Welcome to the ultimate K40 mirror alignment guide for your k40 laser cutter machine.
This guide has some tips and hints regarding the popular K40 laser machine type, but this can be used for any laser machine on the market as the science behind a laser mirror alignment is the same on all of them.

90% of the errors in laser machines are not skewed or non-square gantrys, it´s bad alignment of the three mirrors in the machine not lining up with each other.
Some of you will have a machine of that 10% with a skewed or non square gantry, but follow through this guide to the end anyway and you will find a link my other guide how to fix gantry problems. But first, you have to identify the problems by following this guide.

Please read through the preface about this guide before you start to avoid doing it wrong.
In my old guide about K40 laser alignment i had numerous examples of readers who skipped some parts and ended up doing the alignment backwards. I know it´s tempting to skip a step or two, but please, read everything and let me know if something is not clear 🙂

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This guide will help you align your laser machine to perfection.
It is very important that you follow each step and not jumping around, you will miss important information or details how to identify your machines problems.

Tools you need to complete this alignment
– Any tools needed to adjust the mirrors on your machine.
– Screw drivers, sockets or wrenches to adjust mirror holders.
– Painters tape, labels or paper with adhesive backing for covering the mirrors when test firing.
– In rare occasions, files and drill bits to adjust the holes where mirrors are mounted.
– A pint of beer, wine or a good cup of coffee 😉

How to interpret the results
This guide has a lot of test-firing and looking at the tape/label what the beam does and where it moves. Some parts need you to identify if the beam moves up, down, left or right – when doing this the direction is always as if you remove the tape and hold it in front of you, if the dot has moved right when you look at the tape – you choose right in the sections below.
It does not matter wich way the tape was mounted – just keep it horizontally the same from the mirror to where you look at it.

Adjust the tube if needed so you hit aprox. center on mirror 1.
Also, familiarize with the three adjustment screws on the mirrors which screw moves the mirror in what direction. This will help later in the alignment.

Machine locations and centering the beam
Here is a picture of different position i will refer to in this guide, please have a look to see what is what.
When i mention centering the beam, this has nothing to do with quality or power of your machine, it´s just a easy position to remember. You do not have to be exactly center – keep it close to center so it´s easy to see where the next test-fire will go.

Now, are you ready to align your laser machine? Let´s go!

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Part 1 – mirror 1 and 2

This part identifies the movement of mirror 1, moving up and down (from rear to front) of your machine. Follow each step of the instructions and lick on the button corresponding with your problem to find the information how to solve it.

Step 1 – first fire

– Move the gantry to bottom as the first picture shows
– Do a test fire and have a look at the tape on the 2nd mirror.
– Adjust mirror 1 until you hit center on mirror 2 in bottom left position.


Step 2 – upper axis

– Move gantry to top right position
– Do a test fire and have a look at the tape on the 2nd mirror.


By looking at your tape – did your beam move up or down?

Click on the answer below to see the solution.

Your 2nd mirror is too low.
Make sure the bracket holding the mirror is square and not bent.
Remove the two screws holding the bracket, mark the position so you can put it back and add some shims between the bracket and the gantry so the 2nd mirror is lifted some.

Start over with the alignment and re-center the beam in furthest position and adjust more if needed.

A alternative solution is to lower mirror 1, but do not go that route until you tried the tips above first.

Visual example of movement up.
k40 mirror top top

Your 2nd mirror is too high.
Make sure the bracket holding the mirror is square and not bent.
The solution for this problem is to bend down the bracket a bit if its bent up, which is the most common issue. Second solution is to lower 1st mirror but almost never needed.

Start over with the alignment and re-center the beam in furthest position and adjust more if needed.

Visual example of movement down.
k40 mirror top bottom

Sweet, your vertical movement is already aligned. You can now go to the next step.

Visual example of perfect alignment.
k40 mirror center

By looking at your tape – did your beam move left or right?

Click on the answer below to see the solution.

Your 2nd mirror is too far to the left. Loosen the two screws holding the white plate and move it slightly to the right.

