To become a CNC master (metal cutting), it takes at least 6 years after graduation from university and entering the factory. He needs not only the theoretical level of an engineer, but also the practical experience and hands-on ability of a senior technician.

The first step: must be an excellent craftsman.

CNC machine tools integrate drilling, milling, boring, reaming, tapping and other processes. The technical literacy requirements of the craftsman are very high. Numerical control program is to use computer language to embody the process of processing technology. Craft is the basis of programming. If you don’t understand the craftsmanship, you can never say that you know how to program.

In fact, when we choose the profession of mechanical cutting, it means that the early career is difficult and rough. The basic knowledge learned in the university is pitiful to meet the needs of the factory. Machining engineers are, to some extent, experienced engineers. Therefore, a lot of time must be spent with the workers, dry lathes, milling machines, grinders, machining centers, etc.; then in the office to compile craftsmanship, estimate material consumption, and calculate quotas. You must be familiar with the performance of various machine tools and the skill level of the workshop masters. In this way, after 2-3 years of practice, you can basically become a qualified craftsman. From my personal experience, I suggest that young college students who have just started to work must learn from the master workers with an humility. Once they can pass on decades of experience to you, you can avoid many detours. Because these experiences cannot be learned from books, the choice of technology is a comprehensive consideration of equipment capabilities and personnel technical capabilities. Without the support and trust of employees, it is impossible to become an excellent craftsman. Through such a long time of study and accumulation, you should meet the following technical standards and requirements:

• 1. Familiar with the structure and process characteristics of drilling, milling, boring, grinding and planing machines,
• 2. Familiar with the properties of processed materials.
• 3. Solid basic knowledge of tool theory, master the conventional cutting parameters of the tool, etc.
• 4. Familiar with the company’s process specifications, guidelines, general requirements that can be achieved by various process processing, and process routes of conventional parts. Reasonable material consumption and working hours quota, etc.
• 5. Collect a certain amount of data on tools, machine tools, and mechanical standards. Particularly, you must be familiar with the tool system used in CNC machine tools.
• 6. Familiar with the selection and maintenance of coolant.
• 7. Have a common sense understanding of related types of work. For example: casting, electrical processing, heat treatment, etc.
• 8. Have a good fixture foundation.
• 9. Understand the assembly requirements and use requirements of the processed parts.
• 10. There is a good foundation of measurement technology.

Step 2: Proficient in the application of CNC programming and computer software.

I think this is easier. There are only dozens of programming instructions, and various systems are similar. It usually takes 1-2 months to be very familiar. The automatic programming software is a little more complicated, and you need to learn how to model. But for people with good cad foundation, it is not difficult. In addition, if it is manual programming, the foundation of analytical geometry is also good! Scholars are most adaptable to the learning of this knowledge. In practice, the criteria for a good procedure are:

• 1. Easy to understand and organized, everyone can understand it.
• 2. The fewer instructions in a block, the better, with the purpose of being simple, practical and reliable. From the perspective of programming, I think the commands are also G00 and G01, and the others are auxiliary commands, which are set to facilitate programming.
• 3. Easy to adjust. It is best not to change the program when the machining accuracy of the parts needs to be fine-tuned. For example, if the tool is worn out, if you want to adjust it, just change the length and radius in the tool offset table.
• 4. Convenient operation. The programming should be compiled according to the operating characteristics of the machine tool, which is conducive to observation, inspection, measurement, safety and so on. For example, if the same kind of parts and the same processing content are processed separately in a vertical machining center and a horizontal machining center, the procedures are definitely different. In mechanical processing, the simplest method is the best method. As long as you have practical experience, you will definitely agree with this sentence!

Step 3: Be able to operate CNC machine tools proficiently.

