ATX supplies are super useful for 3D printers!
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- Опубліковано 1 жов 2024
- Why have we stopped using ATX computer power supplies? I explain what the pros and cons are of going with an simple "industrial" power supply vs. a full ATX supply, including being able to shut it down through the firmware yet still getting a solid 5V supply for a Raspberry Pi!
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For a lot of us IT nerds that get in 3D printing, we often have spare ATX power supplies already laying around.
yes so it will be :D
@Billy West depends on them manufacturer. All of my bought printers use 24V, but my built ones have been made from spare PC power supplies. Still a 24V printer power supply from Banggood is pretty cheap
@@danamccarthy5514 Yeah cheap and loud.
I dont understand why and how is word "it" used in this context
@@dinodubroja7433 IT = information technology. system administrators, programmers, etc.
You forgot the biggest reason when deciding on which one to get. What you already have. I used an atx supply for my printer cause I had one an then it's free which most people really like.
usually you can get them for free from scrap pcs.
6:15 Need some random 3.3V and 5V loads to waste some Watts, you say? *FULL RGB 3D PRINTER*
Modern problems require modern solutions.jpg
Gamer RGB 3D-Printer invented!
Don’t challenge me.
Yes RBG gaming 3d printer
The industrial bricks support voltage adjustment. I am running my 12v one at 13.5V witch speeds up the heated bed by one minute.
Pretty much all atx power supplies have a pot for voltage adjustment inside, most will go to 13 or so volts.
RAMPS 1.4 and atmega board? I was thinking of doing the same, but I was a bit afraid it could damage my electronics (especially stepsticks and 12V-5V voltage converter).
You can buy a breakout board that gives you a power button and all the power conectors.
20 Amper ready!?
Hey Tom, greetings!
When I've build my diy 3d printer last year I've used a Thermaltake 500W ATX power supply.
Got a spare PCI Express Adaptor Cable (6 Pin to PCI Express 8 Pin), cut one connector to connect the wires to the RAMPS and the other connector goes straight to the ATX power supply so I don't cut any wires on the power supply which is still under warranty ^_^
Oh and yes, I've attached the green wire of the ATX to the RAMPS, so I can turn the power supply on and off on demand. It works with the Emergency stop too.
The 5V purple wire wasn't really a success for me though. The RaspberryPi was constantly getting corrupted SD card, so I switched it to dedicated power supply (the one it came with).
The extra cables of the ATX are wrapped with a zip tie and hang on the side though.
My TEVO Tarantula is still running on ATX PSU from Thermaltake. It produces very safe power and I leave them at school.
Ages ago I made a IR TV receiver for a multimedia PC that not only send signal to serial on-board header but had uC to decode power button code to turn the machine on/off. Well, on battery, everything was great. Once powered by standby 5v (purple wire), you had to put the remote few cm from receiver otherwise it didn’t work. Reason? Too noisy power line! I had to put a low drop voltage regulator circuit between “purple” line and the receiver board. Maybe the same problem here.
One thing most people don't know is that the raspberry pie is made to run on 5.1 Volt, it will most likely run on 5v but if your power supplie drop a few millivolts lower it can cause unwanted restarts and sd card corruption
I've been watching your videos since the Printrbot days mate, when I first started getting into 3d Printing and needed something new to get into & a change in life choices. You have one of the most, no deffinitely thee most influential & invaluable teachers ever since then and helped me to turn my life around completely. I could never fully return the favor on a level that you have done for me, and you continue to teach me new things every time you make a new video. I hope to return the favor at least a little bit though and become a supporter of your channel soon, as all that I have learned from you is now helping me to finally make the career change I have dreamed of for a very long time. Thank you so very much Tom.
I've been saying this for years. I use a single semi modular atx supply with a raspberry pi on the 5vsb, and remote power for safety. Upon print completion it kills the atx.
"Upon print completion it kills the atx." Sounds quite brutal.
Eli Eli Lema black widow printer 🥺
I'm surprised a noise comparison did get a mention.
My old industrial PSU turned into a wicked musical instrument after a few years. :P It responds to different surge levels with high-pitch squeeks, loud clicks and howling sometimes.
I love when Tom posts this sort of "guide" content
Tom, If I were you, I would change the title to specifically say "Power Supplies" which is more specific than "supplies'. It will help you number of views over time. Good video!!
I use a cooler master 600W that I got for free (hard to beat that price) 😁
24 volts is the key factor for me. Having one power supply for the heated bed, controller board and steppers simplifies everything a great deal cable management wise, 12volts was the obvious choice in the early rep-rap days as they could grab the old ATX ones from desktop PC's but I think Prusa have demonstrated that 24v is the way forward for consumer machines.
I feel that using ATX psu's is still totally viable, as am in the process of switching from the default LED style psu's on a couple of my 12v printers with some single large 12v rail ATX psu's that I still have in boxes as ready spares for well over a year but not needed them (corsair & seasonic = excellent reliability) I wouldn't do this with some of the older pre-haswell compatible class ATX psu's as those tend to need a load on the 5v rail to maintain stability, (I have an old but perfectly functioning Enermax Noisetaker 650w psu from about 2007 which behaves like this and it wasnt a cheap psu either).
