23-year-old Boy Aspires To Win The "Skills World" Turning And Milling Compound PK Competition Championship

23-year-old boy aspires to win the "Skills World" turning and milling compound PK competition championship

The core skill of the manufacturing industry is CNC turning and milling combined processing. This is also a position that many factories are extremely short of when recruiting workers. On the morning of November 25, 2020, at the Zhuzhou City "Skills World" Vocational Skills Online Live Contest, a turn-milling composite ultimate PK competition gave the answer. People who can formulate efficient processing plans are the technical backbone that companies really need.

The winner will be determined within 20 minutes of the match

The competition was held in Zhuzhou and attracted 86 players from across the city. In the end, only 4 people made it to the finals. The competition requires players to complete all operations within 20 minutes, including formulating a processing plan, selecting tools, determining cutting amounts, writing CNC programs, and finally operating a lathe to complete part processing. Time is extremely tight and there is no room for error in every step.

Tang Min, a 23-year-old young man from a local company in Zhuzhou, finally won the championship by relying on solid basic skills and closed-door training one week before the game. He practices on the CNC lathe for more than 10 hours every day, rehearsing all possible processing problems in advance. The judges scored from three aspects: safe and civilized production, parts processing quality, and mechanism movement effect, and Tang Min scored high in all three aspects.

What is the difficulty in turning and milling composite technology?

Even though turning-milling composite processing seems simple and easy at first glance, in the actual operation process, it puts an extremely severe test on the comprehensive ability. Contestants must first clearly understand the content of the drawing, then quickly construct a processing plan in their mind, then select the tools and cutting parameters that meet the requirements, and finally compile and create an accurate CNC program. If there is an error in any of these links, the parts will most likely become scrap.

Take the transmission gear parts in manual transmission automobile gearboxes as an example. When processing such parts, a turning and milling composite process is required. The tooth shape of the gear needs to be processed with high precision, the inner hole needs to be processed with high precision, and the end face also needs to be processed with high precision. The position tolerance requirements are strict, and the dimensional tolerance requirements are equally strict. If the processing plan is unreasonable and the gear is installed in the gearbox, noise will be generated and even the teeth will break, which will seriously affect the performance of the car.

Developing processing plans is the core competency

The most critical step in the competition is to formulate a processing plan. This plan determines which surface to process first, what kind of tool to use, how fast the cutting speed is, and how much the feed rate is. Experienced players will quickly determine the optimal processing sequence based on the material and shape characteristics of the parts, so as to ensure quality while saving processing time.

Tang Min’s plan for the competition was to first roughen the outer circle and inner hole using a combined turning and milling process , and then perform finishing machining until the drawing size was reached. He selected appropriate carbide tools, controlled the cutting speed at about 120 meters per minute, and selected a medium-to-high feed rate. This plan not only ensured the processing efficiency, but also avoided the problems of tool chipping and part deformation.

Tool selection and cutting amount should match

The correct selection of cutting tools can save half of the effort. Indexable inserts are often used during combined turning and milling operations. Different grades of inserts are suitable for processing different materials. When processing ordinary steel, coated carbide inserts are used. Once you want to process stainless steel, you must choose a suitable grade with better wear resistance. When processing aluminum alloys, you need to use sharp blades to avoid the occurrence of built-up edge.

The cutting amount covers the three parameters of cutting speed, feed amount and cutting depth. If the speed is too low, the efficiency will be poor. If the speed is too high, the tool wear will be rapid. If the feed amount is too small, the surface roughness will be good but it will take longer; Feed amount If it is too large, vibration will easily occur. During the competition, Tang Min controlled the cutting depth between 1 and 2 mm based on the diameter of the part and the hardness of the material. This ensured that the cutting was in a stable state and would not overload the machine tool.

CNC programming needs to be fast and accurate

Regarding the writing of CNC programs, this is the most critical final step that determines the final success or failure. The program needs to include tool change instructions, spindle speed, feed speed, cutting path and other information. Tool radius compensation and length compensation must be considered when programming. Otherwise, the size of the parts obtained after processing will be out of tolerance. After the program is written, a simulation run needs to be performed on the machine tool to confirm that there is no risk of collision.

1. Tang Min memorized all the commonly used program modules in his mind in advance. 2. He directly called and modified them during the competition, thus saving a lot of time. 3. He also paid special attention to whether the G code and M code in the program were accurate for the turning and milling compound machining process plan . 4. Such instructions as spindle forward and reverse, coolant switch, program end, etc. were all the same. The 23-year-old boy aspired to win the "Skills World" turning and milling compound PK competition championship, 5. This level of proficiency comes from a lot of daily practice and a thorough understanding of machine tool performance.

Daily training determines game results

For this competition, Tang Min started a closed-door training a week in advance. He practiced on the CNC lathe for more than 10 hours every day. He practiced the processing of parts of various shapes many times, from simple shaft parts to complex turning and milling composite processing solutions for disc parts. He trained each processing step to the point of muscle memory. He recorded all the problems such as broken tools, vibrations, and dimensional deviations encountered during the training and found solutions.

This kind of high-intensity training is not common in manufacturing companies. The reason is that the production tasks are intensive, making it difficult for workers to have the opportunity to practice specifically. However, it is precisely this kind of specialized training that is separated from daily production that enables Tang Min to calmly deal with various emergencies during the game. After the game, he claimed that although the game was tense at the time, he felt at ease once his hands touched the machine tool operating panel. This was because each action had been practiced hundreds of thousands of times.

After reading this article, when you encounter the turning and milling composite machining plan in actual work, the most distressing situation is that the service life of the tool is not constant, you don’t know how to adjust the cutting parameters, or the program is more prone to errors. Please share your experience in the comment area, like and forward this article so that more colleagues can witness these practical competition skills.