Well its been a haul for this old guy but now that the project is as done as I need it to be, here are some thoughts on the process as well as some images of the machine and my first stab at a wiring job. I learned so much!
Machine: Anilam controlled Eagle Knee Mill 1996-ish with Baldor Brushed DC axis drives, Baldor spindle with variable belt and high low range speed control.
Goal: Make it live again!
Mostly I am writing this to those of you looking to jump into a project for the first time. I hope you will benefit from knowing my mistakes. For those of you with experience, I write for your entertainment and to elicit your comments for the further benefit of the plebian cause. For perspective, I am a retired machinist, university mechanician (look it up), IT wonk, project manager and have never done anything like this retrofit. I am presently working out of a larger shared industrial work space in Oakland CA. We have about 25 folks in there of many different skills and crafts. From electrical, electronic and welding engineers, to cabinet makers, artist and entrepreneurs. Quite a fun place to tinker.
So, to start I'll tell that the previous owner's effort to rebuild this machine's control was interrupted by life. He was going to install a PMDX control with Gecko drivers (under powered for the 140V DC servos) and a VFD all of which came with the machine, plus tooling and a couple of vises. I determined early on that the PMDX configuration was not going to work for me. I was aware of Centroid as a possible solution and after coming to know how vibrant community support was by their forum I was sold. It did not take long to know that the AllInOne board would do the trick, if at all possible, and by the looks of it be within my ability (*!*).
Just getting the machine to the shop was a rickety affair, $500 to $3000 were the estimates. I went with the $500 moonlight special, a couple of pod movers with a small tractor trailer rig and one of those tri wheeled truck mounted fork lifts which, it turned out, required that the mill be placed on a pallet for the lift on to the truck. No problem getting it on to the pallet they had but that pallet was sub-optimal for that 2000 to 2500 pound knee mill. All strapped down it appeared ok just sitting there but once we started moving I was biting my nails following them as it bounced and swayed on top of that rickety ass pallet. I am certain that if the CHP saw that set up they would have pulled them over. Fortunately they were all asleep on that Sunday morning. Hair raising was the ride but we made it to the shop and nobody got killed.
I paid $4500 for the machine and was very glad that last part of the job was done. In retrospect, considering what it took for me to finish the machine, time and otherwise, I would not pay that again. Further, there were some basic things I should have done before I wrote that check, like doing drive motor wiring continuity and function checks. I did not do that but got lucky, all drive motors were sound. Testing for backlash was another easy check I could have done. Fortunately Z and X were just under and just over the Centroid recommended maximum of .001. Unfortunately the Y on the other hand was, and still is, .0036 and sub par. I'm 95.23% certain that the ball nut / screw relationship is the problem. I am looking into options and fixes there and might be able to adjust out by the looks of this old ball screw set up. If in the end I have to replace the ball screw and nut, so be it. Attached is a picture of the nut and screw. If you can tell me what that black hex soc head does I'd appreciate it. Retainer for ball bearings? Tension adjustment? Can't really get in to see much more, certainly old school by the looks of it.
It would have been nice to put power to the spindle as well. What a racket it made on eventual power up. Turned out to be a lack of grease. I put grease to the two zerk fittings and it got pretty quiet comparatively speaking. (Is there a belt dressing for the vee belt speed control or are they just inherently noisy?) Probably with those checks and knowing what I know now I would not have paid more than 2K for the machine. Lessons learned were numerous.
Okay now, I roll up my sleeves. The time line might be nice to know. The machine as delivered to our shop June 2019 and I immediately took off for the summer not really getting to it until late November when it occurred to me that I actually had to get to work on it if I ever wanted to see a return on my investment. That is when I started to look at Centroid and my options there. It was really the boost I needed seeing all the support offered and so generously. I guess by January or so I had spent enough time studying the Forum and Centroid manuals, tech bulletins etc that I knew enough to go ahead and buy the AllInOne.
After more lurking on the Forums and watching nearly all of Marty's videos I finally got to the bench testing by March. (Hey! I'm retired, somethings got to give if you don't get up until 9 and really don't have to go to 'work' right?). By that point I fully realized just how little I knew and how much one needs to know to get a project like this done. To illustrate I really did not understand the basics of DC motors, AC motors starting, overheat relays and do much more. On top of that I was super cautious with all the wiring, checking and checking again and triple checking in the end. I'd never studied or for that matter worked off a wiring diagram such as are needed to wire up the AllInOne. If I can do it your can too but man you got to focus, know and frankly remember a lot of stuff, a little tough for my old brain.
Next was the actual installation at the machine. That all went fairly smoothly. I was able to use the old flex cables and had to move a few wire ports around but after a bit and a couple of Forum queries I was confident enough to power it up. The travel calibration with gage blocks and limit testing all went well however I am likely to revisit both on all axes with a better test indicator. Mine was okay but not calibrated itself so I am investing in a Interapid soon.
About mid August I was starting to call it good enough. A few things I ran into along the way now. The wiring of the encoders through me for a loop. I screwed up royally there. Tried to use mechanical connectors at the board not thinking I had the soldering skills but they really don't fit. Turns out I am actually pretty good at soldering those DP9 connectors after all, just not at reading the schematic and knowing the pin numbering. After a couple of tries and again Forum support I got it all working. I highly recommend first timers use the Centroid prewired cables. It would have saved me hours of grief.
