coverting 3d printer to a laserengraver



  • hi, does anybody know how to convert 3d printer with duet wifi to drive a lasertube for lasercutting and engraving?
    thanks for your help!!



  • If you are thinking about a CO2 laser tube, those are quite big and should ideally not be moving (and rather have the laser beam be reflected using a set of mirrors and finally a lens). Due to the way the 3D printer moves the mirrors might not be a good solution.

    What most people do, is buy a cheaper lower Watt laser module, typically something like the one at https://www.amazon.com/F-Yi-Engraving-Machine-Printer-Industrial/dp/B07CRV1STJ/ (comes in many different wattage's, I have seen ones upto 15W; this one is 0.5W but these work the same, so using it as an example). These makes use of a driver board (included most of the time), which is fed 12V as well as a TTL signal. TTL is, as I understand it, a stepped up PWM signal, like one would get from the Heater Outputs (E0 or E1), sometimes at 5V, other times at 12V.

    You would make a bracket to hold the laser on the head (maybe replace the Hot-end assembly, or simply attach to it).

    Next, you will need to wire and set it up, and the guide to follow is at https://duet3d.dozuki.com/Wiki/Laser_PWM_control



  • I believe @Jacotheron covered it very well. Realistically a tube setup requires different optics/mechanics. Solid state modules can be adapted to printer mechanics, but have limits on power (good for engraving, not so good for cutting).

    I've put a two watt solid state on a CR10, and it produced some middle-decent results engraving wood.

    I would add to what jaco said: If you want to engrave and cut, and not spend thousands, I'd go with a generic "K40" 40 watt laser, PLUS several of the upgrades here

    Read that upgrade page... lots of choices, most of them inexpensive... personally, I wouldn't run a K40 without at least some of the safety upgrades... such as interlock on th lid and better exhaust.

    I also happen to have several controllers (TriGorilla ramps clone, TinyG) just sitting on the shelf, so I'd no doubt replace the controller first thing. MIGHT put a DuetWiFi in it... maybe... but since I have a TinyG, that's more likely.

    Anyway, a K40 + upgrades is a great path to REAL laser cutting/engraving, for less than ??$800?? maybe less than ??$600?? depending on what you upgrade.



  • Obligatory safety note: strapping a laser onto a 3d printer creates SERIOUS SAFETY CONCERNS and the majority of people who do it don't follow enough safety precautions and are putting themselves at risk of fires and injury. I won't get into a full rant here, but some key guidelines to keep in mind:

    • Lasers over 0.5w can blind you instantly, and even reflections and dispersed laser flare off objects you're cutting can cause injury and fire. Blue diode lasers use a wavelength of light that can cause melanomas from skin contact in addition to burns. USE A FULL ENCLOSURE AND WEAR LASER SAFETY GOGGLES SUITABLE FOR ABSORBING YOUR CHOSEN LASER WAVELENGTH.
    • Do not put a laser on a machine made of flammable materials. (ABS, PLA, acrylic, wood, etc.)
    • Do not use fasteners that may vibrate loose and dislodge the laser mount.
    • Laser cutters/etchers produce toxic fumes and smoke that should be ventilated outside. Generally you will want to blast the cut with air to carry away vaporized material and smoke so the workpiece doesn't ignite, and then suck that air away to vent it outside.
    • If children, guests, or curious animals have access to the machine, make sure you put a key interlock or host computer password on it to prevent unauthorized laser activation.
    • Make sure you have an E-stop button or a power cable/switch within arm's reach of the front of the machine.
    • An enclosure cover interlock switch to inhibit unprotected laser fire is a REALLY good idea.
    • A laser power supply kill circuit to shut off the +v supply to the laser on ground-switched devices (like Duet heater MOSFETs) in case of component failure sticking the laser on is a REALLY good idea.
    • A smoke detector that shuts off machine power is a REALLY good idea.

    Some of the items above are actually US/EU regulations for laser devices, and you will be in deep doo if you burn down your house or hurt somebody and the insurance company starts investigating.



  • Hi thanks for the reply everybody! maybe my question had not enough info. i am building a machine like this: http://public.iorodeo.com/docs/laser_cutter/index.html
    i have a 3d printer using duet wifi and works perfect. if i read correctly using the fan port can only switch laser on or of for cutting purposes (am i correct?). my question is if there is a possibility for engraving?



  • This part is where your laser driver comes in. Modern laser drivers/power supplies can receive a TTL signal (basically a PWM signal, usually at the 5V) and then use that to drive the laser at lower power.

    It should be noted that the link from my earlier post still apply: you should have that small PCB (either make it yourself, or have someone make it for you) - it is simply a safety board that ensures that the laser can't accidentally fire.

    I am still quite new to the laser parts, but I plan to upgrade my CNC to laser capabilities (taking the above mentioned safety into consideration). Though I plan to simply use a 15W laser module for quick swap in and out (it may not be quick, but should be functional for what I need). The safety board, I am actually trying to remix it so that I have an extra endstop switch for the machine's laser shield - only allow firing the laser if the lid is closed. For this I am thinking of adding the enstop between the 3.3V and either 1a or 1b in a normally open configuration (currently 3.3V is split to both 1a and 1b so that if 3.3V is available, 1y outputs the low to 2a and with the heater_3 going low, outputs the high for the laser).


  • administrators

    To drive a laser TTL control signal, we recommend you use an external 74HCT02 chip to invert and gate the signal (unless you have a DueX or the external stepper breakout board, which both have these already). Searching for 74HC02 and laser in this forum should find that thread.


 

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