More Curious than anything

Ok, so I’m experimenting with some pine 1x4x1. I masked this off for giggles, because I had a roll of backing tape to use. My plan was to mask it off which I did, engrave the name, then paint in the letters.

I cleaned my mirrors yesterday, because I had finished a large tumbler order.
As you can see, the left side of the name is a whole lot darker and deeper than the right side.

I’m pretty sure my laser and others burn harder nearest the tube or mirror 1. Just a guess on my part. I was using a compressor running 50psi to minimize char as well.

How do you go about make sure it engraves the same intensity all across the bed. My settings were 200/45/45. I think I should have cut back on the min power as well. OH, I also did a 5 degree scan angle to see what that does. Never have used that before.

This is just scrap, but I wanted to use my compressor and masking tape to see how it goes.

Thoughts on the difference of burn from far left to far right? Far right was just barely engraved. Far left was a good 1/8" deep.

Footnote: Just noticed that the scrap piece of board was bowed a bit. It was a bit lower on the right side when I put a bubble on it.

Use a longer lens, they have a greater depth of field if you can’t hold the board flat… What makes a laser powerful is the lens/focus… out of focus, loss of power…


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Thanks J.

It’s the only lens I’ve ever owned. Should I see that much reduced power 18" across the bed? That’s the length of this piece of wood. I did find another piece that was flat, and still got the same result.

I did a welcome sign out of the same material around 6 months ago, and it appeared to engrave the same from one end to the other.

I have been contemplating on buying a longer lens though.

Absolutely not… if it’s flat

If it’s not flat, you will have power looking issues, like you have… When a laser goes out of focus it might do nothing to the material that is visible…

Hold it down with something so it’s flat…


That’s what I was thinking. I can see a weeeeeeeeeee bit of power loss in the lower right hand corner -vs- the top left. I actually had another piece that’s been sitting engraved for 6 months at least. I blew the saw dust off of it, and the right side matches the left with regard to depth of the engraving. It was 18" wide as well.

I’ll find another one that is flat. I got a lot of 'em laying around.

Some machines have, what’s sometimes referred to as the 4th corner error where you can’t get a good alignment at all four corners…

Have you checked alignment, especially from the head to the table at all four corners?


Just a little back story. I engraved 400 tumblers with the rotary where it’s at now. I’m jumping ship here, but it’s relevant.

My settings for that entire job was 140 / 40 / 0.0500. They all engraved beautiful. The only problem I had was cleaning the Navy tumblers. I bought BLU and that cleared all that up.

So when I delivered the Tumblers down in Florida last week, I got back and thought, you know what, there’s probably a lot of soot on the mirrors, so I cleaned 2 and 4. Never looked at 4. I will tomorrow.

I put a sacrificial tumbler on the rotary today to test a job, and those power setting “barely” removed the powder coat. I had to increase the power to 80% to get the powder coat off.

BTW, the whole time I running this “test” tumbler, I look at my LCD window on the power supply and it bounces from 01 to 07 ma.

I have NO clue as to what I should be seeing with regard to how many ma’s I should be getting. Just wanted to through that out there. I started off today working with that 18" piece of pine, which Deeply engraved far left side of the piece, and barley burned off the tape on the far right side.

Just food for thought.

Don’t follow you here…

Most of these have 4 mirrors… I’ll assume you meant you cleaned 1 and two… not 3 as it would be on the head and is more difficult to get at…

Most of these that you can clean the mirror in place will maintain their alignment with a simple mirror clean… from what you’ve told me I’d have to assume you knocked it out of alignment .

Anytime you do maintenance and it doesn’t work right the next thing is an alignment check or realignment…

  1. tube works properly
  2. optics are clean and aligned
  3. proper focus

These three and they work…

That’s why we all have analog meters mounted on the case…


Man, I have no clue on even figuring out how to install meters…

I just cleaned 1st, 2nd, and 3rd mirror. Did an alignment test. Everything looks cool. I’ll pick up from here tomorrow.

Thanks man.

It’s not rocket science, I’m sure we can guide you if you wish. There are probably a bunch of videos.

The most difficult is cutting a hole in your machine :rofl:

You clearly changed something or it would be working as good as when you took it down…


I’ve seen guys use some type of power settings file that burns and cuts through lets say 3mm ply. Are these specific to the type of machine meaning 55w -vs- 180w machine?

I have some ply that will cover my entire bed. I thought about placing that image near all 4 corners and see how it performs. I think it’s called a universal test card, or something along those lines. I just want to see how it performs engraving and cutting in all 4 corners on one piece of wood. I guess I can just create some text and different layers with different settings and compare them all when it’s done.

Well, I performed my mirror alignment yesterday. I’m dead on with mirror 1. Mirror 2 is very close to each other when I move the gantry back to the front, and then back to the rear. Mirror 3 is very close as well in the same fashion.
What surprised me was what I saw in a video yesterday. Skip to marker 8:58 on this vid to see what I’m talking about.

My mark looked like this. The white dot is the burn mark on the tape that was tapped under the head after I removed the lens.

Looks like I have some more adjusting to do.

Is a relative term with no real meaning… how much is very close…3mm?

