Thread: Mounting motor under table?
Right, the "intended use" question.
1: PCB milling (from one extreme...)
2: Panel making for instrumentation - aluminium and as-yet-undetermined plastic, <5mm layers, mostly cutting external borders, internal holes for switches. Engraving text. Nothing intricate.
3: Small components as needed for above, odd little brackets etc. Aluminium mostly.
4: If possible, larger aluminium pieces. The "low gantry, tall Z" design is because there might be the occasional taller but narrower piece. (...to the other)
Ideally making new bits to improve the mill or make a bigger, better, shinier one!
I don't expect it to handle steel but you can flippin' well bet I'll give it a try to see what happens :naughty:
I'm hoping that I'll be able to make it stronger/more sturdy by leaving the gantry to handle Z. It also means I can consider adding a counterweight system later if I get adventurous or drunk. I have no idea if it needs one, I just always thought they looked cool. Not... ehh... a proper "technical" answer, I know
Micro stepping is good but mainly for smoothing motors.
10x micro stepping is about the max usable and beyond this is just pointless unless you have a very high pulse width which is beyond the capabiltys of the std parallel port. . . It's gets complicated so wont go there.!
Generally micro stepping should be used but mainly for motor smoothing at lower speeds IE: small tiny moves and lower rpm's but after a point micro stepping becomes an inderence more than a help and this where the drive comes into play.
A good drive will use a technique called morphing where it changes from micro stepping to full stepping along the power curve. This also brings resonance into play and why belts can help.
Poor drives without morphing and usually mid band resonance compensation can suffer from resonance issue's caused by the vibration frequency's that interfear with signal performance and affect the motors making them run really badly and sound dreadfull. . . . Belts act as a natural damperner.
Good drives like Gecko's etc use morphing and Mid band resonance damping and this really does make differance.
If you work on the principle that micro stepping works but mainly to help with motor smoothing at lower rpm's but with the side affect of slightly improving resolution ( too a point) then you wont go wrong. Just don't relay on it soley to give you the resolution you need.
Like I say the good drives do make a big difference.
Go to the Gecko site and read the FAQ section it has some good info on how morphing and micro steeping works.
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I... ahh... won't go into my original driver plans which involved a PIC and some fairly shaky ASM :whistling:
I was actually looking at the linistepper kit originally, again on the grounds that I could probably put a set together for the cost of a single Gecko in the short term. I know "short term" is a dirty word on this board, and knowing my luck unipolar motors will have a whole extra set of problems attached to them
In my experience with helping folks who have try'd to make your own drives and use oddball steppers etc becomes false economy with the end result being wasted time and money.
Good for the experience but with the same result. . Inferior performance and poor reliabilty . . ending in scrapping and buying "Proper drives an motors".! . . .BUT. . .By no means let me saying this put you off thou because it's all a good learning experience. . . Keeps you out of mischief as well. . Lol
I've got some odd steppers lying around to play with for PIC projects, though I had grand dreams of extending functionality in ways that isn't actually needed or, indeed, useful.
Steppers are far enough down the line that I'll hopefully be better placed to source better components. I plan to make up some linistepper drivers anyway, whether or not for the CNC, as there's always mischief to be gotten into!
I already mentioned about microstepping accuracy (or rather lack of) in post #15...
One thing I'm going to try and do with my stepper driver design is make it effectively run using microstepping, for smoothness, yet only require the number of pulses for whatever microstep division you choose. Effectively it will move through each of the microsteps for every step pulse.
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