Agui, the design director of the German TTI company, was mentioned in the previous story. He is really a "geek". He has designed many very "avant-garde" products and won unanimous praise from his bosses and customers. But sometimes he It was really a bit too much to initiate the "boom". He once said, "We will never give up until we make it difficult for the inspectors at Guohui Factory to get down."
In fact, we are also good friends and often drink together, but we often "fight each other" even though we are separated from each other, which is not a pleasant experience.
The "air outlet" he designed last time was difficult for me to "live and breathe", but I finally got it done. After I simplified the part, it was later selected as a test question in the Jiangsu Province Mold Design Competition in 2008. But sometimes the questions he asked were so difficult that I really wanted to bite him to relieve my hatred. However, our Guohui Company and TTI Company have tens of millions in mold business every year. For the sake of business, I dare not offend Agui, so when he offered me a move, I could only "take it" honestly. No, in this batch of molds, there is another "monster" that is "shaking the world and weeping ghosts and gods". It is called the "spherical air outlet". All the engineers in our engineering department shook their heads. Luo Sheng and I looked at this The product is only relatively bitter. Because the plastic is made of nylon and fiberglass, the mold parts must be hardened (quenched), making it even more difficult to make.
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The product is cut open like this:
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I called Agui and said, "Agui, have you gone too far? I, Old Cha, have surrendered. I ask you, 'Old Man,' to be kind and simplify the product, otherwise it won't be possible to remove it from the mold." "Cha Worker, you misunderstood. This part is not something I am embarrassing you about. It was proposed by our German chief engineer. He said it was for aerodynamic requirements and strength requirements. It had to be done this way. I also know that it is done this way. It's very difficult to remove the mold. I tried several times, but to no avail." "It's not very difficult to remove the mold," I said. "It's just that it's impossible to remove the mold. Don't Germans have this common sense?"
The phone call chilled me, but I still didn't give up. I went directly to their company office building in Houjie, Dongguan, and found Agui.
"I said Agui, you are also very familiar with molds. Please tell me. How do you remove the inner drum part from the mold?" "Didn't your company make 'explosion cores' before?" "Explosion." You are so big, the inner diameter of the pipe is only 40mm, and the cross-sectional radius of your inner ring is 20mm. Could it be that the size of the fixed part of the 'explosion core' is zero! There is no chance at all, unless it is made into two halves and then used The glue sticks together. "That's not strong enough." Agui said, "The product has been finalized and supply contracts have been signed with many European customers. It's too late to change it. You'd better find a way quickly!"
It seemed that it was impossible to change the product. When I returned to the company, I took the "prototype" of the product and looked at it over and over again. I felt dizzy.
The boss of their company is difficult to talk to. He looks down on the Chinese at all. They came to Dongguan to set up factories just to take advantage of the tax-free policy here. If our mold cannot be finished, he will find an excuse to deduct a large sum of money from us for the mold. This "spherical air outlet" is an important part, and it is an appearance part. They also know that it is difficult to make. When quoting the mold, our company sent salesman Xiao Chen to sign the quotation. He knew a little about molds, but was not very proficient. When he saw the strange look of the part, he wrote a very high price, which was mixed with more than 100. For other mold quotations, because we are an old supplier, their boss signed the quotation without even reading it, and immediately issued the advance payment. In fact, their boss is the smart man. He must know the difficulty of this "spherical air outlet". Once we take the advance payment, it will be too late to regret it. In fact, our financial department has received the advance payment. Now we are really dumb and unable to talk about the pain.
If the mold design could not be completed, I would be blamed this time. However, I still did not give up. I made dozens of phone calls and invited many friends who were mold makers to study with some of my apprentices. There were 3 tables inside, and it was said that Lao Cha had encountered a "peerless problem". If he couldn't figure out a solution, he would have to "wash his hands in a golden basin"! (impossible)
I won't go into the details of drinking. In order to prevent me from quitting the "modelling world", my friends came up with a lot of ideas. I'll give you two typical ones:
1. Explosion molding, first make it into a straight shape, partially heat it and then blow it with a blow molding machine.
2. For secondary injection molding, first make two halves, leaving a gap between them, and place them in the second set of molds. Use the first injection as an insert and fill the gap during the second injection molding.
It should be said that both of these methods can be done. I have also thought of it and proposed it to Agui, but both were rejected (too disgusting).
At this time, A Guang said in a corner: "Old Cha, haven't you practiced martial arts? I've read about some 'gong transformation method' in martial arts novels. Use your kung fu to remove the inner bulge." The stuff has melted away."
The words caused a roar of laughter. After hearing this, an idea seemed to flash in my mind, and I suddenly thought of a "low melting point alloy" that would melt at about 200 degrees. I slapped my thigh and thought, OK, I have it! This "Da Zhiguang" who only had a "junior high school undergraduate degree" woke up the "dream man" with one sentence.
Once I had the idea, it was easy to make it. I first bought this "low melting point alloy" and after asking for a long time I found out that the supplier was on Jiefang North Road, Guangzhou. I chose one with a melting point of 180°C. It is made of four metals: antimony, lead, tin, and bismuth in proportion. I have used this "treasure" before. It was vigorously promoted by the country in the 1970s and used to make rapid molds. It is indeed easy to melt, and the hardness after solidification can reach above HB200. During the test, I first cast the blank and then turned it into the shape as shown below:
The injection mold is relatively simple. I made it into one mold with two cavities:
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Before injection molding, first put the machined "low melting point alloy" parts into the mold and put them on the movable mold core:
This is what the injection molding looks like:
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The cross-section of the injection molded product is as follows:
Then put the product in oil heated to 250°C. After about 3 minutes, use pliers to hold the nylon product and gently rinse it in the oil to get the complete product. Then use detergent to wash off the oil stains on the product, and that's it.
I took the first batch of products that I tried out and came to Agui's office. Agui still didn't believe that they were injection molded. He looked over and over because he was also very proficient in molds. According to conventional rules, it was impossible to take off this product. Modular. I'm afraid I made the two halves and stuck them together. Later, I showed it to their German chief engineer. That guy was indeed an expert. He only took a second look and saw the four glue entry points on the end face. I knew it was indeed injection molded. Thumb, repeatedly said: "Good Good"
This process is so easy to talk about and there is no difficulty in operation. But when I really thought about this method and the operation process from beginning to end, I was really sweating. It reminded me of a poem by Li Bai: The apes on both sides of the strait can't hold back their cries, and the light boat has passed the Ten Thousand Mountains.
