolant , Tool lifting rate, radius compensation), radial processing parameters (cutting direction error value, maximum angle, incremental angle, cutting point, cutting path allows continuous cutting and lifting), machining gap and edge settings. Select the rotating cup-shaped surface to be processed, the system automatically generates the corresponding machining tool path, and the tool path is converted into the NC command recognized by the CNC system through the post-processing function module in MasterCAM, and then transmitted to the CNC machine tool for processing through the network. Through this process, students will have a deeper understanding of contemporary advanced manufacturing technologies and models.
4 Conclusion This training model is still in the exploratory stage. In the course of practice, we feel that the organization content of training, the use of numerical control machine simulation software, CAD/CAM software, etc. need to be further improved, and strive to establish a system that can basically meet the needs of the society. CNC teacher training model.