laser to cut stand up letters

[Clive Morris]

Hi i am cutting 12 mm wood

but when i try to stand the letters up the bottom always leans forward, is there a way to cut a straight line and not at an angle ??

[Pete Cyr]

The laser only cuts on an angle if the laser head is not perpendicular to the bed. (I assume the letters are being cut with the top and the bottom of the letter in the Y Axis)

So either your bed is not level with the gantry in the Y Axis or the laser is not perpendicular to the gantry in the Y Axis.

Since your letters are falling forward (again assuming the surface you sit the letter is flat and level) I would suspect the laser head is tilted back (top of the head toward the front of the laser laser head cone tip tilted toward the back of the laser) OR (the table is tilted -front is low back is high)

A quick fix would be to shim the wood so the front is higher than the back - a right angle protractor or even a sheet of paper would help define the shim thickness by aligning protractor/paper edge the edge with the laser head and the wood surface to establish a perpendicular orientation. Adjust as necessary.

[Gene Uselman]

If you do a pulse on a piece of wood and move the Z down 200mm and pulse again [the second will be out of focus of course and larger] you should see quickly if you cutting head is correct. Getting a nice square cut is a function of adjusting the second and third mirrors so the beam is vertical as well as in the center of the nozzle.

[Clive Morris]

Hi Pete

originally i had the wood down the left hand side of the cutter (running along the Y axis) so the cut edge that it needs to stand on was going back of machine to front of machine,

i then moved it to the back of the machine running along the X axis, so the cut standing edge was going left to right and it cut perfect

so i twisted the head unit so the nozzle went from right hand side of the machine towards the left and it is almost perfect, so with i little more tweeking that should be ok

Gene
once i get that correct ill do the pulse test and adjust the mirrors as necessary,

thanks for all your help guys

[Joseph Duvivier]

I am having a similar problem with my laser, so I wanted to see if your have the problem solved. In my case the laser cuts from entering the material's surface to the left slightly and exiting the material's bottom surface to the right slightly. I estimate the tilt to be around 3 degrees. The head looks totally level, but the beam is apparently not. You can easily see the tilt in 6 mm acrylic. Could this be due to the beam not being centered on the mirror in the head and thus going through the lens off center? Anyway I messed with the head mirror enough in one direction to cut power and in the other direction as well (before returning the mirror adjustment screws to their previously marked positions) without noticing improvement. This has me puzzled, but I guess I can see if there's a way to rotate the head slightly about its Y axis and then adjust the head mirror to get the beam back through the lens down to the material.BTW the tilt is much the same when cutting left to right as when cutting right to left, that is always from left to right, so I don't think I am seeing beam drag effects. I suppose the lens itself could be not symmetric, that is slightly prism shaped or not centered in the mount - I have not looked - but I think this is highly unlikely.

Comments, anyone?

[Pete Cyr]

Assuming your head is perpendicular to the gantry in both the x and y axis and your beam is centered I would look at the bed and measure the distance to the bottom of the gantry in a few places on the x axis (left middle right) AND perform the same measurements moving from front to back in 2 or 3 places.

Your description would indicate your bed is high on the left - low on the right

[Clive Morris]

i dont have a defined awnser to how i cured it. but i used a spirit level with trial and error. and got irbworking correctly. but i think it was more luck than judgement