Start over with the alignment and re-center the beam in furthest position and adjust more if needed.

Visual example of movement to the left.
k40 mirror left

Your 2nd mirror is too far to the right. Loosen the two screws holding the white plate and move it slightly to the left.

Start over with the alignment and re-center the beam in furthest position and adjust more if needed.

Visual example of movement to the right.
k40 mirror right

Sweet, your horizontal movement is already aligned. You can now go to the next step.

Visual example of perfect alignment.
k40 mirror center

Part 2 – mirror 3 and laser head

Half way there! This part helps you align the laser head in square line with the 2nd mirror. We know the 2nd mirror is in line now since part 1, and now it´s time for the laser head.

Just remember, after each adjustment – re-center the dot on the laser head before test-firing up close to mirror 2 to see where the beam moved.

It´s important that you do not touch the alignment at all from part 1.

Step 3 – bottom right

– Move the gantry to bottom right position
– Adjust mirror 2 until you hit center on mirror 3 (hole in the laser head) in bottom right position.


Step 4 – bottom left

– Move the laser head to bottom left and do a test fire and have a look at the tape on the 3rd mirror.

By looking at your tape – did your beam move up or down?

Click on the answer below to see the solution.

Your laser head is too low.
Mark the position of the three screws on the laser head with a pen or small mark, remove one screw at the time and insert a washer between the standoff and the plate holding the laser head.
Doing this will not ruin the location of the plate, confirm with your marking and adjust if it moved.

Start over with the alignment and re-center the beam in furthest position and adjust more if needed.

Visual example of movement up.
k40 mirror top top

Your laser head is too high.
This is not a common problem and is mostly due to a low 1st and 2nd mirror.
You can try to lower the laser head if possible, but i would suggest shimming mirror 1, 2 and the laser tube with 1-2mm thick washers and start over with the alignment guide.

Start over with the alignment and re-center the beam in furthest position and adjust more if needed.

Visual example of movement down.
k40 mirror top bottom

Sweet, your vertical movement is already aligned. You can now go to the next step.

Visual example of perfect alignment.
k40 mirror center

By looking at your tape – did your beam move left or right?

Click on the answer below to see the solution.

Your laser head is too far away from the gantry. Loosen the three screws holding the bracket and move the plate up (if you look at your machine standing in front of it – looking down on the work area). Up – away from you.

Start over with the alignment and re-center the beam in furthest position and adjust more if needed.

Visual example of movement to the left.
k40 mirror left

Your laser head is too close to the gantry. Loosen the three screws holding the bracket and move the plate down (if you look at your machine standing in front of it – looking down on the work area). Down = towards you.

Start over with the alignment and re-center the beam in furthest position and adjust more if needed.

Visual example of movement to the right
k40 mirror right

Sweet, your horizontal movement is already aligned. You can now go to the next step.

Visual example of perfect alignment.
k40 mirror center

Laser head centering

Aligning the machine in horizontal and vertical plane is almost good enough. The last little part is the laser head. Hitting the hole centered is often not enought but close.

Easiest to do this is to use my tool, cut it out from 2mm acrylic or wood and put on the laser head, test-fire in each four corners and look at the tape to make sure your beam is hitting well inside the lens. Too much movement between the corners needs attention.
As you have perfected the alignment between the mirrors i suggest you add small pieces of paper between the mirror and holder for the laser head if you need to do any smaller corrections.


You have now aligned your machine by all means possible. If you still have problems it´s time to look at the gantry if it´s square, level and in line with your bed and machine.
Click here for the old article about aligning, where i go in to adjusting the gantry a bit more.

I´m sorry to say it, but if this guide cannot align your machine, it has some bigger issues and a general guide like this will not cover the problems it might have if i want to keep it quick and helpful for 95% of the users.

Feel free to comment below

The old version of this guide is archived – it can be found here if you still want to read it!

