[Deano7/11]

Just picked up a 1996 4020 with 28inch z axis.
We brought it without been able to power it up but the price was right so worth the punt.

The good
Ways look good
Electrically runs fine
1400-5 cpu (upgraded according to the parameter sheet ment to have 1400-4)
-5 axis cards
Turcite on x axis looks good from the little I can see.

The bad
Hasn't been running for near 3 years
Backlash numbers are high z=20 y=25 x=30
After running a dti along the screw I have z.02mm x0.05mm y0.025mm thrust bearings and couplings require replacement and/or inspection.
Y thrust bearings are noisey as and you can feel them through the table so need to be replaced.
Spindle is very noisey just trying to track down if it is coming from the spindle (likely) or the motor(unlikely)
The spindle chiller has been completely disconnected.
55k power on hours
18k cutting hours

The plan of attack
First thing is the replace the y axis thrust bearings and coupling then remeasure backlash. Hopefully the numbers will drop considerably. Then move to the other 2 axis.

Does anyone have any tips for thrust bearing replacement especially y axis as that will be the first on the list.
Cheers

[rwskinner]

You can order the thrust bearing and seal kits from several sources like ITS or FadalCNC for around $90 per axis.
The ones I just got from ITS were NSK bearings and had the preload shim with the kit, and all the required seals.

I just did all mine this week and it's pretty simple, especially for me because I removed all my screws to be reworked so my bearing carriers were already off.
Just make sure the thrust bearings are face to face, in other words, the thick side of the inner races will face each other. The shim goes between the faces.

Make sure you get the correct kits. There is one from metric screws and then inch screws. With yours being a 1996 I would imagine they are metric.

Richard

[Deano7/11]

Cheers.
We are in Australia so getting gear from the states is time consuming and costly. Will pull it apart and try to source parts locally.
Can the bearings be replaced without pulling the bearing block off?
My screws need attention also. What did you get done to yours? A reball or replace?

[Deano7/11]

After removing the y axis servo , coupling and mount I can't for the life of me undo the nut that holds the thrust bearings.
Looks like I am about to do what I never thought I would and that is take an impact gun to the ball screw

[rwskinner]

Would you like the numbers for the metric bearings and seals? I still have the boxes. You could probably reuse your old shim.
I also used an impact to remove the stop nuts on the end of the screws. I used short quick burst and they came right off.

On the ball screws and nuts, it's supposed to be a total rework. Regrind and rebuild.
They guarantee, it will be as good or better than new. I guess we will see how good of a job they do.

[Deano7/11]

That would be great thanks. Part numbers are gold.
Impact gun it is .
Cheers

[rwskinner]

3 of SKF Seals 12360 (Inside block coolant seals)
1 of SKF Seal 11138 (Seal for thrust retainer to screw seal adapter)
2 of NSK Angular Contact Bearings 7304BYGUG2 - NB5F 20mm x 52mm x 15mm

1 of preload shim 0.875" ID x 1.375" OD x 0.001" thick

[roberto123]

3 of SKF Seals 12360 (Inside block coolant seals)
1 of SKF Seal 11138 (Seal for thrust retainer to screw seal adapter)
2 of NSK Angular Contact Bearings 7304BYGUG2 - NB5F 20mm x 52mm x 15mm

1 of preload shim 0.875" ID x 1.375" OD x 0.001" thick

Hello I have a VMC15XT, are these bearings and seals for each axis?

[rwskinner]

Hello I have a VMC15XT, are these bearings and seals for each axis?

These are per axis. Mine were for a 4020.

[ianagos]

Hello I have a VMC15XT, are these bearings and seals for each axis?

There were only two seals on my vmc15xt.

The other seals are for the cool power system. Now I don’t remember what the number were for the ones I needed. But it’s one of the two above.

[rwskinner]

Yep, I have (Had) water cooled ball screws, so there is an IN and an OUT port in the screw, which means 3 seals for the cooling, and 1 dust seal for the bearing.

[Deano7/11]

Bloody champion thanks

[Deano7/11]

Seems the bearings are ex production so no stock within nsk worldwide.
Looks like they will need to come from the states or I can change to a proper ball screw support bearing and go away from the angular contact but they are pretty expensive at about $200 a bearing.
Will shoot off an email to the fadal parts places and see what shipping cost and time I can expect and make my decision from there.

