Re: Fw: [CAD_CAM_EDM_DRO] Re: PWM vs Constant current and G-rex

Ron, see.. this is where I go into a nose dive, I'm NOT and electronics guy
so the more 'plug and play' type stuff I can purchase the better. I wish the
suppliers of some of this stuff would post links to show which power-supply
they recommend for their boards and drives, it would make my life alot
easyier.. I realise that it might vary depending on the size of different
things but.. even a chart to kinda get the feel for what I need would be a
start!

I'm actually looking to build a system from the ground up. My intent is for
hobby [at least to start] use only creating composte molds and bucks [ male
parts of which molds are then pulled off of] The total size is fairly large
as some of the parts would have a fairly decent foot-print [ I keep using a
car hood as a refrence] The system is for only milling foam [ and possibly
some MDF on occasion-however this would constitue a fairly hard/heavy cut
for my system] I've heard of people building 5 axis positional systems of
which over time I hope to reach myself.. however this is some time down the
road. If I can get a 3D mill working to cut foam for starters.. I'll be one
happy camper.. [ so will She who must be obey'd as she's ok'd this project..
and I think she's havin second thoughts after hearing my plans--her poor VW
Bug is gonna end up out on the street YET! :-P ] I've got most of my
mechanical stuff designed and am working on the electronics of it all. I've
been looking at websites for a couple weeks now. Its become my full time
'second' job :-) . The mechanical side is a floor mounted bed, channel
cross members and two HSS side beams and with angle iron linear rails
mounted either side of both beams kinda like <[]> and then excentric
cam follower bearings [ 12 to each side of the gantry for a total of 24 on
the x-axis of the gantry] The y axis is mounted at the top of the gantry
and uses the same principle only the angle irons' are turned 90Deg [ upper
one under the top HSS x-member and the lower one on top of the lower HSS
x-member which creats like an X profile [ center of the X is split by
12"] ] and the same cam follower's ride on this [8 followers on the y-axis].
The Z I haven't nailed down how I'm going to do it just yet. Might just buy
a linear slide instead of fabricating it all since it won't be as long as
the rest. It has all been designed in Solidworks [ at least as far as I've
got anyway] I'm hoping to make it modular so that the length and possibly
the width can be increased if required at a later date. One issue I've come
across is finding lead screws of some sort that are long enough. Most Acme
screws are all 72" at best and haven't found much longer than that.. well
McMaster has a Ball Screw that is 20' long but they want $1000 for 1 screw
.. however I might still go that route.. we'll see. I've been thinking I
might have to go to a belted style drive if I can't get something to work..
I think it would be more accurate than just a simple threaded rod. Accuracy
isn't a huge concern for me as machining foam isn't an exact science. If I
can keep most of my parts to about +/- 1/16" I'd be pretty happy. If I get
the accuracy better than that I'm hopeing to spray the foam w/ a high build
primer after the ruff cuts and then re-machine to a better finish. We'll
see what happens.

One other thing I'll mention [ after re-reading the above] is that I might
use a single stepper to drive the x-axis and have it belted out to either
lead screw via a timed belt and just run a huge 400-600 oz/in stepper in the
center, save having issues w/ the system going out of sqr by losing stepps
on 1 stepper [ if I was to use two steppers- 1 on each lead screw].

I should mention that before I build all this I plan on building a MDF proto
just to get all the electronic's working and then start fabrication of the
larger unit.

Anyway.. big hopes and ideas at this point.. just hope I can get the
electronic's all figured out so as to get it all working!
I'm sure alot of you ppl on here have heard it all so .. if anything sounds
totally out to lunch... let me know.. I might as well find out about it now
rather than later!!

Jarrett Johnson

----- Original Message -----
From: "R Rogers" <rogersmach@...>



> Jarret,
>
> Yes, you'll need a power supply for whatever motors you decide to use and
> the Geckos use that same power to operate I think, not sure about that.
> They dont need their own external power supply to operate. . I'd invest
> alot of time reading and researching these forums and the internet. What
> type of machine are you wanting to retrofit and what type of motors are
> you wanting to use? The breakout referenced below is the same type that I
> use on all my machines and has given me excellent service.
>
> Ron