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98 thoughts on “How to align your mirrors on K40 laser cutter machine”

  1. Hello, thanks for your guide. It has proved very useful!
    However, after following all of your steps and getting the laser to hit dead center all the way through to the end of your guide, when I move the laser head to the top right and fired the laser onto the tape then moved it to top left to fire again, the beam moved down and to the right.
    I know this is not part of your guide to check top left but surely it should be firing on the center on top left too? Or is this ok?

    1. If you upper right corner steps up on the mirror, the gantry is leaning down in this corner. Add some washers between the gantry and machine case and test again.

      1. Please i have the same problem, i align the mirrors and when I move the laser head to the top right or left the hit is not in the sender is up and right, What should I do? move the gantry?

        1. Look at my earlier reply, you need to shim the gantry between the floor and gantry to lift it a bit.

    2. Hello. I got same problem. Top right corner laser point move up and left. I lifted gantry at this corner but no success. Please help me. What else i can do?

      1. Lift more, remember to zero out the alignment after each shim you add, if not you get old error + new lift as total error. Move to bottom right and center before testing top right.

    3. I have been trying for a week to align the mirrors.
      It took 30 minutes after watching this.
      Thank you

  2. Worked like a charm. I also had to carefully bend the gantry in the same manner as you recently suggested to someone on the Facebook page, seeing as the right side of the gantry was too close to the tube. Everything’s lined up perfectly now in every position. Thanks heaps!

  3. It worked a treat. I spent 4 days trying to align my mirrors without any success. Following this I am now up and running in a little over 2 hours.Many thanks.

  4. Followed all the steps and then right at the end the laser quite high instead of in the middle.

    I’ve tried everything, am I doing something wrong?

    1. If the beam is high in the bottom left position, your 2nd mirror needs to be lifted, or the laser head lowered.

  5. Hi Thanks for the help , got it aligned but it does not seem as powerful , wont engrave at all and laser I have to turn up to almost max to get anything , please help if you can what I’m doing wrong

    1. Check out the article about proper focus. If you are out of focus the power will go down very hard. Also make sure you are hitting inside the mirror and lens in all 4 corners. Move the gantry around and test-fire to make sure you hit inside the mirrors, and the lens.

  6. Hakan,

    I have been following you for quite some time, you have helped me in many ways.
    Your website is coming along brilliantly and this new format is alot easier to follow.

    I come back here every time i need to realign.

    Un beatable. You should be proud.

  7. Hello,
    Your article was loads of help thank you! But I have an issue I’m hoping you can help me with.
    I bought my machine last week, I had to have a new laser sent out as the first filled with water, I installed the new tube and set the alignments, it worked fine for a few test items yesterday but today I went to use it and it wouldn’t cut. I thought maybe the mirrors needed tweeking but when I tested the first mirror I have two dots on the tape not one like I did when I first tested it. Is is another faulty tube? Thank you

    1. Increase the power if you get two dots. The tube is not in a energized state and can be instable and create two beams. If the two dots doesnt go away on higher power the tube is bad.

  8. Second time using this guide, now with new mirrors and lens I bought ages ago! Thanks Hakan!

  9. Thank you, thank you, thank you! My old K40 has never cut so well! I had a laser head that was about 1.5mm too high which made for a tiny window of steady power throughout the bed. I simply ground down the stand-offs that hold the head to the gantry a bit, realigned, and it working great!

  10. I have watched many videos etc online on mirror setting etc…This is by far the best and easiest if you follow instructions properly. by far the best , will save you alot of time and most of all, FRUSTRATION..\\\\awesome, Thank You for the instructions..

  11. Great info, got every line up, but have a problem: ok lined up all the mirrors,here the problem 3rd mirror at bottom right corner, (furthest point) spot on, when i move it to top right corner, the spot is 2mm to the right. any ideas?

    1. The X is not 90 degrees. You can loosen the coupler holding the axle between the both sides of the drive system, and move the right part a bit down – towards you. and then re-align bottom-right with bottom left again – and then test top right again.

