Lightburn drops lines that are at the Y Axis boundaries, but within the travel space

I am new to Laser Tools and am setting up my tooling.

I created a grid of lines on 1 CM centers covering the entire travel range.

X Axis limits were not a problem.

However, all Y lines are missing from the G-Code.

If I reduce the length of the lines from 850 to 849.998 centered on 425, they work.

Why does Lightburn throw out lines that are at the Y limits?

Perhaps the Ignore out-of-bounds shapes if possible switch is turned on:

If that’s turned off, then if the GRBL Soft Limits setting is turned on, GRBL will report an error when a motion coordinate exceeds the maximum travel limits.

Trying to mark items exactly on the boundaries can run into the various checks along the way, so marking just an itsy inside the limits will work better.

Bonus: if you’re trying to engrave the lines, you must allow for overscan travel on both sides of the line: lines close to the boundaries require travel beyond the limits.

Not to be picky, but if a user provides valid numbers to the drawing, it successfully executes a Framing operation, it is the code which should make sure floating point issues do not cause a valid drawing to fail. Simply rounding to the nearest micron (0.001mm) would likely stop this type of problem.

Especially for my case where I am simply drawing lines from 0.000 to 850.000. No calculations required, actually… Endpoints explicitly provided…

Picky is exactly what CNC machinery does for a living!

Just for fun, what are the GRBL settings for your machine?

Most likely, both $20 and $21 are zero, to disable limit checks. If so, you should set $20=1 to enable soft limits, which will prevent out-of-bounds travel at the controller level by throwing an error when something dumb happens.

Then you most likely have $131=850 to set the maximum travel to 850.0 mm from the home position.

The picky part involves deciding if 850.0 mm of travel from 0.0 should include the final coordinate of 850.0 or exclude it.

One could argue either side of the case with equal fervor (and I have certainly done so), but the simplest way out will be to set $131=850.1 and ahem move on.

Being picky is a commendable character flaw for a techie (and we’re all techies on this bus), but the key point remains: “How stuff works” always wins over “How I think stuff should work”.

Enjoying the conversation… In case you haven’t already guessed, by profession, I am a Systems Engineer, mostly in the Semiconductor Capital Equipment markets. There we measure things in 0.1 nm, or Angstroms if you prefer. In that business, my requirements document would enforce rounding protection… I also helped a friend who owned a Machining business before he retired.

I have not looked into the settings much at all. I bought the laser to make some gifts and prizes for people who exceptionally contribute to a non-profit I help manage. We looked into buying them and the quoted cost was over $5,000. I looked at the cost of a laser and raw materials and can cut the cost in half. It’s making the first batch of the prizes as we speak and, running the laser as I can, will be done by mid August. It’s actually enjoyable so I will probably continue making things and learn more later.

How dose these prices compare to your prices for the machines in your industry?

These are dirt cheap comparably and are not designed to cut out anything that detailed.

Might like this video… even though its a fiber

Good luck, have fun


The Semiconductor equipment cost in the 7 and 8 figure range.

I was talking about the gifts we wanted to provide. They would have cost over $5k. I bought the Laser and accessories for about $1100 and the materials for what we currently need for about $1300 and in my ‘spare’ time will make the gifts. Just a lot of engraved Coasters, Serving Trays, and Plates.

For those concerned about a non profit buying me a Laser, I bought the Laser and the non-profit bought the raw materials. So actually, they actually saved 3/4 not 1/2 of the $5k…

You will have to change your idea of precision…

I don’t think anyone is worried…

Have fun, help your non-profit out…


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