[Johnny G]

Machine: 2007 Haas VF2SS

A couple of months back we started to get vibrations problems. So we had a Haas engineer come out a few times, not massive vibration but enough to make the job look bad. They did some testing includign a vibration tester which the results then got posted to the USA. Turned out it was either SPINDLE, SPINDLE MOTOR, BALL SCREW. So we paid upfront for all these three parts and then which ever we didnt use we'd send back for a refund.

We had the spindle changed and this did make the finish better, but from memory when cutting it doesnt sound quite the same, so since we had a motor sitting here we asked the engineer to change that, that made no difference other than being slightly quieter (when all the guards were off). We then had our old one put back.

So we and haas UK are at a point where we/they dont know whats causing the surface finish problems.

We have bought a brand new 50mm tip cutter as our old one had a small mark on it. No difference though. As you can see from the pictures the finish is dull, and has cross'-hatching, and the 10mm endmill used to do the pocket is terrible.

What do you think the cause is, bearing in mind the things we have had changed/tried? The finish used to be perfect and the surface finishing was mirror like.



This is showing the only surface left from a 1mm pass using a 50mm/4tip alum face mill

This is going diagonal X/Y - finish isnt as good

This is purely X axis travel and the finish is good


Thanks
John

[Delw]

looks like a table problem. check the smoothness of your x ballscrew and back lash in x, also check your backlash in z.
something looks loose could be your tool holder have you changed that? pull stud good, tight. try different tool holder

[underthetire]

See if they can run a ballabar check on all three axis. That will show any way movement or roughness in the drive system. If the ballabar checks ok, then you need to look at holders/spindle/drawbar/balance. Spindle preload in really not that hard to check either, a quick test is to put an indicator on the nose of the spindle and push tool unclamp. Find out what there spec is for correct amount, but usually about .001 would be normal.

[tracyranson]

The pictures that you show remind me of bit chatter caused from a worn out bearing in the spindle. I must have used 50 new end mills before I found the cause. Never can tell until you really dive into it.

[miljnor]

sometimes on a four flute insert style face mill 1 insert will not be in pocket perfectly and then the finish goes to hell.

Or like on a manual mill when the head is slightly out of alignment and the cutter cuts on 1 tangential edge more than another.

first problem is checked with a tool preseter or in the machine with a really accurate tool setting gauge.

second is with a ball bar. or a dial indicator running against a precision ground bar in the tool holder

[Delw]

See if they can run a ballabar check on all three axis. That will show any way movement or roughness in the drive system. If the ballabar checks ok, then you need to look at holders/spindle/drawbar/balance. Spindle preload in really not that hard to check either, a quick test is to put an indicator on the nose of the spindle and push tool unclamp. Find out what there spec is for correct amount, but usually about .001 would be normal.

+1
another thing I was thinking he said he replaced spindle and motor, but did he replace the rubber connector that joins the 2 shafts. if thats sloppy could that cause the problem?

cross hatching like that I would think shows the machine is perfectly level, as the cutter is hitting on both sides, if it was off level it would only show one side of the cutter marks.

Wasnt there a post about 3 years ago on Coining?(like the first picture showed) I think that was on a 2007 ss machine also.

first problem is checked with a tool preseter or in the machine with a really accurate tool setting gauge.

wouldnt the tool presetter only be for tool length and offsets? this wouldnt explain the finish problem would it?

Delw

[Geof]

You didn't happen to change Setting 191 to Rough did you?

[Johnny G]

The pictures that you show remind me of bit chatter caused from a worn out bearing in the spindle. I must have used 50 new end mills before I found the cause. Never can tell until you really dive into it.

We had a brand new Haas spindle a few days ago.
They also put in a new coupling while it was out.

[Johnny G]

You didn't happen to change Setting 191 to Rough did you?

Whats this?

[Johnny G]

sometimes on a four flute insert style face mill 1 insert will not be in pocket perfectly and then the finish goes to hell.

Or like on a manual mill when the head is slightly out of alignment and the cutter cuts on 1 tangential edge more than another.

first problem is checked with a tool preseter or in the machine with a really accurate tool setting gauge.

second is with a ball bar. or a dial indicator running against a precision ground bar in the tool holder

All four tips are exactly the same height, checked this today
And its the same result with the 10mm endmill so i think that rules out holders and cutters

[Geof]

Whats this?

This is taken from the Haas Mill Manual:

191 Default Smoothness
This setting may be set to ROUGH, MEDIUM, or FINISH and uses parameters 302, 303, 314, 749, and 750-754 and G187 to set the smoothness and a maximum corner rounding factor. The default values are used when not overridden by a G187 command.

G187 Setting the Smoothness Level (Group 00)
G-187 is an accuraccy command that can set and control both the smoothness and max corner rounding value when cutting a part. The format for using G187 is G187 Pn Ennnn.
P Controls the smoothness level, P1(rough), P2(medium), or P3(finish). E Sets the max corner rounding value, temporarily overriding Setting 85 "Max Corner Rounding".
Setting 191 sets the default smoothness to the user specified "rough," "medium," or finish" when G187 is not active. The "medium" setting is the factory default setting.
NOTE: Changing setting 191 to "Finish" will take longer to machine a part. Use this setting only when needed for the best finish.
G187 Pm Ennnn sets both the smoothness and max corner rounding value. G187 Pm sets the smoothness but leaves max corner rounding value at its current value. G187 Ennnn sets the max corner rounding but leaves smoothness at its current value. G187 by itself cancles the E value and sets smoothness to the default smoothness specified by Setting 191. G187 will be cancelled whenever "Reset" is pressed, M30 or M02 is executed, the
end of program is reached, or E-stop is pressed.