1991 Fadal VMC20 Y Axis Thrust Bearing Replacement Walkthrough, Saddle Gibs and Way Oil system

Рет қаралды 548

Күн бұрын

0:00 Intro, News, Upcoming Videos and Products
2:10 Preparation and Way Cover Removal
10:30 Y Motor Removal / Disconnection
15:25 Way Oiler
22:08 Gibs Overview (I do end up removing them later in the video, contrary to what I say here)
22:38 Gibs Removal
31:00 Ballscrew Assembly removal
35:06 Begin Ballscrew Asmbly Teardown and Cleaning
35:39 Telescopic ballscrew cover
36:30 Motor Coupler Set Screw issues and coupler removal (Common Lost Motion)
38:17 Begin Removing Bearing/Shaft Assembly
38:30 !! Should be "to the right", failed up save the caption correctly!
41:30 Supporting the block to press out the shaft
44:30 Assemble new bearing into block
56:33 checking seals and cursory check of bearing preload
57:53 Reassemble the shaft, telescopic cover, etc
1:00:40 Inspection before reinstallation (Was also referring to torque of the shaft lock nut regarding the drag, please comment if you know this number!)
This bearing has been recommended with positive results by one Fadal owner (with no preload shim needed):
NSK 7304BWG
I used the 7304B from a no-name provider. Could be it was good but had other issues with my bearing block so can't give it a definitive up or down vote. If you get a cheap one like I did just be prepared that you may have to put together a custom sized shim, or end up buying from a reputable source anyway later, in either case, probably doing this job twice.
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Пікірлер: 6

@wannabecarguy 8 күн бұрын

I was running a new fadal in 2000. It had a firmware problem and would randomly run away. It was the scariest thing a machinist could experience. That was the end of fadal. They could have been great machines. Doosan is going to take over the market.

@MotorsportDiesel 2 жыл бұрын

I just did the thrust on my VMC 20 z axis. I ordered a set (7304B) from ebay, they looked to have been "zero ground" with a sander, and were not even flat. When I put them together, they would have needed a 0.015" shim to get any preload, so I returned that trash and bought an NSK 7304BWG. I only really needed one and with no shim at all I had good preload.

@calphis 2 жыл бұрын

Thanks for the update. I'm not certain some of the slop i had to take up wasn't the fault of the garbage bearings I tried, so I'll update the video description to the bearing you mentioned, hopefully save some others a headache

@efraincaballero7482 Жыл бұрын

Thanks for your video! I'm wondering what was the backlash that you had before making this fix, and the new backlash after adjusting. My Y axis backlash is already at the maximum adjustment (0.0062") and I'm still off by 3 thousands. I was thinking about replacing the bearings first. I don't have the cash right now to replace the whole ballscrew.

@calphis Жыл бұрын

Mine was very very high originally. I think in excess of 0.015" if I'm remembering correctly. It's currently under 0.001". I don't have quality metrology equipment nor the rest of thigns dialed in well enough to get a better more accurate measurement, but I suspect i'm somewhere around 0.0003" - 0.0005" now. I assumed my screw would be worn to have that much initial lash. But it turned out to have little to no wear. Screw wear would also be unlikely to be uniform but more loose in the middle and tighter on either ends (unless production cycles had been frequently run in those spots). so that might be a clue. If you do indeed have a worn screw and its not too non-uniform wear, you could try tilting the ballnut to take some more slop out (ie. shim on just one side so as to "bind" against the screw). Not something one would normally want to do , as it lessens contact/bearing surface and results in premature wear. but if it's end of life anyway, no harm done right. Good luck!

@efraincaballero7482 Жыл бұрын

@@calphis Wow, 0.015" is a lot worse than mine. From what you're saying I think that replacing the bearings will give me what I need, I'm not doing utra-precision parts right now anyways. Thanks a lot for your response, I really appreciate it!