The standard process of CNC machining center programmers, after reading the practical techniques you can also do!
As a representative of advanced productivity in the machinery manufacturing industry, CNC machining has played a huge role in the automotive, aviation, aerospace and mold industries after more than 10 years of introduction and development.
CNC programming is an important aspect that affects the quality and efficiency of CNC machining, especially in high-speed and precision machining. In the machinery industry, due to the different levels of CNC programmers, it is necessary to establish certain specifications to allow everyone to avoid low-level errors and repetitive problems.
CNC machining programming process,he general process of CNC machining programming includes: determining the programming basis, establishing the process model, defining the machining operation, generating the tool path, machining path simulation, post-processing, simulation of the CNC machining program, proofreading and checking of the CNC machining program, issuing on-site machining and CNC machining Procedures are finalized, etc.
- Determine the basis for programming
The basis of CNC programming mainly includes three-dimensional models, engineering drawings and part manufacturing instructions (NC process regulations). The following information can be obtained through the basis of CNC programming: part information, CNC machining process plan, CNC machine tool type, clamping and positioning method, tool, process and Work step, processing program number and product processing status, etc.
- Build process model
The design of the process model based on the part 3D model and engineering drawings mainly includes: trimming of the part 3D model, establishing process reference surface, establishing process positioning hole, pressing plate and position design, and processing surface margin processing, etc.
- Define machining operations to generate tool path
Define machining operations and generate tool location trajectories. The main content includes: define the programming coordinate system, fully consider factors such as the characteristics of the processed material, the cutting characteristics of the tool, the cutting characteristics of the machine tool, and the material condition of the part to be removed, and define the processing method (including various Kinds of tooling strategies, etc.), process parameters (including margin, feed rate, spindle speed, and machining tool path span, etc.), and auxiliary attributes (including tool setting points, safety surfaces, and CNC machine tool attributes, etc.) to generate the final tool Bit trajectory.
- Simulation verification of machining trajectory
The main content of the processing path simulation verification includes: check whether the definitions of cutting tools, machine tools, workpieces, and fixtures are complete and whether the dimensions are accurate; check the processing operations and define whether the size of the parts that should be reached in each process is correct; check the processing methods in the definition of processing operations (such as Whether the rough machining strategy, tool offset machining and cavity machining are selected) is correct and reasonable; check whether there is overcutting, undercutting or collision interference between the CNC machine table, the processed parts, the tool and the fixture during the plasctic CNC maching process Question; check whether the process parameters are reasonable, etc.
Post-processing can be an independent process, or it can be integrated with the tool location file generation process. According to the function of the processing software, select an appropriate processing method. The post-processing has the following requirements:
To generate a special processing program for a specific CNC system, its specific post-processing software should be selected; the development or customization of post-processing software should be combined with a specific control system and machine tool motion structure type; post-processing software should ensure tool position processing information It is fully converted and meets the grammar requirements of the control system; in post-processing, the necessary notes are automatically added to the processing program.
- Numerical control machining program simulation verification
On the basis of programming software or combined with the functions of numerical control simulation software, verify all aspects involved in the numerical control processing program as much as possible to ensure the correctness of the final processing program, and record the corresponding numerical control processing program simulation verification.
The simulation verification mainly includes the following contents: check whether the annotation information in the processing program is correct; check whether the selection of the processing method in the CNC processing program is correct; check whether the tool size information in the processing program is correct; check each process in the CNC processing program Whether the size information of the part that should be reached is correct; check whether the tool compensation information in the CNC machining program is correct; check whether there are over-cutting, under-cutting, or collision interference in the CNC machining program; check the CNC machining program, spindle speed, advance Whether the feed speed matches the current CNC machine tool, etc.
- Proofreading and checking of CNC machining program
The proofreading of the NC program is completely different from the proofreading of the craft file. The program format is a coordinate point. It takes a lot of time to proofread the program content line by line, which is also impractical.
The proofreading of the program is mainly considered from the following aspects.
①Model. The model is the basic element to ensure the correctness of the program. It is necessary to check the correctness of the model and analyze whether all the data of the model are consistent with the process document elements.
②Coordinate system. Check whether the programmed processing coordinate system direction is consistent with the requirements of the process file, whether it is easy to operate, whether the coordinate system selection is reasonable, and whether it is convenient to control the size.
③Processing strategy. The programs generated by different processing strategies are completely different, and the amount of programs is also different. The rationality of the processing strategy is analyzed, mainly to control the tool trajectory of the program, and control the processing quality and efficiency.
④ Tool. The tool material, specification and form are determined according to the part material and part processing position. Different tools directly affect the processing efficiency and processing quality.
⑤The entry point and the exit point. The entry point and the exit point are the main factors that cause the knife to gnaw and puncture the parts, and they are also important aspects that affect the surface quality.
⑥Program format. Different CNC systems have different requirements for the program format. Generally, processing programs that meet the requirements of different control systems can be generated by editing the post-processing program. The proofreading of the program format is mainly at the beginning and the end of the program, which does not affect the processing quality of the program.
The CNC program must be complete, correct, unified and coordinated to ensure that the operator can use the program correctly and process qualified products. The numerical control processing program should be able to ensure the rationality, safety and stability of the whole process.
- On-site trial processing of CNC programs and finalizing of processing procedures
For some parts with complex craftsmanship, difficult machining uhmw plastic, high dimensional accuracy or large batches, it is necessary to organize CNC programmers, workshop process supervisors, operators and inspectors to track and record the on-site trial processing conditions for immediate Correct the unreasonable clamping positioning method and cutting parameters.
For some single-piece production parts, in the case of good manufacturability and low dimensional accuracy, try cutting processing should be avoided as much as possible, but left to the NC machining simulation link to find problems and correct them in order to improve programming efficiency and reduce production costs. For mass-produced parts, the CNC machining program should be finalized and warehousing unified management after the first batch is produced.