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Thread: Laser cutting Question

  1. #1

    Laser cutting Question

    Hello all, I've been a lurker now but had a quick question for you all.

    I recently received a Boss laser LS3655 100W. I have had this for right at two weeks now so I am still learning. The problem I have ran into is one of the first order requests I received locally (most sales our online for us) is for a 24" 1/2" birch three letter monogram. Up until this order, I had been cutting basic 1/4" wooden christmas ornaments basically as something small to practice on. With the ornaments, I have had no trouble at all.

    I decided to cut a test monogram first from the 1/2" to make sure my settings were good to go. However, using 95-100% speed and a speed as low as 2mm, I was unable to cut through the wood completely. To test this a little further, off of some advice I cut a basic 2" circle from the 1/2". I was able to do this at a speed of 6mm. I then attempted to cut the same circle in all four corners of the 36x55 table. The top and bottom left cut through fine. The top right had to be pushed through, and the bottom right didn't go through at all. I have still been unable to cut the monogram or even a simple letter A in the monogram font at the 5-6mm speed range in any area of the laser. Does anyone have any suggestions as to what could be going on here?

    Yes, I have tried a different 1/2" piece of wood, which also had the same results.

  2. #2
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    Quote Originally Posted by Alex Morefield View Post
    Hello all, I've been a lurker now but had a quick question for you all.

    I recently received a Boss laser LS3655 100W. I have had this for right at two weeks now so I am still learning. The problem I have ran into is one of the first order requests I received locally (most sales our online for us) is for a 24" 1/2" birch three letter monogram. Up until this order, I had been cutting basic 1/4" wooden christmas ornaments basically as something small to practice on. With the ornaments, I have had no trouble at all.

    I decided to cut a test monogram first from the 1/2" to make sure my settings were good to go. However, using 95-100% speed and a speed as low as 2mm, I was unable to cut through the wood completely. To test this a little further, off of some advice I cut a basic 2" circle from the 1/2". I was able to do this at a speed of 6mm. I then attempted to cut the same circle in all four corners of the 36x55 table. The top and bottom left cut through fine. The top right had to be pushed through, and the bottom right didn't go through at all. I have still been unable to cut the monogram or even a simple letter A in the monogram font at the 5-6mm speed range in any area of the laser. Does anyone have any suggestions as to what could be going on here?

    Yes, I have tried a different 1/2" piece of wood, which also had the same results.
    Interesting. Well the not cutting the same on differant areas could be as simple as mirror and lens alinement. Is this plywood or solid wood? Or it could be a not up to power tube?
    Do you have a mA meter on the machine, that can tell you a lot.
    Retired Guy- Central Iowa.HVAC/R , Cloudray Galvo Fiber , -Windows 10

  3. #3
    As a general rule, you aren’t going to cut 1/2” thick wood with a 100w laser. The focal band of a 2” lens is 1/8”. When you try and cut 1/2”, the beam goes out of focus and the power density drops drastically. The beam diameter exiting is probably .060”-.090” wide.

    Not on a good thing to do. You can take cuts, move the focus down into the work and cut again.
    Lasers : Trotec Speedy 300 75W, Trotec Speedy 300 80W, Galvo Fiber Laser 20W
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    Real name Steve but that name was taken on the forum. Used Middle name. Call me Steve or Scott, doesn't matter.

  4. #4
    Scotty is right, 1/2 inch is well over the sensible capacity of a 100 watt tube'd DC laser, with a longer focal length lens (you would need an 8 inch) the power density will be so low you won't be able to cut it anyways.

    1/2 inch anything is router materials

    (I'm sure there will be a few posts saying "But I cut 3 foot thick stone with my 20 watt etc etc) and they are true, but the quality will be dreadful and will take hours
    You did what !

  5. #5
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    Quote Originally Posted by Dave Sheldrake View Post
    Scotty is right, 1/2 inch is well over the sensible capacity of a 100 watt tube'd DC laser, with a longer focal length lens (you would need an 8 inch) the power density will be so low you won't be able to cut it anyways.

    1/2 inch anything is router materials

    (I'm sure there will be a few posts saying "But I cut 3 foot thick stone with my 20 watt etc etc) and they are true, but the quality will be dreadful and will take hours
    Absolutely correct. I did cut some 1/2" mdf with my 80 watt Trotec but only because the pieces I needed to cut took less time than it would have to drive home and cut them on the tablesaw... The edges were pretty charred but for this application, fixtures for my fiber, it didn't matter, and I had to have them asap.

  6. #6
    Alex;

    It will be slow but you should be able to cut 1/2" plywood with your 100w laser.

    The issue you are having could be one (or both) of two issues;
    Misaligned optics - this was mentioned earlier. If the optics are correctly aligned then the power delivered should be consistent over the entire bed of the laser.

    Laser bed is not flat - if the laser bed is not flat then the laser will go out of focus as it travels across the bed and the cut will be inconsistent.

