Double line error after about halfway across the bed

As some of you will know im a complete newbie to these things…

well my “ridgeway” k40 arrived, got my cooling set up and the exhaust fan etc (venting up a bedroom fireplace seems to work well). did some small cuts on some 3mm irocho hardwood, the thing punches through it no problem at all, scary power !! only thing is at the right hand side of the original sprung bed im getting a double line appearing like its creating a secondary beam after the gantry is about halfway across ?? any simple suggestions? all the alignment screws are locked in place with some weird white paint

Definitely mirror alignment. Take the time to do it right. The machines are only setup to work in a narrow area of the bed.

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hi thans for replying, will try an alignment when I get home from work tomorrow, as a bit late in the evening now

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had an attempt at aligning but then noticed when the tube u is during I can see a yellow circle on the frame of mirror 2 and the same circle appears just down wind of the spot on my wood…

I hope this shows, i didnt want to leave my phone in the enclosure too long…

this pictures shows it too, i used the 10mm jog on k40 whisp to manually step out a grid and fired single dots onto the board as shown by the allen key end… you can see the “ghosts”

Ghosts are often caused by mirror contamination, cracks etc.
Also reflection inside the objective lens from the beam hitting the side of the enclosure, contamination cracks, etc.


hope not machine has only a few minutes of use on it. I guess I need to pull the mirrors and check them… thank for your reply

These machines rarely come with proper optical alignment so I suggest you perform one :slight_smile:


was hoping to avoid it as all the mirror adjustment screws are locked in place with some weird white crap, but guess I know what I’m up to over Christmas

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I don’t remember whether we’ve yet shared alignment resources with you, but just in case we haven’t, here’s our standard alignment help…

From K40 initial setup and regular maintenance: Alignment

The path that the laser takes along three mirrors and the lens needs to be precisely aligned. Here are three resources that may help you understand how to do this.

If you prefer video instruction:

Ep6: Laser Beam Alignment. The DIY CO2 Laser Cutter / Engraver Build Series

If you prefer written instruction, here are two guides:

Note that if the third mirror does not align the beam with the middle of the lens, the beam will not be focused correctly and will not be aligned with the hole in the nozzle. You may wish to use a device that helps you align using a red visible laser. One kind uses a “beam combiner” that slightly reduces beam power, and the other is a tool used only while performing alignment .

did an alignment to the best of j Jr ability and all seemed well but on higher settings in still getting the ghost spot, so will try again and report back, it was working well f though to complete a couple of jobs though

i cut the blanks with my little cnc as the 5mm birch won’t cut as I’ve not got air assist yet, i can get it through with multiple passes but they are blackened edges

Remove the nozzle, put tape on the bottom of the tube, mark the circumference of the tube with a pen, and do a test fire. Then remove the tape and check the mark. If it’s not in the center of the tube, you are likely getting reflections from the inside of the nozzle.


still got alignment issues but had to do some paying work so addressed some of the safety issues… interlock microswitches made and mounted

then added a defeat inside to enable me to fire the laser during alignments etc

this involves an actual piece i have to remove to disable the microswitches.