Kitamura MyCenter 1/485 - ground up rebuild and retrofit

Ive been updating my build log on another forum and figured you guys here at the zone might find it interesting. Ill summarize my posts on the other forum in this single post and then continue to update. The project started approximately a month ago. I hope to wrap up by the end of the year.

10/29/18
I picked up a Kitamura MyCenter 1/485 this past weekend and moved it into my garage for a full retrofit before moving it to my shop for permanent use. Working on it at home rather than at work should hopefully give me less distractions and a much faster turn around time.

As the machine sits today. We had to remove the enclosure for transport:
https://i712.photobucket.com/albums/...a/IMG_0738.jpg

The machine has the following specifications:

Fanuc 0M control

Fanuc red cap servos all around @ approximately 1.8kw per axis. Spindle motor is a 3.7kw continuous, 5.5kw 30 minute rated servo.

13k rpm spindle with air oil lubrication and refrigerated oil cooling.

Box ways

16 tool ATC.

Plans for the rebuild and retrofit:

Strip down to core components for paint stripping and then repaint with a 2k urethane. Ive great luck with a Sherwin Williams product previously and will try it again on this project.

Spindle rebuild with grease packed bearings to eliminate the air oil system and chiller. This is possible thanks to new greases and a switch to steel ball angular contact bearings as opposed to the existing ceramic units. This aids in thermal transfer of heat out of the spindle.

Way inspection and repair. If there is any bad Turcite bonds theyll be replaced with Moglice. Ive used this previously with fantastic success.

Swap ATC geneva drive to a servo and belt system to speed tool changes.

Centroid Oak board with ADD1616.

Complete replacement of servo drives and motors. Spindle drive and motor will also be updated with a true servo spindle and drive as opposed to a VFD.

10/29/18

Got the way covers, axis motors, and spindle cartridge off. No plates on the motors but manual lists them as 5M series. I’ll start sizing motors soon and ordering replacements.

I can only assume the machine was used with straight oil as coolant. The chips are held together like syrup under the way covers. What I can see of the ways so far looks to be in very good condition.

https://i712.photobucket.com/albums/...32D9773E35.jpg

10/30/18

I got the motors sized. Originally the 5M motors on the X and Y axes produced 0.9Kw and are 2000rpm. The Z was a 10M motor which produced 1.8Kw and was also 2000rpm. The X and Y motors are 130mm frame size and the Z is a 180mm frame size.

In order to make the retrofit as simple as possible and eliminate the need for motor adapter plates and odd sized shaft to ballscrew couplings I've chosen motors with the same frame sizes. What that means, however, is that the motors will be oversized. The new X any Y motors are 1.5Kw units, and the Z is a massive 4.5kw motor. Just goes to show how much servo technology has progressed in the last 32 years. Over sizing the motors isn't the best practice from an energy consumption standpoint. Typically the inertia mismatch of a motor to load should be 10:1 or better. Im now well under the 10:1 ratio and should have good performance. The new motors are a bit faster RPM wise and so rapids may increase by 20%.

The original spindle motor is 3.7/5.5kw (S1/S6 ratings). The new motor is 4.0/6.0Kw. A little extra umph which given that the machine is stout as a tank wont be a bad thing. I assume the BT35 taper will be the limiting factor as far as speeds/feeds are concerned.

Axes drives run off of single phase 220. Spindle runs off of 220V 3 phase. Motors and drives will be ordered tonight. Ill post pictures as soon as they come in. Will likely be a few weeks.

I picked up the paint today. Its a 2 part acrylic urethane. Goes under the brand AIC, but its manufactured by Sherwin Williams. The system consists of a base, hardener, and reducer. When mixed together they begin to harden. Pot life is somewhat short but full cure is under 24 hours in balmy Arizona and the end result is a tough and durable finish resistant to chemicals.

Tonight Ill begin gutting the electronics cabinet. As far as I can tell the current electronics are mounted straight to the enclosure. Ill probably tig weld some standoffs in the enclosure and mount a removable subpanel which will make wiring much easier.


Electrical cabinet before and after. Some pretty nasty stuff in there.
https://i712.photobucket.com/albums/...9F906CE877.jpg

https://i712.photobucket.com/albums/...F99C3E9872.jpg

11/06/18

Making good progress on the tool changer assembly. All the parts have been cleaned and primed and will get a coat of paint. The only remaining part in need of priming is the umbrella itself.

I took some time to model up the existing way covers for the x axis in CAD. They’re made of fiberglass and after 31 years aren’t in great shape. Why they made them out of fiberglass I don’t know but I get the impression they handed this part of the machine over to the new intern with a Fiero obsession.

