How can one be considered a true CNC expert?
How to be considered a CNC expert? I believe this is an unsolvable problem! Because CNC machining involves many aspects, it requires not only rich theoretical knowledge, but also superb practical experience and hands-on ability.
Generally speaking, it takes at least 6 years to develop a qualified CNC technician after graduating from the CNC major and entering the factory. There is absolutely no quick fix skill in this industry! Nowadays, the job division in factories is becoming increasingly detailed. Don't think that you have mastered a certain skill and don't hesitate to make progress. Only by constantly pursuing technological progress and excellence can you establish yourself as a master in the enterprise.
01 must be an excellent craftsman
CNC machining integrates drilling, milling, boring, reaming, tapping and other processes, requiring high technical literacy from process personnel. In fact, when we choose the profession of mechanical cutting, it means that the early stages of the industry are difficult and rough. The basic knowledge learned in school is meager when faced with the needs of factories. Mechanical processing engineers, to some extent, are experienced engineers, so a lot of time must be spent with workers, such as working lathes, milling machines, grinders, machining centers, etc; Subsequently, in the office, process planning, material consumption estimation, and quota calculation were carried out.
After 2-3 years of cultivation, you can basically become a qualified craftsman. Young people who have just started working must humbly learn from the workers and masters. Once they can pass on decades of experience to you, you can avoid many detours. Because these experiences cannot be learned from books, the selection of technology is a comprehensive consideration of equipment capabilities and personnel technical capabilities.
Through such a long period of learning and accumulation, you should achieve the following technical levels and requirements:
1) Familiar with the structure and process characteristics of drilling, milling, boring, grinding, and planing machines;
2) Familiar with the performance of processed materials;
3) Solid theoretical knowledge of cutting tools, mastery of conventional cutting parameters of cutting tools, etc;
4) Familiar with the process specifications, guidelines, and general requirements that can be achieved by various processes of our company, the process route of conventional parts, reasonable material consumption, and work hour quotas;
5) Collect a certain amount of information on cutting tools, machine tools, and mechanical standards, especially familiarize oneself with the cutting tool system used in CNC machine tools;
6) Familiar with the selection and maintenance of coolant;
7) Have a common sense understanding of relevant professions, such as casting, electrical machining, heat treatment, etc;
8) Having a good foundation in fixtures;
9) Understand the assembly and usage requirements of the processed parts;
10) Has a good foundation in measurement technology.
Proficient in CNC programming and the application of computer software
This is relatively easy, with only a few dozen programming instructions. Various systems are similar, and it usually takes 1-2 months to become very familiar with them. CAM programming software is slightly more complex and requires learning modeling, but for people with a strong CAD foundation, it is not difficult. Readers are most suitable for learning these knowledge.
In practice, the standard for a good program is:
1) Easy to understand and organized, the fewer instructions in a program segment, the better, with the goal of simplicity, practicality, and reliability. From a programming perspective, the main instructions are G00 and G01, while the others are auxiliary instructions that are convenient for programming;
2) Easy to adjust. It is best not to change the program when fine tuning is required for the machining accuracy of parts. For example, if the tool is worn out and needs to be adjusted, simply change the length and radius in the tool offset table;
3) Easy to operate. Programming should be based on the operating characteristics of the machine tool, which is beneficial for observation, inspection, measurement, safety, etc. For example, the same part with the same machining content can be processed separately on a vertical machining center and a horizontal machining center, with different programs.
In mechanical processing, the simplest method is the best method. Any colleague with practical experience would probably agree with this statement!
03 Proficient in operating CNC machine tools
This requires 1-2 years of learning, and the operation is sensitive to the touch. Beginners, especially students, understand how to do it in their hearts, but their hands are not obedient. In this process, you need to learn: system operation, fixture installation, alignment of part benchmarks, tool alignment, setting of zero point offset, setting of tool length compensation, radius compensation, installation and removal of tools and tool holders, grinding of tools, measurement of parts (proficient in using vernier calipers, micrometers, dial gauges, inner diameter lever gauges), etc.
Practice of operation requires comprehension! Sometimes there is a mood of "leisurely heart, difficult to tell you the beauty"! Just calm down and practice well in the CNC workshop! Generally speaking, the process from machining the first part to achieving qualified machining accuracy requires CNC programming technicians to personally complete it. You cannot pass this level as you are not proficient in operating the machine tool.
04 Good foundation in tooling and measurement technology
I have listed the tooling and measurement technology separately here because they play an equally important role in the quality of part processing as the accuracy of machine tools, and are one of the indicators reflecting the level of process personnel. The entire process system: The accuracy of the machine tool is guaranteed by the machine tool manufacturer, and the cutting tools and parameters are provided by the tool supplier. Generally, there are not many problems, only the tooling fixtures are specially designed by the process personnel for specific parts. Generally, parts used in CNC machine tools are difficult, so unexpected problems often arise. There are very few fixtures that do not require rectification for CNC machine tool user parts cutting debugging.