This requires 1-2 years of learning, and the operation is very handy. Beginners, especially college students, know how to do it in their hearts, but they just don’t listen. In this process, you must learn: system operation mode, fixture installation, part datum alignment, tool setting, zero offset setting, tool length compensation setting, radius compensation, loading and unloading of the tool and tool holder, and the cutting edge of the tool Measurement of grinding and parts

Table) and so on. The ones that best reflect the level of operation are: horizontal machining centers and large gantry (moving beams, top beams) machining centers.

The practice of operation requires savvy! Sometimes there is an artistic conception of “a leisurely heart, but a good point is difficult to talk to you”!
In the CNC workshop, you should calm down and practice hard!

Generally speaking, the process from the processing of the first part to the qualified machining accuracy requires the CNC programmer to personally
carry out. You can’t operate the machine proficiently, you can’t pass this level.

The fourth step: Must have a good tooling and fixture foundation and measurement technology level.

I list the tooling fixture and measurement technology separately because it is as important as the accuracy of the machine tool for the quality of parts processing, and it is one of the signs that reflect the level of the craftsman. The entire process system: the accuracy of the machine tool is guaranteed by the machine tool manufacturer, and the tools and cutting parameters are provided by the tool vendor. Generally speaking, there are no big problems. Only the tooling and fixture are specially designed by the technicians for specific parts. Most of the parts on CNC machine tools are

There is a certain degree of difficulty, so there are often unpredictable problems. I have been engaged in CNC machine tool user parts cutting and debugging for more than 10 years, and I have never encountered a fixture that does not need to be rectified.

During commissioning, the first part was unqualified, and more than half of the reasons were caused by the unreasonable positioning of the fixture, the clamping pressure point, and the unreasonable clamping force. The difficulty in analyzing the cause of the fixture is that it can only be qualitative but difficult to quantify. If there is no experience in fixture design and part clamping, the difficulty will be great. In this study, it is recommended to consult the senior technicians who are doing precision jig boring machines. One of the basic skills of machining to accurately measure the level is to be able to use vernier calipers, micrometers, dial indicators, dial indicators, inner diameter lever meters, calipers, etc. proficiently. Sometimes parts processing, three-coordinate measuring machine can not be counted on. Must be measured manually. Imagine that the quantity of parts is not accurate. Which leader or worker will trust you?

It can take a long time to practice measurement techniques!

The fifth step is familiar with CNC machine tools. Proficient in the maintenance of CNC machine tools.

The so-called familiarity with CNC machine tools should:

• 1. Familiar with CNC electrical components and control principles. Can tell the name and function of each component in the electrical box, and understand the electrical schematic diagram. The alarm content can be found based on the electrical alarm number.
• 2. Understand the structure and transmission principle of the ball screw. Know which factors have a greater impact on the accuracy of the machine tool.
• 3. Understand the structure of the bearings at both ends of the machine tool screw and its influence on the accuracy of the machine tool.
• 4. Understand the lubrication system of the machine tool (bearings, main shafts, motion pairs, gearboxes, etc.), and be clear about the distribution of lubrication points. The brand of machine lubricating oil and the normal consumption of oil every week or month.
• 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: Is it a linear rail or a sliding rail, how rigid (carrying capacity) is?
• 8. Common operating faults can be eliminated (such as: exceeding limit, tool magazine tool number error, etc.)
• 9. Proficient in various precision (static and dynamic) indicators and detection methods of machine tools.
• 10. Familiar with the tool magazine mechanism and the principle of tool change.

For the above items, if you don’t have more than 3 years of exercise, I am afraid it is difficult to meet the requirements. And many companies do not yet have the conditions to learn. It is recommended to consult the master of the equipment maintenance department.

I won’t talk about the details of machine maintenance. Each company has its own experience and standards.

