Hardinge CHNC build

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03 Dec 2011 07:57 #15320 by wizard69
Replied by wizard69 on topic Re:Hardinge CHNC build
You really don't need two sets of rotary encoders per axis. Your best bet is probably to stick with the we encoders on the motors. A qualifier here would be the resolution of the auxiliary encoders. You say they are higher resolution but how much higher. The other thing is this, if the drive takes step and direction and requires the motor encoder you might not gain much. It depends on how you are driving the drive, but if the encoder is used for velocity loop closure the encoder resolution is often higher than what the drive resolves per step.

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04 Dec 2011 06:01 #15353 by justin
Replied by justin on topic Re:Hardinge CHNC build
I got one of the motors and drives in the mail yesterday and spent a bit of the day making an adapter plate to mount the new motor on the x axis. I still have to make up a few cables. The new x motor is much smaller than the original but have similar specs.

The encoders on the ball screws are 20000 per revolution, so with the .200" pitch ball screw it is equal to .00001 of axis travel.

The motors are 2048 ppr, which I believe is electrically processed into 4 times that.

Seems like having in one the ball screw would give me better positioning accuracy because it would take the belt out of the equation right?

At some speed would I exceed the maximum input frequency with 20000 pulses per revolution?

Rob the original rapids on x were 200 inches per minute, I could probably speed that up a little with the new motors but it is a small machine so I don't know how much I would gain. The z axis would be more advantageous to speed up. Having a direct mount x axis motor does make sense, I just left it as is for now as it was pretty quick work.


The VFD I have is an AC Tech SCF series v/f drive. 15hp so I run it on single phase.


I was browsing the Hardinge website and noticed there new version of the machine does use a servo to index the turret. Here is a interesting comparison..
www.hardingeus.com/usr/pdf/turning/T-416_CHNC_Compare_Final.pdf


The Ipac4 keyboard emulator is the one:
www.ultimarc.com/ipac1.html

The unique feature that this one has that the others don't seem to is you can set a shift key and the assign a secondary value to all the keys, vital on those Fanuc keyboards that only have the commonly used letters. They have a simple Windows based program for setting up the inputs and after that it is recognized as a normal keyboard by linux.



As for the leaky collet closer I was planning on contacting Dunham and see if they have a rebuild kit, probably just a couple o-rings. Adapting a hydraulic actuator would be interesting project. Converting the turret to use a servo motor seems like a major project!

Thanks for all the suggestions, I will get into the drives and motors soon enough.

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04 Dec 2011 10:03 #15357 by robh
Replied by robh on topic Re:Hardinge CHNC build
yea i dont know about chnc2 but on the 1 its an odd gear ratio so altho the old dc could do 3000rpm the gearing limits it to the 5m/min as u say. i think the 3 is quicker, as direct drive but never seen one up close but id say 2 and 1 it will easy do the 10m/min in X well mine will when its done :)

Z should already been 2:1 gear so does 10m/min they was 750w DC motors on mine would be the same on yours i say for both axis.

new turet has the servo on the side of the slid if rember right. still drives the worm and gear to index..(you can find a machine manual on there site if u google the site sorry lost the link) im just sticking the motor where air one is modded the casting and all. just need to make a shaft now to drive it all..
my buiild pics are in this section some where.. been too bussy latly to finish it..

be nice to see how your VFD runs.. the one we put on the mill which is a 7.5kw motor we find it lacks abit of torque if you put a cut on with a 50mm face mill, 3/4mm cut it struggels to drive it where the old drive would be fine with it as we have to run in V/F (Hz) mode as vector would not do the 6000+rpm
next time i think id try a yaskawa they are still in CNC game for spindle motors and drives.

be intresting to see vid when its done keep up good work
hydraulic on collet would be nice but apaint to fit it all id say as no hydraulic stuff on it.. unlike new ones that have it
rob

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