Material question

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haz
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Material question

Post by haz »

Question.
Got some dead shafts happening in an antweight that will probably have printed wheels. These will be ground steel, like silversteel etc about 2mm dia. How do you guys think running a white strong and flexible wheel straight onto this would go. Of course there would be a fair amount of friction but would it be enough to negatively affect the robot's performance? I don't really have the space for a bearing in the wheel and a live shaft isn't an option. I could fit a small bronze bushing in the wheel but I'm unsure if it is necessary.

Hoping some of the hardcore shapeways guys can give me some ideas. Thank you.
EpicentrE
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Re: Material question

Post by EpicentrE »

Should be absolutely fine, in my experience. I've ran printed things rotating on printed shafts, and steel is far smoother, so I don't think you'll have any problems whatsoever.

I'd get the hole printed very slightly wider (I normally use 2.1mm), then when it arrives, use a 2mm drill to get any gunk out of the hole. If it doesn't rotate freely, widen the hole very slightly (I normally do this by putting the drill bit through and then wobbling the item around, but I'm sure there's a more technical way to do it) until it rotates smoothly. Just take it slow and don't remove too much material.
Scott Fyfe-Jamieson, Captain of Epic Robotics. Champion of AWS38/41/42.
http://www.epicrobotics.co.uk
haz
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Re: Material question

Post by haz »

Ok, thank you. Is having holes fractionally off size and then opening them out the best way to go for printing? In general throughout the robot I mean.
Going back to the wheels, the material is slightly porous right so would a few dobs of a light oil help things friction wise?

Thanks again.
EpicentrE
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Re: Material question

Post by EpicentrE »

In my experience, a 2mm hole when printed can be anywhere from 1 to 2mm. I'm assuming it depends on the specific printer, where the model was in the printer, the orientation, etc. I always err on the side of caution by printing the hole at the final size I want it to be, and then widening it out manually if it's too small upon arrival.

Oil probably would help, but honestly I don't think it's required. If you get the hole the right size it should rotate smoothly anyway.
Scott Fyfe-Jamieson, Captain of Epic Robotics. Champion of AWS38/41/42.
http://www.epicrobotics.co.uk
haz
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Re: Material question

Post by haz »

All right, seems sensible. Cheers
haz
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Joined: Thu Apr 15, 2010 11:20 am
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Re: Material question

Post by haz »

Bump as I have another question about some printing. Is anyone doing an order soon and can slip a couple teensy parts in for me? Can even up at the AWS or I can paypal not bothered. Cheers.
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