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Leo Dearden

I'm committed to the RepLab project.

Tools of interest


  • support material
  • for electronics
    • Pick n place
    • conductive material deposition
  • for mold making
  • for ceramics

CNC Machine Tools. Lathe, Router, Mill.

  • air bearings based on graphite blocks for linear slides and spindles
  • casting whole machines from epoxy/granite/carbon fiber composites
  • using laser interferometers during fabrication and operation to tool up to extreme accuracy from inaccurate components and with inaccurate tools.
  • fabricating low cost high performance linear motors for extremely high motion performance low to moderate load tools
  • carbon fibre composite air bearing screws for high load high performance tools

Software tools

  • Electronics place and route for RepRap
  • Unsupervised CAM (subtractive cutting path generation)

Curing oven for composites Vacuum mixing and casting systems for composites Vacuum pumps Air Compressors

Personal Participation

I will work on (in order, subject to revision)

  • CNC router bootstap:
    • improved spindle mounting
    • 4th axis.
    • Later, vacuum clamping and precision kinematic clamping.
  • RepStrap (based on CNC router cartesian bot)
    • single plastic extruder head
    • second hot extruder head
    • paste head
    • low melt alloy and copper composites for extrusion
    • printing circuits
    • pick and place.
  • Powerful and high precision machine tools as detailed above.

I'll offer advice and comment wherever it's welcome.


I have a fairly extensive personal workshop (http://fabricationsofthemind.blogspot.com/2008/10/in-praise-of-good-workshop.html).

I'm peripherally involved with the RepRap project, and will get more deeply involved as I work on my RepStrap. I'm a well liked friend of the explosively growing Noisebridge San Francisco hackerspace. I currently work for Google. I may be able to harness or evoke contributions from any of these, and I will listen for opportunities to do so.

Funding Model

I've funded my work so far from my income. In the next three years I intend to bootstrap through having more free time to taking paid work based on RepLab technology to develop and deploy machines. The things I learn in that work will be contributed open source and the money from it will support me and my work. If possible, I will replicate this model, supporting others in doing the same.

Time Budget

I'm working very full time at the moment. I can currently contribute a very little. I'll have a little more time in the spring 2010, and hope to secure one day a week to work on open source circuit printing, as part of my paid job, later 2010. Beyond that, more and more time as I can arrange it.

RepLab Tool List Opinions

Build/Defer is ever only a personal opinion. FWIW, I'm open to persuasion, and more importantly, whoever wants to Build anything, can of course get on with it. :-)

1. Laser cutter - large DIY community exists for C02 lasers

Very handy. It's basically a new tool head for a plasma table or similar. Defer.

2. ShopBot - RepTab is the Factor e Farm version

RepTab looks like a good plasma table. I'm not sure how well it will handle cutting loads. Perhaps it will require modification to do that, but some sort of gantry router will work well and should definitely be in the toolkit. Build soon.

3. Precise router for milling circuits

Precise router, for many things. If we can make it stiff and coolant proof enough, it becomes a Mill, too. If it's heat and RF resistant enough it's a plasma table. If it's fast enough it's a laser cutter, or a RepStrap. Build soon.

2 and 3 can have a lot in common. 3 is just smaller and more precise. Common designs could be mostly parametrised to provide both.

4. Plasma cutter - power circuit is main point to opensource

Yes. The head is also non-trivial, IMHO. I suggest: Defer.

5. Welder - power circuit is main point to opensource

Yes. Likewise, Defer.

6. Oscilloscope - can a computer oscilloscope cover most needs?

Yes it can. It can be just as good as (or better than) a standalone one. There are projects out there to make these already. Obtain, commercial or open source.

7. Rep(st)Rap

Build or Obtain a kit then Build our version as discussed in other posts.

8. Mill


9. Drill

Hand drill, drillstand: Obtain. Pillar drill can be built as part of the Mill.

10. Lathe


11. Induction furnace - power electronics are main point to opensource


12. Ciruit fab - automated process including pick-and-place


13. Aluminum extrusion

14. Metal casting - of ingot from induction furnace, and other molds 15. Hot rolling 16. Cold rolling 17. Forging 18. Metal shear and hole punch for up to 1" steel 19. Wire drawing

Defer all.

The heavy industrial infrastructure will be easier once we have the machine tools working. We'll also have a better idea of what we want and need.

Beyond RepLab

Air compressor

Vacuum Pump

  • 0.1 mbar, >10cfm for degassing and lamination.
  • 0.1 bar, >100cfm for vac clamping.
    • i hear a shop vac + light duty pump and check valve works great

1 phase -> 3 phase converter.

Shaker, for casting