I welded up a replacement cover today to test fit. Works well. I’ll finish up the other side and the telescoping parts tomorrow.
https://i712.photobucket.com/albums/...093D54F249.jpg

https://i712.photobucket.com/albums/...8CFA7A3705.jpg
11/09/18

All of the ATC parts are cleaned and primed. Will paint them this weekend. The spindle is starting to come apart for a whole new set of belleville springs and all new spindle bearings. Ill post photos of that soon.

In the meantime Ive ordered all the necessary parts for converting the ATC umbrella to servo drive rather than geneva drive. I couldnt find a HTD pulley the right size with the correct hole patterns, so I made one. See below:
https://i712.photobucket.com/albums/...a/IMG_0789.jpg
https://i712.photobucket.com/albums/...a/IMG_0791.jpg

11/11/18
When I was initially taking the head apart I noticed the spindle bearings didnt sound great. The noise plus my dislike for the ancillary cooling and lubricating equipment convinced me to take the spindle apart for a rebuild. This weekend I got the spindle apart to clean and inventory the parts. I have new bearings ready to go in and will tackle that next. The bearings were definitely contaminated with both dirt and water at some point. The top bearing was the worst, being the least protected and the machine not being cleaned well. I think a lot of material sat on top of the spindle for a long time collecting dust and coolant sludge. The lower bearings seemed to be in ok shape, but weren't ceramic as the parts manual suggests. They were likely replaced at some point but from what I can tell about the markings on the bearings, they weren't replaced at the same time which means one of the bearings has likely been in and out a few times. This is problematic from a cleanliness standpoint and also that the bearings arent a matched pair. Most P4 bearings are going to be very tight on tolerances so buying a matched set isnt super critical. In any case, both bearings came out.

The drawbar was next and, as you can see in the photo,s was quick a shocker. 10 or so of the 131 belleville springs were completely shattered. Im glad I took the time to dig this deep now. It would have been a let down to have poor finishes right out of the gate once the machine is running. Without a legit drawbar force tester finding the problem could have taken some time and led me down some wrong roads. New springs have been ordered. McMaster of all places ended up being the least expensive. Ill be replacing the whole stack.

https://i712.photobucket.com/albums/...98E915B905.jpg

https://i712.photobucket.com/albums/...a/IMG_0809.jpg

https://i712.photobucket.com/albums/...98E915B905.jpg

11/12/18

Tonight I got the spindle spotless and ready for rebuild. Part of that process meant lubricating the bearings. This spindle has two angular contact bearings up front and a cylindrical roller bearing at the rear. Its very important to get the proper amount of grease in each bearing. I learned all I could from this resource:

https://highspeedtechnologies.com/how-t ... gs-part-1/ (This is just the first of six parts, all of which can be found on their blog).

If you're interested into what goes into rebuilding a spindle this is a good primer. I spoke with the manager on the phone a few weeks ago for some input and they were very friendly.

I bought some Kluber Isoflex 15 online. I think the 50g tube was about $35. You can see in the photos I sucked the proper quantity for each bearing into a syringe. You can buy a prefilled syringe from Barden if youre so inclined.

For the exact quantities for each bearing I referenced NSK's documentation about greasing high speed spindle bearings. For the two front angular contact bearings I needed 1.7 cubic cm each. For the roller bearing I needed 1.4.

The bearings are now sealed in bags to keep them clean until installation.
https://i712.photobucket.com/albums/...ra/RY59HRQ.jpg
https://i712.photobucket.com/albums/...ra/R10DQ9S.jpg
https://i712.photobucket.com/albums/...ra/R07LURN.jpg
https://i712.photobucket.com/albums/...ra/RTKC7S7.jpg

11/13/18

I got the spindle back together today! Actually was a lot easier than I anticipated. I stuck the main shaft in the garage freezer all day. The bearings just slid right over the shaft with the perfect amount of friction. The cold shaft chilled the bearings by the time I got the sliding the whole assembly in the housing. Slid right together and spins just incredibly. I also got the bellevilles in today and coated them with anti-sieze. Loaded the drawbar up and it popped right in.

Of course, this is no guarantee itll pass the break in procedure but everything is well lubricated, well fit, and very clean (dont let the wear from 31 years of hard use fool you. I could eat off of this thing) Here's hoping. I got a thermometer unit with dual thermocouples. One will go at the top near the roller bearing and the other will go at the nose close to the angular contact bearings. The idea is that you increment your way up to full speed in 500RPM increments, waiting to increase at each level until the temperature of the bearings plateaus and then dips. Once it dips, you go up another 500RPM. This was supposed to be a 13k rpm spindle. Ill be happy if I can get it up to 9-10 which is probably prudent with the switch to grease and dropping the chiller.

https://i712.photobucket.com/albums/...ra/R3QCBR6.jpg
http://i712.photobucket.com/albums/w...ra/RZZHD9V.jpg
http://i712.photobucket.com/albums/w...ra/RXGJ2P5.jpg


