Now it's almost the season for graduation design again, and it's sent out for your reference.
When I was in college, I did a hammer and a mineral lamp for metalworking, as if I had an ABS phone...
"I want to make a bicycle for graduation project," I said to my tutor.
"You do it"
The whole decision-making was very efficient, with no sun exposure, no pull-up, no grip.

Finished town building

Because of the limited time, I drew several versions of the plan and asked the tutor to review it. No other plan could be found in my mobile phone,,
The design scheme is on the one hand, on the other hand, because it is a hand-made car, but the cognition of the relevant molding process is basically 0, so I spent almost 1/3 of my time learning the relevant processing technology and bicycle design method.

When designing a bicycle for the first time, I learned a lot of nouns, such as RC, FC, Q value, forward extension distance, and also knew the name, brand, selling price, etc.

After checking a lot of processes, I decided to cut polyurethane foam with laser, and then polish the shape manually as the inner mold of the frame and paste carbon fiber by hand.

Except that the front fork is a finished product, the frame part is completely made by hand.

The head tube part needs to be equipped with a bowl set, so Taobao also bought a standard carbon tube here, and then glued it with the frame.

The white part here is electrical tape to facilitate the breaking of polyurethane foam from the cavity after the carbon cloth is cured.

Because there is no professional equipment to vacuum, only transparent winding tape can be used to wrap the carbon cloth tightly and extrude the excess resin.

According to different positions, carbon cloth of different sizes is cut out and posted locally.

Usually the resin can be cured in one night. The winding tape is torn off the next day and the second and third layers of carbon cloth are covered. I remember that the whole frame is covered with three layers. The first layer is plain cloth and the second and third layers are twill cloth.

The yellow part is Kevlar, which is used for reinforcement. It can be used not only to reinforce bridges but also to make bulletproof vests and explosion-proof shields.

Some key stress points have been reinforced

After the reinforcement is over, cover the carbon cloth again.

The prototype of the whole frame is basically in place, but the nightmare has just begun.

Because the carbon fiber is pasted by hand, the surface of the resin will be uneven after curing and will be polished and smooth by sandpaper.

In places like this, you need to brush the resin again after polishing, and wait for it to be cured and then polished and leveled to reciprocate.

The polishing was basically over. I found an auto repair factory outside and spent 200 yuan to help spray the whole car's bright oil.

Effect of spraying bright oil

Pushing the car to the south gate of the school to find the car repair uncle to install the chain for me, and later scraped my wheel hub,,

If I remember correctly, 15 years was the first time that the Red Star Award was solicited. The director asked us to take part in the competition for this graduation project. After graduation, the teacher called me and said that I had won the award. Let me pay the fee, like more than 600 yuan.

Gogoro released an electric moped in 2021. The whole car is also carbon fiber Kevlar, and the bicycle is close to 3W RMB
I tried it and felt good.
Looking back
Graduation design was seven years ago.