PlywoodRepRaps < Main

Main.PlywoodRepRapsr1.3 - 27 Oct 2008 - 22:35 - VikOllivertopic end
---++ Plywood?!
NOTE: Work on this has now stalled, as it is cheaper to cut a [[PonokoRepRap][simpler design from acrylic]]. The acrylic design is also much more tolerant of the material thickness issues experienced with the plywood design.

<a href="http://picasaweb.google.co.uk/VikOlliver/RepRap/photo#5185179602262618562"><img src="http://lh4.google.co.uk/VikOlliver/R_V1YEF28cI/AAAAAAAAAd8/CK2WdLTWdMA/s400/dsc03809.jpg" align="right" /></a>Yes, plywood. Plywood cut with frickin' lasers. Toby Borland did the initial work, and modified that to be broadly compatible with Darwin parts. So you can assemble a plywood one, and as you churn out the parts in plastic, retrofit them. [[http://ponoko.com][Ponoko]] cuts the materials on demand, so we don't have to hold stock. That's the theory, and Toby's work has been shown in the London Science Museum to prove it.

Documentation for the assembly of a Toby Borland original can be found [[TobyBorlandOriginal][here]].

Toby's work used 4.0mm ply, but this turns out to translate into 4.4mm ply as suppliers like to quote 10% tolerance - they can mix metric and imperial sources that way. So Vik Olliver converted that into 4.4mm and it should still be pretty much Darwin-compatible. Also, we're exploring the use of ball-chain belts for the Z axis at least, so the new design uses different gears.
<br clear="all" ><a href="http://picasaweb.google.co.uk/VikOlliver/RepRap/photo#5185184262302134738"><img src="http://lh5.google.co.uk/VikOlliver/R_V5nUF28dI/AAAAAAAAAeI/9Ir_75jbTB0/s400/dsc03808.jpg" align="right" /></a>At present we've not finished one. At time of writing (4th April 2008), our design requires 2 x P3 sheets of technoply and 1 x P3 sheet of 9mm MDF. The whole lot cut, taxed and shipped costs about US$385 but we hope to bring this down. The goal is to fit everything on one sheet of MDF and one sheet of ply. May not be possible, but we'll see.

Designing parts is actually the reverse of the RepRap philosophy, so cutting stuff out costs money. This means the less unwanted cutting there is, the more money you save in production. Also, I'm told cutting curves costs more, and logic says it would cost more than straight lines. Consequently, some of Toby's neat curves have been somewhat savaged.

Ponoko kindly sponsored some prototyping work, and the second attempt has just been received. Initial problems are:

   * Add X Carriage, twit.
   * Remove excess MDF bracket
   * All wide MDF parts removed from ply
   * Z motor adaptor plate
   * Hack corner cubes square
   * Hack Z bracket corner mount square
   * Corner cube has one tight slot
   * Slightly shrink ball-chain gear
   * Thicken ball-chain tooth root
   * Bed corner bracket completely wrong, wrogn, worng.
   * Lots of letters are cut right through

Source tarball of SVG files appended.

-- Main.VikOlliver - 28 Oct 2008
   * [[%ATTACHURL%/ponoko_take_2.tgz][ponoko_take_2.tgz]]: Second attempt at lasercutting a RepRap via Ponoko.com
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