What appeared in Ye Qing's eyes was a silver-white standard hexagonal nut.
Gently pinching the nut, Ye Qing's first reaction was that the nut was very heavy.
A standard nut of the same size as it is, about seven grams. Ye Qing often deals with these things and has a very accurate grasp of its weight. But when the nut came into his hand, it weighed about fifteen grams.
The increase in weight shows that the nut is made of a denser high-hard alloy.
When Ye Qing pinched the alloy nut in his hand and observed the inner wall thread against the crystal light overhead.
Ye Qing, who has been polished by the monsters to have a tough nerve, couldn't help but be surprised.
There are no threads in this nut.
The insides of the lustrous nuts reflected a faint metallic light under the light.
There is a reflection, which means there is a metal mirror. But the inner wall of a nut is as smooth as a mirror as a seamless precision tube.
A nut without a thread, can this still be called a nut, maybe it is more appropriate to call it a metal washer.
What is a nut?
Nuts are the most common metal parts in modern industry and life. Nuts and screws, the two are tightly combined to fix objects, even first-grade children know the principle.
The inside of the nut is called the internal thread, and the top of the screw or bolt is called the external thread. Only two nuts and screws of the same specification can be connected together.
The diameter is the same, and the tooth spacing between the threads is the same.
If there is no thread, how can it be tightly connected to the screw?
Ye Qing believes that the Japanese Institute of Technology can't make this kind of mistake that violates the common sense of physics. Since they were so proud to give this nut as a gift, there must be something special about it.
"Is there a magnifying glass?"
Professor Cai Chenning nodded solemnly and handed over a Calander 300x portable microscope.
Portable microscopes with their own light sources are usually used to observe the surface of jewelry and the surface thickness of metal materials. It is only the size of a mobile phone and is very suitable for carrying.
After adjusting the resolution and light source, Ye Qing aimed the lens of the portable microscope at the inner hole of the nut.
Ye Qing's face also became serious. Under 300 times magnification, the inner hole of the nut, which originally looked as smooth as a mirror. A series of internal threads appeared. These threads circled around each other, and the space between the threads was so small that it was unbelievable.
Under the observation of 300 portable microscopes, they could barely see that there was a trace of a depression between the teeth.
How thin are these teeth?
The average thickness of a strand of hair was 0.06 millimeters, but a strand of hair could be easily seen with the naked eye. If the strands of hair were arranged neatly with a gap of the same thickness in the middle, would the human eye be able to see it?
If one looked closely, they would be able to find some clues. Ye Qing pulled out a strand of his hair and observed it under the portable microscope. He memorized the focal length and approximate width in his mind and then aimed at the inner wall of the alloy nut.
Compared to a strand of hair, the distance between the threads was so small that it was impossible to judge. This meant that the gap between the tattoos was far smaller than one-tenth of the width of a hair. As for how small it was, it was beyond the visual analysis ability of the human eye.
"We have measured it with a laser interferometer. The thread pitch is 0.2 threads and the thread depth is 3 threads," Professor Cai Chenning answered.
"No wonder."
Ye Qing understood that the human eye could distinguish things that were much thinner than a strand of hair. Under sufficient light and different color contrast, even silk could be seen. However, such a small thing had reached the limit of recognition with the naked eye.
A single strand of silk was fine, but if two strands of silk were close together with a gap of the same thickness in the middle, the human eye would default to one strand of silk.
The threads in front of him were based on the same principle. It was too thin, only one-thirtieth of the thickness of a strand of hair.
The circles of ultra-thin threads had, of course, exceeded the visual identification limit of the human eye, resulting in the illusion that there were no threads on the surface of the nut.
1 mm, in industrial processing, was often referred to as 1 thread, and 1 thread was equal to 0.01 millimeters.
Now, the accuracy of the international five-axis machining center was usually 0.2 thread. The domestic accuracy was 0.8 thread.
This was just theoretical data. In actual operation, if you wanted to reach the accuracy of 0.2 thread, you must adjust the machine tool to the best level, use the laser to adjust the tool from time to time, and automatically compensate for the tool wear.
The nut in Ye Qing's hand represented the processing limit of an ordinary five-axis machining center.