[ianagos]

Seems the bearings are ex production so no stock within nsk worldwide.
Looks like they will need to come from the states or I can change to a proper ball screw support bearing and go away from the angular contact but they are pretty expensive at about $200 a bearing.
Will shoot off an email to the fadal parts places and see what shipping cost and time I can expect and make my decision from there.

I order them from Misumi for very cheap. They do international shipping I’m pretty sure. Any 7304 bearing should work.

[rodney247]

Download for free All Fadal Manuals do not pay for them several places https://flintmachine.com/fadal.php or Fadal Manuals | ItsCnc.com parts manual, maintenance, troubleshooting etc. etc.

[rodney247]

Oh and by the way many of the small components (belts, air valves , relays etc.) on the fadal can be bought from https://www.mcmaster.com/

[Deano7/11]

Cheers guys.
Pulled the y axis off.
Just had regular 7304 bearings in it with something that may have looked like a shim many years ago.
I will get some regular 7304 and see how the axis comes up.
The old bearings were very stuffed.
The issue with international freight is the cost. One axis bearing rebuild kit is something like $120usd in freight 3x kits is $250usd freight.it is hard to stomach.
If I need 3 axis kits 3 x ball screws and a spindle the freight for all that is about 3kusd that is a bit over 5k of our money. Nearly double the cost of the machine.
I would be better off getting it sent to a address in the states and buying a $800 return tix and flying over to the states and bringing it all back as carry on and stowed luggage.

Re manuals. I have a couple of sets. Thanks for the tip tho.

[ianagos]

Cheers guys.
Pulled the y axis off.
Just had regular 7304 bearings in it with something that may have looked like a shim many years ago.
I will get some regular 7304 and see how the axis comes up.
The old bearings were very stuffed.
The issue with international freight is the cost. One axis bearing rebuild kit is something like $120usd in freight 3x kits is $250usd freight.it is hard to stomach.
If I need 3 axis kits 3 x ball screws and a spindle the freight for all that is about 3kusd that is a bit over 5k of our money. Nearly double the cost of the machine.
I would be better off getting it sent to a address in the states and buying a $800 return tix and flying over to the states and bringing it all back as carry on and stowed luggage.

Re manuals. I have a couple of sets. Thanks for the tip tho.

Did you look at misumi bearings are like $20 each and I’m pretty sure freight will not be that much. I believe they carry the seals and shims aswell but I’m not sure.

Also I’m about to order some bearings if you want I can add some to my order and ship it to you if there’s no other option. Nsk bearings run me $15 each. It won’t be cheap to ship but probably won’t be $250. The seals are easy to find skf 11138 seals but I can send those aswell.

The bearings could be any brand you can get they just have to be 7304 b. See if someone local has them.

[Deano7/11]

Did you look at misumi bearings are like $20 each and I’m pretty sure freight will not be that much. I believe they carry the seals and shims aswell but I’m not sure.

Also I’m about to order some bearings if you want I can add some to my order and ship it to you if there’s no other option. Nsk bearings run me $15 each. It won’t be cheap to ship but probably won’t be $250. The seals are easy to find skf 11138 seals but I can send those aswell.

The bearings could be any brand you can get they just have to be 7304 b. See if someone local has them.

Cheers mate.
Yeah 7304b are very available here for stuff all. Seals are also plentiful so no issue there. Will grab some next week from the bearing supply and reassemble the axis. I have some .002 shim so will throw some of that in and see what we end up with.
Ballscrews can be specially ordered from many manufactures so might make a note of the size and end machining and get a quote. They take 6 weeks to get made but ones I have had made previously came up great.
They are a double nut style c1 from memory grade ground screw.
As for couplings I am replacing them as well. They are 5/8 on the screw and 7/8 on the motor. Was going to use a flex disc style.

[Deano7/11]

Cheers mate.
Yeah 7304b are very available here for stuff all. Seals are also plentiful so no issue there. Will grab some next week from the bearing supply and reassemble the axis. I have some .002 shim so will throw some of that in and see what we end up with.
Ballscrews can be specially ordered from many manufactures so might make a note of the size and end machining and get a quote. They take 6 weeks to get made but ones I have had made previously came up great.
They are a double nut style c1 from memory grade ground screw.
As for couplings I am replacing them as well. They are 5/8 on the screw and 7/8 on the motor. Was going to use a flex disc style.

Attached is the coupling I want to use