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(Smaug) 100w 1500x1000mm CNC Laser

Discussion in 'Laser Cutters' started by DeltaModworks, May 4, 2021.

  1. DeltaModworks

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    DeltaModworks published a new build:

    Read more about this build...
     
  2. DeltaModworks

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    Hello, I am building a 1500mm x 1000mm laser cutter and am having some problems with excessive noise/ vibration during slower moves. I have tried different micro stepping configurations but this doesn't seem to help. The longer Y axis with two motors has much more noise than the X.
    Any suggestions?

    I have attached 3 videos.
    Y moving slowly and making lots of vibration
    Y moving fast and sounding much better
    X moving slowly and sounding alright
     

    Attached Files:

  3. Peter Van Der Walt

    Peter Van Der Walt OpenBuilds Team
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    I would say
    1) Theres a lot of whipping on those leadscrews, get them in tension
    2) The seperate Y drives are a house fire waiting to happen with a flying optics laser - consider (seriously) re-engineering to mechanically link the two sides (driveshaft or link belts, etc) - if one motor skips mid-job, your gantry goes skew. Laser beam misses mirror 2 or 3 because the off angle its running at now, and aims out directly at the nearest flammable surface. Or an eye. And yes, it happens. A certain Makerspace in Durban lighting a next door clothing cubicle in an event hall on fire - I was there
    3) Enclose the laser
    Sorry got off track with the safety issues

    Sounds like bad drivers? What are you running? Pics doesn't show clearly? Consider a BlackBox docs:blackbox:startc [OpenBuilds Documentation]
     
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  4. DeltaModworks

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    Thanks for the input. I have tension nuts and thrust bearings for the screws. My couplers are slipping when I put sufficient tension on the screws. This is another issue that I'm currently working on.

    I'll think about your second point. I have experimented with the gantry being misaligned and this does not cause the laser to miss the final optic. The mirror on the gantry is fixed to the gantry so it would rotate along with the gantry beam if twisted.

    I will be enclosing the laser after the mechanical issues are sorted out.
     
  5. Peter Van Der Walt

    Peter Van Der Walt OpenBuilds Team
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    Also sounds like a driver issue, being underpowered - should spin a tensioned leadscrew with ease
    Another thing to consider, did you check the Coil Voltage rating of your motors - if they are not 3v motors, you'll have a hard time too.


    But as the Entry angle of mirror 2 is fixed, the error on the exit is twice that of the gantry - that causes it to shoot past the mirror mount. As its a mirror, the beam bounces off at the same angle it came in, and in this case is thus wider than when its square. Trust me, I have seen it happen, and I may be the most annoying advocate for locking the two together there is, but it really is a super dangerous (and very likely) failure mode.
     
  6. DeltaModworks

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    The problem isn't the motor torque. The screw is pulled linearly out of the motor coupler when I pre tension the screw.

    I will heed your advice. Thank you for bringing it up. I haven't had any issues at all with my leadscrew converted router table but I see where it could be a bit more of an issue here. Perhaps I could use a low power laser emitter and detector which when no longer aligned, triggers an emergency stop.
     
  7. Kevon Ritter

    Kevon Ritter Veteran
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    There's a lot of red flags. The method of motion just doesn't match the machine purpose.

    Aside from the glaring safety issues...
    Do you plan on adding some sort of bed?
    What about ventilation?

    If you have the crews tensioned from the outside of the plates, it shouldn't be pulling through.

    Your router doesn't depend on having a beam hit 3 points before hitting the laser head. Unless the point of contact on the mirror is the pivot point when the machines goes out of whack, it WILL deviate.
     
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  8. Peter Van Der Walt

    Peter Van Der Walt OpenBuilds Team
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    Check your stack up against the XL tension bundle in the store, you may be missing something or have the wrong or inferior parts.
     
