Hardinge CHNC retrofit- Another one on the way!

Another Hardinge retrofit, this time it’s a older Chnc. This is my first retrofit, and I was originally planning on doing an even older hardinge Ahc. However I ended up winning a eBay auction for a Chnc that should be much easier to retrofit. I paid $525 for the lathe, 3 control cabinets and a hardinge bar feeder. Shipping however kind of soured the whole deal, I ended up getting the lathe shipped from Ohio to Reno Nevada. Total for the lathe with shipping was around $2k. I should of just left the control cabinets in Ohio, as none of them start, just dead weight, lol. Luckily the lathe came with a lot of documentation, I have all the schematics for pretty much everything.

I plan to retrofit the lathe using linux cnc in 2 stages. Stage 1 will be to get the lathe working using the original Hi ack servo amps and spindle motor. Stage 2 will be retrofit to 1.5kw ac servos for x and z, and 4kw C axis spindle. I have already tested the x and z axis amps with a AA battery and they seem to work good, the z axis smoked a few isolation caps, but still works. I will be replacing the caps as soon as Digikey ships the replacements. I have yet to test the spindle motor. I think If I understand correctly I need to force on the spindle brake relay, to release the brake, and then I need to ground the Inhibit pin to be able to test with a battery.

I will be using the Mesa 7i33, 7i37 and anything io 5i20 cards for control. I still need to find a good motherboard and processor for the panel pc. Will be doing a 5 wire restive touch screen with a 15 or 17 inch monitor for pc interface. I think I will be replacing the resolvers and tach with a Us Digital differential 2500 ppr encoder , since It will be cheaper than the resolver converter boards on the market. The only problem I see with that is the current amps have a 6v tach signal feedback, and I don’t know if the Us Digital encoders can provide 6v tack signal. I’m not sure if I even need the tach feedback at the amp?


encoder link

usdigital.com/products/encoders/incremental/rotary/kit/EC35

Red is where the tach feed back is at the amp, that terminal block is the amp input terminal.

it's a pretty straightforward machine to convert , Mesa do a resolver and analog servo conversion that will suit the resolvers , far easier than replacing the resolvers erc
you'll need a lot of IO , but over all not a bad machine to convert .

i'd go with using the existing drivers , nothing wrong with them if they are working , it's a major job to replace them .
the majority of problems with the older electronics are as you have found dry'd out caps , but once you replace them with more modern ones they run fine .

some spindle motors do not have the brake fitted .
check out all the axis and the spindle motor using a 3v dc battery supply , theirs an actual test circuit in the manual using a pot , which works fine too .

The Hiacks you have seem to have had the top boards replaced,as the originals were not dark green,they are a brownish yellow.I have a Hiack manual with schematics if you need a copy.They are easy to fix.They are a velocity amp and do require tach feed back though and by todays standards are not very effectent. The spindle motor is a dc brush motor made by porter peerless.They still support their product.Dont even try to get Ge or AB to help you,as most of they guys who knew that stuff are long since retired and GE will charge you 185.00 an hour for support!!.


The only real differences between a chnc and an hnc are the hnc had a GE550 NC control and a mechanical variable speed spindle drive.The chnc had an AB 7370 true cnc and a servo spindle drive.The chnc was more expensive.My sources tell me the AB is a bear to keep running and that Hardinge wanted a low cost control from Ge and the only thing ge had at the time was the then outdated,but rock solid 550T.The full size 1050t was to expensive and the 1050h wasnt available yet.Hardinge did use the 1050H on HLX machines ,but I have heard they didnt intregrate it very well and they had problems.

I saw the same machine on ebay and almost bought it,didnt have the room!!!

hey J.R.


would you be interested in telling me how you tested your axis drivers

mine look the same as yours but my lathe is a little different, instead of the control being behind the lathe it is connected by braided cable/conduit I am in the process of trying to upload photos.

they are hiak and are mounted in the large control cabinet. I would like to test them before deciding whether to replace them



thanks


bob

I like the idea of reusing the resolvers simply for the ease of it. I was a little worried about the compatibility, so I did a little surfing the interwebs as well as disassemble a resolver. Found out that the tach is a servo tek dc generator producing 20.8v/ 1000 rpm. The axis resolvers are Harowe servo corp part number 11BRCT-300-F95A/5-01, and the spindle resolver is 11BRW-300-F58A. I circled them in the photo below.

The resolver is kinda a strange duck, Hardinge mechanically geared the tach and resolver up 5:1 vs the ball screw. I think this was done to increase the accuracy of the machine. because of this I am not sure about how emc or the 7i49 will handle the resolver imput. I assume that emc will be able to scale the 7i49 output to correct for this? Also its not clear if the 7i49 can output 12v to power the harowe resolvers or not? I guess they could run on a lower voltage however I think I would loose some fidelity. I think I may call mesa tomorrow to discuss. If the 7i49 will work, then I think thats the route to go.

JR1050 I would apreciate a copy of the Hi acks schematics, would help me alot since I will be maintaing them. As for the spindle motor, it is a very large dc motor, which got me thinking, I wonder if it could be rigged up as a true C axis using emc?

The Allen bradley 7300 series controlls are huge, I had 3 shipped with the machine, they weigh around 300 pounds each and are 3ft x 3ft. I tried all 3 on the machine, none worked, however I did get a free fire works show when the tantalum caps explded on one . They are on Ebay now. I didint have room for the machine either, I had to sell my Ahc to make room. I bid on it casually, didint think I would win, .

I scrapped the Hiacks in favor of AMC 25a20's for two reasons,the hiacks were huge and I didnt have the room and they used tachs which required eithier reusing the resolvers or buying super expensive encoders.I have Hiack amps on my B&S mill and if memory serves me,you will have to jump the contactor and pull the inhibit pin low,I cant remember which pin it is, H or J ?Then you can put a battery on the inputs on the amps,I use a size aa...

I have another hnc and like the idea of using the resolvers,but then i need a resolver and encoder board(u need an encoder on the spindle).I can scan the Hi ack book.send me your email and Ill try to get it done in the next couple days.Yes,you could use the spindle as a c axis.The pitch on the screws is .200,not 5mm...I surfed all day,Im beat....

On the attached schematic, I jumped pin E to pin B to disable feed hold. next you just need to apply a voltage to pin H, with ground at pin G, to move the other direction reverse the polarity. I used a AA battery with some wire taped to the ends. You might want to remove the drive belts from at least the x axis for safety reasons. By doing this you are effectivley forcing the motor on. The slides will not respond to the limit swithces so you can crash the axis into its end of travel if not carefull.