Machine tool hydrodynamic way bearing

[zukes3140]

I am having a lift problem with a Vertical Boring Mill way bearing. The O.A.Dia. of the table is 120in & weighs about 16,000 lbs. The load placed on the table to machine is 44,000 lbs. and covers the full dia. of the table. With the table removed, looking down on the way surface, there are 2 circular ways. The way in the middle is 31.5 dia. X 5.5 wide. The outside way is 79in. dia X 7in. wide. Thus, it appears like 2 donuts seperated by a recess. The speed of 40 RPM or approx. 754 S.F./Min. for the outside way. The bearings are lubricated by 4-- 0.5 dia. holes in each way in the base. The oil is Mobil Vactra #3 at 50 PSI. The way in the bed way is cast iron and the way material on the bottom of the table is Amco 18. The bottom of the table has oil groove that lines up with the inside oil hole in the base; 0.5 wide X .080 deep that is[1] circular. The inside way has 8 annular oil grooves, like spokes on a wheel, that are 0.5 wide X .080 deep. These grooves are 90 deg. to tabel rotation. The annular grooves on the large way are 18 in number. We used a ball end mill to cut these grooves and radiused the top of the groove to prevent shearing the oil as the way rotated. The ways are scoring next to the circular oil groove. There is appearance of lack of oil at this location. However, I have increased the flow of oil to 9 gal./ min. @ 50 PSI. The inside way is not scoring.

 

[sreid]

Contact Alex Slocum at MIT. Trust me on this, just do it.

http://meche.mit.edu/people/faculty/index.html?id=80