Sometime recently I read about someone who acquired an older millingmachine that had hydraulic feed on the table. I wondered about howthese tables might be controlled and if any lathes have been designedusing hydraulics to move the carriage or crossfeed instead of lead orfeedscrews. (After all, there are mechanical, hydraulic and pneumaticlinear actuators.)I don't know if you could control hydraulics as precisely asfeedscrews (with respect to headstock spindle rotation) for cuttingthreads, but you'd never have to worry about worn screws and metric/inch conversions. I imagine that the big problem is in designing thefeedback system and getting it to respond well.I've seen descriptions of hydraulic systems made by companies likeEnerpac that control the balancing of bridge sections to keep themlevel while being positioned with cranes. I know that hydraulics canbe controlled with electronics and proportional or servo valves.Probably it's difficult to beat mechanical feed and leadscrews becauseit's a simple and accurate system, but I was just curious.

We have an older NC lathe, "Sheldon Tape Lathe" that uses Moog proportioning valves.IIRC The valve needs a 0-20 mV signal to operate.Our resident electronical guru made us a pair of boards that turns +/-10V servo control signal into the signal that makes the Moog valve happy.We retrofitted using a galil dmc740 motion controller.This works great for really big iron.Unless you NEED it, I'd try to avoid hydraulic servos.

Hydraulic lathes?

Jul 31, 2008 24 Replies

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DaveB 17 years ago

I agree Anthony, no one is more surprised how well the machines we build run than me.

I went way out as far as warranty on this type machine ,not really knowing how reliable they would be both from the software as well as hardware aspect.

One advantage we have is we build it, so it makes it easier to troubleshoot and tune.

Having good heat exchanger and well filtered oil is one important issue.

Look forward to meeting you at ITMS.

Daveb

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ED 17 years ago

Interesting industrial video, but wow!! the next pic is a keeper :-) Care to share the details??? ED

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Anthony 17 years ago

snipped-for-privacy@nt.org (DaveB) wrote in news: snipped-for-privacy@news4.dslextreme.com:

A mistake in my typing......... that should have been 0.0002 mm (not microns) (0.2 microns)

I'll be at IMTS Monday and Tuesday. We all need to designate a place and time to meet up.

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DaveB 17 years ago

snicker......

Daveb

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DaveB 17 years ago

I noticed the typo....at first I thought WOW !

Daveb

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