ReuseDaBox

From RepRap
Revision as of 15:50, 11 January 2014 by Moorelife (talk | contribs)
Jump to: navigation, search
Crystal Clear action run.png
ReuseDaBox

Release status: Experimental

ReuseDaBox.jpg
Description
development notes on building a Mendel type WolfStrap in a cabinet.
License
Author
Contributors
Based-on
Categories
CAD Models
External Link
makereal.moorelife.nl


Overview

The thought occurred to me yesterday, after discussing the possible design and construction of a 3D printer with a colleague at work who already owns one which he built from a kit. To each his own of course, but being a diehard engineer, I figure that building a RepStrap would be way more fun, and much more of a learning experience. Looking around this wiki it seemed a WolfStrap would be the most reuseable way to go, since I have an old TV cabinet in my garden shed which forms a perfect sturdy wooden frame for what I wish to create. On top of that, it already holds at least four drawer guides which can be reused for the various translation movements!

Phase 1: making the cabinet a solid base

Base cabinet.jpg

The base of this design can be just about any rectangular cabinet, that you deem will provide sufficient work volume. I chose an old TV cabinet from the days that TV's were still massive beasts which required superhuman strength to lift, or cooperation of two humans like in Dire Strait's awesome hit...

The turntable on the top unfortunately did not have sufficient rigidity in its sliders to serve for the motion train of the extruder head, but the board halfway did have good supports. So I removed the top, the backside and the middle shelf. By cutting a rounded rectangle in the hind board, it maintained its support capacity, and screwed back in that gave the cabinet its left to right sturdiness again.

Mounting Guide.jpg

My board already had drawer guides, but if yours doesn't, you could just make it a bit less wide and mount drawer guides you have lying around, or can acquire from a local DIY store. My effort in making this design however is to keep the spirit of RepRap, in reusing as much as possible. (even the turntable might go to a friend wanting to make solar panels turn to the sun...

In order to perfectly align both drawer guides, I spaced them from the bottom of the cabinet and the backside by inserting a few temporary boards while I screwed them in place. This makes certain that the bed will move smoothly. Measuring the base position against the fully extended position, it gave me about 275 mm work space from back to front. So if I can mount the mechanical parts for the Y movement outside on the back of the cabinet, I'll actually have that much working room!

Bed Extended.jpg

I may have to do some reinforcing of the top board, because time has left it a bit sagged from the weight of those TV monsters. But it will always be a nice place to put the spools of material, and the old reused PC that will eventually drive it!

To my engineering eye, mounting dual stepper motors left and right on the back of the cabinet, driving threaded rods will ensure the bed moves perfectly forward. I also choose to use dual end switches, because I like the better fail safe it gives you over just one home switch. And rather than use new switches, it will even be possible to just use two paper clips and screws with washers. But maybe that is pushing reuse a bit too far!  ;-)

As for reusing old mechanical parts versus designing to be 3D printed parts is something I will think about next. Perhaps I can get my 3D printer owning colleague to print me the needed parts for this project if I pay for the needed base material...

Z-Axis Guides.jpg

And luck keeps falling into my lap: just now I remembered that I'd recently taken apart two cabinets with drawers that my youngest daughter no longer wanted because she got a new one to stash all her clothes. It turns out the drawing guides in there were far too weak to support the weight of the drawers orthogonal to their direction of movement, but I had exactly five working ones left. And four of those, mounted two by two left and right inside the cabinet gave me a Z-axis movement of about 239 mm!

Of course, if I decide my Z-Axis isn't enough, then taking out part of the top board might solve that, but then I'd have to find me longer guides...