Wednesday, January 14, 2009

McWire - Perspex parts: Part 2

My Dad came home today with all the plastic bits... the perspex & PTFE bearings...
4 A4 size perspex sheets for the X, Y, Z & Backing stages. 2 Strips of perspex for the bearing arms. A meter of PTFE bronze plastic for the bearings. All the perspex is 5mm in thickness.
I decided to cut a PTFE bearing first. My dad & I had an argument about printing out the templates & using them... so we drilled the holes with out sticking templates on top... then put the drilled baring against the template... & it was slightly off... so we used the templated from here onward.
Easy descision really... (His argument was that it would take too long to cut them out & stick them on...)
We didn't have any prit so we used clear tape. A little tricky to align on the perspex.
Drilled the holes.
Cut the end stop off. I clamped the strip to a piece of chip wood & cut through the perspex & the wood so that when I got near to the end of the perspex it wouldn't flap around with the vibration of the blade.
There's the first end stop... not to bad I think! Its a bit big on the sides but I will file it down later if it is an issue.
After idividually sticking on each sticker, drilling the holes, then cutting it off, we decided to get clever... I stuck the remaining 5 end stop stickers on, leaving enough space for the jigsaw to cut inbetween, then drilled all the holes at once.
My Dad drew some alignment markings & screwed the jigsaw in place & flipped it over so that just the blade was exposed to us. Our jigsaw had a trigger with a switch to have the jigsaw permanently on...
This slowed us to cut much faster & do the curves of the bearing arms. I'm not sure how actuate these semi circles need to be... some of our bearing arms have triangular corners. I'm quite happy with this jigsaw cutting method. No more vibrations going through my arms!
It took about 3hrs to get the 10 end stops done & 7 bearing arms done (the 8th sticker became unusable) I have stuck the rest of the bearing arms on the perspex & will do them tomorrow. Then the PTFE bearings, Then the 4 stages... :) Hopefully that will all get done tomorrow..

The aluminum is on order & should also hopefully arrive tomorrow as well as the springs & the skateboard ABEC3 bearings.

I really hope to have the mechanics of this McWire cartesian robot done by the weekend so i can work on the electronics side... more etching...

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