Turbocharging a bigger MaxNC

Message: 12
Date: Tue, 08 May 2001 19:33:19 +0800
From: John <machatak@...>
Subject: Turbocharging a bigger MaxNC

Folks, need advice!
Have a MaxNC that has extended x axis table (600mm or 24"), still using
1/4-20 rod.

[Did you build that yourself?]

Now feel the need for speed, and the routes i see are:
a) software stay with MaxNC, get a phase to step and direction adaptor,
and fit step and direction drivers e.g. Gecko
b) software (still in DOS and freebie if possible), s+d drivers as above
c) Master 5 from Art, (windoze), s+d drivers
d) make the jump to EMC, and s+d drivers (open loop initially, then go
for closed loop steppers)

[Why not use MaxNC's closed loop system? I've been pretty happy with it for
contouring, and it sure goes a lot faster than their open-loop drivers. I
was never able to go faster than 12 ipm with the latter (using their 145
oz/in motion control kit) but I can go 90 ipm reliably with the closed-loop
stepper system.]

Without starting a flame, it it possible to get some advice on which way
to go.

[Just keep it clean- we've got some unmarried people on this list now...]

Mechanical bits will be a scaled up version of a MaxNC, using an angle
grinder motor (200 to 11000 RPM) for Spindle. Have done over 1000 hours
on one already, with no problems, will admit the carbon brushes do spark
a bit.

[Are you fitting this with a collet chuck, or using it to drive the
existing spindle?]

What i use it for is organic shapes, most of my work is surface
modelling, i do mainly formers for dipping latex balloons, using HDPE,
no metal work, but would like to go for 7075 T6 for motorsport
components if possible.

[Aluminum shouldn't be a problem as long as the spindle can keep up with
the feedrate. This can be a problem with the standard 1/5 hp motor, but
maybe the grinder motor will perform better.]

To give some better ideas of the way i abuse the current machine, some
programs are over 4 MB without line numbers and longest duration was
over 52 hours continuous machining, just tidied up with a industrial vac
cleaner every few hours. Main reason it is soo long is that i use same
tool for roughing and finishing pass, a bit of a compromise, but beggars
cannot be choosers! Anybody got a solution for economy ATC????

[The duration would go down if you got the feedrates up. Why do you use the
same tool for roughing and finishing- can't afford two? For what I've been
doing, I find that roughing with a 1/4" tool and finishing with a 1/8" is
more efficient than trying to do it all with the 1/8". But if there weren't
any places that the 1/4" couldn't reach, I suppose it could all be done
with the one tool, perhaps finishing crosswise from the roughing path.]

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Andrew Werby - United Artworks
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