Processing application of UG software on MF Twin65 turning center

I. Introduction

The introduction of ugII software in the past two years has opened up a new way of designing and processing, and has brought a new level of mechanical manufacturing capability. In the past, for general parts processing, manual programming can be used. However, for more complicated cavities or curved surfaces, due to the cumbersome calculation, it is easy to produce errors and affect the processing quality, which brings certain difficulties to machining. According to the characteristics of a typical part, using the processing module of UG software, the design of the machining process (including machining type, machining geometry, machining tool selection, machining allowance and cutting parameters, etc.) is completed, and the machining simulation software is used. The machining process was inspected, and the improper processing parameters were properly corrected. The post-processing was completed for the MF Twin65 CNC machine tool, and a machinable NC program was generated. After the actual machining of the part samples, the requirements of the design drawings were met. This method not only reduces the amount of computation of the programmer, but also improves the manufacturing quality and production efficiency of the product to some extent.

Second, the machine tool introduction

The CNC machine tool for machining is the MF Twin65 machine imported from Deckel Maho Gildemeister in 1997. It is a turning center with a double-spindle double tool holder. Its main feature is that it has two centers. The main spindle of the center is called the main spindle and the counter spindle. These two spindles can realize the automatic transmission of the workpiece between the two spindles simultaneously. At the same time, it also has two upper and lower cutter heads, all of which are equipped with 12 cutter positions. Separate and cross-operating the two spindles can also be used in conjunction with the two spindles. The upper cutter head has a y-axis for y-direction movement and milling, so complex parts can be machined.

For the machining characteristics of the double-spindle double tool holder of this CNC machine tool, it is determined to select a typical part for machining. Two spindles and two tool holders are used in the machining process, and the automatic transfer of the workpiece between the two spindles is realized. The y-axis milling function of the upper cutter head. In order to maximize the use of this equipment, most of the machining functions that can be used on this machine are used in the machining of this part.

Third, CAM design

The main steps of using UG software to complete CAM design are divided into the following steps:

(1) Implementing a three-dimensional shape according to the part drawing;

(2) Determine the machining process according to the geometry and dimensional accuracy requirements of the part;

(3) Prepare the tool path file; (after defining the machining geometry, machining tool and other machining parameters, calculate the machining tool path);

(4) Using Vericut software to simulate the relevant tool path files, adjust the machining parameters in time according to the simulation results, and finally determine the tool path source files;

(5) Post-processing the toolpath source file to generate a standard PTP file;

(6) Properly edit the PTP file;

(7) Program input machine processing.

Firstly, according to the design drawings of typical parts, the solid modeling part of UG is used to build the 3D solid model of the part, and then the process analysis is carried out for the specific shape and size of the part. Since the inner hole of the part is deeper, the upper tool holder cannot be realized. The combination with the main spindle, and the right part of the part is easier to clamp after finishing the machining, so it is determined that the two main axes are used in combination with the two tool holders, and the total process route of the left part of the right part of the part is processed first, and then the NC machining is performed. The process was specifically arranged.

(1) é•— The inner hole of the part, including the threaded bottom hole, is in the form of a lathe finish.

(2) Machining the undercut and the inner annular groove, using the lathe groove.

(3) Pick the internal thread M52×1-6H and use the lathe thread.

(4) Roughing the outer part, leaving the finishing allowance 0.2mm, using the roughing method (lathe rough).

(5) The outer part of the finished car is made of steel material No. 45, so the remaining amount of 0.2mm is divided into two passes, and the lathe finish is adopted.

(6) Machining the outer circular groove, using the lathe groove. (After completing this procedure, the part is transferred from the main spindle to the counter spindle)

(7) Machining the end face annular groove, leaving a finishing allowance of 0.05 mm on both sides of the groove, using a lathe groove.

(8) The left end of the roughing part has a tapered outer circle, leaving a finishing allowance of 0.2 mm, which is a roughing method (lathe rough).

(9) The left end of the finished car parts has a tapered outer circle and is finished by lathe finish.

(10) Processing the outer circular groove, using the lathe groove.

(11) Milling two notches, using fixed contours.

According to the above process arrangement, the UG's manufacturing module is used to define operations one by one, including machining boundary, safety boundary, tool control, feed rate, feed retraction mode, machining allowance, number of passes, front and rear commands, etc. Finally, a .cls file (tool position source file) containing various machining data is generated.

Fourth, processing simulation research

The vericut (processing simulation) software used in this application study can interactively simulate the process of removing the demonstration material by the NC tool path data. The entire simulation process is completed on the computer. This is done before the machining. An excellent tool for verification. Vericut software can be used to verify the accuracy of the tool path and determine whether the simulated part is consistent with the original design model, which can greatly reduce the cutting process errors and make it easy to quickly and correctly adjust the tool path file.

1. Simulation process

Simulating with vericut requires three prerequisites, namely the blank model, tool path data, and a description of the cutting tool. Prepare as follows.

(1) Make a blank model in UG according to the blank size of the machined part and save it as a .stl file that vericut can directly call.

(2) The tool path data is the .cls file (tool position source file) generated by the UG's manufacturing module design.

(3) There is a special tool control in the CAM design section, in which the respective tool parameters are set in the above various processing steps, and these parameters are included in the contents of the .cls file.

