Li Tianfeng walked to the imported CNC outer cylindrical grinder and saw the worker doing the preparations before processing. The parts to be processed were neatly placed in the wooden box next to the machine tool.↖

The parts to be processed have good quality, good surface conditions, and look very beautiful. Li Tianfeng thought in his mind that no matter how picky the people in Harry Poton are, they are afraid they will find it difficult to find any problem.

There is no problem with the processing size! All technical conditions meet the requirements! The appearance quality is also excellent, and Li Tianfeng is confident in this batch of parts.

Of course, this outer cylindrical grinding process is very critical and there must be no problems, otherwise all previous efforts will be wasted!

"How is the preparation work done?" Li Tianfeng personally asked the worker master who was doing the preparation work.

Seeing that it was his immediate boss, the worker was a little excited and immediately said, "Mr. Li, the preparations before processing are done immediately. You can process the first part in a while. However, I have rarely encountered such high-demand parts that have been working as a grinder for my whole life."

Li Tianfeng nodded. The outer circle of this grinding journal is extremely high, with an outer circle tolerance of only one or two. The contour of the journal is required to reach 5/1000. The outer circle of the journal requires the outer circle of the reference a to be within 5/10000.

All are a few thousandths of a requirement, and the processing difficulty can be imagined!

Li Tianfeng did not dare to be careless. Such requirements are the requirements of some key shaft parts on aircraft engines. This is just a part on oil drilling equipment. Foreigners' requirements are really strict.

Although he thought so in his heart, Li Tianfeng was still cautious and must pass the processing as required. Li Tianfeng personally watched the inspection work before the processing of the worker.

"I think the grinding wheel is not enough, so I will repair it for me." Li Tianfeng said.

When grinding, grinding wheels are usually carefully repaired before processing. As the grinding wheel wears during the processing process, grinding wheels may need to be repaired from time to time.

When counting the trucks, they found that the turning tool was worn and the new turning tool could be replaced, while the grinding process was different. After the grinding wheel was worn, it could not be replaced, but instead it was repaired. A large grinding wheel must be repaired so that it cannot be further repaired and then replaced.

Li Tianfeng found that the grinding wheel was not yet well repaired, so he asked for further repair.

The worker also looked carefully and looked at Li Tianfeng with admiration. The grinding wheel can really be better for grinding.

CNC outer cylindrical grinders are equipped with special diamonds for repairing grinding wheels. The hardness of the grinding wheel is very high, otherwise it cannot grind all kinds of metal materials. The grinding wheel must use something with higher hardness than the grinding wheels. Diamond is the best choice.

Diamond is a diamond. Of course, the diamond used for grinding wheels is not gem-grade diamond. Otherwise, it would be valuable if it is so big. This is industrial-grade diamond, which is not as dark as it is. Although it is not beautiful, it is a veritable diamond with hardness there.

The worker took out the grinding diamond, installed it on the CNC outer cylindrical grinder, then operated the grinding machine, and began to repair the grinding wheel.

The grinding wheel is very wide. It rotates at high speed. When the grinding wheel touches the diamond, it immediately raises waves of dust-like powder. The powders fly, and in a flash, the grinding wheel is grinded very flat.

"It's OK!" Li Tianfeng said.

Upon hearing this, the worker immediately stopped repairing the grinding. Li Tianfeng said, "Now you can start processing. Install the parts you want to process."

Installing parts is also a meticulous job. The worker applied a little oil to the tip holes of the two ends of the shaft to be processed, and then used the two tips of the CNC outer cylindrical grinder to push the two ends of the parts up, and then carefully rectified the parts.

"No, you need to make further corrections. It is best to have a beating within three thousandths of the bend when processing is processed."

The process regulations require 5% of the 10000. To be on the safe side, and for the better processing quality of the parts, Li Tianfeng put forward higher requirements, finding within 3% of the 10000.

The worker master did as he did, but he was within three thousandths of a thousandth. Don’t look at it, which was only two thousandths of a thousandths of a thousandths of a thousandths, but the difficulty increased a lot. The worker master spent the boss’s effort to find the right, and the processing surface finally beats within three thousandths of a thousandths.

Seeing that the corrective dial meter finger was always within three thousandths of a thousandth, Li Tianfeng nodded, "It's OK, it's up to the requirements."

If there is a dial table, there is a dial table. The dial table divides one millimeter into one hundred equal parts. One circle on the dial is one millimeter. The dial table divides one millimeter into one thousand equal parts. A small grid on the dial is one thousandth of a millimeter. A circle is generally one millimeter in zero point, and a small grid is one micron.

In some processing processes with high requirements and very small tolerances, dial gauge is often used, such as the grinding process of this shaft journal.

