Reprap

20 12 2008

Seeing as I’ll be doing a lot of prototyping, I figured it would be good to have my own rapid prototyper. So I’ve built a reprap, it’s almost finished. This is the ponoko model. Progress so far:  ponoko





First Coil

11 12 2008

coil1I ended up using ruby-serial to control embedded code in the Arduino. The problem with the wrong number of steps per revolution was from packet loss, by slowing down my ruby program the error went away. I need to get some more test wire to wind a full torus now!





Coil Winder

5 12 2008

Here are the pieces for the coil winder, partially assembled.coil_winder11

 

you can see the grain of the rapid prototype: 
coil_winder4

Already I can tell the bobbin is not well supported axially. I doubt it will be able to keep tension with 12 gauge wire. But we can test thinner wire on this iteration. 

Putting it together:

assembly1

As expected, the axel needed reinforcement:

assembly2

 

Doing some quick checks. The stepper motors are supposed to take exactly 400 steps to complete a revolution. However, when I program the bobbin to take 400 steps forward then 400 steps backward, it appears to come just short of a full revolution! WTF! It looks like it’s closer to 415 steps per revolution. But I can’t trust that number to be accurate over many revolutions.

I’m learning RAD, a gem for controlling the arduino from ruby. Very cool.





Rapid Prototyping

1 12 2008

I’ve been researching various methods of rapid prototyping. So far I have used FDM to create the parts for the coil winder, including the bobbin. I’m leaning towards using SLA to fabricate the chassis itself. SLA offers the largest build envelope (20″ X 20″ X 20″), and new resins are strong and heat resistant.








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