CNC 3020 Router gets a Power Supply Upgrade

CNC3020 Router power supply upgrade

We’ve covered these CNC 3020’s in the past. They are physically solid machines but the electronics offer some room for improvement. [Peter] is certainly no novice at working on these machines. He’s already fixed a failed power supply and he’s back at the upgrades, again focused on the power supply. This time he’s replacing the transformer-based one with a couple switching power supplies.

The stepper controllers and spindle speed circuit need both 48 and 24 VDC. [Peter] purchased two separate power supplies, one for each voltage required. Before installing the new supplies, the stock one had to be removed, along with the transformer. Even with the old parts removed, there was still not enough room for both new supplies to be installed inside the stock case. [Peter] decided that mounting them to the top of the case would be appropriate.

CNC3020 Router power supply upgradeThis current setup has been in use for several months now. [Peter] reports that it has been working well and does not get hot even during long-running programs. If you are interested in  [Peter's] previous power supply repair or his PWM spindle speed control, check this out.

Comments

  1. Json says:

    This should be titled, replaced power supply.

    Would be nice if he re boxed the whole thing.

    Am I hating, nope, I would do the same in a pinch, but I would not stand proud as a hack, because it’s not. Can we post my LCD hack to a fadal 4020 cnc machine? No because it already had vga output, I just swapped CRT for LCD.

    • whitequark says:

      I really wanted to re-box it. I spent countless hours on ebay but there are no power supplies that would fit into available space at all.

      I think it’s useful because the process is non-trivial (though not very hard) and the note conveniently describes everything you need for full conversion with same or similar supplies.

      • 0xfred says:

        Exposed mains wiring? There’s no excuse for that. If only you had something you could use to machine a new enclosure…

        • whitequark says:

          I’ve an article about machining acrylic in queue, yes. Turned out to be somewhat complicated.

          • 0xfred says:

            Milling acrylic is easy if you ensure that you use cast acrylic. Extruded acrylic melts too easily and is a total pain to work with. It’s only good for laser cutting and even then it stinks far more than cast.

            I was going to mill an acrylic enclosure for my CNC mill’s PSU and stepper driver. However my mill has a very small working area, so I ended up laser cutting it instead.

        • whitequark says:

          Tl;dr: I used cast acrylic (huge homogenous transparent sheets) and it still melted really badly, so I started to use coolant as water. Which worked really well but added a few problems of its own, about which I’ll write.

          • Jorgga says:

            I’ve used engine coolant(anti freeze) when machining extruded styrene-acrylonitrile resin. Works really wellm and as it’s supposed to transfer heat and protect the engine from rust and corrosion, what could be better. Just make sure you get the non poisonous one.

        • whitequark says:

          I don’t think there would be much difference between antifreeze and water wrt/ heat transfer… it’s about specific heat capacity, and water beats pretty much anything else at that property.

          It’s also nice that I can use it once and then discard, because it also removes the chips, and filtering some more expensive fluid would be a pain.

      • Smorges Borges says:

        I scrapped some old laser printers recently and saved some nice aluminum panels specifically for making small enclosures. The stuff is easily bent. I also saved some stiffer steel.

        An enclosure can be as simple as two panels, each with two bends.

  2. Smorges Borges says:

    For those who haven’t done their reading yet, it is worth mentioning that a loss of power to a stepper driver board can easily fry it.

    So it is worth being a bit pro-active in having a solid power solution.

  3. Josh Martin says:

    What about my wonderful setup that involves hot glue, an fr4 sheet, stepper drivers thermal peroxided to L extrusion, and using the PSU’s fan to cool the drivers down?
    I was in a pinch since it wouldn’t fit into the old UPS I was hoping to use so I glued the other half on a sheet of FR4. It’s worked for hundreds of hours, gets dust encrusted, and so forth… PC still needs the SSD upgrade. But hey the steppers drivers are open source from Massmind and there is an arduino that powers the drivers with 5V so it’s all good!

    • Josh Martin says:

      Hrm… The resolution is abysmal.
      This should fix it.

      http://pho.to/5qALE/hs

      • whitequark says:

        What’s that? Looks horrifying.