  9. DeltaModworks

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    I' have etched and blued steel sheet down to prevent penetration to the wood table. I'll have adjustable height holders of a wire mesh for work holding.
    I have a 3.5" fume extraction system that I'll use directly on the cutter head until it's enclosed. I'm printing a hose holder and intake plenum over the night.
     
  10. DeltaModworks

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  11. Peter Van Der Walt

    Peter Van Der Walt OpenBuilds Team
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  12. DeltaModworks

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    It is not. I did just realize one of my problems though. I only have a tension nut on one side of each screw. The other side has been held in tension by the motor coupler but I think it will be better for the coupler to only be handling the rotational force.
     
  13. REdington

    REdington Well-Known
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    Your building a cutting laser only. Your leadscrews will be whipping going the speed you need to any serious engraving work. You would be a lot better off using belts in my opinion.

    I will also agree with what @Peter Van Der Walt said about enclosing it before you even try firing the laser and get rid of the second motor on the Y axis. I can visualize one of the motor missing a step and the laser beam going right across your belly and burning you and catching your clothes on fire.

    Because of the size, I really don't think your table it up to the task of keeping all the mirrors aligned without having to do a realignment every time you go to use it. Just a change in the humidity will throw them all out of wack. Even if one corner moves a 1/16", you'll have to do a realignment and keeping the beam centered down the middle of the tube on the head will be difficult. I've read about guys that have China made cabinet lasers on roll around carts that have to do a realignments every time they move them.


    These are all my opinion, but I do want you to be safe. There has been a lot of costly fires started by laser cutters/engravers.
     
  14. DeltaModworks

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    Thanks for the reply. I don't have the materials to enclose the whole laser yet but have some steel tube to enclose the path of the beam for two of the travels. I had two tension nuts and thrust bearings off of my router at home so I'll see if the screw under tension can handle the higher speed with more tension.
     
  15. REdington

    REdington Well-Known
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    I helped build a friend's laser and he started with 5 start, 5/8" diameter, 1/2" lead (moved 1/2" ever revolution) leadscrews and they whipped badly. He switched to belts after he used it for a few months. The only bad thing about belts is that you have to have software with backlash compensation to get great engravings.

    BTW that was over 12 years ago before we had all the options from China. It has a 50 watt RF, duel tube Synrad on the gantry with no external mirrors on it.





    [​IMG]
     
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  16. DeltaModworks

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    I may look into belts but this laser is mostly for cutting 12mm EVA foam and needs a pretty slow cut speed.
     
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  17. Peter Van Der Walt

    Peter Van Der Walt OpenBuilds Team
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    @REdington You should share your Build thread with him, your machine is my new "standard" for a laser build - done to perfection. Particularly your driveshaft setup.


    Belts can still run slow too. But its nice to traverse fast BETWEEN the slow cuts, if 50% of your job is seek moves, imagine the time saved. But mostly, a driveshaft, with dual belts, is the key to keeping it square, ie, safety
     
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  18. DeltaModworks

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    That's something I'll definitely consider as an upgrade. I'd like to get it working first and improve one thing at a time.
     
  19. REdington

    REdington Well-Known
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    Wow, Peter, that is one hell of a complement. Thank You very much.

    Here is my build if you haven't already viewed it.


    Rodney's new Laser
     
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  20. DeltaModworks

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    I tightened the screws by putting tension nuts and thrust bearings on the motor side. I also 3D printed motor mounts to allow coupling the motors.The whipping looks a lot better and the sound is actually a bit better but still way louder than it should be.

    This is making me more certain that the problem is the motor drivers like previously suggested. They are "Microstepping" but still a lot of cogging and resonance is still occurring.
     

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  21. REdington

    REdington Well-Known
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    Damm, that's loud. Sound like you have too much amperage and trying overcome a lot of friction. Adjust your amperage as low as the driver will go, and then start increasing it till you have the motor running nice smooth without missing steps. Also see if the leadscrews turn freely.
     
