What appeared in Ye Qing's eyes was a silver-white standard hexagonal nut. Pen, fun, and www.biquge.info

Gently pinching this nut, Ye Qing's first reaction was that this 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 he has a very accurate grasp of its weight. But this nut weighs about fifteen grams.

The increased weight indicates that the nut is made of a denser carbide.

When Ye Qing pinched the alloy nut in his hand and aimed it at the crystal lamp above his head to observe the threads on the inner wall.

Ye Qing, who had already been polished by the monsters, couldn't help but be surprised.

There are no threads in this nut.

The inside of some crystalline nuts, under the light, presents a faint metallic reflection.

If there is a reflection, it means that there is a metal mirror. But the inner wall of a nut is as smooth as a mirror like a seamless precision tube.

A nut without a thread, can this still be called a nut, perhaps it is more appropriate to call it a metal washer.

What is a nut?

Nut is the most common metal part in modern industry and life. The nut is equipped with screws, and the two are tightly combined to play the principle of fixing objects, which even the first-grade children know.

The inside of the nut is called the inner thread, and the top of the screw or bolt is called the outer thread. Only two nuts and screws of the same size can be connected together.

The diameter is the same, and the spacing between the threads is the same.

If there is no thread, then how can it be tightened with the screws?

This kind of mistake that violates the common sense of physics, Ye Qing believes that it is impossible for Rili Polytechnic to make it. Since they proudly gave this nut as a gift, there must be something in this nut.

"Is there a magnifying glass?"

Professor Cai Chenning nodded a little seriously and handed over a Calland 300x portable microscope.

Portable microscopes with their own light sources are often used to observe the surface of jewelry and the surface roughness of metal materials. It's only the size of a mobile phone, making it perfect 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, and under 300x magnification, the inner hole of the nut that originally looked as smooth as a mirror. There are actually internal test threads, these threads are circled, and the spacing between the teeth is unbelievably small.

Under the observation of three hundred portable microscopes, I can barely see a trace of depression between the teeth.

How fine are these teeth?

The average thickness of a hair is 0.06 mm, but a hair can be easily seen with the naked eye. If the strands of hair are neatly arranged, leaving a gap of the same thickness in between, can the human eye see it?

If you look closer, you can find the clues. Ye Qing pulled a piece of his hair down, put it under a portable microscope to observe, and wrote down the focal length and approximate width in his mind, and then aimed at the inner wall of the alloy nut.

Compared with the hair strands, the thread spacing is so small that it is impossible to judge. This shows that the gap between the tattooed teeth is far less than one-tenth of the length of a hair, and as for how small it is, it has exceeded the visual analysis ability of the human eye.

"We measured it with a laser interferometer and the thread spacing was 0.2 wires and the thread depth was 3 wires. Professor Cai Chenning gave the answer.

"No wonder. ”

Ye Qing understood that the human eye could distinguish things much thinner than a hair, and under sufficient light sources and different color contrasts, silk could even be seen. But something so small has reached the limit of what the naked eye can recognize.

A single silk is fine, if two silks are close together, leaving a gap of the same thickness in the middle, the human eye will default to one.

The same principle applies to these threads in front of us. It was so thin, only one-thirtieth the thickness of a human hair.

The ultra-thin threads surround the nut and naturally exceed the visual recognition limit of the human eye, giving the illusion that there are no threads on the surface of the nut.

1 humi, in industrial processing, is often called 1 filament, and 1 filament is equal to 0.01 mm.

At present, the accuracy of international five-axis machining centers is usually 0.2 wires. The domestic precision is like this in 0.8 wires.

This is only theoretical data, in practice, in order to achieve an accuracy of 0.2 wires, it is necessary to adjust the machine tool to the optimal level, use the laser to set the tool from time to time, and automatically compensate for the tool wear.

The nut in Ye Qing's hand already represents the processing limit of an ordinary five-axis machining center.

"Open your eyes, who can imagine that the Japanese University of Science and Technology can make a nut like this?" Professor Cai Chenning said with some sadness: "When we got this nut, we still have students who don't know how to do it, and ridicule the Japanese University of Science and Technology for not even being able to distinguish between the nut and the washer, and send a washer without a thread, insisting that it is a nut." ”

"Some people also asked me that the commercial five-axis center can control the accuracy at 0.2 wires, so theoretically, in the laboratory, the accuracy can be controlled higher, why can't a screw be made?"