      1. Hello! I have a similar problem. I can follow your guide and do the alignment without any difficulty. However, after adjusting the head in the lower right corner, if i move the head to the upper right corner the beam goes up 2mm.
        I already tried to moove up the gauntry in the upper right corner, but when doing this and after repeating the alignment, the mirror 2 follows the movement and continues all the same (up 2mm).
        I do not know what to try more …

        1. Only solution is to lift the gantry in top right corner. Lift it more without re-aligning the beam.

  12. Haven’t tried yet, but I’m a bit confused about the head adjustments. It seems to me like moving the head would be tricky. I would think that as long as you are centered on mirror 1, adjusting mirror 1 angle would be sufficient. All other mirrors could be aligned w.r.t. mirror 1. Could you explain why moving the laser head is a more desirable way to go?

    1. You cant bend light. No matter how much you adjust a mirror, you can never resolve a laser head not beeing in line with the mirror, or the 2nd mirror in line with the 1st. The laser head have to move left to right in the same 90 degree angle as center on the 2nd mirror, if not the beam will wander all over the mirror and in the end – miss the lens or hit inside the head 🙂

  13. This is the best guide I’ve seen so far, but for me, one thing is still missing. I still haven’t entirely figured out how the knob screws behave in adjusting the mirrors.

    I’d sure like it if you could describe which knob to turn in which direction to get the desired movement.

    So, for example, “If beam moves up, turn knob #3 half a turn clockwise.”

    1. Also, I’m wondering if it’s possible that the gantry might be unevenly, imprecisely or improperly set, will it them be impossible to accurately alight the laser beam?

  14. HP, thanks for this guide!
    Beam was hitting my 3D printed air assist nozzle when mirror 3 is in certain position causing double lines.
    I’ve successfully adjusted my mirrors and now beam hits center of third mirror no matter where it is at.
    I have a few suggestions to make this guide better:
    1. Please make the first image showing which mirrors are which larger. I know you can click it to make it larger, but IMHO it is critical to convey which mirror is which it should not require reader to click.
    2. When explaining how to adjust the mirrors, please include a photo/diagram as to which screw does what.
    3. Under section “Part 1 – mirror 1 and 2” in this sentence “Follow each step of the instructions and lick on the button”, I’m sure you meant click instead of lick 🙂
    Thanks again Håkan!

  15. I am having an issue that I have spent about 12 hours trying to fix with no luck. I will try and explain it properly here.

    So… First I aligned Mirrors 1 and 2 that went off fairly well. Then I aligned 2 and 3 in the bottom right and left positions. Took some fiddling but got it to track back and forth and stay in place on the laser head. Here is where the problems start.

    Next i moved it up to top right and it is shooting about a centimeter above the previous dot in the center on the bottom right. When it is in top left the position on the head is good but goes way outta whack in the top right and it moves up really fast after about moving up in the y axis about 6 inches the dot shoots up. I have tried correcting it by bumping the tube up and down. If I get the top right fix the bottom right is way out expect a cm too low. It almost seems like there is a twist in my machine but I check the corners and they are square, the rails run level to each other. I have been pulling my hair and getting nowhere. Any ideas would be greatly appreciated. Thanks

    1. Only adjust the tube to hit inside mirror 1, after that you should never touch the laser tube again. If the dot moves up in top right position, that corner is lower than rest of the gantry.
      Shim it with some washers, about half of the movement you see, aprox 5mm. Then re-check so the beam is good between mirror 1 and 2, and from 2 to head in bottom position, and lastly test top left-right positions again, use the data you get to shim more or less in that corner.

      1. I’m having this exact same issues except only my front right position shoots about 8mm to the right. All other positions hit the same spot.

        1. Front right, is that close to the tube? If that happens the right side of the gantry is moving too far.
          You can solve this by moving it to the bottom (away from the tube) Loosen the axle coupler and move the right side 1-2mm down – towards you. Tighten the coupler again and re-test the alignment. You might need to move it more.
          This allows for the right side to move without the left moving.

  16. Hi there,

    I’ll start by saying your guide is amazing and I wouldn’t be where I am now without it. When I do the alignment for mirror 3, I can get it in the center perfectly but it is clipped and looking like a half moon when positioned on the bottom right. When positioned on the top right is worse and actually barely left a mark. I’m now nervous to touch either mirror 2 or 3 because I don’t want to make it worse. Any suggestions?

