Monday, March 1, 2010

Nigel's summary of meeting #1

Here's the contents of a followup email that Nigel sent to the gang:
Here's what I think we need (more or less):

1. CAD software - I have an old version of Solidworks kicking around
which will work fine for creating models of the parts we want to cut out.

2. CAM software - Mastercam is a popular commercial product. I don't know
if there are freeware alternatives out there. This takes in a solid model
and generates a set of tool paths in "G code" format. Someone will need to
scope this out and get something functional up an running. Any reasonably
recent PC will work for this, and it doesn't need to be dedicated to the cutter.

3. CNC software - Freeware TurboCNC from DAK engineering should work. This
will need to be installed on the dedicated cutter PC.

4. Dedicated control PC - something with a built in printer port, a monitor,
and a keyboard. Only really needs to run DOS. We may need to pull 5V power from the PC
to run the processor on the linistepper motion control board. Marc will pull this together,
if I understood correctly.

5. Motion control boards. I have three Linistepper version 1 boards.
Documentation is here: There
are lots of links to follow and lots of good info on how to make these things go. Another

6. Stepper motors able to handle 1 amp at some voltage up to 50V. I have two:
6.1: 1.8 deg/step, 3.1V, 1A. May be a bit weak and a bit too fine for this task.
6.2: 15 deg/step, 12V/phase, current unknown. Physically bigger than the other one,
but I don't know how much torque it will generate.
We may need to find other motors - someone needs to assess these ones and try to
come up with a rough idea how much torque/speed/power we'll need overall.

7. Control Wiring. We need PC to driver and driver to stepper wiring. Ideally we
would also have PC-controlled plasma starting, but we can use manual control for now. I have
a parallel cable with conductors big enough to solder to, but not much else of use. We'll
also need female connector bodies - check the linistepper page from item 5 for details.

8. Mechanicals - bed, rails, motor mount, drive screws/belts/cables, bearings, torch
mount bracket, etc. I likely have enough bearings kicking around, but I haven't done
a full inventory. I'll spend a bit of time soon looking at what I have and don't have.
Some ideas:

9. Plasma cutter - I have a lower power machine for now, but I'm willing to upgrade if
this works out nicely.


The next meeting will probably be at Nigel's place so that we can all get a look at things, and figure out our next steps.  Hopefully Marc will have put together a computer for it.

I mentioned that it would be nice if we could end up controlling things via USB, making it much more versatile (use any laptop etc.) but that's not how the controller circuits that we all ready have are set up to work.  Possibly something to add in V2?

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