Because this screw must be made in one go, hundreds of threads that are invisible to the naked eye must be processed on it.

The key is that you have to have a tool that can be tapped, don't say that I can't buy it on the market, so I made it myself. It is far more difficult to make a tool that can tap a screw than to make one of these screws.

There is also ~ the tooth of this screw or nut is too thin, and if the factory machine tool gently cuts it from the alloy steel, it will cut the thickness of a wire.

The cut off will never be a vertical piece of metal, but a lollipop-like curllipop.

It's metal stress, thermal deformation, the cutting angle of the tool, the toughness of the metal, and so on.

Professor Cai Chenning thought to himself, how did the Japanese University of Science and Technology process hundreds of ultra-precision threads with only 0.2 wire 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 to this nut is made of metal. Ye Qing stared at the nut, which represented the most cutting-edge processing technology, and said softly: "Japan has made great achievements in the field of special alloys, ordinary metals are not resistant to high temperatures, and the alloy materials they use should be able to avoid metal stress and thermal deformation." ”

"I'm guessing that's the case. Professor Cai Chenning asked cautiously: "But no matter what kind of alloy, as thin as 0.2 filaments, it will be deformed with a light touch." ”

"The disciples I took with me grinded out an extremely fine probe by hand to test the hardness of the thread. I thought it would be deformed with a slight touch, but the thread of this nut is not. ”

"It may be that the nanoscale coating increases the hardness, and the plasma vapor deposition method can be used to coat a layer of diamond grinding with a thickness of only a few nanometers. Ye Qing, who was brought out by a group of top monsters, said with some uncertainty.

Professor Cai Chenning, who also knows a little about this process, fell into a long wry smile alone.

Because of any kind of process technology that Ye Qing said, they can't do it.

Not only can't they do it at Zhongyun University, but none of the Seiko companies that Professor Cai Chenning knows can do this.

Therefore, he cheekily called Ye Qing and wanted to invite Ye Qing to dinner.

Even the principal, who had a clean breeze on weekdays and almost never participated in the dinner, came and looked at Ye Qing with a blank eye.

"Ye Ye...... Anyway, then you... Can you make this kind of screw?" the elegant principal Wang Hongnian blushed a little at this time. He is a typical old-school educator, who usually sees students and maintains his stereotypical and serious image with a strained face.

Ye Qing is also his student, and at this time, Principal Wang Hongnian asked Ye Qing for help with a cheeky old face, and there was always a feeling that his image was completely ruined.

Especially at the table, there are more than a dozen students seated.

But at this time, no one cares about the problem of the principal's image or not.

Soon, Zhongyun University's face will be gone, and now in the campus forum, the mechanical engineering department has become a national sinner, this screw can't be done, they can't even find the object, and they still have time to care about the president?

Everyone was looking at Ye Qing with their eyes open, Ye Qing held his chin: "It's easy to make screws, the key is that I have graduated now, and this academic exchange meeting is all students." ”

It's easy to make screws!

It's easy to make screws......

Principal Wang Hongnian, who summoned the wolf of the Japanese University of Science and Technology, didn't hear the latter sentence at all, his brain was hot, and he stood up from the chair with a slam, his expression was more excited than when he became the director of the Education Bureau: "Mr. Ye quickly make a screw out and teach those arrogant guys a hard lesson." ”

"Mr. Ye~ When I first graduated, didn't the school send a graduate application form?" Professor Cai Chenning's eyebrows were about to fly, and he kept rubbing his hands excitedly.

"It seems that there is a ......" Of course Ye Qing remembered the form, but Ye Qing knew that he was not the material, and he would not pass it if he filled it out, so he kneaded it.

Professor Cai Chenning snapped and slapped a blank form on the rotary dining table.

"Welcome Mr. Ye to our school for graduate studies, you don't have to go to class, if it weren't for that damn procedure to go, with your professional knowledge, it would be no problem to get a doctorate directly. (To be continued.) )