"Who would have thought that the Japan University of Technology could make a nut like this?" Professor Cai Chenning said with some sadness, "When we got this nut, we had students who didn't know the industry. They laughed at the Japan University of Technology for not being able to distinguish between a nut and a washer. They gave us a washer without threads and insisted that it was a nut."
"Someone also asked me why the commercial five-axis center could control the accuracy to 0.2 thread. In theory, the accuracy could be controlled higher in the laboratory. Why couldn't a screw be made?"
Because this screw must be processed in one go and hundreds of threads invisible to the naked eye must be processed on it.
The key is that you have to have a tool that can be tapped. Not to mention that you can't buy it on the market. Making a tool that can tap a screw is far more difficult than making a screw like this.
Also, the tooth pattern of this screw or nut is too thin. If the factory machine gently cuts a knife on the alloy steel, it will cut a thread thickness.
Then, the sliver that was cut off would never be a vertical piece of metal. Instead, it would be a lollipop-like piece of curly skin.
This is the result of metal stress, thermal deformation, the cutting angle of the tool, metal toughness, and other factors.
Professor Cai Chenning wondered how the Japan University of Technology could process hundreds of ultra-precision threads with only 0.2 thread spacing in a nut with a height of five millimeters.
The most important thing is that the threads processed by others are not deformed.
"The answer lies in the metal material used in this nut." Ye Qing stared at the nut that represented the most cutting-edge processing technology and whispered, "Japan has made a lot of achievements in special alloys. Ordinary metals are not resistant to high temperatures. The alloy materials they use should be able to avoid metal stress and thermal deformation."
"I also guessed that was the case." Professor Cai Chenning asked cautiously, "But no matter what kind of alloy, as thin as 0.2 thread thickness, it will be deformed with a light touch."
"My disciple used hand grinding an extremely thin probe to test the hardness of the thread. He thought that it would be deformed with a light touch, but the thread of this nut did not. "
"Maybe the nano-level coating increased the hardness. Using the plasma vapor deposition method, a layer of diamond grinding layer with a thickness of only a few nanometers can be coated." Ye Qing, who was brought out by a group of top monsters, said with some uncertainty.
Professor Cai Chenning, who had a little understanding of this technology, fell into a long period of bitter laughter.
Because they couldn't do any of the crafting techniques that Ye Qing mentioned.
Not only could Zhongyun University not do it, but none of the Seiko companies that Professor Cai Chenning knew could do it.
So, he shamelessly called Ye Qing and invited Ye Qing to dinner.
Even the principal, who was usually clean and almost never participated in dinner parties, came and looked at Ye Qing eagerly.
"Ye Ye … President, then … can you make this kind of screw?" The elegant Principal Wang Hongnian's face was a little red. He was a typical old-school educationist. Usually, when he saw students, he would keep a straight face to maintain his rigid and serious image.
Ye Qing was also his student. Now that Principal Wang Hongnian shamelessly asked Ye Qing for help, he felt that his image was completely ruined.
This was especially so when there were more than ten students sitting at the table.
But at this moment, no one cared about the principal's image.
Zhongyun University was about to lose face. Right now, on the campus forum, the mechanical engineering department had become a national sinner. If they could not make this screw, they would not even be able to find a partner. How would they have the time to care about the principal?
Everyone looked at Ye Qing eagerly. Ye Qing held his chin and said, "Making a screw is easy. The key is that I've already graduated. This academic exchange is for students, right?"
Making a screw was easy!
Making a screw was easy …
Principal Wang Hongnian, who had invited the wolf of Japan University of Technology, did not hear the last sentence at all. He was hot-headed and stood up from his chair with a bang. His expression was even more excited than when he became the director of the Ministry of Education. "Mr. Ye, quickly make a screw and teach those arrogant guys a lesson."
"Mr. Ye, when you graduated, didn't the school send out a postgraduate application form?" Professor Cai Chenning's eyebrows were almost flying. He was so excited that he kept rubbing his hands.
"I think so …" Ye Qing certainly remembered that form. But Ye Qing knew that he was not cut out for it. Even if he filled it out, it would not pass. So, he just rolled it up.
Professor Cai Chenning slapped a blank form on the revolving table.
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