Re: [CAD_CAM_EDM_DRO] Universal CNC Controller HSM 1/2003+

Bob,
Haven't seen a discussion or had any replies to my inquires about
the same on several boards. I've built it and ran into some
problems. I tried to follow the plans and specifications exactly, so
if you are running a bit looser then you might not have the same
issues.

1. On the aluminum plate, there are some duplicated hole locations.
I don't have the plans handy, but there are 2 holes (of different
dimension) that share the same location on Roland's charts. I
emailed him and never heard back. He designed the unit to be
expandable with a tremendous flexibility, but didn't indicate what
purpose of all the holes. The duplicated holes are under the
breakout card. I don't know what they are for since he didn't provide
any sort of component location diagram and I probably will never need
them. I re-did the layout in Vectorworks. Roland set the plans up
with the long axis in the Y direction, which makes machining it much
more difficult - I set it up in the X axis so you can do all the
holes in one set up on a Bridgeport. I added overlays with all the
components to help me visualize it, along with inter-hole dimensions.
It's much easier to drill the holes if you know what component goes
where; for instance, it's more critical that the 4 holes to mount a
Gecko are properly spaced in relation to each other that to the
distant corner of the plate. I suspect he just dumped the dimensions
from his CNC program to machine the plate, not real helpful if you
are doing it from manually. I can try to convert the Vectorworks
drawings to a generic CAD or pdf format if you think it might be
useful - contact me off-list.

2. Components - I got my filter capacitor from Roland. Try
http://www.newark.com. Part no. 95F4480, $29.21. Don't forget the
bracket, Newark's largest seems to be 2.5 in dia, that capacitor is
3". Mouser (http://www.mouser.com) part no . 539-VR12, $1.35 is
ideal. Mouser doesn't have a 100V, 27000µF capacitor, they do have a
75V one that would probably work. If you are using Gecko's, I'd use
the alternate wiring that he proposed in a follow up article to lower
the voltage. Also, the bleed resistor is probably not necessary.
With one Gecko attached, the capacitor bleeds down in about 10
seconds. Just don't forget that it will stay charged for a while
with nothing hooked up (or the fuses blown). I got 187 oz steppers
from Herbach & Rademan for $35 each - not the best deal around but
good motors. I'd also recommend fuses between each Gecko and the
capacitor. Also, when testing, be sure to fuse everything, don't
just temporarily hook things up directly to "try it out" - trust
me.... I've got a nice Gecko paperweight.

3. Major issue - the computer. A main attraction to the project for
me was having everything enclosed in a single unit. To get
everything in the enclosure he recommended (special order from
Newark, took only 2 weeks to arrive) you need a miniature computer.
There are some installation issues with EMC and the miniature
(idot.com) computer that he specifies in the article. I contacted
Ray Henry about getting set up. He offered to sell me the unit used
in the article. On follow up he never sent me info on how to pay,
etc. I'm not (nor have the time to be) a Linux guru - I need the
machine up and running so this has been frustrating. I think I will
just order the idot machine and use a windows or dos CNC program. I
wish he had given the specs for the computer he used; at least then
I'd know the installation was possible. Idot has several models and
multiple options so the chance of me getting a EMC compatible one is
about "0".

If I was doing it over, I'd get a computer that was "Emc friendly"
then try to get everything to fit inside the computer (like Sherline
did in their new CNC setup). It would have been cheaper and quicker
to do, by far.... and achieved the goal of getting everything into
one box (though not sealed, or as robust as Roland's specified one).

Since you are building a X-Y table, his layout has far more than you
need. He allows for 6 Geckos, 2 transformers, Variable speed driver
plus other things. You could get the breakout board, 2 geckos and
power supply in something much smaller. Plus you wouldn't need the
large transformer or capacitor he specs.

BTW, noticed your internet provider - same as mine. I'm in NE
Louisiana - if you're close I'd like to know.

Regards,
Joe Travis

>Does anyone know if there are active discussion groups related to
>the Universal CNC Controller featured in the Home Shop Machinist
>starting January 2003? I'm trying to locate parts including the
>filter capacitor and some decent 135 oz. stepper motors (frame size
>23). I'm building an XY table - probably 5' X 10' for a CNC Plasma
>cutter.
>
>Any suggestions would be appreciated. Especially the location of an
>active discussion group where people are putting together the
>electronics.
>
>Thanks,
>
>Bob Jacoby
>

--
J. T. Travis
1911_fan@...
NRA Life Member
Member IDPA, USPSA, NSSA, NSCA, LSA

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