Sunday 19 April 2009

FAITH - the CopyCat Bot

How It All Started - a brief (ie 4 day) history

Wednesday 15th April 2009
Thinking about buying a plastics printer, and looking again at the RapMan. It doesn’t seem much different from the latest Darwin, and costs are reasonable, but…

Thursday 16th
…..looking at Darwin development, and the RepRap site with its “How to build a ….” reprap or a repstrap……. “I just wonder if….”
I hadn’t heard of the Repstrap, so I followed the link and was fascinated….

Lots of research about what may be doable – well the site does say it should be buildable by someone with "no special knowledge or expertise"…. well, that's me!

Friday 17th
The more I look into it, the more I want to build my own and have opted for the McWire (http://www.reprap.org/bin/view/Main/McWire_Cartesian_Bot_1_2) because it appears to have the most comprehensive pictures/instructions and hints. By Friday evening I’m hooked, and I’ve posted on the RepRap builders’ forum.

Saturday 18th
Research: it wasn’t easy to find the steel plumbing pipe in the UK, so I looked for alternatives.

I stumbled across the Wiki for the Lego reprap and the Fisher Technik one – WOW! I also kept on reading about other’s versions and problems and solutions.

Some people had used solid bases instead of plumbing pipe.
Advantage: no skewing
Disadvantage: lack of clearance below moving parts.
Plan: use a wide u-shaped solid base.

I also read that getting the holes in the right places wasn’t as easy as it should be, given that you can print off diagrams to tape onto parts in order to locate those holes. This was when I decided to use MDF for the x,y,z stages instead of expensive, and breakable acrylic.

Then what to use for the upright? Small sections of timber, propped with triangular support blocks.

Then how to hold up the upright known as “vertical base” without the plumbing pipe and flange? Hmm.

I’m spending a lot of time thinking about the plans, by now, so I added my marker to the RepRap map.

Sunday 18th
After a night of thinking about it, I had an idea of using a furniture leg with its attachment plate instead of the flange.
After a little scouting round B&Q, I found the perfect answer: a square-profile, hollow leg with plate with pre-drilled holes. Not expensive either, and fits smaller screws than the bolts required for the plumbing flange, thereby negating the need for really thick material for the vertical base. At least I think that’s why that sheet is thicker than all of the others. Time will tell when I start to put this thing together.

OK, committed now – having bought (some of) the bits, SHE’S OFF!

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