acceptable face runout on large VTL?

[Kahran_Ramsus]

Working on a SCHIESS VTL, 1600mm faceplate (about 63"), 2016 model. After finish facing, I'm measuring aroundd 0.02mm (0.0079") of face runout on a part that's OD 500mm, ID 370mm, thickness 31.5mm.

Question is: is that kind of runout considered normal tolerance for a machine this size, or should I be digging deeper? I know with large faceplates you're always chasing some flex or setup variables, but I'd like to know if 0.02mm is something most operators would shrug at, or if it points to an alignment or chucking issue I should address. What do you guys normally see on a VTL of this scale?

 

[vipers_98]

I used a similar Schiess VTL in a big shop, same size faceplate and parts. A 0.02mm runout on a 500mm part is actually pretty good for a machine that size. Most would say that's normal, especially after finish facing. Unless you need super tight fits, I wouldn't worry.

 

[IVGrbn]

Working on a SCHIESS VTL, 1600mm faceplate (about 63"), 2016 model. After finish facing, I'm measuring aroundd 0.02mm (0.0079") of face runout on a part that's OD 500mm, ID 370mm, thickness 31.5mm.

Question is: is that kind of runout considered normal tolerance for a machine this size, or should I be digging deeper? I know with large faceplates you're always chasing some flex or setup variables, but I'd like to know if 0.02mm is something most operators would shrug at, or if it points to an alignment or chucking issue I should address. What do you guys normally see on a VTL of this scale?

To be honest, 0.02 mm (0.0008 inch) of face runout on a 500 mm part coming off a 1600 mm chuck is excellent. I think you might have mistyped the conversion because 0.02 mm is 0.0008 inch, not 0.0079 inch. If you really meant 0.2 mm, that would be a serious problem. So assuming you meant 0.02 mm, that's considered acceptable for a machine of that scale. This measurement includes part flex and chuck pressure too. The tolerances are generally much looser due to the massive components and bearing systems on a machine this size. What material are you running?