11/15/18

Christmas came early. Fedex still has two of the drives. But all the motors are here. So far Im pretty impressed. These are from a company called Bergerda - BGD for short. Everything was very well packaged. Documentation is complete although a bit hard to understand in place. Im working with the mfg to revise the manuals for better clarity.

http://i712.photobucket.com/albums/w.../IMG_08521.jpg

11/16/18

I got the x axis ways/table off today. The bond lines are good on the Turcite but wear is uneven. Looks like an oil line was plugged and the front liner is worn about .015". I will be redoing these with Moglice but I wont order material until the remaining ways are inspected.

http://i712.photobucket.com/albums/w...ECC47F2355.jpg

11/17/18
I cleaned up the table today.
http://i712.photobucket.com/albums/w...F5F29AB2B1.jpg

11/24/18
Have I mentioned yet this machine is filthy? I’ll get the head off on Monday and focus will shift to getting the machine base cleaned and painted. I need it finished so I can start getting parts off the floor and assembled on the machine. The tool changer for example is taking up a bunch of floor space and parts bins I need back for further work.

http://i712.photobucket.com/albums/w...45670C32FE.jpg

11/26/18
I stripped all the remaining wire and pneumatics including the chiller and oil mist system as well as the way lube pump. Both side cabinets need to come off so the machine base can be painted. If you've ever wondered how much wiring is in a VMC, I can safely say its about 50lbs worth.

http://i712.photobucket.com/albums/w...C9697ED9AA.jpg

Got it down the the base this afternoon. Next is cleaning and paint.

Attachment 406734

Primed.
Attachment 407096
Attachment 407098

You sure have made the dirty girl look nice.

Great job BTW.

How tall is it?

With the z down and the motor removed it slid under my 7’8” garage door with maybe 1/2” to spare. The photos make it looks a bit smaller than it is.

I got the second coat of paint on today.

Attachment 407246

This is a quite ambitious project. I was looking previously doing the similar thing, pretty much buy a mechanically functional machine and completely replace the electronics. Looking forward to seeing your end result.

So far my experience has been that the things I couldn't see have been the most problematic. I even had the service records but there was a major gap between when the last service record was recorded and when the machine was sold. The two previous owners before me quickly realized the machine wouldn't work for them which i why I acquired it for a paltry $900.

Thats the biggest issue in buying a non-functional machine. No way to test pretty much anything. Visual inspection is all you have.

As far as actually retrofitting the electronics it feels like the only two options that can give a VMC its full potential back are either a Centroid system or some of the boards based around LinuxCNC. Ive done a Centroid job before on my Romi Bridgeport EZ-Path lathe. The documentation is GOOD. They even have all the wiring diagrams done. Its just.....complete. Good tech support too. Im not affiliated with them, by the way. Just a satisfied customer. The linux route was a non-starter for me. Its a big enough job to do all this work, let alone learn to code in C.

Thanks for following the progress!

Any updates?

Quote:

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Originally Posted by gwiz

Any updates?

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Yup. Ive posted more over at the Centroid forums. Holidays took up a lot of my spare time and I've taken a few weeks off to focus on a couple more pressing matters. However, here's the latest....

- I went through the entire parts diagram book and ordered every last nut and bolt. The old hardware is nasty and will take far too long to clean. Itll be easier to start with fresh fasteners.

- Got the ATC all assembled. Was quite the feat making all the little parts to get it to servo belt drive from geneva mechanism. I made a new pulley, drive shaft, belt tensioner, homing sensor mount and adjustable homing flag. The ATC mechanism got brand new IKO cross roller slides for the push out arm and new thrust bearings for the carousel. New fasteners all around.

-I never imagined that rebuilding a VMC would involve body filler, but it does (at least in the case of Kitamuras of this vintage). Several key machine parts were coated with filler to conceal the rough surface finish of the raw castings. The filler was removed at the same time the paint was so Im having to recoat and sand as I go. Z axis head is the last part. Im using Evercoat Rage Ultra. Sands so much better than Bondo but is a good 30-40% more expensive. Worth it IMO.

-I got new wipers on the way covers today and primed my last parts. Old ones weren’t wiping a dang thing.

NIce. Glad to see it.

Just my luck, a kitamura post that isn't 5 years old!
First off, wow. That machine looks brand new. Looks like a pretty darn high quality machine despite it's size.
I didn't know these existed until yesterday, but I've got a customer with an '83 mycenter 1 that needs new ballscrew bearings on the Z axis.
Unfortunately, like most machines of the era, their parts manual has been lost to the wind.
If it's not too much trouble, could you please list off the bearings we'll need?? Thanks!