Laser cuts 3-5 degree angle through wood and Acrylic

I have an issue with all my cuts having a slight angle in them. I have verified that my cutting table is level. The lens is clean and the laser beam appears to be centered on all mirrors. None of my cuts are 90 degrees through the material. It is consistently off on both sides of a square, circle, and rectangle. It is really noticeable when cutting 1/4" acrylic in 2x2 squares. Any ideas would be appreciated.

Thank you in advance,
Jeff

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Very likely your nozzle with mirrors nr3 and the lens is not at 90 degrees to your work table.
You can test it by lowering your table as much as possible and making a test shot, then, without moving your test subject, move your table as high as possible and shoot again. If you have not only one dot but 2 then you have an “angle problem”.

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Or a drinking problem :smiley:

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Lasers have an hourglass beam at the cutting area aka kerf.

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That’s right, but if the angle is only to one side, then this is the most likely problem mentioned above.

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it gets complicated if 2 laser beams come out AND you drink too much

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This appears to be the issue, do you adjust the head with a square to get it straight then adjust the mirrors? or is this a molehill I’m turning into a mountain…

Have you ever used this product? Do I need to get this tool to make it easier?

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It is almost better to fine tune your laser head after the deviation on your test subject, it takes some time but needs to be done. Loosen the screws only slightly and with a small plastic hammer or similar you can knock it in the right direction - very carefully. If it is in Y-direction you need to adjust, here with some types of nozzles it is necessary to put very thin material under the holder either at the top or under the lower part of the nozzle holder
I hope the translation does not ruin the meaning of what I want to say.

I have with interest seen some videos from this company and can well imagine that it can be a great help in adjusting one’s mirrors in general. But here and now … just loosen the bolts and get started :wink:

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If your settings are reasonably ok, I do not think you need to adjust everything from scratch, 1 or 2 degrees corresponds to this short distance to a few tenths of a millimeter.

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Is it bad forum to piggyback a question concerning the exact same thing I have going on with my brand new machine?

New 180w 1300X900 table.

I set up the machine, adjusted both the beam alignment and the beam path. I made sure I was center/center at every mirror, at every location when testing.

As soon as I cut some 1/2" thick acrylic, it was obvious the cuts being made on the Y axis were not vertical.

I loosened the screws holding the cutting head and ended up shimming it a full 1.08 mm before getting it to cut vertically. I have a pinpoint laser coming through the exact center of the cone.

When I look at the cutting head from the front of the machine, it looks like it is at least .05 degrees listing to the right. Everything in my head tells me this shouldn’t work and that the tube and cone should be 90 degrees to the aluminum beam on the Y axis.

I ran it all day this way until a neighbor came by and convinced me I was crazy. I disassembled the cutter head again, removed the shims and showed him how it was cutting on an angle. I replaced the shims to get back to where the cuts were once again vertical.

Am I crazy?

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No not at all, if it works for you it is the right thing you have done. There is probably some angle that does not fit, but as long as you get the entire laser beam right through the nozzle hole and the focus fits, at a 90 degree angle to your material, it must be ok.

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Agree. No matter what it looks like from the outside, as long as the laser is doing this:

then I guess you’re okay.

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Jeff, I like your graphic explanation and that it is also made in LightBurn :wink: :+1:

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The frame ensures movement across the X, Y, Z-axis during the cutting process. The only requirement here is that they must be highly stable. This high stability of the tools helps you in improving the cut precision.

So, while considering laser components, do not only consider the properties of product material, but also make sure to evaluate the performance of the laser components. For this, you can consider trumpf nozzles, trumpf eco nozzle, trumpf lens, amada nozzle, prima lenses, etc.

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I’ve seen it recommended to set the z with whatever tool you use and then add half the thickness of the material to that measurement so the focus is on the center of the material. The entry and exit thickness are the same that way. You are getting an angle on both sides of the material in opposite directions because you are cutting exactly how the directions read. This method means it’s not quite as crisp and the kerf is larger, which doesn’t work for me.

Only if the nozzle is 100% perpendicular. It’s often a problem people overlook. With the right Lense, it is (up to some material thickness) not necessary to focus in the middle of the material, the laser beam does not become super thick the first millimeters …

True, but someone might suspect the nozzle isn’t perpendicular if they are getting angular cuts, that’s what I was referring to.

I think speed, power and the way the material evaporates during cutting have an influence on how straight a cut is. When cutting thicker acrylic, I have sometimes observed that the cut surface is not quite as expected. There is something called beam tracking, clever minds have written books on the subject and Russ Sadler has made evening-filling videos about it…
But, the problem could also be as simple as a wrongly mounted/placed M3, it’s been seen before.

Is this a new machine? Did it always do this?

:smile_cat:

cut a circle (disc) from wood or acrylic, Mark the x and y axis . Look at the disc from the side (and look at th hole left by the disc you just cut. Is it sloped evenly all the way around or is is more on one side than the other. Same for the hole. The laser beam will cut a slight V shape. but an uneven slope will indicate the beam is skewed… Often because the lensholder and 3rd mirror holder are skewed or rotated a bit.