    1. Take a piece of paper and put in front of mirror 1, then mirror 2 and see where it hits the edge. If it clips the edge on mirror 2 you need to adjust mirror 1.

      1. Thank you for replying back!!! I was able to get it centered perfectly! Lots of patience.

        I now face a different problem and I’m hoping you can point me in the right direction. I did a test with a square that was 100mm by 100mm. After I cut the square I measured 100mm (x) by 97mm(y). I did contact support for my Laser cutter but all they said was to tighten up the coupler in the rear. I didn’t think that would help and it totally didn’t, I still have the same results.

        1. What software are you using? Some are cutting on the line and the width of the beam sometimes makes parts smaller, and if its only one axis i also think its a belt issue. But try making the box 150×150 and one 50×50 and see if it keeps the error ratio, choose engrave on something just to get lines to measure.

          1. Hi! I have adjusted the alignment on my old Red Sail multiple times. I have a new blue Chinese laser, and I’m stumped. When I pulse without any mirrors covered with paper it will mark my bed material. When I put paper on any of the lenses to try to align it the papers will not mark at all. I’ve adjusted the power of the pulse, I’ve put a whole sheet of paper up in case the beam is majorly off…but nothing…help?

          2. Start with the 1st mirror, put a piece of paper in front of it and try to mark the paper, move on to 2nd, 3rd and then the bed to see where you lose the beam, there´s where you need to check more what is happening.

  17. Thanks for this guide, from mirror 1 to 2 , needed 4 washers, then needed longer screws, then needed more washers to compensate for the screws being too long and not tightening, and its not even perfect yet, still 1-2 mm above and left.
    What im saying is this is a very tedious and time consuming, wish ther was a Prusa version of this price/quality

  18. Brilliant guide thanks. My issue is, mirrors 1 and 2 aligned but when i fire at the head it doesn’t even mark the tape. How can i bring mirror #2 to hit the centre of the laser head?

    1. Put a piece of paper in front of mirror 2 in both top and bottom position so you are sure the beam hits the mirror.
      If it does, take a larger sheet of paper and start close to mirror 2, pulse the laser and move the paper to the right side to see where the beam goes – and adjust mirror 2 until you hit the laser head. Keep your hands out of the beam and look away when pulsing to prevent any flash backs.

  19. Have a problem with alignment. Have all mirrors align so that all 4 corners hit same spot on laser head. The problem is when I cut it ghost in the middle right side. When I check with tape on head all 4 corners are still right, but about 8″ up on the right side the beam drops about 4mm. Very Confusing. Thanks for any ideas.

    1. You are probably hitting inside the laser head, or the edge of the lens or some mirror.
      In the download section on this website, you can find a tool to see if the beam hits in the middle of the lens or not, try it out! Go to FAQ in the menu and then downladable files.

      1. Hi Great guides! I am a little confused by the .txt intructions supplied for your aligntool download.

        when you say glue the pieces together in what orientation? stacked on top of each other like playing cards? and is the tool fitted over the beam input hole going to “mirror 3” or under the lens at beam output from laser head as it exits the lens?

        Maybe a few pictures added to the ultimate mirror alignment would help clarify?

        Many thanks

        1. Stack the pieces on top of each other, and the tool fitted at the exit of the laser head. You want to see if the beam is exiting the laser head in the center or not. Thanks for the comment, i will add some more pictures in the PDF file.

          1. thank you for the reply… I am setting a kh 3020 at the moment to replace my old windows XP only K40 so your guides have come in very handy. Ammeter fitting next on the agenda.

  20. Hi,

    many thanks for that perfect guide.

    I hit every mirror perfect in the center. But when I move the laser head to top right, the laser spot is 2-3mm left from the center??

    Any ideas, what I can do?

