Wednesday, July 3, 2013

3. CADing and prototyping

dimension drawings....
solidworks model

This week,we received all the parts we ordered last week and have been busy CADing on solidworks. We kind of come up with the mechanical structure of the whole kart, how to build it with the materials we have (80/20 aluminum frame, 0.125'' and 0.25'' aluminum plate). After figuring everything out, this is what we come up with:

So we are still adopting the 'kneel down' gesture. And we decided to let the driver (which would probably be me) put her chin on the chin support structure (the tallest thing in the picture) And the person is sitting on the triangular-shpaed structure. We first thought that the two vertical aluminum frame would be a good support for the driver as he makes turns, so there will be some force given to the driver to avoid them from being thrown out of the kart. BUT, our first prototype proved that it would not work....

We laser cut the joints with plywood, and cut the aluminum frames. We made our first prototype of the chassis last night:
bike from the recycle bin, could be useful in the future?
parts we've ordered ;)

Jia wei working on the annoying screws
Everything looks so tiny when we actually make it....Anyway, lessons learned: don't design a structure that needs too many joints to connect. The screws are very annoying and the thing with those 80/20 aluminum frame is, if you mess up one screw, you may have to unscrew the rest and do it all over again....And the frames all have sharp edges so be careful! One problem we are running into right now is at some parts, the joints are not strong enough to hold the whole structure. We're guessing it's probably because of the property of the plywood and we didn't use the proper setting when we laser cut so some parts are burned a little bit and the whole wood is kind of crispy. Maybe it will get better with aluminum plate, if not then I guess we'll just have to buy steel plate....ALSO, always remember to delete those crosses on your dxf file before sending them to lasercut.....Or you may ruin the whole joint. I'll post a picture of our first physical prototype later tonight or tomorrow. We're also exploring different methods of joining parts together....And Jiawei drilled the holes on the gear to fit our motor and adjusted the holes on the washers, so we'll probably assembly the rear wheel today or tomorrow. Front wheel we'll just need to wait for our second BOM to arrive :p

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