H.E.S. 24NCS Lathe (24 X 60) conversion

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19 Feb 2013 12:36 #30306 by canner
Hello and thanks for the help ahead of time.

I purchased a machine shop from a retired machinist one year ago and am finally able to get serious about retrofitting the HES Lathe. It is an early 80's machine that had the original controller, drives, and motors stripped out when I received it. The original motors had been replaced with steppers and the new controller was made by Ahha, I am in the process of stripping the machine down now and rebuilding it with linuxcnc and Mesa cards. I have several questions to start with of what I am sure will be many.

First should I continue to use the stepper motors that are on this machine? I would like to price servos but don't even know where to start, where to buy, or what size. Any help here would be appreciated.

Second the machine has separate mpg's? for both the x and z axis that use motor generators and resolvers. The previous overhaul did not use these but they are still in place and might be good (might not also). If they are good is it possible and reasonably easy to use these with some combination of Mesa cards?

Third the previous owner had purchased a new ball screw to replace the old one on the x axis and I plan on putting this in but on the z axis there is about .005 of backlash, does anyone have thoughts on if I could get rid of most of this by replacing the balls in the nut? Or if this is a good idea?


Russell

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19 Feb 2013 14:30 #30309 by emcPT
Hello.
Were are you located? Maybe I can help you with hardware.
The use of steppers or servos depends, in my opinion on the size of the machine, although servos are "always" better.
Can you post a picture of the machine?

I am in a similar process of retrofiring using also mesa cards that I already have.

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19 Feb 2013 18:47 #30315 by Rick G

First should I continue to use the stepper motors that are on this machine?


Well you have them, they are installed and I take it they work properly.

Second the machine has separate mpg's? for both the x and z axis that use motor generators and resolvers. The previous overhaul did not use these but they are still in place and might be good (might not also)


If you go with your steppers you will not need them, so if they are bad it will not matter.

Are the stepper drivers in good working condition?

Third the previous owner had purchased a new ball screw to replace the old one on the x axis and I plan on putting this in but on the z axis there is about .005 of backlash

Is the backlash the same across the entire length of the travel? Are you sure the backlash is the ball screw and not the thrust bearing?

Rick G

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20 Feb 2013 00:30 - 20 Feb 2013 00:43 #30324 by canner
emcPT

I don't have a picture that I can post right now but it is similar to the one at this website: fp1.centurytel.net/dansmachines/new_page_2.htm

Yea, I think I will go with the steppers for now and see how I like it. I am located in the Pacific Northwest, USA. Any help would be appreciated.
Last edit: 20 Feb 2013 00:43 by canner. Reason: duplicate information

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20 Feb 2013 00:41 - 20 Feb 2013 07:40 #30326 by canner

First should I continue to use the stepper motors that are on this machine?


Well you have them, they are installed and I take it they work properly.


Second the machine has separate mpg's? for both the x and z axis that use motor generators and resolvers. The previous overhaul did not use these but they are still in place and might be good (might not also)


If you go with your steppers you will not need them, so if they are bad it will not matter.



Are the stepper drivers in good working condition?


Third the previous owner had purchased a new ball screw to replace the old one on the x axis and I plan on putting this in but on the z axis there is about .005 of backlash

Is the backlash the same across the entire length of the travel? Are you sure the backlash is the ball screw and not the thrust bearing?

.

Rick G


Yes, the steppers do work properly but I worry about speed and accuracy. I do think for now I will probably stick with them though.

The resolvers are not used to report the position of the different axis's to the controller but to run the machine manually. They are not mpg's but I don't know what you would call them (maybe a manual analog generator MAG?). They work similar to an mpg in that you turn the dial and the machine moves that axis a certain amount in that direction. They would be convenient to have working but it is not make or break.

Yes, the motor drivers are working and I have several of the same model as back ups, they are about 10 - 15 years old now.

How could I determine if the backlash is in the screw or the thrust bearings? Is there an easy way to check this without the machine running?

Russell
Last edit: 20 Feb 2013 07:40 by canner. Reason: clarify

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20 Feb 2013 09:46 #30341 by jaredts
Thrust bearing endplay can be checked by putting a magnet base indicator on some fixed part of the machine and touching its indicator tip to the end of the ballscrew. Rotate the ballscrew by hand back and forth and the total indicator reading is how much the thrust bearing play contributes to backlash. With some bearing arrangements some of this can be adjusted out. You can assume the rest is ballscrew/nut or put your indicator base on the moving component (turret, saddle, cross slide, etc.) and put the indicator tip against the side of a turn of the ballscrew. Rotate the screw in both directions and TIR reading is ballscrew/nut endplay.

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20 Feb 2013 09:56 #30343 by canner
Thanks for that tip on checking the thrust bearings. In hindsight it is so obvious it hurts. I will check that out tonight.

I read a few threads on here concerning wiring in resolvers and then the Hal files to make it work. First I am going to check the resolvers to see if they are still good. I could change them to encoders easily but don't want to spend the money if I don't need to, plus it seems like there will still need to be work with the Hal file with encoders on the dials for manually driving the carriage and cross slide.

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25 Feb 2013 04:03 #30537 by andypugh

I read a few threads on here concerning wiring in resolvers and then the Hal files to make it work. First I am going to check the resolvers to see if they are still good. I could change them to encoders easily but don't want to spend the money if I don't need to,

I don't know of any cheap and good ways to read resolvers. Both Mesa and Pico make good solutions, and I am using the Mesa card on my own machine. It only works with the N x 50pin Mesa PCI cards. (5i20, 5i23. Not the 5i25).
I have a cheap (but not good) way of doing it: wiki.linuxcnc.org/cgi-bin/wiki.pl?ResolverToQuadratureConverter which might be adequate for MPG.
The Pico device converts resolver output to quadrature pulses, and that ought to work more readily with digital inputs. pico-systems.com/resolver.html
You might find it more cost-effective to swap to encoders, though.

If you were to find some suitable resolver-feedback servo motors (which seem to be cheaper, due to lack of demand, despite the fact that resolvers are more expensive and better than encoders) then the 6-axis Mesa card starts to look like a good solution.
The following user(s) said Thank You: canner

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25 Feb 2013 07:48 #30543 by canner
I have gone ahead and ordered encoders from automation direct, mostly because I don't have a wiring diagram for the old machine. I could not figure out how the motor generators connects to the resolvers and what the function was for the different pieces. I am saving the generators and resolvers, maybe they will be useful at a later date.

I have everything stripped out of the control box and am starting to remove all of the shielding and the paint. I will use a Sherwin Williams industrial paint to repraint and try to come close to the original color.

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08 May 2013 12:25 #33753 by canner
I am working on this machine again and have a question about the stepper motor drivers. The current drivers are microkinetics dr8010. I have not been able to find the information on these drives that I will need for setting them up with linuxcnc (stepon time and such). I have called the company and emailed them as well without getting an answer. if someone know that the timing requirements are for these drives that would be great. If not should I look for replacements or is there another way to figure this information out.

I could also replace them but then which drives to go with, the motors are 7.8amps so if I went with the Gecko 203v I would lose 10% of that. I am tempted because these drives have worked so well on the mill. Can anyone tell me does the morphing from microsteping at low speeds to full steps at higher speeds really make a difference? I have not found, to my knowledge, other drives that offer the same feature.

I am open to ideas on this and any suggestions that are out there for making the current drives work or replacing them.

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