During debugging, more than half of the reasons for the unqualified processing of the first part are due to unreasonable positioning, clamping points, and clamping forces of the fixture. The difficulty in analyzing the reasons for fixtures lies in the fact that they can only be qualitative and difficult to quantify. If you lack experience in fixture design and component clamping, the difficulty becomes greater. In this area of learning, it is recommended to seek advice from technicians who specialize in precision coordinate boring machines.
Accurate measurement is one of the basic skills in machining, which requires proficiency in using vernier calipers, micrometers, dial gauges, dial gauges, inner diameter lever gauges, calipers, etc. Sometimes during parts processing, a coordinate measuring instrument cannot be relied upon. It must be measured manually. Imagine, if the quantity of parts is not accurate, which master would trust you? Practicing measurement techniques well will take a long time!
Proficient in the maintenance and upkeep of CNC machine tools
To be familiar with CNC machine tools, one should first:
1) Familiar with CNC electrical components and control principles. Can name and function each component in the electrical box, and understand electrical schematics. Can identify the alarm content based on the electrical alarm number.
2) Understand the structure and transmission principle of ball screw. Clearly identify which factors have a significant impact on the accuracy of machine tools.
3) Understand the structure of the bearings at both ends of the machine tool screw and their impact on the accuracy of the machine tool.
4) Understand the lubrication system of the machine tool (bearings, spindle, various motion pairs, gearbox, etc.), and understand the distribution of each lubrication point. The grade of machine tool lubricating oil and the normal weekly or monthly oil consumption.
5) Understand the cooling system of machine tools: cutting (water, air) cooling, spindle cooling, electric box cooling, etc.
6) Understand the main transmission structure of the machine tool and the specific data characteristics between the speed and torque of each machine tool.
7) Understand the characteristics of the machine tool guide rail pair: whether it is a linear rail or a sliding rail, and how rigid (load-bearing capacity) is it?
8) Can eliminate common operational faults (such as exceeding limits, incorrect tool numbers in the magazine, etc.)
9) Proficient in various precision (static, dynamic) indicators and testing methods of machine tools.
10) Familiar with the tool magazine mechanism and tool changing principle.
Without more than 3 years of exercise, it may be difficult to meet the requirements. Moreover, many companies do not yet have the conditions to learn. It is recommended to seek advice from the technicians in the equipment maintenance department.
I won't go into the details of machine tool maintenance, as each enterprise has its own experience and standards. The key to machine tool maintenance is "maintenance", and attention should be paid to it in daily life (long-term records should be kept):
1) It is important to pay attention to whether the starting load changes of each axis of the machine tool are normal when starting up every day. If the starting load changes abnormally, it means that the resistance of the motion or transmission pair has changed. It is necessary to stop the machine quickly for inspection. Otherwise, over time, it will cause great damage to the machine tool.
2) Pay attention to the normal consumption of lubricating oil. Both too much and too little must be checked.
3) Clean the air conditioning filter and vent filter of the electric box frequently. Once the integrated circuit board of the internal power module and drive module of the electrical box is contaminated with dust containing iron powder, the machine tool will sound an inexplicable alarm, and it cannot be repaired properly. Just wait for the board to change!
06 Cultivate good habits and adapt to the characteristics of CNC machining
A master suitable for CNC machining should be humble, rigorous, calm, with meticulous thinking, organized and independent in their work.
1) The processing of some large parts not only involves a lot of processing content, but also involves the transformation of spatial three-dimensional coordinates. The calculation of machining trajectory is very complex and difficult to determine. If the problem is not carefully and comprehensively considered, the calculation is not accurate, and the program modification becomes more and more chaotic during debugging, the probability of errors is higher. "Think twice before acting" is the most appropriate use here.
2) The part debugging process is a collaborative process involving multiple people, including operators, inspectors, fixture designers, fixture assembly personnel, etc. When problems arise, seek their opinions more, conduct more experiments, and avoid making arbitrary conclusions. Don't blame employees who make mistakes too much, and have a compassionate attitude.
3) The operation of CNC machine tools is controlled by instructions. During debugging, you must be very clear about the trajectory of the machine tool before pressing the "start" button. Be rigorous and meticulous, and never let the machine tool move before proceeding. Once the program has errors, compensation parameters are incorrect, or the coordinate system is selected incorrectly. Mild cases can result in scrapped parts, while severe cases can lead to safety accidents. Those who have a rough temper, lack a clear idea when doing things, and refuse to improve after repeated teaching are not suitable for operating CNC machine tools.
4) When encountering problems during debugging and processing, it is important to remain calm and not panic. Misoperation should be avoided, and psychological resilience should be maintained.
5) When the component debugging fails multiple times, the analysis should be organized and the responsibility should be based on evidence. Some relevant departments may provide various explanations for various reasons. In this case, you need to have your own opinions and remember: it doesn't matter if you do something wrong, but you can't choose the wrong way to do it.
6) Any craftsman, due to environmental limitations, always has limitations in their technical abilities. With the rapid development of technology, there is always room for improvement. After the internal technology of the factory has been digested, the vision should be outward, closely following the advanced processing technology at home and abroad, learning and digesting.
Through this article, you should know that doing CNC also requires learning so much and doing so much. Everyone is not easy, everyone needs to work hard on their own, and only by putting in effort can they make progress.