    Thank you very much

    1. Try moving the gantry with the software, if you push it by hand you might move the right side more than the left. It might be a small skew in the gantry too making this, but try with moving the gantry with software jogging first. Second to try is to loosen the coupler on the motor and move the right side 2mm and then tighten the coupler again. (motor and coupler between left and right side)

      1. Many thanks for your help! But how do I loosen the coupler on the motor? Are that the round things left and right of the motor in the middle/back of the machine?

        Sorry for stupid question!

        1. Between left and right side there is a axle connecting both sides to the stepper motor. The axle is held to the motor with this coupler, small torx or socket head screws, if you loosen the screws you can turn the axle for one side a bit to compensate for any skew in the movement. Mark the position with a sharpie so you know where “zero” is if you need to go back, or the other way.

  21. AMAZING write up on how to align the machine! Like you stated at the beginning I thought my frame was WAY off. Then I found your site and went through the steps and it was easy as could be. Thanks a bunch!

  22. My stock Blue/White K40 tube hits the first mirror quite low– down by about 4.5mm. I can’t lower the bracket the mirror is mounted on so I assume I need to move the tube itself upwards. The large plastic brackets that hold the tube don’t appear to have any up/down adjustment. Do I unseat the tube from the plastic brackets and place shims under the tube? Or rather, I should ask “What is the correct way to up/down align the tube?”

    1. 1st mirror is not that important, the 2nd is though. But if you want to lift the tube – put some shims between the metal and the holders of the tube, use acrylic or wood. Then start over aligning it on the 2nd mirror and go from there.

  23. I’m centered on step 3 and step 4 but when I put the leaser in home position it’s high right

    1. Your gantry is leaning down in top right position, add washers or similar between the floor and gantry to lift it (top right only).
      Zero the beam in bottom position after you added this before test-firing again.

  24. My 2nd mirror when its far from the first mirror its perfectly in the middle but when it gets close to the first mirror it goes to the upper right corner only for like two and a half millimeters.I wanted to ask if you can tell me a way to solve this problem.and get it perfectly in the middle in both ways.When its close and when its far.i already tried to adjust it but it didn’t work.

    1. The only solution for this problem is to move the 2nd mirror holder about 1 millimeter to the left (towards the side of the machine), loosen the two screws holding the white bracket. After this, put 2nd mirror in bottom position, test-fire and adjust until you hit center – then move up close and test-fire to see if it aligns in center.
      To adjust the height difference, you need to lift the gantry in top left position – add a washer or two between the floor and gantry. You need to unbolt it from underside. After adding this, center the beam in bottom position before test-firing.

  25. Hej HP,
    1000-Tak for dit fantastisk fine styke arbejde!, det har sparet mig for mange timers arbejde.
    Har det rigtigt godt


  26. Hi, I have aligned all the mirrors, but nothing comes out of the head. I have placed a small bit of card between the 3rd mirror and the lower lens. There are burn marks on the card, a bit off center but they are there. I just don’t know what to do next. I have polished all the mirrors, turned the lens around so much I now don’t know the correct way, is it the oval face facing up or down. I thing that it must be that somehow the beam is just not hitting the lens center, but how do I adjust that.?…

    1. Rounded surface is up. But if you do not get any burn marks below the lens, make sure the beam is hitting straight down. You are probably hitting inside the nozzle or the edge of the lens. If you have the original laser head, check out the download section for a piece to use to see where the beam hits. You need the laser to cut it though, but it can also be 3D-printed, or cut by hand in thicker cardboard.

  27. is there a guide pr can you tell me how to adjust my x axis belts? there are two philips that adjust tension, but i cant tell which way to adjust. im getting curved lines where there should be straight lines. Im very frustrated over something that seems so simple! Thank you

    1. Do you get curved lines in all axis? The belt should not be super tight, but at least give some resistance when pushing on it.
      Also check the wheels, if they arent perfectly round or worn out it will make the laser head move or vibrate creating strange lines.
      Bad alignment can also make this, either by hitting the edge of a mirror or lens – or inside the laser head.