    Check both and fix as required.

    Quote Originally Posted by Alex Morefield View Post
    Hello all, I've been a lurker now but had a quick question for you all.

    I recently received a Boss laser LS3655 100W. I have had this for right at two weeks now so I am still learning. The problem I have ran into is one of the first order requests I received locally (most sales our online for us) is for a 24" 1/2" birch three letter monogram. Up until this order, I had been cutting basic 1/4" wooden christmas ornaments basically as something small to practice on. With the ornaments, I have had no trouble at all.

    I decided to cut a test monogram first from the 1/2" to make sure my settings were good to go. However, using 95-100% speed and a speed as low as 2mm, I was unable to cut through the wood completely. To test this a little further, off of some advice I cut a basic 2" circle from the 1/2". I was able to do this at a speed of 6mm. I then attempted to cut the same circle in all four corners of the 36x55 table. The top and bottom left cut through fine. The top right had to be pushed through, and the bottom right didn't go through at all. I have still been unable to cut the monogram or even a simple letter A in the monogram font at the 5-6mm speed range in any area of the laser. Does anyone have any suggestions as to what could be going on here?

    Yes, I have tried a different 1/2" piece of wood, which also had the same results.
    Guy Hilliard

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  7. #7
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    Maybe 3/8" wood will cut fairly decently. My 80 watt will cut that thick but barely. And it won't look pretty. Sorry, I agree with Scott, Gary and Dave, 100 watt isn't that much higher and while it might cut some, it won't be consistent, nor good. Fergit if you have anything with ANY knots.
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  8. #8
    Quote Originally Posted by John Lifer View Post
    Maybe 3/8" wood will cut fairly decently. My 80 watt will cut that thick but barely. And it won't look pretty. Sorry, I agree with Scott, Gary and Dave, 100 watt isn't that much higher and while it might cut some, it won't be consistent, nor good. Fergit if you have anything with ANY knots.
    That explains a few things for me. No matter what I try, I haven't been able to cut 1/2" MDF on my 45w Epilog 24TT. If a 100W is underpowered for 1/2" wood, then it's no wonder.

    Home Depot 1/4" MDF though cuts beautifully, almost like it was made for lasering.

  9. #9
    Do test your height from table to cutting tip in all 4 corners. I found that by running my table up (Z) and having it be stopped by the head or whatever that the level get off a bit.
    Chinese 6040 by NiceCut. Originally 60 Watt upgraded to 150 Watt.....I thought I had pretty much every problem in the book of laser cutting. It turns out that there is a set of books.

  10. #10
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    Like others have stated 1/2" is To much for a 100 watt laser to cut consistently. We have found that 1/4" is the economic cut off for our 100 watt machines - Anything thicker isnt worth the extra cut time and error rate. You can cut 1/2" hardwood and plywood but it will require very slow speeds and/or multiple cuts and normally it leaves poor edge and surface quality.

    Plywood: Different grades of plywood will laser cut differently. We use baltic birch BB Grade plywood and it works great. If you try some big box store plywood you will find the cut can be very inconsistently because of Hard spots created by inconsistent glue levels and core materiel, knots.
    3X Camfive 1200 48" x 24" 100watt Tube
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  11. #11
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    He said that it cut a test circle and then it cut 2 inch circles in some of the corners. So that was impossible?

    From above: To test this a little further, off of some advice I cut a basic 2" circle from the 1/2". I was able to do this at a speed of 6mm. I then attempted to cut the same circle in all four corners of the 36x55 table. The top and bottom left cut through fine. The top right had to be pushed through, and the bottom right didn't go through at all.
    Last edited by Bill George; 11-20-2017 at 3:03 PM.
    Retired Guy- Central Iowa.HVAC/R , Cloudray Galvo Fiber , -Windows 10

  12. #12
    There is something to be said for what type of cut you are doing as to wether it will get all the way through. I find my ULS cuts at a slower feed rate in curves and angles than in straight line cuts, so I have to slow down for the worst condition and go from there.
    Brian Lamb
    Lamb Tool Works, Custom tools for woodworkers
    Equipment: Felder KF700 and AD741, Milltronics CNC Mill, Universal Laser X-600

  13. #13
    So today I double checked the alignment, and confirmed everything is level. Yes it is 1/2 birch plywood coming from lowes. I see that several people here and other sites use 9mm/10mm instead of 1/2", where is the best place to purchase that? Attached is the four circles I cut from the corners, as well as the monogram (prior to knocking it off and breaking it) the outer perimeter of it cut fine. As you can see the center pieces is where the trouble began.
    Attached Images Attached Images

  14. #14
    The black spots are hard spots in the cores, usually wood filler and an absolute bug bear to try and cut no matter how much power you have available
    You did what !

  15. #15
    Could be attributed to being low grade Lowe's plywood?

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