        • Josh Martin says:

          It’s a working CNC machine and it’s been paying for my college/rent/etc for the past 6 months. I’ve killed 4 palm routers and finally gave it a 1 HP VFD setup.. There were a lot of little hardware iterations (I didn’t build the frame) so it needs to be pulled apart, and everything needs to be placed into an enclosure. I have a second frame and set of electrical parts that are going to build a second “organized’ machine, then I can work on this one. My degree is a business degree not an engineering one, plus I’m inherently disorganized to say the least.

          • Tumblebeer says:

            How did you manage to make that kind of money with a small home cnc setup? I’ve always thought homebrew cnc was one of the fastest and most enjoyable ways to loose all your money. It sure has been for me.

  4. pcf11 says:

    I am seeing markings on your power supplies L, N, and G. I assume that is for Line, Neutral, and Ground. Where I come from Line is coded black in color, white is Neutral. You have things backwards. I’m glad it works for you but it is wrong. No, the wires for alternating current are not all the same. Neutral is really Ground, just Ground is not mechanically designed as a power return. That is the only difference between those two. Go ahead and measure continuity between Neutral and Ground. If your house isn’t super fucked up they should ring out. There should also be no power on your Neutral line either. If there is that means you have fucked up shit either in your wiring, or something fucked up plugged into your wiring. Those things do happen.

    Call a licensed electrician to sort things out. Because anyone who runs a white wire to the Line terminal is not qualified. :)

    • profke says:

      where I live, ground & neutral are not interchangeable. search for GFCI.

      heck, there are parts of our country, where instead of 230Vac & 0V, they receive +115Vac & -115Vac. Ground still is at 0V, there.

      • rj says:

        Two-phase mains (such as a 240V circuit in a US house) is supposed to be +120Vac and -120Vac… it’s not an accident. Half the 120V circuits in a US house should be one phase, and the other half on the other.

        That said, you may not be in the US, in which case, apologies!

        • blua says:

          “half on one phase” is kinda misleading. What a US home really has is 240V single phase coming in off of a center tapped xfrmr. Either leg of the single phase 240 to the center tap is 120. that center tap is neutral which is SUPPOSED to be the same as ground in theory, but in practice this is not always true, which is why ground exists, as a “reduntant” saftey measure. thats why 3 prong outlets becmae the norm as we got older and wiser w/ elecricity. Neutral is arbitrariliy defined as 0 in the system, which hopefully is the same as ground, or you are going to have a bad day. However new GFI outlets can tell when ground and neutral are not behaving and trip things.

          this is by far the best reference I have ever seen on the topic, although it could use more diagrams, but I bet wikipedia has all the diagrams a man could ask for.

          http://www.ab.com/support/abdrives/documentation/techpapers/rfignds.htm

    • JRDM says:

      Yeah.

      I never understood why color coding is the way it is. Black in DC is most often ground. Black in AC is live line? But then, China has brown & blue for AC.

      Oh well.

      • Shakipu says:

        And if you’re color blind, it’s a real nightmare.

      • Stormdog says:

        And in the military, I believe black is also ground. I used to have a job where I worked with people fresh out of the military. It was often difficult to convince them not to tie black to the frame of the machine. Sometimes even after repeated shocks.

    • whitequark says:

      I’ve been told that, yes (I should have retaken that photo…). But since the EU plug can be inserted either way, you can’t be sure whether Line actually has line voltage or neutral one, anyway, so there’s no real difference.

      • Dude Love says:

        If a switch is placed on the neutral line instead of the live line , then the power will still travel through the circuit and at any time you could accidentally close the circuit by grounding part of it, even if the switch is turned off. If the switch is on the live line, then when open, no power flows through and it makes things more safe. Also when switching more phases, say 2 , the switch should be DPST (dual pole single throw) so that both lines are disconnected from the circuit when not in use.

  5. jolee says:

    Yes I thought machines cost money, I am eager to see how an enterprising student can pull in steady profit.

  6. Josh Martin says:

    It’s $2k USD or so a month with highs and lows. I do very small runs with expensive woods that’s $30-$40 per 144 cubic inches or a board foot. Everything is 3d profiled so it comes out very smooth, then i sand, and finish everything very well. The frame isn’t DIY but the rest is a cobbling of misc pieces.

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