high-speed spindles

G'luck with it.

Probably want to think about adding the cost of a small water chiller unit also.

PCS fired this volley in news:ff3d1f2c-86f9-45e1- snipped-for-privacy@m9g2000vbc.googlegroups.com:

I think a 30-gallon shallow metal coolant tank will provide enough cooling! These motors barely get warm under light loads, according to what I've read in some user-reviews.

Lloyd

- lots of info

Randy

1.5kw? as in 2 hp? Seems excessive for drilling .020 inch diameter holes in pcb's. Milling .001 inch copper sheet isn't a major job either. Maybe 1/4 hp would be adequate, surely 1/2 hp? If you run across a spindle in that range (30000, 40000, 50000 rpm), let it be known. I looking for such a beast for milling stencils in 3 mil & 5 mil brass.

Hul

Lloyd E. Sp> I need to equip my R2E4 with an add-on high-speed spindle for drilling

snipped-for-privacy@kbrx.com fired this volley in news:kk26j6$t5$ snipped-for-privacy@reader1.panix.com:

It would be, but with 2HP, I can also do high-speed milling of tougher materials, and the difference in cost between a 0.5KW spindle and a 1.5KW version is about $30.

I have not seen one in the 30Krpm range... most metal bearings get weak in the knees at those speeds, and most inverter drives top out at 400Hz, which is the rated input for these at 24Krpm.

Lloyd

What I heard about those spindles is that they are junk. But they may be cheap enough to just try out.

i

Assuming you can stand the noise (one place a "real" spindle beats the heck out of them) laminate trimmers are a typical 30,000 rpm small-horsepower unit. Routers if you need a bit more beef. I come at this myself from the "I have a CNC router and I begin to see why I might want a 'spindle' to cut the noise down" viewpoint. The deafening roar of an aircooled universal motor gets old, fast. The sparks off the brushes would presumably mean Lloyd couldn't use one, though I suppose he might have machine areas that are not in the "go boom" zone, but if he's looking at watercooled spindles I'm thinking he wants it quiet, comparatively, anyway.

Runout may not be the greatest, but the same is probably true of low-budget chinese spindles. On the laminate trimmers/routers, avoid the cheap chinese ones or you'll really regret it, IMHO.

Or, if you have large horsepower shop air and don't mind using it, use a die grinder. Kinda spendy for much long-term use in operational cost...but you can get 50,000+ rpm out of one without a sweat.

Hmm. Combine the concept of watercooling and turbine air, maybe there's some market for a water-turbine spindle - power it by dropping the well-pump of your choice (or the power you need) in a drum of water and recirculate...LLoyd could use that in the "go-boom" area, and you'd get those nice non-contact watercooled bearings. Probably imractical due to no such small water-turbine units being in large-scale production, but it's a nice thought.

Ignoramus26995 fired this volley in news:n9idnXnyK8VENvnMnZ2dnUVZ snipped-for-privacy@giganews.com:

I sorta thought that, but after posting the same in the CamBam forum, I had replies from three other guys who've been running them about 10 hours a month with not a problem for over three years. Not even bearings... and two of those guys have the air-cooled units.

FWIW, I'd consider them 'advanced amateurs', and trust their opinions.

Lloyd

Ducky has one--uses it to inlay mother of pearl and the like..swears by it..

Personally, I rather to use redhead, setco or parker-majestic.

"PrecisionmachinisT" fired this volley in news:YvidnQBOdOeJRvnMnZ2dnUVZ snipped-for-privacy@scnresearch.com:

Thanks. That would be MUCH more compact in place on my spindle nose. If I only used it for PCB drilling, I think it would be ideal.

But I wonder how one would speed regulate such a spindle for actual milling... any clues? Do they have throttling regulators for those?

LLoyd

Vey cool, but "relatively low cost" scares me. Any idea what these sell for and where?

"Pete C." fired this volley in news:51656994$0 $52165$ snipped-for-privacy@ngroups.net:

Pete, the more I look at those, the less I think they'd be well suited to milling where one must control chip loads. Although they spin to enormous RPMS, they are not speed regulated under loads.

I think they'd do fine for fragile, brittle materials where chip loads are secondary to just cutting through the stuff (like PM said... mother of pearl, or fiberglass PCB material), but wouldn't work well at all cutting aluminum.

They're made specifically for grinding, where speed is important, but tight regulation of speed not as much.

LLoyd

The 300 l/min should scare you, too! That's a LOT of air! (about

10 cuft / min., or maybe 10 Hp on a single-stage compressor.)