The main point of machine maintenance is to “raise”, and you should pay attention to it in normal times (long-term records should be made):

• 1. Turn on every day and pay attention to whether the start load changes of each axis of the machine tool are normal. This is very important. Start load changes
  Abnormal, it means that the resistance of the movement pair or the transmission pair has changed, and it is necessary to stop the machine for inspection. Otherwise, over time, it will cause great damage to the machine tool;
• 2. Pay attention to the normal consumption of lubricating oil. Too much or 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 power module and the drive module inside the electric box is stained with dust containing iron powder, the machine will give an inexplicable alarm, and the repair will not be possible. Just wait to change the board!

Sixth, cultivate good habits and adapt to the characteristics of CNC machining.

(This one is my personal opinion. Whether it is reasonable or not, you can discuss it.)

The masters who are suitable for CNC machining should be humble, rigorous, calm, careful thinking, methodical and independent.

• 1. The processing of some large parts not only has a lot of processing content, but also has the conversion of space three-dimensional coordinates. The calculation of the processing trajectory is very complicated and difficult to determine. If the problem is not considered meticulously and comprehensively, and the calculation is not accurate, the program modification becomes more chaotic when debugging, and the probability of error is greater. “Think twice before acting” is the most appropriate here.
• 2. The part debugging process is a process of multi-person cooperation, including operators, inspectors, fixture design, fixture assembly personnel, etc. When problems arise, you should consult them more, do more experiments, and avoid making arbitrary conclusions. Don’t blame too much on employees who make mistakes, and have a “compassionate” mentality.
• 3. The work of the CNC machine tool is controlled by instructions. When debugging, you must be very clear about the track of the machine tool before pressing the “Start” button. Be rigorous and meticulous, and never let the machine tool move first. Once the program is wrong or the compensation parameters are incorrect, or the wrong coordinate system is selected. From scrapped parts, to serious accidents. Those who are grumpy, clueless, and do not change after repeated instruction are not suitable for the operation of CNC machine tools.
  Let me tell you a fact: It turns out that our company has more than a dozen user debugging and cutting technologists, all of whom are well-informed and experienced, but none of them has not broken the tool in any year.
• 4. When there is a problem during debugging and processing, please calm down and never panic, and then misoperation occurs. The psychological quality is better.
• 5. When the parts are unqualified for many times during debugging, the analysis must be organized, and the responsibility must be based on basis. Some relevant departments will give various explanations for various reasons. At this time, you must have your own opinion and remember: it does not matter if you do one thing wrong, but you cannot choose the wrong way to do it.
• 6. A craftsperson always has limitations in technical ability due to environmental constraints. Coupled with the rapid development of technology, there is always room for improvement. When the internal technology of the factory has been digested, we must keep our eyes open and keep up with the advanced processing technology at home and abroad to learn and digest. Be a good adviser to the boss in terms of technology.

Generally, tool compensation in CNC refers to the wear caused by the cutting tool during the cutting process, which forms a positive tolerance. Therefore, adding tool compensation in the CNC panel can only directly eliminate the wear recommendations and avoid re-tooling to save time. Theoretically speaking, the tool will only wear out, the gap will become larger, and there will be no need to reduce the compensation value. Unless the tool is changed, it must be re-calibrated.

The original intention of tool compensation is to allow users to program without considering the size of the tool, but to program directly according to the contour size of the workpiece. Otherwise, the tool is always changing, the program needs to be constantly changed, and problems such as excessive before and after must also be considered.
Generally, tool compensation is divided into two parts:

1. Radius compensation
2. Length compensation

(1) When programming, it is regarded as the movement of a point to compile the movement trajectory. In fact, the tool always has a certain radius of the tool or the arc radius of the tool tip, so the movement trajectory of the tool position point during the contour processing of the part It is not the actual contour of the part. There is a tool radius difference between them. In order to make the motion path of the tool location point coincide with the actual contour, it must be offset by a tool radius. This offset is called tool radius compensation

(2) Tool length compensation is the tool position compensation for the tool tip to reach the programmed position.
You can refer to the relevant machine tool manual to set the relevant compensation in the parameters to ensure the accuracy of the processing.