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Thread: Laser not cutting properly on horizontal/X axis

  1. #16
    Quote Originally Posted by Rich Harman View Post
    The burn test you did in post #4 looks non-ideal to me. Could be that it always looked like that but the ring around the center might be an indication of tube failure.
    It's an Laguerre 01 profile Rich, not unusual

    page1-789px-Laguerre-Gauss.pdf.jpg

    I think there is nothing to be gained by that, and a lot to be lost.
    very much so

    cheers

    Dave
    You did what !

  2. #17
    Join Date
    Dec 2012
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    Rickmansworth, England
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    just a thought but has the operating/ambient/chiller temperature changed recently?
    could impact power output
    Trotec Speedy 300 50W
    Gantry CNC Router/Engraver
    Various softwares
    Always keen to try something new

    Please don't steal - the government hates competition

  3. #18
    Join Date
    Mar 2014
    Location
    Perth, Australia
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    10
    Thanks for your input guys, I'll retry the focal length and play with the power/speed of the cut. I wonder if the new lens I put in has anything to do with it. I noticed the one I took out had a convex side and a very gentle concave side, and the one I put in has a convex side and a flat side. From what I've read that makes a wider cut and is less focused. I'll also invest in a Mahoney 100 watt laser power probe.

    And of course I'll let you know how it all goes. Next laser cutter I buy I think I'll buy new so I can get some support with it.

  4. #19
    Meniscus is curved both sides (the best type of lens) the other one is a Plano-Convex, although a slightly less defined beam shape it won't affect things in a noticeable way at anything under 500 watts or so.

    I'll also invest in a Mahoney 100 watt laser power probe.
    Save your money Rick, they aren't very accurate and only really provide a *best guesstimate*, good for comparing a tube when it's new to later on in it's life but for actually measuring power they are pretty dire (not a quality issue as such just that they can be affected by a lot of external factors)

    Failing that, make one yourself using Dr Lindsay Wilsons instructions.

    http://imajeenyus.com/optical/201304...ly/index.shtml

    Next laser cutter I buy I think I'll buy new so I can get some support with it.
    If it's a direct import from China don't bet on support being much better

    cheers

    Dave

    PS:

    just a thought but has the operating/ambient/chiller temperature changed recently?
    could impact power output
    Very valid point and can make a big difference
    You did what !

  5. #20
    Join Date
    Oct 2013
    Location
    Seattle, WA
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    morning Dave!

    I was curious about your suggestion on the power meter. I had pondered getting one for use someday when a laser actually shows up at the house. My thought was to wait a few weeks till I have some time on the tube and it has settled in, (an EFR tube) and then make a few measurements to establish a baseline power for the tube when new. That way I had a point of reference if I had problems later in its life. If I am reading you right, that was how you were suggesting a meter had some value as opposed to looking at a discreet power level reading taken out of context? Or do you think it is not worth the dollars even for that use?

    I was not looking at it as a tool that would give a single discreet measurement, but one that might provide a trend overtime. In the way that a BP cuff is not really accurate in a single use given all the externals involved in getting a measurement, but is pretty good at looking at longer term trends.

    Dave
    900x600 80watt EFR Tube laser from Liaocheng Ray Fine Tech LTD. Also a 900x600 2.5kw spindle CNC from Ray Fine. And my main tool, a well used and loved Jet 1642 Woodlathe with an outboard toolrest that helps me work from 36 inch diameters down to reallllllly tiny stuff.

  6. #21
    but one that might provide a trend overtime.
    pretty useful for that my friend, trends rather than outright measurement of power. For pure measurement of raw power you would need a power wizzard wand or an Ophir set up (my Ophir was just under $5,500 so not cheap)

    cheers

    Dave
    You did what !

  7. #22
    Join Date
    Mar 2014
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    Perth, Australia
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    Quote Originally Posted by Dave Sheldrake View Post

    just a thought but has the operating/ambient/chiller temperature changed recently?
    could impact power output
    Very valid point and can make a big difference
    Actually I had to replace the water flow sensor recently and couldn't find one that was an exact match and lets the water through at a greater rate. Could that have anything to do with it? The temperature hasn't changed much.
    Last edited by Rick Underwood; 11-18-2014 at 6:27 AM.

  8. #23
    Join Date
    Mar 2014
    Location
    Perth, Australia
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    10
    I've played around with the settings - and are still continuing to do so. I've also played with the focal lengths and worked out what works best. It seems with the lens I put in a difference of just 1mm can affect the cut.

    Now I've cleaned all the mirrors and the lens again it is back to doing a good cut on the Y axis and a poor cut on the X axis. Frustrating.

    The pic below is of the back of the 1.8mm chipboard and the test rectangle below is 45.5mm by 7.1mm. As you can see the Y axis/horizontal cuts fine.

    20141122_153459.jpg

    I'm starting to wonder if this laser is just a hobby laser and we shouldn't be trying to make a business from it, just like you wouldn't start a printing business from a home printer.
    Last edited by Rick Underwood; 11-22-2014 at 2:39 AM.

  9. #24
    Join Date
    Mar 2011
    Location
    Olalla, WA
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    My next two guesses;

    1) The beam is not perpendicular to the table. Easy to test - fire a dot, lower the table several inches, fire again. Thermal paper makes this easier.

    2) The travel speed is not the same for x and y.
    Shenhui 1440x850, 130 Watt Reci Z6
    Gerber Sabre 408

  10. #25
    I'm starting to wonder if this laser is just a hobby laser and we shouldn't be trying to make a business from it
    I had one of them otherwise known as the LS6840, bomb proof machines and usually very reliable.

    The travel speed is not the same for x and y.
    quite possible if the step count has been badly adjusted or changed in the past by the previous owner
    You did what !

  11. #26
    Join Date
    Mar 2011
    Location
    Olalla, WA
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    1,532
    The travel speed is not the same for x and y.
    Quote Originally Posted by Dave Sheldrake View Post
    quite possible if the step count has been badly adjusted or changed in the past by the previous owner
    ...or the max speed on the y axis could be set lower such that it is not allowed to go as fast as the x. I think the head being out of perpendicular is the thing to check first.
    Shenhui 1440x850, 130 Watt Reci Z6
    Gerber Sabre 408

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