  22. Peter Van Der Walt

    Peter Van Der Walt OpenBuilds Team
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    Still curious of this question too. They all look the same, black heatsink and green connectors, all the way from the $6 junk, to the $80 Leadshines. At least from the picture angle. If we know what you have, we can better say if that noise is expected or not :)
     
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  23. REdington

    REdington Well-Known
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    I just went back and looked at the photo of the drivers and you do have the amperage set low, so I don't think it that. The 2 Y axis drivers look to be set at 1600 steps and the X axis driver looks to be set at 400 steps.




    Really need this information to give you more suggestions to check
     
  24. DeltaModworks

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  25. Peter Van Der Walt

    Peter Van Der Walt OpenBuilds Team
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    Ok so those are actually pretty OK drivers.

    What controller and Motors are you using?
    Paste your Grbl Settings
     
  26. DeltaModworks

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    3 x 23HS8430B stepper motor 76mm 270oz-in dual shaft
    SainSmart GRBL usb controller: SainSmart 3-Axis GRBL USB Driver Controller Board DIY Engraver Control Board for GRBL - - Amazon.com
    Raspberry pi 4b running UGS

    GRBL Settings:

    "key": "$10", "value": "3", "units": "mask",
    "description": "Alters data included in status reports.",
    "shortDescription": "Status report options"

    "key": "$11", "value": "0.010", "units": "millimeters",
    "description": "Sets how fast Grbl travels through consecutive motions. Lower value slows it down.",
    "shortDescription": "Junction deviation"

    "key": "$12", "value": "0.002", "units": "millimeters",
    "description": "Sets the G2 and G3 arc tracing accuracy based on radial error. Beware: A very small value may effect performance.",
    "shortDescription": "Arc tolerance"

    "key": "$13", "value": "0", "units": "boolean",
    "description": "Enables inch units when returning any position and rate value that is not a settings value.",
    "shortDescription": "Report in inches"

    "key": "$0", "value": "10", "units": "microseconds",
    "description": "Sets time length per step. Minimum 3usec.",
    "shortDescription": "Step pulse time"

    "key": "$1", "value": "25", "units": "milliseconds",
    "description": "Sets a short hold delay when stopping to let dynamics settle before disabling steppers. Value 255 keeps motors enabled with no delay.",
    "shortDescription": "Step idle delay"

    "key": "$2", "value": "0", "units": "mask",
    "description": "Inverts the step signal. Set axis bit to invert (00000ZYX).",
    "shortDescription": "Step pulse invert"

    "key": "$3", "value": "0",
    "units": "mask", "description": "Inverts the direction signal. Set axis bit to invert (00000ZYX).",
    "shortDescription": "Step direction invert"

    "key": "$4", "value": "0", "units": "boolean",
    "description": "Inverts the stepper driver enable pin signal.",
    "shortDescription": "Invert step enable pin"

    "key": "$5", "value": "0", "units": "boolean",
    "description": "Inverts the all of the limit input pins.",
    "shortDescription": "Invert limit pins"

    "key": "$6", "value": "0", "units": "boolean",
    "description": "Inverts the probe input pin signal.",
    "shortDescription": "Invert probe pin"

    "key": "$120", "value": "500", "units": "mm/sec^2",
    "description": "X-axis acceleration. Used for motion planning to not exceed motor torque and lose steps.",
    "shortDescription": "X-axis acceleration"

    "key": "$100", "value": "200.000", "units": "step/mm",
    "description": "X-axis travel resolution in steps per millimeter.",
    "shortDescription": "X-axis travel resolution"

    "key": "$122", "value": "10.000", "units": "mm/sec^2",
    "description": "Z-axis acceleration. Used for motion planning to not exceed motor torque and lose steps.",
    "shortDescription": "Z-axis acceleration"

    "key": "$121", "value": "250", "units": "mm/sec^2",
    "description": "Y-axis acceleration. Used for motion planning to not exceed motor torque and lose steps.",
    "shortDescription": "Y-axis acceleration"

