Originally Posted by
hanermo
Industrial machines have a typical basic accuracy of 0.0001", or 2.5 microns, plus or minus.
== 5 microns max error.
Haas, leadwell, all of them..
This is *easily* achieved by
1. making the machine rigid enough,
2. using ground screws and servos
+/- 2.5 microns is easy.
+/- 1 micron is easy.
Manual machine have done this 40 years ago. Jig grinders. Whatchmakers jig bores. Sip. Secondary offsets adjust for screw error (from early 1900s). etc
The screw accuracy is critical.
But..
its expensive, in terms of the screws.
Today, secondary feedback via glass scales makes 1 micron accuracy easy, and relatively cheap.
Its very rare, and I dont know anyone who has it running.
About 2k€ for controller, 2-3k for scales.
I will do it, on lathe, but my lathe is very expensive, by most users standards, about 8 k€ wholesale just in parts (10k € retail).
My industrial csmio-ip-s controller supports it (mach4), but most dont.
2.5 micron machine accuracy+resolution is NOT machining accuracy of 2.5 microns.
It means potential accuracy to 2.5 micron (or better).
Methods and technique matter quite a lot, after 0.01 mm or 10 microns.
Best-in-class VMCs, like Mori Seiki DCG machines, can machine a round hole to 0.7 micron TIR or roundness, about 7x better than 2.5+/-.
Best lathes, like Moore Nanotech, do a round nickel ball to 0.3 microns, with 0.01 micron glass scales and linear drives.
My lathe retrofit has about 1 micron or better incremental resolution, using 0.2 micron step sizes (w ac servos).
This means I can makes features with 1 micron features.
Its not the same as accurate to 1 micron.
Ie I can make a graduated pin with 1 micron step sizes.
Say 50.000 mm D with 5 decreasing steps.
I wont know in advance, if step 1 or 2 is 50.000 mm.
But I DO know the steps themselves are 0.001 mm, and one of them will be 50.000.
Using tests, trial and error, I could make any nr of pieces with the exact same 50.000 size.
Via probing and references to known-good standards, like gage blocks, or gage pins, or setting ring gages, etc.
This is not a machine "accurate" to 1 micron.
(It will be, if the scales work.)
Its using manual techniques and leveraging automation to deliver highly accurate results.
Commonly stated temperature etc stuff is mostly (or partly) hookum.
Mostly, its very hard to make large parts very accurately.
After about 200-300 mm or 14" or so, it gets very hard, very fast.
Hand lapping, or adjusted/applied to homebrew cnc, can get there, and better, with the right technique, but its nothing to do with Moore Nanotech.
Hand work (or cnc-hand work) can do 0.1 microns easily.
Most accuracy stuff to 1 micron is FUD.
I expect to make ultra precision leadscrews on my lathe, for sale ie commercial, at some point soon.
So far, 100k€ in current stuff and 10 years/15.000 work hours, and I am getting there.
Spindle rebuild or c axis was 200+ hours.
So far, z axis rebuild is == 300 hours, and maybe 3-10 hr to finish (version 2) to working state.
My ground screw (used) was crap. 100 hours wasted.
No pics atm- sorry.
Commercial reasons.
For example, I use a 2 cm thick tool steel plate at the back of lathe, to connect to saddle.
200x300x20 mm == 16 kg.
Z axis coupler mount plate = 250x200x50 mm = 20 kg.
Ie its 2 inches thick tool steel.
Also, for example on the mill, "capacity" or "strength" is 50 tons metric, for 500 kgf force or 2 kW spindle power.
50:1.
Accurate machine = rigid = much stronger than stress used.
Ie mill is 50x stronger than stress, as that => accuracy.
Mill uses 35 mm rails, and overconstrained, 12 blocks, of 4000 kgf each.
You need to vastly upgrade your expectations re: strength/rigidity.
By about 20x.
Smile, grin - So did I, way back when.