After rectifying the parts, the worker checked again, and the worker said, "Mr. Li, can you start processing?"

Li Tianfeng pointed a little, "You can start processing!"

Hearing this, the worker pressed the machine tool start button. Because it is a CNC external cylindrical grinder, the processing process is naturally controlled by CNC program. The grinding wheel rotates at high speed. When it gently touches the slowly rotating parts, a "hiss" sound began to grind.

Grinding processing has a very characteristic, that is, the grinding linear speed is very fast, much faster than processing such as counting and milling.

The soft sound of processing sounds very pleasant. Under the full cooling of milky white cooling, the processing is very stable.

The processing allowance for grinding is generally not large, and the same is true for this part, with only a few dozen wire allowances, that is, a processing allowance of a few millimeters. It doesn’t take long, and only a dozen minutes. The CNC program shows that it has been processed to the required size.

If it is a counting truck processing, the tool can be removed when the processing reaches the required size and then stopping the processing, which means that the processing has been completed, but the grinding process is not.

After processing to the required size, the CNC external cylindrical grinder does not withdraw the tool under the control of the CNC machining program, but continues to grind without margin.

The so-called "free grinding" means no processing allowance, which is equivalent to an empty knife. The parts are still rotating slowly and the grinding wheel is still rotating at high speed, but it does not enter the tool, but is moving back and forth with left and right, horizontally.

It seems that there is no margin grinding, but this is not absolute, but the grinding amount is too small and almost nothing. It is called "free margin grinding". The purpose of this is to further correct the outer circle of the part, that is, the outer circle of the journal of the shaft.

"Grinding without margin" was carried out for at least one minute, and Li Tianfeng could clearly see that the grinded shaft neck was bright and almost like a mirror, which indicated that the surface roughness of the processing surface was very good and completely met the required standards.

After this grinding without allowance lasts for more than a minute, the machine tool begins to withdraw the tool, the grinding wheel leaves the parts, and slowly rotates freely, and then gradually stops.

Parts are processed!

After the grinding wheel completely stopped rotating and there was no remaining rotation at all, the worker took the air gun to blow the coolant on the part, then picked up the measuring tool and started carefully checking the table, preparing to first measure the outer diameter of the part.

For parts with extremely small tolerance sizes and such strict requirements, it is very particular to measure the outer circle of the part, rather than just finding a caliper or micrometer, because the tolerance of the outer circle of the part is only one or two, that is, 0.012 mm, a special micrometer is required.

This special micrometer must be strictly calibrated before measurement. Just like our common high-precision electronic scale, the electronic scale has a weight, which is only used to calibrate the electronic scale. The same is true for this special micrometer, and it also has a calibration part.

This calibration part has an outer circle dimension marked on it, which is generally accurate to 4 digits after the decimal point. Before measuring a formal part, use a special micrometer to measure the calibration part to see if the measured value is basically consistent with the value marked on it, which is accurate to 4 digits after the decimal point. It is impossible to be completely consistent, because there is a measurement error, and it is enough to be within a allowed range.

Li Tianfeng noted that this worker master has good skills and the operation of using this special micrometer is very standardized, and there is nothing to be picky about.

After carefully calibrating the micrometer, Li Tianfeng felt a little nervous and was about to measure the outer circle of the part, which was the outer circle of the shaft journal that he had just grinded and processed.

The worker took a micrometer and began to measure the outer circle carefully. Li Tianfeng noticed that the worker's master looked serious, but soon Li Tianfeng discovered that the worker's master's face had changed slightly, and there seemed to be something wrong.

There may be something wrong!

After the worker's face changed slightly, he continuously measured several places on the shaft journal where the outer circle had just been grinded. After measuring these several places, the worker's face changed again.

Zhang Can was also very surprised and immediately said nervously: "What's wrong? Is there a problem?"

The worker sighed and said, "Director Zhang, the parts are too poor!"

Parts are out of reach!

That is to say, the size is not up to standard!

Upon hearing this, Zhang Can's face also changed, and he hurriedly asked, "How many are the differences?"

The worker said truthfully: "The grinding is five-thousandth less."

Five percent smaller!

As for processing outer circles, it is easy to deal with if they are large, because they mean that there is still processing allowance. You can continue to grind. If you are careful to process carefully, you may be able to process until you pass, but it will be different if you grind it smaller. You can't grind the smaller ones, because grinding will only make the grind smaller and smaller.

All previous efforts were wasted!

Zhang Can's face turned pale. Unexpectedly, such a problem would occur. It was scrapped at this critical moment, and his previous efforts were abandoned.

Li Tianfeng's face also changed. Li Tianfeng was far from expecting that such quality problems would occur, and it would be reduced by five thousandths.

...
Chapter completed!