Your video states it’s centered at m1, it’s clear at 4:16 mark that this is not true.

It’s like he used a nuclear pulse to blast the alignment tape… should be a light brown mark with a darker center…

You will also miss the ability to check for the tubes TEM00 resonance state… the traces for determining this is obliterated.

At 7:12 you can see the bubble in his tube… do not fire the laser without coolant flow… The bubble is there because his output hose is not positioned vertically to allow these bubbles to escape .

If you lase when a bubble, like this, the tube heats excessively in this ares… Large bubbles like this should be avoided…

At the end of the video, you can see a small bubble in the tube. It’s not good to have any stuck bubbles…

Moving the beam across the X axes of the down tube, you have to move the head in the Z direction… might not be possible with your type of head…

I can’t find what your machine looks like… Monport currently only sells a 40W and 60W up… I assume your machine is more like the 60W than the 40W, that is more of a K40 type.

Be aware that some heads do not have the hole in the center of the mirror… this is from my OMTech China Blue…

This is a m2 target, a pulse for both near and far burns… you can distinctly see both burns, not a black hole… which tells you more about the alignment?

If your machine can cut paper I’d suggest you design and cut your own targets and do away with the tape method… I use watercolor paper, relatively thick and easy to handle… easy to read

On m1, you need the beam to strike m2 at it’s center when it’s closest to m1. His video shows him sliding it back and forth… my experience has been if it isn’t centered at m2 at it’s closest position, it won’t be near the center at it’s maximum distance… nor will it stand any chance of being aligned…

I adjust m1, while pulsing it with my other hand… if it’s off, two or three more pulses I’ll have it right on… Well, I’ve done it more than once :face_with_spiral_eyes:

Once it’s centered, you have to move the spot at the maximum distance to the position of the minimum distance.

I think you have some adjusting to do… I don’t recommend to most to mess with the mirror mounts… most have to no way to ensure they are aligned to 45 deg, it’s tough to get a right angle or 45 deg object in such tight quarters…

If you change something, ensure you can put it back in case you have issues and get yourself lost… I’m speaking from experience… :frowning:

I use a target on the top of the down tube at the start of the vertical alignment and use this jig to ensure it’s vertical.

You’ve got enough to digest here and I have other laser problems to chase…

Have fun… :rofl:


Thanks J.

I’ve watched Roger Webb quite a few times on the subject matter as reference.
BTW, I know I know for a fact I don’t have bubbles as well, especially since I bought a chiller, but have made sure NO bubbles in the tube… I’m paranoid that way.

I’ll try to make up some targets. I’ve got to create some samples for some new customers, so I can’t spend much time on this until I get those done.

Thanks for all the info. Hopefully I’ll have time later this week to create the targets and spend the needed time to align.

Follow your own instincts, be open minded and you’ll do fine…

Good luck


Well, I made some good progress today.

First off. Made sure my honeycomb bed was level to the gantry. It wasn’t. Fixed that.
Cleaned my mirrors with eyeglass cleaner and a soft cloth.
Got mirrors very very close. Close enough for government work.
Next was to see if the head of the cone on the laser was at the same height across the bed from left to right. It wasn’t. I used a combination square to get all that correct.

Right side of the bed is getting power like the left side was on that sample earlier in the thread. To make sure I wasn’t screwing around with a piece of plank that might be bowed, I engraved the letter H in it on the left side of the bed, then just turned it around and burned the other H on the right side. Depth in both were almost identical.

Now the funny part. I went to create a sample for a customer I got last week using a cork coaster, using my old settings. It almost cut it in half, so going forward, I’ll have to document my new settings.

I’m getting a good engrave on it now using 200 speed / 9 pwr.

It may not be setup like some of ya’ll, but it’s progress on this end… ROFLMAO.

Thanks for the help and assistance as usual.

Hope it works better than our government :rofl:

How can this happen if the bed and gantry are square>

How did you correct it without disrupting the previous step?

All you need do, use the materials library and create a new entry based on the selected layer… then you can just click assign to layer…

Moving forward is always a good thing…

Have fun… sounds like you most of the bugs out of it…


Good Day Mista Jack.

Don’t get me started on gov work or even local municipality work… Doesn’t help my blood pressure. Anyhooo. I got my sequence wrong in my statements, but the long of it, was my bed wasn’t even with my gantry. Had no clue it wouldn’t be. It’s still my believe that these Chinese machines are slapped together, crated up, and shipped to a US warehouse. It doesn’t pay for them to make sure everything is square, mirrors aligned, etc before shipping them out to customers.

If that wasn’t the case, you wouldn’t see endless threads on FB with regard to OMtech, Monport, etc…

Anyway, I believe I’m on the road even though I don’t do a lot of wood engraving or cutting. Just not my thing.
I’ve got to get better educated on Fiber Lasers. Not so much technically, but I want to find one that I can engrave 20 and 30oz tumblers without having to buy another rotary.

Have great one out there today.

You brought it up :rofl:

Fiber machines are expensive and pretty technical, but many use them with great success… most fiber machines are pulse compared to the continuous wave of a co2…


Where would I find the Laser targets that you are talking about, and will it work with my K40? Looks a lot easier to use than the tape. Thanks in advance for the reply, - Bill