Circle / Squares not cutting true

[smilerpete]

Hi Tom
Sorry for the confusion.
Whatever size I cut it is still out of true, but the larger the piece I cut it is more noticeable.
For example when I have cut a piece out and then rotate it 90 degrees and put it back in the hole it came from, it will not fit, it is out by 1 mm or so.

[Tom]

Hi pete
Thats what i thought yes you will be a tooth out

[Daven]

I'm not convinced it is the belts - when you hit datum the head goes to the home position and starts from there surely? When I replaced one of my bearings I did not have any issues so was either very lucky and got the tooth alignment spot on by pure chance or it does not matter.

I would check the settings in laserCut (give HPC a call and get them to confirm the worktable settings with yours - or if someone here can do a screen dump from the 6090) .

Cheers
Dave

[TimBobTastic]

is it possible that the X and Y axis are not perpendicular to each other? that would account for correct size vs out of square, and it would of course be more noticeable on larger items...

There is probably a very long list of things that could cause this, and as I do not own the same machine, I will not offer advice on what it could be... But.... Toms comment about being a tooth out.... COULD be correct (as far as there may be some left to right miss alignment) if the front to back drive is the same as the LS3060....

Edit (the top bit may be wrong)

Thinking of how the 3060 works... the left right axis is mounted on-top of the forward backwards axis.... so if your machine is the same any miss alignment would need to be between fixed geometry...

This means that regardless of tooth placement the X and Y axis will always be perpendicular (unless something fundamental has changes)

Assuming the drive is identical to the 3060

which I am afraid just confuses things a little....

BUT... if the 2 axis are fully independent of each other (one is not mounted on the other) then I stand by my first statement... if its like to LS3060... my first statement is incorrect

EDIT 2 (The top bit may be correct)

The more I think about it... I realise my first Edit is wrong... There could be left to right misalignment on the LS3060 that causes out of square components... especially if there is a tooth pith error....

Tim
Its been a long week

[Tom]

It is hard to diagnose problems for the written word and everyone will probably give several answers
But as Daven said give HPC a call
I still think its a tooth out

[Lightnin]

do you get a true 90 at the corners ? or do you get a parallelogram ?
I'm wondering if the top carriage has become out of square with the lower one ?

[smilerpete]

Hi everybody thanks for all your replies.
I will check again if the X and Y axis are perpendicular, but I think Tom you may be right about it still being a tooth out which may affect the X an Y axis being out as I know the belts had slipped a couple of teeth just recently and noticed that the head did not travel in line with the bed from right to left from the datum point so probably just needs tweaking more.
I do not get a true 90 degree angle at the corners, but do get a parallelogram which would account for the top left and bottom right corners looking like they are being stretched.

[Lightnin]

I'm inclined to think the same as DaveN
If a tooth has jumped, when it has homed, it will be ready to move the correct amount/teeth in each axis and should be square

[Tom]

The X axis is attached to the Y axis via two belts and the Y axis is run by one drive shaft
So if the X axis is out by 9mm and Pete's bed is 900mm on the X axis
For every 100mm it will be out by 1mm across the x axis but the Y axis will be true
Now i know 9mm is a lot to be out and the machine would jam but you get the jist of what i'm on about

But this can be an alignment issue as the X axis moves along and the beam moves on the mirror
I've reread pete's first post and top left corner should be the only place that the alignment should be right all the time
Pete you should get in touch with hpc

[Spooky]

If it jumps a tooth on the Y rail it will cause an out of square in the X axis (in effect pulling the Gantry out of square with the side rails) had this happen to one of mine a few weeks back

From memory the 90 has a single rod at the back with two belts, one either side, if the left or right belt has moved a tooth it will put the gantry on the piss so making X axis cuts out of square.

Have to agree with everybody...it's an HPC job unless you are very familiar with belt problems (its easy to make it a lot worse)

Diagnosing a tooth issue

front to back cuts straight and parallel to each other (the two uprights on an H figure)
Left to right cuts a straight line but not at 90 degrees to the H cross bar

If so, its skipped a tooth or two