Li Changming asked: "Then why are you so sad these days?"
Then Li Wenjun talked about car cylinders and molds.
Li Wenyong was also very interested and asked: "I don't think it's difficult. I already know the dimensions, so I just make a mold."
Li Wenjun sighed: "Actually, many people know the principles, but cannot make them. Just like everyone knows the principles of nuclear weapons, but few countries in the world can make them the same. Because of limitations in precision, materials and technology. For example,
For this cylinder, the flatness error is required to not exceed 0.05 mm at a distance of 1 meter, which is thinner than a hair. The processing mold itself has errors, and then pouring will increase the error. Therefore, the error of the mold is even greater than this.
Be small."
Everyone didn't quite understand it, but they also understood the contradiction.
Gu Zhanyan asked: "What if there is an error?"
Li Wenjun said: "Because the gasoline inside the cylinder is sprayed from the nozzle, if the error is large, there will be oil leakage, air leakage, and in serious cases, it will catch fire."
Liu Dongsheng had already demonstrated to everyone the consequences of poorly manufactured engines that day.
Li Changming watched the process and naturally knew the danger. Li Wenjun didn't say it directly because he was afraid that Liu Dongmei and Gu Zhanyan would be scared after hearing it.
Li Wenyong said: "Then there is nothing we can do?"
Li Wenjun said: "That's not true. The current sand casting technology is not perfect enough. The lost wax method is the most accurate. Apply ceramic liquid to the outside of the wax mold, dry it and then fire it. The ceramic is sintered but the wax is burned off, and it becomes
A mold. But the lost wax method requires wax components before the mold can be made..."
Li Changming thought for a while and asked: "Can wooden components be used?"
Li Wenjun was stunned and said: "Yes, it makes sense. When the ceramic mold is fired, the temperature is enough to burn the wood into ash. After cooling, just rinse it out with water. It needs to be wood that can burn quickly and completely."
Li Changming said: "Let's use pine wood. Give me the dimensions. I'll try it."
Although Li Wenjun had no hope, he still asked Zheng Yuehua to draw the cylinder model built on the computer and give it to Li Changming and others.
Li Changming took the drawings and went to study with Chen Zichen.
Chen Zichen was originally engaged in technology, and he knew everything Li Wenjun said.
After hearing what Li Changming said, Chen Zichen took a breath of air: "This is a bit difficult, I can only give it a try. Can something made by hand be so precise?"
Li Changming said: "When we make mortise and tenon structures, don't we require precision? Besides, I told you about our carpenter ancestors making Lingyuntai. That precision will not be worse than today's."
When the Lingyun Tower is made, all positions are balanced without the slightest error. When the wind blows, the Lingyun Tower sways with the wind, but it never falls.
Later, Emperor Wei Ming saw that the Lingyun Tower was so high and swaying as if it was unstable, so he used brackets to support it. As a result, the brackets were not accurate enough and destroyed the stability of the Lingyun Tower. Instead, the Lingyuntai fell down.
Chen Zichen sighed: "It's too difficult. Even if we can do it, how can we test it? The vernier caliper can only be accurate to 0.1 mm."
Li Wenjun smiled: "This is easy to do. There is something called a micrometer, also called a spiral micrometer, which can accurately measure to 0.01 millimeters. I asked someone to buy two from Haicheng, one on each side of the woodworking workshop and the fitter workshop."
------
Pine trees are easy to find, and they are the most abundant on the mountains behind.
However, the model can only carve out the shape on the whole piece of wood and then polish it bit by bit. It also requires accuracy, which is a test of craftsmanship.
Li Changming and Chen Zichen, masters and apprentices, had not encountered such a challenging job for a long time, and they regained the enthusiasm they had when they first studied Li Wenjun. They worked day and night, and did not come out except to go to the toilet.
Li Wenjun delivered three meals and boiled water to them at the door. When they were hungry or thirsty, they would come out and take the food and water in to eat and drink a few mouthfuls, and then put the empty boxes at the door.
They didn't go back at night. When they were tired, they fell asleep on the simple bed in the workshop.
Li Wenjun was really worried that the two of them were so tired that they would faint if they couldn't bear it.
I wanted to knock on the door to remind them to rest, but I was afraid of disturbing them.
After all, if your hand shakes, all your previous efforts may be wasted.
------
Li Wenjun asked Zheng Yuehua and two technical school students to draw all the parts of the engine, and then Master Qian and others made them out of stainless steel.
Ever since Li Wenjun successfully solved the jamming problem of the sweater knitting machine by tightening screws last time, the fitter class has completely believed that every step must be carried out accurately according to certain requirements, otherwise the requirements will not be met.
Moreover, with the previous experience of making sweater knitting machines, the fitter class will not think that Li Wenjun's requirements are too much when making any precise machinery.
The fitter team was afraid of being embarrassed if the products were not up to standard, so they vowed to control the tolerances of all parts within the requirements given by Li Wenjun, not once twice, not twice, not three times.
That person's level of turning around day and night and forgetting to eat and sleep is comparable to that of Li Changming and others.
Then the canteen had another task, which was to deliver lunch and dinner to the fitter class.
Even Zhou Liguo lamented that in the entire mining area, they were probably the only ones with such drive and research energy.
Tao Guangming scolded Li Wenjun: "You have never poured cast iron components, so you just thought of a random way to torment my uncle. If something goes wrong with him, it's up to you to do it."
Li Wenjun sighed: "There must be no problem with the method. I didn't expect the two of them to work so hard."
------
When Li Wenjun put dinner at the door that day, he heard someone say: "That's it, all parts are accurate enough."
He straightened up and the door was opened in front of him.
Two men with unshaven beards and sunken eyes appeared in front of him, which startled him.
He realized that it was Li Changming and Chen Zichen, and he couldn't laugh or cry: "Why did you two become like this?"
Li Changming said: "I've made three. You can take them and try them."
Chen Zichen: "We have to go back to sleep and take a shower."
Fortunately, it was winter. If it were summer, I don't know how stinky these two people would be.
There was a high pile of scrap wood piled high in the corner.
Li Wenjun was afraid that they might feel uncomfortable on the way, so he asked two workers to take them back. Then he took a spiral micrometer and carefully measured the three wooden cylinders made by Li Changming and others.
The accuracy fully met the requirements. His hands trembled involuntarily with excitement.
You can try it.
He walked out and called out: "Tao Guangming."
Tao Guangming immediately responded and ran down. Staring at the wooden piece in Li Wenjun's hand, he asked in surprise: "Eh? It's done?"
Li Wenjun said: "Yes, come with me to the municipal steel plant tomorrow."