    "key": "$102", "value": "80.000", "units": "step/mm",
    "description": "Z-axis travel resolution in steps per millimeter.",
    "shortDescription": "Z-axis travel resolution"

    "key": "$101", "value": "200.000", "units": "step/mm",
    "description": "Y-axis travel resolution in steps per millimeter.",
    "shortDescription": "Y-axis travel resolution"

    "key": "$20", "value": "0", "units": "boolean",
    "description": "Enables soft limits checks within machine travel and sets alarm when exceeded. Requires homing.",
    "shortDescription": "Soft limits enable"

    "key": "$21", "value": "1", "units": "boolean",
    "description": "Enables hard limits. Immediately halts motion and throws an alarm when switch is triggered.",
    "shortDescription": "Hard limits enable"

    "key": "$22", "value": "1", "units": "boolean",
    "description": "Enables homing cycle. Requires limit switches on all axes.",
    "shortDescription": "Homing cycle enable"

    "key": "$23", "value": "0", "units": "mask",
    "description": "Homing searches for a switch in the positive direction. Set axis bit (00000ZYX) to search in negative direction.",
    "shortDescription": "Homing direction invert"

    "key": "$24", "value": "100.000", "units": "mm/min",
    "description": "Feed rate to slowly engage limit switch to determine its location accurately.",
    "shortDescription": "Homing locate feed rate"

    "key": "$25", "value": "2000.000", "units": "mm/min",
    "description": "Seek rate to quickly find the limit switch before the slower locating phase.",
    "shortDescription": "Homing search seek rate"

    "key": "$26", "value": "250", "units": "milliseconds",
    "description": "Sets a short delay between phases of homing cycle to let a switch debounce.",
    "shortDescription": "Homing switch debounce delay"

    "key": "$27", "value": "3.000", "units": "millimeters",
    "description": "Retract distance after triggering switch to disengage it. Homing will fail if switch isn\u0027t cleared.",
    "shortDescription": "Homing switch pull-off distance"

    "key": "$131", "value": "15000.000", "units": "millimeters",
    "description": "Maximum Y-axis travel distance from homing switch. Determines valid machine space for soft-limits and homing search distances.",
    "shortDescription": "Y-axis maximum travel"

    "key": "$130", "value": "1000.000", "units": "millimeters",
    "description": "Maximum X-axis travel distance from homing switch. Determines valid machine space for soft-limits and homing search distances.",
    "shortDescription": "X-axis maximum travel"

    "key": "$111", "value": "2200", "units": "mm/min",
    "description": "Y-axis maximum rate. Used as G0 rapid rate.",
    "shortDescription": "Y-axis maximum rate"

    "key": "$110", "value": "8000", "units": "mm/min",
    "description": "X-axis maximum rate. Used as G0 rapid rate.",
    "shortDescription": "X-axis maximum rate"

    "key": "$132", "value": "200.000", "units": "millimeters",
    "description": "Maximum Z-axis travel distance from homing switch. Determines valid machine space for soft-limits and homing search distances.",
    "shortDescription": "Z-axis maximum travel"

    "key": "$112", "value": "200.000", "units": "mm/min",
    "description": "Z-axis maximum rate. Used as G0 rapid rate.",
    "shortDescription": "Z-axis maximum rate"
     
    #26 DeltaModworks, May 7, 2021
    Last edited: May 7, 2021
  27. JustinTime

    JustinTime Journeyman
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    Can you turn the screws by hand? I can turn mine by hand with no problem at all. It turns smooth and easy and moves the gantry with little effort from me.
     
  28. Peter Van Der Walt

    Peter Van Der Walt OpenBuilds Team
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    Theres Optos on that board, and again a set of Optos inside the other drivers - which could introduce signal skewing. Try setting
    $0=20 or 30 (little longer step pulse to get across both optos)

    Or, seriously, consider a BlackBox
     
  29. DeltaModworks

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    Adjusting pulse lengths didn't seem to change anything.
     
  30. DeltaModworks

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    Yes, they move fine by hand.
     

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