MPCNC laser engraver checklist

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This topic contains 6 replies, has 5 voices, and was last updated by Profile photo of Damien Damien 1 week, 2 days ago.

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  • #19289
    Profile photo of Damien
    Damien
    Participant

    Hi,

    I would like to build a MPCNC for laser engraving. I am opening this thread to check if I don’t miss something, and I will update first post according to resolutions.
    I think that the J Tech upgrade kit is a good choice, with the line lasers.

    First, a few questions…

    – What can the presision of the laser “pixels” ? Can it be better than the video on their site ?
    – What can be the biggest MPCNC size without loosing precision ? I would like to have min 1m square size, larger is better… I know that for long distances metal can bend, what can be the recommanded way to avoid this ?
    – Can I easily change the tool (let’s say Dewalt DW660 to do some carving) with a structure this size ?
    – As for the height, what can be a reasonably good height for laser engraving, and also carving ?
    – If needed, how can I stiffen the assembly ?
    – More questions will come later for laser line wiring, practical wire attachement to avoid engraving wires…

    MPCNC Parts list :
    – MPCNC parts bundle : http://www.vicious1.com/product/mostly-printed-cnc-parts-bundle/
    – MPCNC printed parts : (according to tubes size) http://www.vicious1.com/product-category/bundles/
    – LCD display : http://www.vicious1.com/product/full-graphic-smart-controller-big/
    – Big Red Button : http://www.vicious1.com/product/emergency-stop-button/
    – A test file : http://www.vicious1.com/product/logo-dxf/

    JTP parts list :
    – Laser kit : https://jtechphotonics.com/?product=3-8w-laser-and-2-5amp-safety-compliant-driver-kit
    – Fan upgrade : https://jtechphotonics.com/?product=laser-fan-upgrade-2-2w-or-2-8w-laser-kit
    – Laser shields : https://jtechphotonics.com/?product=445nm-laser-shielding
    – Goggles : https://jtechphotonics.com/?product=laser-safety-goggles-for-445nm-lasers

    Additionnal printed parts :
    – LCD case : http://www.thingiverse.com/thing:1562144
    – Laser mount : http://www.thingiverse.com/thing:1025450

    Additionnal electronics :
    – Line laser : https://www.adafruit.com/products/1057

    Bonus question :
    – The MPCNC board has its own power supply. The JPT laser also (12V adapter). Can they be eventualy replaced with a computer ATX PSU and driven by the Arduino ? So only one power supply, I have some ATX PSUs in stock and I will post how to use it as MPCNC (+ laser) power supply.

    #19295
    Profile photo of vicious1
    vicious1
    Keymaster

    I’m not sure of the minimal focus size, but it can be found by googling the laser and lens combination you want. There are a few really smart laser guys out there testing this stuff.

    If you are just putting the laser on there you can go vey large 1Mx1M should be easy. If you start to get sag you can use mid-psan supports on the outer pieces. or start with stainless steel.

    Best to just make 2 machines if you want to mill and use as a giant laser.

    The laser needs about 50mm to focus, no reason to go any taller. As for milling no taller than necessary, a few inches is best 2-4.

    Looks like you have it all on the list.

    For the power supply you can get the 30A kit and use it to power both, if you really feel the need to. but really the 2 included power supplies would be fine.

    #19297
    Profile photo of Jason
    Jason
    Participant

    Rails on my build are 5 feet. I have no noticeable issues with sagging even with the DW660 on. Accurracy is spot on.

    Changing tools is as simple as a few screws… Although I need to come up with something better for wire management… Quick connects or something.

    As for height I would recommend giving yourself ~4 inches of adjustment. If you are engraving something with depth. I have been engraving mirrors and while most frames are pretty thin there are some that are quite thick. The added height should not really matter even on the milling side, you can always raise the work a bit.

    #19365
    Profile photo of Alvin
    Alvin
    Participant

    for the J Tech Photonics laser kit you linked, I think it already contain everything you need, including the fan, shield and googles. Confirm with Jay (he’s been very helpful). You really don’t need the line lasers 🙂 I actually ordered those and printed the same mount before I even got my lasers. Ended up breaking the line laser mount, cut some shields to put them around that mount and just set my fan to 3 (this should give you a very low light from the laser) and focus using that.

    If you want to mount your router and laser at the same time, use Leo69’s mount -> http://www.thingiverse.com/thing:1301138
    It actually mounts to the tube, leaving your router mounted as is. This is what I’m using right now. The shield can be adjusted using magnets and a 1/4-20 screw

    #19662
    Profile photo of Jay Johnson
    Jay Johnson
    Participant

    Hi Damien,

    That looks like a pretty good list. Alvin is correct, the J Tech Laser kits all come with the laser driver, laser, goggles, and power supply. Additional goggles are recommended if you want to have a friend in the room as well. Here are some answers to your questions and a few additional comments:

    – The precision of the laser depends on the laser kit you buy. The higher the power, the slightly larger the laser spot size. Each pixel will be converted into a laser “dot”, so the resolution is based on the laser spot size. Here are some typical spot sizes for our lasers:
    1W 405nm : 4 MIL = 0.004″ = 0.1 mm = 100 micron
    2W 445nm : 8 MIL = 0.008″ = 0.2 mm = 200 micron
    2.8W 445nm : 9 MIL = 0.009″ = 0.23 mm = 230 micron
    3.8W 445nm : 15 MIL = 0.015″ = 0.38 mm = 380 micron

    Remember it can be slightly smaller than this because it is up to your ability to focus the laser. We put in a little cushion in the spec here based on the fact that some people will not be as good in focusing. We can actually get our 3.8W laser down to under 10 MIL (0.38mm) with a proper focus. For more information on the differences in the lasers check out this page here:
    J Tech Laser Product Specifications

    – As for the height for the laser focus, our lasers are set to 3″ from the shop here. You can have a good focus anywhere between 1″ and 3″. Above 3″ then you will start to not have the ability to focus the laser to the minimum specification. For more on focusing check out this:
    Focusing Your Laser 101

    – For the power supply, we recommend using the included power adapter with the laser. It provides a clean and tested supply of power to the laser. Using ATX supplies with the laser has the potential to destroy the laser as it produces incredible voltage transients at the start up that can get around the protection included in the laser driver. These ATX supplies are built very cheaply without concern for current spikes and high voltage transient suppression. If you want to use a single power supply for the system then we recommend using an industrial supply that has protection from transients. These include supplies made by MeanWell and others.

    Please feel free to contact us directly for any questions you have before, during, and after your build!

    Best Regards,
    Jay

    #20201
    Profile photo of Damien
    Damien
    Participant

    Hi 🙂

    Can’t edit my first post… :'( I have to update the links to the new shop, and add a few more items.

    I have finally found and bought the tubes \o/ So it will be 25mm tubes.
    I have bought the MPCNC items. I have taken the 30A power, added roller limit switches.
    I have also bought the laser items.
    There is only the additionnal printed parts I have to get.

    About roller limit switches, people have disussed about why and why not, I will add only the start switches, because “when the work is done I will go home”.

    #21824
    Profile photo of Damien
    Damien
    Participant

    Hi again 🙂

    I received all pieces, I have started to mount everything. I have to wait some days to free some space for final assembly (Z axis, feet, steppers are mounted, remains the X/Y axis, and the gantry).

    I have also ordered a print for a ramps box, laser mount, and endstop mounts.

    Due to the available space I will have, I have to reduce the available working area from 1m x 1m down to 1m x 0.5m (half Y).

    I have plugged the ramps board, I love the startup logo 😀

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