Complex curved surface machining

  "After chatting about the cabinet, Hu Yang asked: 'Xiao Lin, how come you have time to come and sit here today? Is there something on your mind?'"

  Lin Zhenhua said: "Nothing much, just feeling a bit mixed up inside and wanting to find someone to talk to."

  "Is it because of the reporter's matter?" Hu Yang asked, the reporter's interview was known to everyone in the factory, and Hu Yang had always been concerned about Lin Zhenhua, so he was naturally very concerned about this matter.

  Lin Zhenhua nodded.

  "Journalists mainly interview about what things, does it have an impact on you?"

  Lin Zhenhua said: "Their original intention was to understand the division of housing. I got a suite, someone was jealous and wrote an anonymous letter to the newspaper to report me. However, after talking with these two reporters, they were not so concerned about the suite, but instead began to focus on our labor service company's contracting issues, wanting to write an internal reference report to the top."

  "What's going on?" Hu Yang was shocked, "How did you manage to stir up such a big mess?"

  "Is it very serious?" Lin Zhenhua asked back.

  "What's with those two reporters?"

  "One is a young reporter from Jiangnan Daily, the other is slightly older and is from Xinhua News Agency's Jiangnan branch. The one who wants to be an internal reference is from Xinhua News Agency."

  Poplar trees took a cold breath: "Xinhua internal reference ah, Little Lin, this matter has been passed on to the heavens."

  Lin Zhenhua said, "Old Hu, I think it's better to go through the proper channels. The country is now encouraging exploration and Comrade Deng has proposed feeling for stones while crossing the river. For things like our service company, if we leave it at the grassroots level, the lower-level cadres may sympathize but won't dare take responsibility. If this matter can be reported to higher authorities, a word from above might make everything easier."

  "Heaven's will is hard to predict," Hu Yang said. "Xiao Lin, you are too young, you don't know the ferocity of a political movement."

  Lin Zhenhua said: "Old Hu, I think that large-scale political movements should not appear again. At most, there will be some small repetitions, with Deng Xiaoping at the helm, it should be fine."

  Hu Yang hesitated and said, "Comrade Deng's thinking is indeed very open-minded. This kind of thing, it's really hard to say. Maybe because I'm a timid person, my courage is too small. Xiao Lin, the things you're doing now, contract system, performance-based salary, two years ago would have been enough to get your head chopped off. Now although the higher-ups are turning a blind eye, if another movement comes along, it'll be troublesome. If everyone keeps quiet about this, then it's no big deal, but now that it's been reported in the internal reference, I'm afraid everyone will find it hard to keep quiet."

  Lin Zhenhua said: "Old Hu, I feel that China will no longer carry out movements, you can rest assured."

  Poplar said with a wry smile: "I'm not as optimistic as you, we're all old athletes, afraid of exercise."

  Lin Zhenhua can fully understand Hu Yang's worries. In that era, probably except for the people who traveled through time and space, no one dared to make a judgment that China would not have any more movements. Everyone's speculation about future movements was limited to big or small movements, "no movement" was not an option.

  Lin Zhenhua couldn't explain his understanding of the future to Hu Yang, so he gritted his teeth and said: "Old Hu, I'm also going all out... as long as you're not afraid of being beheaded, not afraid of going to jail, not afraid of your wife divorcing you..."

  "You little scamp, who did you learn from? You must have learned from the Gang of Four!" Hu Yang was amused by Lin Zhenhua's teasing, because this phrase had long become a joke.

  "Lao Hu, you're quite free now, aren't you? You even have time to help me with furniture? How about those books, are they all finished? Is there any new demand for books?" Lin Zhenhua changed the subject and asked casually.

  As soon as he mentioned reading, Hu Yang's enthusiasm came back. He grabbed Lin Zhenhua's hand with his paint-stained hands and said: "Little Lin, you're just in time. I've been inspired by that book 'Complex Surface Machining' you helped me buy these days."

  As he spoke, he didn't care whether Lin Zhenhua was interested or not, and he brought over a stack of papers from who-knows-where, pointing at them as he said to Lin Zhenhua: "Little Lin, look, for a surface like this one, traditionally we would be completely unable to machine it with a CNC lathe, because we can't design the path for the tool's feed. When we encounter a surface like this, all we can do is use manual labor to process it, relying on workers using files to slowly file it out bit by bit - not to mention production efficiency, but more importantly, the surface roughness and residual stress of the workpiece machined in this way cannot meet design requirements... did you understand?"

  Lin Zhenhua understood this, and mechanical processing not only needs to consider the shape of the processed product, but also the processing process. The parts processed by high-speed machine tools are different from those polished by hand, even if the shapes are exactly the same, their physical properties will be very different. He nodded and said: "I understand a bit, you continue."

