Anyone using the millkins module to correct for skew..?

[Clive S]

Wal Are sure it is not the BK bearing nut come loose. Try sticking a DTI on the end of the screw. Is it just on one axis? If you can hear a click it must be a reasonable amount. Clive

[Wal]

Hi Clive - I've stuck a dial on the edge of the table and measured the click at around .05mm - needs pushing on a fair bit to get the click, but it's there. I'll stick the dial on the end of the screw to see if it's the bearing nut although something tells me it's ballnut...

[Wal]

Oh yeah, Millkins:

http://wiki.linuxcnc.org/cgi-bin/wik...kew_correction

When you know how much you're out by use the module to have the machine compensate.

Wal.

[magicniner]

If there's a click in axis movement isn't it a simple backlash setting issue?

- Nick

[Wal]

If there's a click in axis movement isn't it a simple backlash setting issue?

- Nick

Hi Nick,

Probably not as a bit of force is needed for the 'click' - there are probably times in the cut where there had been no backlash and other times where perhaps there is - it's probably not consistent and where the cutting forces are slight there's probably no backlash at all... I'm not in a position to take a photo right now but there's an interesting observation I made on the part itself, I'll post later...

Edit: I get that the above might not make a great deal of sense as backlash is backlash and the reasons for it should be consistent regardless of forces... I'll double check the bearing nuts but I'm pretty sure I've tightened 'em in the past and the situation hasn't changed!

[magicniner]

If you've got a mechanical error which only occurs occasionally surely any software solution will have to either detect or predict the error and only correct when it occurs?

[Wal]

Well yeah - where would you even start with that..?! The (possibly intermittent) backlash is something that I can live with for the moment as 90% of my cutting involves pretty low forces. I really do suspect that the ballscrews/nuts are just a bit shite and it's a problem best sorted by spending a bit more on decent running gear... BUT as suggested I'm going to be nipping stuff up again during my next clean/service. The skew (again, miniscule on the sizes I work at) is something I'd like to have a go at dialling out.