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Axis hydraulic clamping

priitm

Aluminum
Joined
Dec 28, 2014
Location
Estonia
Does anybody know the principle, how the axis hydraulic clamping works? I see only the pressure lines entering to ways. Hydraulic pump itself keeps pressure, but looks like somebody has disconnected control of the hydraulic valves. Its milling machine SINN, similar to MAHO.P1233426.jpg
 
I was once shown a nice system used on Thiel 140 or 150 manual mills.

A long small-diameter plastic tube is placed into a slot on one side of the way dovetail (or perhaps behind the gib strip). To lock the axis, the tube is pressurised with hydraulic oil. This makes the tube swell a small amount, increasing its diameter slightly. That generates pressure which pushes the gib strip against the sliding way and blocks the motion. As I recall, a hand-screw mechanism is used to generate the pressure. It's very effective!

I do not know if axis clamping on CNC machines is done in a similar way or differently.
 
Its not CNC, just a lightly used manual machine with servos for feed adjustment.Made in 1980.
I suspect that pressure element is broken and previous owner disconnected the system.If I push the valve open manually, pump starts running and pressure drops down. All three axis behave similar.
 
Bruce:
To answer your question, the Deckel CNC's control the axis movement or lac of by servo action...no hydraulic clamping. Think this is usual for most CNC's.
Position is held dynamically using the servos...When in use you can remove the cover from the tachometer commutator (connected directly to the end of the servo armature) and you can see it move ever so slightly...hunting back and fourth maintaining position.

There is a way to "lock" an axis that uses the electro magnetic brake in each servo motor.....They use permanent magnet plates that are released when the opposing plate/coil is powered....Normally the brakes are released when the machine is powered.
This allows normal servo movement via power or hand .. Lock an axis and the brake is engaged (power off)
Shut the machine off and the brakes come on...prevents the "Z" axis from creeping down ..
Cheers Ross
 
The older Maho with a P controle and Trapezium spindles use a hydraulic brake
I took some appart a long time ago
I do not remember how exactly it was But pretty straight forward
It seems sometimes people are afraid of taking something apart
In this case it looks like a few nuts removed and one can take of the holding plate on top revieling the mecanism
Simple
More time is involved in writing the initial post as it would have cost in getting the answer

Peter
 
But how the pressure is released ?
I see only lines coming from pressure side of pump through solenoid valves to gibs.
 
Yeah
What more do you need The solenoid dumps the oil in the tank Pressure is off the mecanism then No clamping then That mecanism has almost and needs almost no stroke

Peter
 
Perhaps the valve has a bleed off port that is open when the valve is off...when energized the valve closes the bled and directs pressure to the clamp mechanism....
Gotta do a little detective work here as i don't believe it is likely that anyone posting here has a similar machine...so in effect you are pretty much on your own.
Cheers Ross
 








 
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