Bad face mill finish. Profile is perfect

Hi fellow zones, I have a 1990 fadal 6030 it's always been a great machine. A while ago I noticed a surface finish issue started, it was fine the day before. Anyhow it has not been an issue because parts get painted etc. Now it's a issue. Information I have collected. I put a holder in the spindle and mounted a wrap indicator to the holder and moved it to indicate against the frame of the spindle.
If I put a screwdriver at the Gage line gap between the spindle and the holder I can move it. 002. If I use a pribar against a block on the table and the spindle I can move that .002 as well. So I'm thinking either the resolver or maybe the draw bar bellview washers. Any help would be appreciated, thank you.

If the tool holder is not pulling in tight to the spindle bore, the tool holder would flop around in the spindle taper a bit and you would be able to see some lateral movement in the toolholder and it would probably chatter like crazy when cutting. You could have a belleville washer problem and may need to change them out, but from what you said, that does not seem too likely. This sounds like a mechanical problem rather than a resolver issue.

My best guess is spindle bearings, especially if you can move the spindle relative to the head. Backlash in the Z ball screw could also be the problem. You need to make some measurements to find exactly where play is coming from.

Your test is too vague to isolate the issue. All your test proves is that there is a problem between the spinny bits of the spindle and the housing. If there is a locking key for the toolholder, indicate against that. If you see the error there, then the problem lies somewhere in the tool retention system (bad tool holder, bad tapered bore, belleville washers, drawbar, etc....). If there is no play there, then the play is likely in the bearings as Jim has speculated. It might be as simple as a preload adjustment or wear in the bearings.

Check the spindle bore to ensure that it is smooth and clean. From your description of how it started from one day to the next, it is possible that a chip got into the taper and welded itself to the bore. Make sure the bore is clean.

bob

I agree with Bob, I need more information. If you pry on the top of the toolholder while in the spindle, .002" is not unreasonable. What you really need is a taper test bar to see if you have a taper issue. I think you also need a force gauge to see what the retention pressure on the drawbar is as well. You should see 750 lbs of drawbar pressure or more which depends on the drawbar type you have. If your spindle nose it tight, you probably have an issue with one of your resolvers or motors not moving smoothly, thrust bearings or a bad ballscrew. If you see a step in each pass of the cutter, you need to adjust your spindle tram.....after you level and square your machine.

Replacing your drawbar springs each year is a good PM measure and will insure that your pressure stays tight. Let me know if you have any questions and I will help as I can.

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