  28. Have followed Your guide mirror 1-2 hit centre target but not dead, Moving to mirror 2 – laser head, at the bottom right target hit centre at bottom left target hit centre but not dead, moving to top right target hit up to the right. Please help with solutions.

    1. This is often beacuse the gantry is lower in the top right position. Remove the bolt holding the gantry and add some washers between the “floor” and the gantry to lift it. Double check alignment in bottom position and then check top right again, add more if needed.

      1. URGENT!!!! in your mirror alignment guide you said we should place mirror 2 at the far end before setting, you now mentioned ADJUST MIRROR 1 UNTIL IT GET TO CENTRE OF MIRROR 2, my question now is, are we to adjust the mirror with the knob behind mirror 1 or adjusting the mirror itself to get the dot to the centre of mirror 2.

        1. Always adjust the knobs on the mirror before the one you are aiming at.
          If you aiming at mirror 2 – adjust 1
          If you aiming at mirror 3 – adjust 2nd
          And you always do this in the furthest location away from the mirror you adjust the knobs on – and after that move it up close to see what more adjustments needed on the gantry or mirror holder.

          When you have placed the beam in middle of 2nd mirror, or 3rd mirror and you get problems when its moved closer – you cannot adjust this error on the knobs, it has to be done on the base of the mirrors itself as explained in the guide.

          1. After the centring from the bottom left of mirror 1 to mirror 2, moving mirror 2 close to mirror 1 the DOTS are beside each other with the use of the 3 knobs behind mirror 1, in your guide you said we should loosen the mirror 2 and slightly move it to the right and start all Again.
            My Question is, DO WE NEED TO UNSCREW THE 3KNOBS TO IT ORIGINAL POSITION before starting allover with the alignment and re-centring.

          2. After you move the mirror holder or laser head, start over with centering the beam in furthest position again. Dont move the screws until you need to move the beam to center. Then test-fire up close again to see if you need to adjust it more.

  29. How much to have you help me align? I can’t figure it out. Mirror 2 hits center and mirror one is off to the far left and down. About to the rim of the mirror.

    1. Mirror 1 closest to the tube doesnt matter, just hit inside the mirror.
      2nd mirror – adjust the screws on mirror 1 until you hit in aprox. center on mirror 2 in furthest position – move up close to see what´s needed to be adjusted.
      3rd mirror – adjust the screws on mirror 2 until you hit in aprox. center on mirror 3 in furthest position – move up close to see what´s needed to be adjusted.

      Dead center isn´t needed either, the important thing is that the beam doesnt move over the surface depending on location of the gantry – this will cause issues with sizes and engraving quality/position. I just use center as a good location to aim for in my guide to align your machine.

      I´m on vacation right now so i dont have the tools or time at the moment, just looking in on the comments now and then.

      1. ha if all mirrors are in alignment but the laser beam is hitting on the inside of the air assist head what is the fix for that?

        1. 3rd mirror not aligned 90 degrees from the beam, so it hits inside. Or the head not level.

  30. Hi there, first let me say thanks for the articles, very helpful. I have just bought one of these machines and your alignment advice is great for me, the only thing that I am struggling with is the lens adjustment using the tool – would it be possible to add a photo to show the tool in place to help understand the usage?

    I am trying to get my machine to cut MDF and acrylic, and so far test pieces show that with the 40w tube I can only cut a maximum of 1mm deep in one pass, and to get any deeper requires many (15+) passes, so am suspecting that something is up with the lens alignment. Of course, I had to follow many of your tips to get the machine to that stage! They are cheap, but you get exactly what you pay for!

      1. Amazing guide had to shim up second mirror and shim up right side of my tube now my beam on all mirrors are centred cuts like a dream!!!!!!

  31. Hello You say to add a shim on the mirror to raise it ?? what is a shim ? how do i do that ?

    Thank You

    1. Can be anything, i personally use acrylic or metal/aluminium. Washers, thin metal, or acrylic if its bigger gaps.
      But metal is the best, as it doesnt compress. Washers for bolts works good, as they already have a hole in them.