I got lucky with the encoders themselves. After much thinking about it I devised a plan to use the motor end caps to support the encoders. It was a solution that required drilling an access hole into the wiring port mount so that you could tighten the encoder set collar set screws to the motor shaft. I stuffed a bunch of rags in before I drilled and tapped for the access plug and vacuumed thoroughly after. The encoder itself is positioned and held using centered standoffs from the inside of the cap.
In the miscellaneous stuff department I ended up using a small form Dell PC Inside the control box. I might hang it from the door at some point... I ordered a panel mounting thumb drive for that convenience but not sure yet that we will be using the DXF functionality as of yet... The plug in MPG is a great add on, highly recommend it... Made a few parts for one of the shared space denizens. They were to spec and looking good... Oh yes, I was going to use the VFD that came with the machine but after failing to get it to function I decided to go with the hi / low ranged and belt controlled spindle. I used to use Trak Mills and got a lot of mileage out of them in spite of having to use manual spindle speed control. For prototyping and one offs it is great for managing chip load...
Dunno what more I can say other than to repeat praise for Centroid and the members of this forum. Use it!
Use their stuff! Works great!
Those In-The-Know: Please have a look at by report and let me know what you think. Hope I did not miss anything too important.
Anilam Eagle Knee Mill - Oakland CA
Moderator: cnckeith
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Anilam Eagle Knee Mill - Oakland CA
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- Location: Mesa, AZ
Re: Anilam Eagle Knee Mill - Oakland CA
Congratulations on completing your build and sharing the journey. Its the best way to give back for the help you received. It will inspire others to consider doing the same thing.
I can't agree with you more. Spending the money on prewired encoder cables should be considered. Its the right cable, and the DB9 connectors are preinstalled. Use Encoders supplied by Centroid and the other end plugs right in.
I hope you took notes and made sketches of your electrical system. You might need them in the future.
Hope it gives you lots of service.
Marty
I can't agree with you more. Spending the money on prewired encoder cables should be considered. Its the right cable, and the DB9 connectors are preinstalled. Use Encoders supplied by Centroid and the other end plugs right in.
I hope you took notes and made sketches of your electrical system. You might need them in the future.
Hope it gives you lots of service.
Marty
Reminder, for support please follow this post: viewtopic.php?f=20&t=383
We can't "SEE" what you see...
Mesa, AZ
We can't "SEE" what you see...
Mesa, AZ
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Re: Anilam Eagle Knee Mill - Oakland CA
thanks for posting! nice work!
Need support? READ THIS POST first. http://centroidcncforum.com/viewtopic.php?f=60&t=1043
All Acorn Documentation is located here: viewtopic.php?f=60&t=3397
Answers to common questions: viewforum.php?f=63
and here viewforum.php?f=61
Gear we use but don't sell. https://www.centroidcnc.com/centroid_di ... _gear.html
All Acorn Documentation is located here: viewtopic.php?f=60&t=3397
Answers to common questions: viewforum.php?f=63
and here viewforum.php?f=61
Gear we use but don't sell. https://www.centroidcnc.com/centroid_di ... _gear.html
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- Location: Minnesota
Re: Anilam Eagle Knee Mill - Oakland CA
Check the backlash of the Y at each end of the travel and the middle. If the backlash in all three positions is close to the same (less then .001) then the nut and screw are in good shape and only the balls are worn. This is actually by design, the balls are suppose to be the sacrificial part. If that is the case, you can simply "reball" the screw for $20-30 worth of precision balls.Fortunately Z and X were just under and just over the Centroid recommended maximum of .001. Unfortunately the Y on the other hand was, and still is, .0036 and sub par. I'm 95.23% certain that the ball nut / screw relationship is the problem. I am looking into options and fixes there and might be able to adjust out by the looks of this old ball screw set up. If in the end I have to replace the ball screw and nut, so be it.
Go here: https://www.precisionballs.com/?gclid=C ... QzEALw_wcB
Measure the balls you have and get some that are appropriately larger based on your measured backlash.
I have done this and it took my backlash from .0040 to .0005 for $11 vs $1500 for a replacement ball screw assembly.
I hope this helps,
Tim
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Re: Anilam Eagle Knee Mill - Oakland CA
If you can get an indicator on the machined end of the ballscrew, then you can check for axial play as you jog the axis in alternating directions.
If you see a significant change in the average indicator reading jogging plus vs. minus, then the issue is with the support bearings, and not with the ballnut.
This is worth checking before you pull the ballscrew out and start replacing balls.
If you see a significant change in the average indicator reading jogging plus vs. minus, then the issue is with the support bearings, and not with the ballnut.
This is worth checking before you pull the ballscrew out and start replacing balls.
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- Location: Minnesota
Re: Anilam Eagle Knee Mill - Oakland CA
Yes, I should have mentioned that. In the case of the Analam Ball screws, if they are like mine, there is a shim that preloads the tapered roller bearings that you can change.cncsnw wrote: ↑Mon Sep 21, 2020 3:16 pm If you can get an indicator on the machined end of the ballscrew, then you can check for axial play as you jog the axis in alternating directions.
If you see a significant change in the average indicator reading jogging plus vs. minus, then the issue is with the support bearings, and not with the ballnut.
This is worth checking before you pull the ballscrew out and start replacing balls.
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