  "For this problem, I have been thinking for a long time. These days, looking at your book "Complex Surface Machining", it talks about how to use the principle of envelope lines to divide the machining process of a curved surface into several times, each time making the feed motion of the workpiece move along a specific curve, and after repeated iterations, it can form the required machined surface. I used the finite element analysis method you taught me, and then used computer calculations to simulate such a machining process. Look, this is the process file I wrote."

  Lin Zhenhua took the stack of drawings given to him by Hu Yang and looked at them for a while, hesitantly asking: "Old Hu, according to your processing technique, not only does the workpiece need to have forward and backward as well as up and down feed motion on the CNC milling machine, but it also needs to add its own rotation, which is equivalent to the machining process of a five-axis CNC machine."

  "That's right!" Hu Yang slapped his thigh, turned his face to Qin Ying and said: "Xiao Ying, see? I told you Xiao Lin would understand. He's a man of insight."

  "Come on, Old Hu," Lin Zhenhua asked, "where can we get a five-axis CNC machine? Five-axis CNC machines are restricted for export by the US government. Even if Sino-US relations are in a honeymoon period now, I haven't heard of any unit being able to buy one."

  Hu Yang smiled and said, "Xiao Lin, this is the issue I wanted to discuss with you. This design of mine only requires some minor modifications to existing machine tools, and it can mimic the effect of a four-axis machine. Of course, even if we had a four-axis machine, our motors wouldn't be able to keep up, our precision screws wouldn't be able to keep up, and our precision bearings wouldn't be able to keep up, so we still wouldn't be able to reach the precision of foreign machine tools. But don't forget, we have people, we have highly skilled workers with exceptional techniques, their experience can make up for the shortcomings of the machines."

  "Let me take a look." Lin Zhenhua continued to study the process file written by Hu Yang, following the thought process introduced by Hu Yang. Only then did he realize that in many operational links that should have been automatically implemented by the five-axis machine tool, Hu Yang had added human intervention components, including tool alignment, center correction, and micro-feed, etc. In simple terms, this was equivalent to workers performing cutting operations one knife at a time under the assistance of the machine tool. If the worker's technical skills were high enough to ensure that each operation was accurate, then it was indeed possible to achieve the effect of five-axis machining, and in terms of precision, it might even be higher than that of an ordinary five-axis machine tool.

  "Lao Hu, you're really amazing." Lin Zhenhua was truly impressed.

  "How about it, Manager Lin? Can't we find an opportunity to give it a try?" Hu Yang looked at Lin Zhenhua with full of hope and said, "Just use this drawing to try our hand, all kinds of processing methods are included."

  "What is this thing?" Lin Zhenhua asked with a frown, holding up the blueprint of the poplar painting.

  The workpiece on this drawing looks like a fan blade of an electric fan, but it is slightly larger in size. The entire blade is twisted into a complex curved surface, and the drawing can no longer reflect the requirements of this curved surface. Each curve can only be described by some strange equations. Such drawings are definitely incomprehensible to workers, who can only follow the process files written by Hu Yang, processing line by line, with specific size requirements for each step. As long as these requirements are met, the entire curved surface is considered processed.

  Hu Yang seemed a bit shy about the drawings he had made, and muttered: "Xiao Lin, this thing is just an experimental tool, mainly to test the feasibility of the craftsmanship. As for the drawings, I copied them from the book you gave me, they're not very useful."

  Lin Zhenhua naturally had some doubts about Hu Yang's explanation. He looked at it for a long time, but couldn't think of any place that would use such a strange part. Maybe it was really as Hu Yang said, the purpose of designing this part was just to test the feasibility of the processing technology, otherwise, why would it be so complicated?

  "Lao Hu, what do you plan to try?" Lin Zhenhua asked.

  Hu Yang said: "I think, you are now also a local official with some power. Can't you use the name of your service company to ask Jin Gong's workshop to help make it? This thing can't be done by ordinary workers, it must be done by Peng Gang, Zhou Houcheng and Sun Changyuan."

  Lin Zhenhua counted on his fingers: "Hehe, milling workers, lathe workers, and grinding workers, the technical elite of the metalworking workshop, let you sweep them all away."

  "I've been in the factory for many years, I still have a good idea of who's technical skills are what." Hu Yang said.

  "Alright, I'll talk to the factory director and tell him it's a task from our service company. I'm sure he'll agree. Peng Shifu and Sun Shifu were originally hired by our service company, they're just borrowed by the factory for use." Lin Zhenhua said with a smile.

  "There's another difficult point, which is the control circuit of the four-axis. I can imagine it, but I couldn't design it. I heard you say that you have a friend from Beihang University who majored in electronic engineering and did well in automatic control?" Hu Yang asked.

  "Teacher Wei?" Lin Zhenhua said, "He's purely into electronics, automatic control and all that. Not very proficient, but it's not a big problem. I'll work with him on it. He'll handle the electronics part, I'll handle the transmission part. Two tinkerers can make up for half of Zhuge Liang."

  "I'll take one too," said Hu Yang.