Jon

I've always just run that type of things wide open, save for the slight pitch change that occurs when they come under a load.

rec.crafts.metalworking Re: high-speed spindles

Harbor Freight's 1/4 inch electric die grinder was tried, first for drilling some small diameter holes in aluminum blocks and then milling solder paste stencils in 3 & 5 mil brass sheet. In both cases the results showed excessive runout, unpredicted by stationary measurements. It is a nice tool for the intended purpose though. Convient to mount also. "Grinders" have the advantage of self conforming grinding stones - if the cutter shows runout, it won't do it for long. The Harbor Freight die grinder showed little runout on a tool's shank close to the collect but, apparently, the shank(s) was not pointed exactly down the axis and an inch or two down that axis, ie at the tip of a drill, the runout was noticebly greater. Milling the brass sheet brought the same conclusions. The diameter of the endmill used is .015 inch but the width of a resulting slot was 10 or 11 mil oversize - .026 inch. Much to big a minimum size for a pcboard stencil with component pads at .025 between centers - and that's considered big; .020, half a millimeter, between centers is a common now, and headed even smaller. Porter Cable's laminate trimmer looks good as does (did) the 1/4 die gringers, but the collet design shows the primary problem. The shank is held just inside the screw retained collect cap. The collect itself contacts the shank for a length of 3/8 in. The shank typically fits into the motor shaft roughly another 1/2 in. with several thousandths clearance - suitable holding for router work on wood or with grinding stones ala the 1/4 inch die grinders, but with tiny tool work in metal it doesn't fit. Vibration is a possible explanation for some of the lack of accuracy with the die grinder - both within the grinder itself and the equipment it's mounted on. I tried Harbor Freight's 1/8 in. air powered die grinder with the thought of reducing vibration, but the runout/rattle was numerous thousanths - an air bearing maybe. Unfortunantly, Harbor Freight's horse didn't even get out of the gate - wouldn't rotate. Still, the idea of an air driven spindle is attractive. Another difficulty with using 1/4 inch die grinders for cutting tools 1/8 in. & below is the need of a tool holder, typically a piece of 1/4 inch bar stock with an 1/8 in hole for tools with 1/8 inch shanks. A little epoxy and careful holding while curing gets within .001 thou pretty reliably. However, on an .010 endmill, the size for the next effort, .001 thou is a giant. The equivilent of .050 runout on a .500 in. endmill. From here where? Go small. "Smaller tools, smaller runout" seems reasonable. This leads to 1/8 in. spindles, preferably those packaged with a driving motor, be it electric or air. A Dremel grinder next will be the next try. That tool definitely leads to less vibration and the 1/8 inch collet clears one previous problem. If threads on the Dremel's foremost part are actually 20 mm/2.5mm as appears likely from rough measurement, mounting should be simple. However, there are likely better spindles than a consumer hand held grinder for this application. If anyone knows of one that fit in along these lines, do let me know.

Hul

So you actually tried a Horrible Fright die grinder (showing a complete lack of good judgement), and damned a brand-name quality-controlled laminate trimmer without actually trying it, because in your judgement they are exactly the same?

Your reasoning is flawed. Better bearings, smaller runout. Proper collets = no need for shady adapters. Or you buy tools with the proper shank size for a collet you have. And not from HF. Not any of it from HF.

"precision rotating machinery" and "horrible fright" only go together in the manner of: Don't buy "PRM" from "HF"

Likewise, if you want a decent "thing that resembles a Dremel tool" neither Dremel nor the cheap knock-offs are a good bet. Crummy bearings.

I suspect from your choices thus far you are beyond help. Have fun.

I've been making solder stencils using the exact same process and equipment I used to make PC boards. I use 3 mil brass shim stock (I started with 5 mil, but the 3 mil works better). I wet-sand the brass to remove an oil or plastic film that prevents tarnishing. I use a hot roll laminator used for laminating dry film photoresist to PC boards to put the resist on both sides of the shim stock, using a paper shim to get the right roll pressure (as the machine is adjusted for laminating .062" PC board stock). I run the brass through the laminator twice to get both sides coated with resist.

I built a laser photoplotter some years ago, and make two master artworks, one a mirror image of the other. I glue the two artworks together, aligning them on a light table. I slip the resist-coated shim stock between the artworks and put in a vacuum frame, and expose both sides to UV. I develop in dry film developer and etch in a spray etcher with ferric chloride for about 2 minutes.

The big problem with this is figuring out the right aperture size for each pad size. I am getting this process dialed in, and the boards are coming out better and better. I do some parts with lead pitches down to 0.4 mm, which is real tricky. SO and even SSOP chips are working perfectly now, but anything smaller than 0.65 mm and I have some bridging.

Jon

When I see folks attempting or proposing accurate production-type performance with HF tools, my initial response is Are You Serious?

I know in some minds cheap is better than quality, it replaces quality with imagined performance and value. But.. some RCMers have had moderate/good success with some HF products, usually combined with a lot of time and effort.

I think it was Bob (La Blond yumabassman) that achieved a certain level of sucess with high speed milling of mostly aluminum with HF's flex shaft rotary tools. He was making molds for fishing lures on a CNC'd mini-mill. IIRC, the spindle speed was about 15k RPM.

I don't know how the new Goog groups search works anymore, I can't even get postings to display, and I dunno another way to search RCM archives.

I believe there were at least a few others that have utilized major brand name laminate trimmers for high speed spindles.