Hi. Newguy's first post outside the "introduce yourself" forum here.
I signed up here at H-M because this is one of the few places where google turned up semi-recent discussion of Proxxon rotary tools among people who may actually know what they're talking about. I'll get to questions after all the blah blah here, I promise.
I'd like to CNC mill circuit boards for fine-pitch surface-mount parts, which means something like <0.2mm/10mil wide cuts through <0.05mm/2mil copper plate on hard plastic. And other small CNC fun. As an arbitrary challenge, I'm spending time instead of money trying to do it with a repeatable design of least cost hardware including a general-purpose rotary tool.
I've worked through a few iterations of a little machine that actually does pretty well -- when I get lucky to chuck a 0.1mm Vbit with sufficiently small runout in not-very-repeatable Dremel or dremel-like collets.
With runout randomness as the limiting factor, I broke from the 'least cost' rubric and bought a PROXXON IBS/E rotary tool for the advertised <1mil runout (at the collet). From Amazon, who handle returns/exchanges generously. I'm about to return the third one.
The first one did exactly what I spent the money for in terms of repeatable low runout. That was great for cutting the copper plate and I was very happy with that. But it had ~0.2mm/10mil axial free play, which compared poorly with cheaper tools and became a factor when milling in material vs. thru plate. I traded a few emails with a Proxxon rep who didn't have a spec for axial play. After finding one report of 0.1mm play after long use, I exchanged that unit hoping for better.
The second unit had less axial play, a little under 0.1mm. Still worse that cheaper tools, but I think I could live with it in trade for small runout. But runout was poor, about 3 mil at the collet and 2-3x worse at the tip of a short bit. So I exchanged again.
The third unit had axial free play similar to the 2nd and less runout than the 2nd but not better than cheaper tools and nowhere near the dead nuts first unit.
I had 2nd and 3rd both in hand for a while before returning the 2nd, so I could swap and compare parts. According to a somewhat crappy dial indicator in inexpert hands, all the collets within each set showed similar runout, and runout followed the collets not the main units when swapping. I didn't have anything to chuck in the smallest collet of each set to measure those, but the holes thru the butt ends of those two collets were _obviously_ off center. They were also bigger diameter than the collet jaws so that wasn't necessarily bad but it didn't seem very German.
So I thought maybe the stock at Amazon had a bad run of collets and asked Proxxon who sent me another 3.2mm collet to try -- which I hoped might come from someone's desk drawer or otherwise not from the same production run. That still wasn't great - about same as with the collet that came with the 3rd unit.
And, ironically, because the Proxxon collets have better repeatability, that's worse than a random collet that's occasionally close enough.
So this one is about to go back, prolly as a return without exchange.
Really? Is this par for the course with Proxxon IBS/E tools?
Was the first one a lucky freak that I should have treasured?
If I give Amazon half a year to cycle stock, or try from another source, should I expect better or more of the same?
Curious to compare notes...
-Paul
I signed up here at H-M because this is one of the few places where google turned up semi-recent discussion of Proxxon rotary tools among people who may actually know what they're talking about. I'll get to questions after all the blah blah here, I promise.
I'd like to CNC mill circuit boards for fine-pitch surface-mount parts, which means something like <0.2mm/10mil wide cuts through <0.05mm/2mil copper plate on hard plastic. And other small CNC fun. As an arbitrary challenge, I'm spending time instead of money trying to do it with a repeatable design of least cost hardware including a general-purpose rotary tool.
I've worked through a few iterations of a little machine that actually does pretty well -- when I get lucky to chuck a 0.1mm Vbit with sufficiently small runout in not-very-repeatable Dremel or dremel-like collets.
With runout randomness as the limiting factor, I broke from the 'least cost' rubric and bought a PROXXON IBS/E rotary tool for the advertised <1mil runout (at the collet). From Amazon, who handle returns/exchanges generously. I'm about to return the third one.
The first one did exactly what I spent the money for in terms of repeatable low runout. That was great for cutting the copper plate and I was very happy with that. But it had ~0.2mm/10mil axial free play, which compared poorly with cheaper tools and became a factor when milling in material vs. thru plate. I traded a few emails with a Proxxon rep who didn't have a spec for axial play. After finding one report of 0.1mm play after long use, I exchanged that unit hoping for better.
The second unit had less axial play, a little under 0.1mm. Still worse that cheaper tools, but I think I could live with it in trade for small runout. But runout was poor, about 3 mil at the collet and 2-3x worse at the tip of a short bit. So I exchanged again.
The third unit had axial free play similar to the 2nd and less runout than the 2nd but not better than cheaper tools and nowhere near the dead nuts first unit.
I had 2nd and 3rd both in hand for a while before returning the 2nd, so I could swap and compare parts. According to a somewhat crappy dial indicator in inexpert hands, all the collets within each set showed similar runout, and runout followed the collets not the main units when swapping. I didn't have anything to chuck in the smallest collet of each set to measure those, but the holes thru the butt ends of those two collets were _obviously_ off center. They were also bigger diameter than the collet jaws so that wasn't necessarily bad but it didn't seem very German.
So I thought maybe the stock at Amazon had a bad run of collets and asked Proxxon who sent me another 3.2mm collet to try -- which I hoped might come from someone's desk drawer or otherwise not from the same production run. That still wasn't great - about same as with the collet that came with the 3rd unit.
And, ironically, because the Proxxon collets have better repeatability, that's worse than a random collet that's occasionally close enough.
So this one is about to go back, prolly as a return without exchange.
Really? Is this par for the course with Proxxon IBS/E tools?
Was the first one a lucky freak that I should have treasured?
If I give Amazon half a year to cycle stock, or try from another source, should I expect better or more of the same?
Curious to compare notes...
-Paul
