Huxley

Huxley

Release status: experimental

Description
License	unknown
Author	User:Ed
Contributors
Based-on	Huxley
Categories	Mini-Mendel Variation
CAD Models	STEP STL
External Link	Original Blog Post

Introduction

RepRap Version III "Huxley" is being developed on this and associated pages. It is based on Ed's Mini-Mendel design, together with a lot of work already put in by others (especially Erik).

The machine uses M6 threaded rods and M3 nuts and bolts (as opposed to the M8/M4 used on Mendel) and NEMA 14 steppers. The reprapped parts are about 30% of the volume of those for Mendel, which is to say it could reproduce three times faster.

Mendel can print itself, and so will Huxley. In addition, Mendel will be able to print Huxley, and Huxley will be able to print Mendel. We will continue Mendel development to turn it into a multi-material machine. Huxely will be a one-material machine, though we will probably also add a pen plotter so we can write etch-resist on PCBs and use an oil pen to facilitate separation of support material for overhangs.

Things to do

Add to this list...

1. CAD Files
   1. Put them in which !*$!! format?...
2. Put files in Git repository
3. Get rid of filament storage underneath
   1. This is a neat idea in principle, but should not be integral. How about a filament cartridge with the geared extruder drive built in, and a PTFE Bowden tube with the filament coming out to a snap connector onto the extruder.
4. Get rid of under-dents on X motor bracket
5. Redesign X motor bracket so belt does not go back on itself (A basic version of this has been posted on thingiverse here and here).
6. Nema 14 geared extruder
   1. Roman gears?
   2. Mount by Y idler?
   3. Polymer transport path?
7. Z gears incorporate 1 flange
8. Nop's pulleys
9. 4 vertices - add feet
10. Slider bearings rather than ball bearings?
11. Printable frog
12. Heated bed
13. XLR bracket on frame
14. Electronics location?
15. Opto stops
16. Add PCB-pen/oil-separator-pen holder

Supplies

I've (Erik) found suppliers for all of the parts, and the estimated cost of the Mini-mendel would be under 350 euros (in Europe). Note that because the design is not yet stable, you may need to order more to get everything working satisfactory.

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<iframe width='900' height='400' frameborder='0' src='http://spreadsheets.google.com/pub?key=tw60t_E6G8tVNhBgMqAjcbw&single=true&gid=1&output=html&widget=true'></iframe>

You can ask ErikDeBruijn for edit permissions to this Google Docs sheet.

Parts

Apart from the sources listed here, also check out the forSale-subforum in the RepRap-forum.

Printed parts

• You can easily print these production files in 14 makerbot-sized plates.
• You may print an (experimental!!!) shelled MiniMendel using less material and time
• single parts can of course be printed too

Electronics

The primary electronics design will probably be the Pololu Electronics, as we are very close to being able to make the PCBs for these in Mendel. Huxley will also be able to make them.

Identical to Mendel or you can use the BitsFromBytes -electronics that allow standalone operation from SD-card. When using the BitsFromBytes electronics, be advised that this requires a proprietary tool chain to build new firmware that works with the mini-mendel. Also, the latest versions of the source code for their electronics are frequently not publicly available.

Sources:

EU:

• German RepRap Foundation
• Watterott
• BitsFromBytes (alternative Elektronik)

Bowden cable

EU:

• German RepRap Foundation
• US
  • mcmaster

Steppers

Standard 3xNEMA14 and 1xNEMA17(extruder) steppers. Smaller and less expensive than on the full sized Mendel.

Sources (steppers):

• EU
  • KD85 (NEMA17)
  • German RepRap Foundation (NEMA14 and NEMA17)
  • active-robots.com NEMA14 and NEMA17
  • totalrobots NEMA14 and NEMA17
• US
  • makerbot store NEMA17
  • phidgets.com NEMA14 and NEMA17

Sources (Allegro A4983 based stepper-drivers):

• EU
  • watterott.de
• US
  • pololu

(or use the BitsFromBytes-electronic that include stepper-drivers)

Extruder

The MiniMendel uses a bowden-extruder that has less moving mass and thus higher speed due to the stepper not being on the print-head.

Sources for parts:

• EU
  • reprapsource/shapercube
  • watterott (use the hot-end -part of the MK4-kit)
  • German RepRap Foundation
• US
  • makerbot-store (use the hot-end -part of the MK4-kit)

Timing belt

The MiniMendel uses the same 5mm pitch Synchroflex timing belt as is used on the Mendel.
"Synchroflex(R) timing belt,800Lx10Wmm" and
"Synchroflex(R) timing belt,550Lx10Wmm"

sources:

• EU
  • German RepRap Foundation
  • Watterott (2010-05-05: avaliable within this week)
  • rs-online
  • farnell (slightly different lengthes, need adjustment in other parts)
• US
  • mcmaster

Bearings

• EU
  • German RepRap Foundation
• US
  • VXB

Nuts and bolts

All metric and obtainable in every home-improvement-store. 608-bearings can be found cheap everywhere you can buy or repair a skateboard.

Thick sheets

These 2 sheets can be cut from plexiglass or wood with simple tools.

Success stories

• Erik
  • I've printed all RP parts in ABS, they weigh about 300 g. This means you can print 2 sets with your first kg of ABS if you use rafts.
  • Update: Mini-Mendel built and working!

Ongoing development

• Main development seems to be going on in the RepRap-forum
  • German sub-forum
• Marcus Wolschon is currently trying to create a hollowed Mini-Mendel that can be found HERE and uses even less material. Prints and tests for mechanical stability will have to be conducted.

• Marcus created a Shelled MiniMendel that only required 110g of ABS and less then 10h to print. (It may be filled with epoxy after printing but that is not required in all cases.)

• Mini-Mendel/Spacexula Documented Build

• The Mini-Mendel is the first step in optimizing replication time; further steps in that direction are discussed at RepRap Breeder.