New User here. New to Laser Engraving. Having Problems

[ModsUnlimited]

so obviously im new here. hi everyone.

i had just recently aquired a K40 Co2 engraver and everything was going good until today. the engraving starts in the top left of the machine and works its way down. but as it goes down and towards the lower right hand corner the engraving gets very very light. almost to the point to where its not engraving at all. and im at a complete loss in what to do.

i can and will provide pictures if needed.

thanks guys!

[LINUS]

I think there are two things that I can suggest:
1.Platform uneven,so the top left hand corner foucus different right hand corner
2.Laser beam no right,you should Align Laser beam

[Downunder35m]

1+
These K40's are notirous for alignment problems!
I had to fix a few things on mine as well to ensure all stays aligned.
You things you would expect to find in such machines, like spring washers, locking nuts or for fix and forget parts at least thread locker glue.

I checked the bed level with a pencil and paper.
Use some sticky tape to mount a short pipe or tube onto the head that is just wide enough to fit a pencil through.
Place some paper on the bed (just for the fun) and move the head around.
You can see on the tube if the pencil moves up or down - a little mark on the pencil or the area with writing helps to see it better.
Getting to the bed screws is a real pain as you need to work through the clamping hole in the center.
Be aware that chinaman loves to use oversized nuts between bed and mount to adjust the height, if you hear something falling you know what to look for.
There are two ways to fix an uneven bed that worked for me.
a) simply use washers or thin metal strips between bed and mounts to get it really level. Bit of a long procedue but it works.
b) use long grub screws and additional nuts to make it adjustable within limits.
The grub screws need a nut near the top to make them flush with the bed instead of a head poking out - use thread locker once in the right spot.
On the mounts you need to glue a nut in place - best to do this with 2K glue and with all 4 nuts at the same time.
Using the bed as a template make a stiff cardboard dummy that you use to keep the grub screws in place.
As the cardboard is thinner you can use nuts to secure the screws to it.
Once cured you can adjust and level the bed with the grub screws but be aware the bed will only rest on them so you really need to make sure the
the nuts are glued into the mounts properly.

To align the mirros and lens I prefer clear sticky tape instead of the paper method although I am working on making a detector card as well.
Start with the mirror adjustment with the mirror near the tube.
Place the sticky tape on the mirror that moves down and push it all the way to the endstop.
Do a testfire at about 7-8% - short one!
Move the axis down to check where the laser hit.
You should see some wrinkling around a slightly oval melting mark - there should be no hole for the first testfire, if there is use less power for the next ones.
Now use a black marker to make a dot right on this burn mark.
Move tha axis down a do another testfire - check where it is located and if no match with the first mark adjust the mirror near the tube until you have the marks aligned.
You will need to repeat this prcedure until the spot is always in the same area no matter where you move the axis.
I use the sticky tape a bit longer so I can just peel it off and move the marks out of the way before repaeting the process.
Once this axis is done you do the same with the x-axis.
Just that you now adjust the mirror to the left to keep the burn marks dead center in the hole of the laser head.
Now you see why I prefer clear sticky tape over paper - you see the alignment in relation to the mirrors
I also do a last test under the lens to make sure the beam hits dead center as otherwise it can cause the beam to hit the target in an angle other than 90°.

While you are at it do yourself a favour and double check the entire wiring of the machine!
The wires on the endstops are often fixed with heat shrink and I had bad solder connection on them causing intermittent problems with the axis.
In my case there was no protection on the metal where wires pass through, it pays off to fix that issue even if it is just with cut rubber tubing and glue.
Pay special attention to the high voltage wires and connections on the tube!
There are reported cases where the tube connections were not properly insulated or a bit of the wire was poking out.
This can cause arcing onto the case and will possibly destroy the electronics with a good chance to damage the power supply too.
If in doubt use self vulcanising silicone repair tape (automotive parts shop, home depot) to address this issue.
Also make sure to locate the HV cables as far away from the electronics as possible to prevent interference.
Last but not least: check if the fan in the power supply is monted the right way!
Mine was not and instead of blowing air onto the electronic it was sucking the air our resulting in insufficient airflow on the hot electronics.
But newer power supplies addressed this by placing the air inlets to allow the airflow to reach the hot parts.
In any case it is worth checking and I always prefer to blow clean air onto electronics instead of sucking contaminated smoke over them

[LINUS]

Very professional answer.Very cool

[Downunder35m]

Was trapped in exactly the same boat and had to do it a few times since I got the machine.
Cleaning, fixing, one or two accidents...
So I though with the same machine it will be helpful to get some more model specific info on the procedures and traps involved.
With a bit of TLC these cheap imports can actuall do really decent jobs.

[ModsUnlimited]

Downunder35m Thanks for the detailed info and thanks to everyone else for helping out!

I think we got it figured out. it actually seems to be an alignment issue. never knew it could do that in just one corner. this is all a learning experience to us so thank you for helping out.Im going to print off Downunder35m post and use it as a checklist and have my partner go over it. and let y'all know what we find lol

[Downunder35m]

Just one extra to save you some time:
The adjustment screws on the mirrors work basically for three direct directions.
Up, down, diagonal/left/right.
With you first adjustments overdo the turns a bit and only use one screw - this way you get really good feeling what screw does what and why.
Turn it back to the previous position and after another testfire use the next screw.
It will quickly make sense to you how turning one of the screws changes the placement of laser spot on your mirror.
Once you figured the directions out properly you only adjust on screw at a time to center the beam on the laser.
Does not have to be perfectly center as it is a flat mirror - just as a hint in case you ever find a bad spot on a mirror
Just make sure the spot stays in the same spot when you move the axis.
Example:
Do the first testfire in the home position and mark where it hit.
Move the axis all the way out and fire again.
If the new spot is to the right you want to reflect the beam a tiny bit more to the left.
Repeat the procedure but still only use one screw.
Once the spot stays in the same spot for the direction you adjusted you tackle the next screw.
Not too hard to get a hang of it and once you did it a few times you will do it in under 10 minutes.

[KennethLop]

There is a video to Align Laser beam

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