After these three necessary conditions are ready, start using vericut for simulation processing. First, load the defined blank model into the computer screen → select the desired .cls file, set the display parameters, and start the 3D simulation processing of the blank model, observe the accuracy of the tool path → measurement simulation processing The parameters of the completed part are compared with the original design model, and the data is consistent.

2. Problems in the simulation process

It is impossible to complete the turning and milling simulation in a tool path file: it was found that the machining coordinate system of turning and milling was different, so the CAM part was improved, and the machining coordinate system of turning and milling was consistent, so that The car and milling simulation in a tool path file.

Simulation of the groove and thread cannot be realized: this part has three annular grooves and one thread machining, but it is not simulated during the machining simulation. The analysis is due to the problem of tool control.

It was found that the cutting depth in the outer circle of the rough car was too large, and the phenomenon of emptying the knife was observed. When observing the machining process, it was found that the cutting depth of 1.5 mm (radial direction) was too large at the time of rough machining, and the phenomenon of emptying the knife appeared. Not only is it easy to produce tool wear, but it also affects the surface quality of the workpiece. Therefore, the cutting depth is adjusted to 1 mm (radial direction) in time, which makes the cutting parameters more reasonable and reduces the processing difficulty.

Five, post processing part

The biggest difficulty encountered in the use of UG software to complete the processing is that its manufacturing module and CNC machine tool can not be organically combined, because the CNC system of each CNC machine tool is different, you must make different post-processing for the specific machine tool. The machine file generated by UG is converted into a program file executable by the CNC machine. The CNC system used in the MF Twin65 machine is the Siemens 840C. There are 14 main menus in the post-processing part of the machine. The first five options affect the machining. The machine type, the validity of the axis, the preparation code and auxiliary code definition, and the machine tool are defined step by step according to various menus. Control and post processing commands.

1. Machine type

Two solutions for determining the type of machine tool, one is to complete the rear part separately for turning and milling, and then use it in combination. This solution separates the car and the milling, and the rear part is more convenient to manufacture, but it needs to be combined and used. The second is to use the machining center to set both the turning and milling methods. This solution is completed in a file by the car and milling function. The rear part has more content and is more complicated to make, but it is more convenient to use. After comparison, we decided to use the second solution to define the machine type as the machining center.

2. Axis validity

In this part, it is mainly determined whether the car and milling modes use the M and G code output and the milling system coordinate system of the machining center and how to distinguish the machining mode of the car and the milling.

3. Preparatory code and auxiliary code definition

In this section, the M and G code formats are set. The number of G codes in each block, the user can define the content of the text input. These options enable the generated program to conform to the format recognized by the CNC system.

4. Tool Control This option is to set the G code to control the movement, which needs to be set according to the different G code meanings of the machine.

5. Post processing command

It allows you to set how to output the post command in the .cls file, control the validity of the command, its format, etc., mainly lists the 40 post commands commonly used by the machine, one by one according to the CNC machine system manual. One by one is set, and finally the machine's post processing file mf65.mdfa is generated. The automatic transfer procedure of the workpiece between the two spindles is solved by making a CAM template file: The UG software has standard M code and G code post-processing program. The MF Twin 65 machine can be regarded as having 4 spindles and 2 knives. Rack, so it not only has a general CNC command, but also many instruction codes specific to the machine. These commands are not tool path data files, but are pre-command commands for machining, mainly controlling spindle movement, coolant switch, knife. The movement mode of the frame, etc., and the actual part of the program is basically processed into a fixed format, which can be directly applied at the time, but in the post-processing part, it is impossible to put such a program of about 25 sentences. Add it in, so we try to use the way to create a template file in the CAM design section.

(1) In the CAM design, this fixed live program is defined in the user-defined way to the operation's pre-command;

(2) Save the .prt file containing the operation to the UG's mach subdirectory;

(3) Open a template set file .opt and define the saved .prt file as the standard CAM template file of UG.

When using, just select the set template file in the operation manager window, and select different machining boundaries and tool parameters according to different machining parts. This method can not only solve the problem of similar fixed module program, but also The typical operation of some typical parts is also made into a similar template file, which is called directly.

In this CAM design, the flat end face, the rough outer circle, the outer circle of the fine car, and the thread are all made into template files. In the future, when a batch of materials with similar materials and similar shapes are programmed, these modules can be used in large quantities. Save time.

Sixth, CNC machining process

The NC program generated by UGII software is sent to the machine for trial processing. The whole process of the program is smooth. There is no error due to the program. After the first piece of test, the machining dimensions are measured. It is found that the tool compensation data is due to the tool setting error. Some deviations caused the individual dimensions to be slightly out of tolerance. The remaining dimensions and surface finish were ideal. After adjusting some of the tool compensation data, the machining was performed, and the dimensions of the processed parts were up to the drawings.

Seven, conclusion

The UG software is used to complete the whole machining process and simulation of the machining process by using the UG software on the MF Twin 65 turning center. Basically, the UGII manufacturing module can be used to generate the NC program of the MF Twin65 machine tool and the vericut software for machining simulation. Through the trial processing of typical parts, the feasibility of applying UGII software to realize the automation of CNC machine tool programming is verified, which lays a certain technical foundation for the realization of CAD/CAM/CAE integration of mechanical products in the next stage.