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Trouble Calibrating 3.8w Laser

Try setting the Max 3rd Axis Depth (S value) higher. 10000?

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Increasing the power some and switching firmwares helped.
The laser is sorta focused, the burn it leaves is .014h*.025w. Am I doing something wrong? Is that why it has that striped look?

Getting there. Lower the Pixel Resolution to bring the burn lines closer together. Try .007. You will have to resize your image in the editor for the Pixel Resolution your using. The instructions are on page 7 in the Tutorial.

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Thanks, any idea why the laser has a wide ~1:2 aspect ratio?

I’m not sure what you mean. Aspect ratio of what?

The thickness of a horizontal line is .014" and a vertical line is .025".
The line settings used was 40ipm and S255

Actually, I have an idea how to better visualize it, I will post it tomorrow

I am going to take this image, set the
Pixel resolution to .001 or .002, then run it at 65ipm at S200.

As I mentioned before, the beam is not quite round. When it’s not focused properly, it magnifies the ratio. The shorter the focal distance is, it’s harder to focus and it’s not as tolerant if your material is not quite flat.

If you raise the laser out of focus you will see the laser’s beam is a rectangular shape. Rotate the laser module in the heat sink until the long side of the rectangular beam shape is parallel with either the 45 Left or 45 right engraving angle. Then set the focal distance at 3.00" from the heat sink bottom face to the top of a piece of black anodized aluminum placed on the X-Carve’s bed. Focus the laser beam to the smallest focal point as possible. Then secure the lens in place so it will not move by dabbing some hot melt glue a few places from the lens thread to the laser module. Only engrave at the 45 degree angle you rotated the beam to.

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We moved the laser ~.5" down and we rotated the laser, anything else we are missing

Did you make changes to the J-Tech grbl settings that I posted a link to in my first post in this thread? Also since your now using Varied Intensity, increase the Min 3rd Axis Value so it will start burning the lighter shades. 10-20?

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I believe I did. The min axis is set at 25 I believe, the fr is 70-75 ipm with a Feed Rate Change of 25%

At this point, you will just need to play with the settings until you get results your happy with. It does look like your on the right track.

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Alright, thanks. What power laser was this? How well would these settings transfer to an X-Carve?

That has a 3W LD, but since the EmBlaser’s grbl is configured for a CoreXY belt configuration, there is a feedrate curve which I had to set the feedrate a little higher in PEP5 to compensate for it.

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Alright, so I should be good at 75ipm? I tried raising the max power, but it turned into a dark blob. Should I turn up the min power? It appears to be Furniture Grade Birch Plywood, we got a truck bed full of it for $30. I will do a single 45° line to see If I have the resolution right.

With our Shapeoko 2 and the 2.8W J-Tech, the settings we used on Birch Ply was 100IPM, 25% FRC, .006 Pixel Resolution, min 10 and a max of 255 and engraved at a 45D angle. The Feedrate was accurate without any curve with it. With the 3.8W you should be able to run at 130-140IPM, 25% FRC and max at 255. The Min needs to be increased until it starts burning the lightest shades, but not burn at all in the white areas.

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Hello again,

it has been a while since I posted about calibrating my laser, I have been busy with a lot of medical issues and such that have prevented any progress being made with it. We want to do it right this time, we felt like we kept going in circles last time, so we are looking for structured guidelines or testing procedures people use for setting changes to make in each iteration of calibration testing. Thank you for your help. We are still using pic engrave with JTECH GRBL.


Here is the latest multimode grbl 1.0c firmware for laser & spindle use if you have not upgraded to it yet.

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Alright, I remember hearing that someone was working on it. Are there any limitations to that version of GRBL as opposed to switching between versions? Do I have to change anything in the settings I upload or are there specific settings I should upload?

There are no limitations. Here are the instructions to setup your grbl settings in Larry’s MultiMode grbl 1.0c Firmware with the latest released version of PicSender.

You can use the X-Loader to flash the new firmware.

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