newb's first CNC mill (3040), advices


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    Default newb's first CNC mill (3040), advices

    Just got this second hand. https://www.ebay.com/itm/US-CNC-3-Ax...YAAOSw7-palR5Y

    (not exactly the same model as the above ebay seller but they all look the same generic china design).

    The seller showed me it in operation and seems good enough for my personal usage for cutting and engraving 1.5-2mm acrylic.

    To give an idea of my experience level:
    I've never owned a small CNC miller but I've had 2 3d printers before and have had them disassebled/reassembled and upgraded parts, both all the electronics as well as the mechanical components.

    So I guess my questions are these but if there are other things/advices you think I should know please also post.

    1) What cutting speeds can I expect from this stock 300W spindle with 2mm acrylic?

    2) There are some videos on swapping the spindle with a powerful but cheap dremel. is that a good idea? Besides the overheating/short lifespan and difficulties of controlling the rotation and speed in software I don't see why not.

    3) What control software should I use?

    4) The seller gave the CNC to me with a thick plastic slab bolted on the base plate. I guess its a good idea to keep it on so not to damage the baseplate? But is 40mm thick one maybe too much?

    5) What mill bits to use and when?

    6) Any obvious newbie dos/don'ts?



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    Default Re: newb's first CNC mill (3040), advices

    1) Not sure; start off slow and if that works, see how fast you can go without errors. If it starts failing, back off on the speed. There are a lot of variables, like depth of cut, cutter configuration, strength of your spindle, chip clogging, etc you need to balance to arrive at an optimum speed.

    2) No, that's a step backwards. The Dremel frame is plastic, and it distorts when the tool gets hot. If you want to upgrade the spindle, get one that's more powerful but with an all-metal structure.

    3) If it didn't come with any, you have a choice: Mach3 (Windows), LinuxCNC, or UCCNC (Windows) are the main ones people here talk about.

    4) That plastic slab is on the bed? If so, it's called a "spoilboard" and gives you something to hold workpieces down to. You can get rid of it if you want, but then you have to be more careful about cutting too deep.

    5) For straight cuts in acrylic, most people prefer single-flute "O" style cutters. If you're doing 3D contouring, you'll want 2-flute ball endmills.

    6) Don't unplug the motors when they're powered up. If a stepper seems to be failing, don't take it apart. If you're losing steps, reduce your acceleration.

    Andrew Werby
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    Default Re: newb's first CNC mill (3040), advices

    1. Agreed. Speeds will be determined by the available torque at spindle and axis drivers, and by the stiffness of the frame. You'll need to have a play with some offcuts, start slow and drive it harder until it stalls or skips.

    Note that the cheap spindles tend to be pretty gutless at low RPM. Grab a copy of FSWizard Light for your phone (or spring for the full version of it or HSM Advisor) or similar for a handy dandy reference/calculator for maximum speeds and feeds and build your way up.

    2. The dremel will also be a lot, lot louder than a spindle. Upgrade the spindle if required, but note - for a cheap 3040 it probably isn't worth it, do what you can with that machine as is then sell it and upgrade when/if you need better capabilities.

    3. Mach3 is easy and most cheap hardware will talk to it. LinuxCNC is easy if you have some linux experience and your hardware happens to be compatible. UCCNC is nice if you happen to have their hardware. There are plenty of others specifically targetted at a manufacturer's controller hardware, as well as some open source jobs.

    Personally I'd look at Mach3 as an easy way to get yourself up and running, then move on to something else if you need to.

    6. Play with it, a lot. Check your work - run anything on a simulator first and make sure it isn't going to do anything crazy. First few times, set your Z height well above the bed and do the job in air to make sure it isn't going to crash etc, then set Z properly and run from there. Prepare to disappear from the world for a while, this stuff is addictive and you'll lose track of time



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newb's first CNC mill (3040), advices

newb's first CNC mill (3040), advices