  32. got a question. in the beginning of the guide it says if the test fire it to low or too high at the second mirror, then the bracket for mirror 2 maybe to low or too high. what about any adjustments to the screws on mirror one. do they ever come into play?
    im having an issue where i cant really cut anything on the right hand side of the cutting platform. lens and mirrors are clean. i dont appear to be hitting the inside of the air assist nozzle.

    1. Only use the screws to adjust the beam so you hit center on the next mirror.
      Like this
      Adjust the screws on mirror 1 – so the beam hits center on mirror 2 when its furthest away (down)
      Adjust the screws on mirror 2 – so the beam hits center on laser head – when its furthest away (down right)

      After this, you cannot correct any deviations with the beam moving over the surface in different positions with the screws, you have to move the 2nd mirror holder or laser head left-right or up-down depending on the movement of the beam when you move the gantry.

  33. Thank you for the mirror alignment instructions. I have my mirrors aligned, but when I start my engraving project, there is a shadow. I’ve had this problem before and fixed it, but I cannot remember how I did it. My mirrors are aligned and clean. Any suggestions?

  34. I love you man. 3 days of work and nothing. 30 minutes with your guide and everything is perfect. Thank you very much

    1. First make sure you are hitting center on 1st and 2nd mirror in all positions.
      After that you can adjust the 3rd mirror to align the beam to center. Depending on the laser head you might need to put in thin paper on the edge of the 3rd mirror to lift it in one corner to aim the beam.
      Put the paper on the opposite side of the beam. If it hits on left edge (seen from the front of the laser) – put a piece of paper on the right side of the lens between the laser head and mirror. Test fire again, you might need to fold the paper to lift it more.

      If you have a adjustable mirror, use the thumb screws to align the beam in the middle.

  35. after did all of this and 3rd mirror is centered and i try to cut my wooden piece but unfortunately it is not like before.power is very lower and why is it?

    1. Make sure you hit in the center of the lens and not hitting the inside of the laser head.

  36. Hello, I am having an issue aligning my mirrors. I’m stuck on the first step. After I adjust the screws on mirror one so that the laser hits the center of mirror two in the far position, I move mirror two to the near position and test the laser again. There is no change vertically, but horizontally the laser is firing several mm to the left of center. The guide says to adjust the white plate that mirror 2 sits on to correct for this. However, I can only adjust the plate 1-2mm before it is scraping against the side of the frame and prevents the gantry from moving. And, I don’t notice any difference in results when I make this minor adjustment and then start over from the beginning. Is there something else that could be causing my 2nd mirror to be in the wrong spot? And, is it normal to have so little room to work with when moving the white plate?

    1. You can get the same effect by moving the 1st mirror further away from the laser tube to get better adjustment of the white plate.
      This problem is due to faulty installation by the manufacturer, they just drill holes and guess the alignment.

      A skewed gantry could give similar effect. Measure it diagonally to see its square.
      You can align this slightly on the laser tube too, by moving the tube holder further back on the right side (seen from standing in front of the machine) but it will never be 100% with this method as the gantry is still out of whack with the 2nd mirror not 90 degrees to the 1st.

      1. Thanks for the help. I ended up moving the whole gantry (and consequently mirror 2) as drilling new holes for the first mirror would have been a lot more work. When I moved the gantry as far to the right as the pre-drilled holes allowed, I was able to get everything aligned in a matter of minutes. I’m guessing it had shifted during shipping.

  37. Hello
    First theank you very much for this isntructions .I do all the steps but one i can not get it wright .STEP 3 dont matter what i do the beam move 2 mm up …i try to put something onder to elevate the head but still i get the twoo mm diffrence .Do you please have any ideea what can be .
    Kind regards

    1. The only solution is to lift the laser head. Make sure you reset the beam in bottom right position before testing again – if not you will not see the difference.

      Like this: Add something under the head to lift it 1mm, a metal washer or similar. Then move the laser head to bottom right – Test-fire your laser and adjust mirror 2 until you hit center on the laser head, then move the laser head to bottom left and test-fire again to see the difference made by your lifted head. Add more if needed.

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