you do need limit switches. two should be for home that is a given.
you will need to create a touch probe, but that could be as simple as a positive and negative wire, so when the 'sensor' touches the part, it closes the circuit. often a touch, back off, then a very slow feed to determine the actual location.
at that point, you only need to hit a re-set button to zero that axis.
pre-canned routines like move X axis to xx.xxx and return (or stay)
or move to xx.xxx, then to y-0.05, then return.
the micro would be the controller and drive the stepper drivers.
one way could be to move the that starting point, hit start
move to the end point, hit end
then determine the actions. end and stop or return, or move y and return, or return,move y and repeat.
that would cover slots and pockets, permitier, and reducing heights of surfaces.
just my 2 cents
--- In GrizHFMinimill@yahoogroups.com, "Yuriy K" <ycroosh@...> wrote:
>
> I hear you with the computer comment :)
> I'm a software enginer as well, but I work with higher level stuff at work (C# .NET etc.). I can do some damage with C and assemly but I'm nowhere near "hireable" in that area. I will defintely take you up on your offer :)
> In my free time I like playing with robots, so "robotocising" my mill is a natural instinct. The whole idea with spepper based power feed was justified by a "ah, what the heck, why not". :)
>
> As far as the CNC goes... I've been working on mine for a good part of 5 years. Mine will be relatively small, with 18"x18" work area, and I intend to use it mostly for plastics, circuit boards and thin aluminum (in other words, "small robot parts"). I know it won't be anywhere close to the real thing, but so far (with the gantry done and mounted to the base) it's pretty tight. I'm using 0.5"-1" thick 6061 aluminum plate for the base and most structural parts. I'm cautiously optimistic that it will handle my work reasonably well.
>
> Thank you for the feedback and the advice.
>
> Regards
> Yuriy
>
>
>
>
>
> --- In GrizHFMinimill@yahoogroups.com, "bbass408" <bbass408@> wrote:
> >
> > My teammate who I work with every day is from Moscow and just told me the pencil story last week. They even work upside down. :)
> >
> > I was just playing with my post title. I went off and read your blog and you're having some serious fun with all of this and I don't want to slow that creative flow.
> >
> > Rick's pics are going to be useful for you. If there's anything I can do to help, get back to me. I'm a software engineer during the day so all of that part is not new to me -- first job as an assembly language programmer for years.
> >
> > All kidding aside, my first response to your original post was really along the lines of "let's get the computer (any kind of computer) out of the picture if we can." That's just my opinion in trying to achieve goals of simplicity which sometimes fight feature richness.
> >
> > I have 4X4 foot CNC router. I say, "Don't do it. It's a trap!!!" :) I ended up coughing up serious coin and time on that thing and I bought most of it premade. I ended up hating that thing for so many reasons. It's been tarped for over 5 years.
> >
> > Some observations:
> > 1. If you make it yourself, it's going to be rickety no matter what compared to a 100K rig. You might be talking about 20-30 thou accuracy which I can get with hand tools on a good day.
> > 2. It's loud and dusty. Dusty is somewhat solvable.
> > 3. I love woodworking. Watching a robot do it for me was interesting for about 5 minutes then got really boring.
> >
> > But, that's just me...
> >
> > --- In GrizHFMinimill@yahoogroups.com, "Yuriy K" <ycroosh@> wrote:
> > >
> > > Well, I was told that putting "smart", "digital", "green", "organic" and "i" in the product name/description makes it sell better :)
> > > Question, though: where do I find Rick's pictures?
> > >
> > > Thank you
> > > Yuriy
> > >
> > > P.S. My boss likes to tell the story about the space race, where Americans and Sovients had to find a way to write in 0 gravity. NASA spent $8,000,000 developing a "space pen"; Soviets used pencils...
> > >
> > >
> > > --- In GrizHFMinimill@yahoogroups.com, "bbass408" <bbass408@> wrote:
> > > >
> > > > I couldn't resist that title based on the recent post and the fact that I spent so many hours on my bootleg of Rick's power feed and just finished about an hour ago. I'd happily post pics, but they look so much like his it's pretty much embarrassing.
> > > >
> > > > Rick, thank you so so much for all of your help, answers to posts, great ideas, etc. Couldn't have done it without you and probably wouldn't have even tried..
> > > >
> > > > Cost of parts: $50.00+some nuts and bolts and stuff.
> > > > Cost of new tools I "needed" to buy to finish this very important project (as told to my dear wife): Way over 500.00...
> > > > Being a lot better at metalworking than I was 3 weeks ago: $???
> > > > Watching my mill move left and right without touching that f-ing crank: Priceless....
> > > >
> > > > If anyone else attempts this, note that every thing you see in Rick's pics where things are filed or machined is almost always avoiding a bump. Everything is so close that the tolerances are in the single digit millimeters and usually around 1 or 2. I should try to post a good, measured CAD drawing of the motor mounting plate since the resulting placement is critical.
> > > >
> > > > If anyone has any questions, just ask Rick. :)
> > > >
> > >
> >
>
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