Spindle's reliability
Spindle's reliability
(OP)
Hello,
I work for a company that make wood planers. We have been having several problems with our spindles for a couple of years now. The spindles fail too fast (sometimes they don't last more than 3 months). Here are the specs :
Motor's speed : 3600 RPM
Motor's HP : 100 to 200 HP
It's an overhung desing with a tool that weights 550 pounds and has a 16'' diameter and a 10'' width. The spindle is motorized with a coupling. Bearins are a 7020 15 degrees precision pair at each end. They have a light preload.
For the load calculation, I used (hp*63025/(rpm*Radius))*2
I used a load factor of 2 because it's a high vibration application.
The boards can go through the planer at 3000 ft/min with a 6'' gap between each board.
I would like to have some opinions on this design.
Thank you
I work for a company that make wood planers. We have been having several problems with our spindles for a couple of years now. The spindles fail too fast (sometimes they don't last more than 3 months). Here are the specs :
Motor's speed : 3600 RPM
Motor's HP : 100 to 200 HP
It's an overhung desing with a tool that weights 550 pounds and has a 16'' diameter and a 10'' width. The spindle is motorized with a coupling. Bearins are a 7020 15 degrees precision pair at each end. They have a light preload.
For the load calculation, I used (hp*63025/(rpm*Radius))*2
I used a load factor of 2 because it's a high vibration application.
The boards can go through the planer at 3000 ft/min with a 6'' gap between each board.
I would like to have some opinions on this design.
Thank you





RE: Spindle's reliability
If the bearing is not sealed , I would look at adding a seal there to deflect the dust before it enters the bearing.
RE: Spindle's reliability
RE: Spindle's reliability
RE: Spindle's reliability
RE: Spindle's reliability
RE: Spindle's reliability
First problem was not enough lubrication. Then the guys packed it with grease & oil; too much lube causes overheating too. Packed full it won't run, burns motors.
I went through the bearing application and it calculated to last 25 years at the current rate. So I called an application engineer at the bearing manufacture and he said:
Add a fill hole into the pillow block that houses the bearings and add just enough motor oil to contact the lowest ball or roller by about 1/8". That's it, never had another problem. Your setup may be a little different, but I think the basic machine is similar.
My pillow block held about 5 ounces of oil which was changed after each test. If you don't change your bearing or design you might have to add fluid capacity, a filler hole, a drain hole, an external site level, and a oil change schedule. As yours is a product you might add an oiler unit, but an application engineer should be able to provide a permanent solution for you over the phone.
You can get stick-on temperature gages from McMaster Carr for a song. If I remember right we blew about $250 for bearing set each time before the fix. And the fix was well tested as those machines ran for days on end at high speed.
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www.tailofthedragon.com
RE: Spindle's reliability
RE: Spindle's reliability
RE: Spindle's reliability
If you have a floating problem, you will not usually see indentations. You will just get sudden thermal runaway, and both sets of bearings will be detroyed. It is possible that you would then see more thermal damage on the the two inside bearings of the back to back pairs, although everything gets so hot so quickly that it might be hard to detect a difference. By "back to back" I mean bearings assembled adjacent to one another with opposed contact angles.
RE: Spindle's reliability
RE: Spindle's reliability
RE: Spindle's reliability
Nick