Hi Stefan
I figure CNC drilling is definately on topic - at least if using
lasers to drill and "mill" PCB's is on topic too :)) (sorry guys,
could not resist - AND it was interesting)
With regard to the slides, the slides used in the link are NOT those I
refered to. The ones I refered to DO NOT use ball bearings. Instead
the balls are palced along the whole slide making it extremly stiff
and precise.
While I do understand your motivation to create a general all purpose
milling machine, I will choose a different aproach. I intend to build
a cnc DRILLING only machine for PCB's sized 200 cm x 160 cm max. ( 80
x 64"). This is realtively small, and there are almost no side forces
involved when it comes to drilling. My intention is to create a
machine that does not cost more than $100 - INCLUDING the steppers and
hopefully also the controller. Provided I manage to do this, I think
building / buying a MILLING machine later on and continue being
married should be possible :)) . In other words, why not have two
machines in the end? :))
This is just what I intend to do, and of course does not mean that
others should do the same thing. I also look at this drilling machine
as a learning experinece. Again, I'm currently held VERY busy and
hence haven't started anything yet but will do so as soon as time
permits.
Markus
>mostly @markus:
>
>I just saw drawer slides used for cnc machine, but it was a cnc foam wing
>hot wire cutter...
>
>http://www.8linx.com/cnc/
>
>
>very low forces here....
>seems to be REALLY simple to build a cutter for foam..
>not much more complicated than the automatic unit i built for use with
>templates...
>(the template making takes a hell lot of time...)
>
>but enough "damn model plane stuff" - off topic i know.
>
>
>
>i currently emailed to a german guy who uses the "rod with three bearings"
>type of sliding mechanism...
>he is very satisfied with it.. uses metric allthreads with two nuts spring
>loaded to... M8 works...
>
>
>with similar designs even 8mm Aluminium can be worked (with aluminum rails
>.....).
>
>i still do not want to use the drawer slides, i want to make a cnc not only
>for drilling but also for other things
>(front plates, perhaps pcb milling, various stuff) and i still think these
>slides are not as good as the 3 bearings method.
>
>but i saw slides constructed the same way (like drawer slides) as
>"linearführung" or so at rs-components for big $$...
>
>i hope to have found a supplier for precision steel rods/pipes in vienna,
>waiting for reply mail..
>
>
>i would really like to make the machine as sturdy as possible. using
>"heavy" material (mostly steel) not aluminium.
>maybe then i need really strong steppers... damn.. hoped to use the 10
>motors i have lying around.. too weak i think...
>
>i want to weld the framework together where i can (no play, more solid than
>screws), maybe use sqare steel tubing which i have in huge
>quantities...
>
>maybe i can use a angeled steel profile in a uside-down V arrangement over
>the round rail.
>then maybe drill holes in it for the lower bearings (these will sit on two
>screws m8).
>
>the one guy i emailed who uses "three bearings" doesn't spring load one.
>he uses 3mm (4mm) alu sheeting bent to hold the bearings.. sheeting is
>flexible enough to ensure no play he says...
>i still think about loading the top bearing with 20kg spring force or so...
>
>
>but i am sure the cnc is in the "think about it before you start" phase for
>2 month or so from now...
>too much other things... but i had a look at some web pages and feel
>confident now that it is possible
>to make a good unit without a metal mill or lathe... (using angle grinders,
>drill stand, arc welding, hand tools)
>
>
>
>okay, i hope i will soon read about some progress from you guys here...
>
>i know there are better places to discuss homebrew cnc but not much else is
>happening here so please don't
>ban it steve....
>
>have a good night.... (oh yes in a couple of hours at your site but here
>it's dark outside now.....)
>
>stefan
>
>
>
>
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