If I had to use an older atx psu I would 1st check the label for how its power distribution is laid out, some very old ATX psu's tend to have most of the current dedicated to the 5v rail rather than the 12v, so after looking at the label if it had more juice on the 5v rail then I would reject it - thanks for posting
Hi Tom, at first I thought you have a +12v and a -12V on your ATX, that means you do have 24V between them, which you do..........But even though you can get 24V it will be useless because the -12V rated for 0.5A max. So you could run ....... a 24v fan:):). Dang, at first I thought I was onto something. Oh well.
Great insights, the 5V standby voltage is very useful, but the large size of the ATX power supply and 12V only (vs 24V) would be a limitation for me
The thing with ATX PSUs is that it's easy to get everything up to 500W Gold for 10 Euros +shipping used in good qualities, from known manufacturers and sometimes even modular. Really would have liked to see that mentioned here
Best 12V supply I ever used... was a used HP Server power supply that put out over 60 amps continuously .,,. $15 off Amazon.
link?
You don’t lose “capacity” from “dry capacitors”. You lose voltage regulation
How's that "best stepper for TMC2130+" coming along?
I loved the couple of times you dubbed yourself! I can't tell you how many times I wanted to do that when I was editing my videos!
24V is the way to go 👌
I am using a server power supply. Even at standby it can supply my controller and raspberry pi
same here. octopi and psu control via a relay
@TheSysops666 for me it did. And is working for quite a while now
And you can make 24V out of two of these (but please don't let them touch each other). I have 24V with 80 Amps. I want to power my heated bed with 24V to the 12V rail. That means 4 times the power and one fourth of the time to heat up. Haven't finished it yet but I can't wait to see it (?burning?)
@TheSysops666 its not as straight forwards as atx (at least for the server psu im using) requiring a boost reg ontop of the relay but its not much more than an atx along with less wiring to hide and a "more reliable" psu
Server PSUs are also typically 90% efficiency or better.
I've found ATX supplies have very thin cables which get too hot in some environments. I had to change the original wiring because some cables got burned.
I use a hp server 450w power supply
It has a platinum rating
My ATX computer power supply has a 12v - and 12v+ when used this way it's 24v.
how many amps could it supply as 24 V ?
Tom, great information. I have known about ATX supplies in conjunction with 3d printers for several years and have actually built a hat for a Raspberry Pi in combination with a Octoprint plugin that controls the printer, Pi, LEDS, fans, etc. I have had one running for the last several years without any issue. The ATXPiHat is a one stop shop solution for ATX supplies and interfacing with 3D Printers. It started out as a small single PCB that you de-soldered the connectors from and solder them to the PI, etc. What a mess. The newer solution is plug and play. It handles all of the output muxing of the wires to handle the voltage/amperage requirements, load on the 5v rail to handle power sagging, etc. I wish that there was a 24 volt ATX solution. ATX supplies are more stable, better manufactured, and the power is much cleaner. Computers really do not like crappy power. Thanks again for the great video.
I currently use a thermaltake 500 watt atx and a 24v power supply. I use the 5vsb to power the Raspberry Pi 3b. When I turn on the power supply in Octoprint the 12v from the atx powers a relay to turn on the 24v supply. The 24v supply is used for the stepper drivers and heaters while all the fans are run off of 12 volt. I am currently using a ramps 1.6 and mega for the main board and a ramps 1.4 and mega for fans and extra temperature sensors. Im using Klipper for the firmware to tie it all together.
Is it really okay to parallel two 12V rails? It is important that they have some buffer resistors on the output of each rail (like 0.1R) to ensure they share the current draw equally. If not you can get current flow out one rail into the other and things heat up quickly.
Like if you try to stack
opamps it becomes unstable. Buffer resistors can be critical.
You bring up a good point. I had a near melt-down in a connector where I have bridged ATX rails. Even a small voltage difference can result in large current loops.
This is great information. It's too bad these psu prices aren't as low in 2022.The good news is that printer psus are the same price as atx psus right now so thats nice.
Are there multi-rail PSUs without a common ground? Then you might also be able to get your 24V if you put them in series.
You need to combine -12v and +12v. its possible on all PSUs but it cant take that much load...
It's also worth mentioning the thing that was in view for the whole video: that fan. ATX power supplies include fans, which can be noisy, and which will circulate air in a place you may not want it circulated (because you are trying to maintain an average air temp around the bed, for example).
The 140mm fan of my ATX PSU (on my (homemade printer) is way more silent than the fan on my Ender 3 Pro meanwell PSU :)
It’s put underneath the printer so no unwanted airflow on the print
Can't I obtain 24v from the ATX power supply by using the yellow cable (+12v) with the blue cable (-12v) to close the circuit, instead of the black (GND)???
Yes, but the single -12v connection usually has a low amperage limit.
the link to the 24v 10A supply is broken
Thanks, fixed!
@@MadeWithLayers How about more information on 24V vs 12V? Some people said they can't see any difference with motors and print quality. Is it really worth to change from 12V to 24V? So far it seems I can win on smaller internal power cable at the cost of replacing fans and heaters.
@@vladimirseven777 It's more important for heatbed. If you have a 300x300mm heatbed you will be thankfull to use 24v instead of 12v.
2:25 Did he really just say 12 floppy drives........ XD Boi
i just use a server power supply, about the same size as the industrial units, pumps out 850 watts and is pretty quite
"I'll enable member tiers here on UA-cam at some point"
Bald ist es ein Jahr her, Thomas.
"One big transformer". No, this is incorrect, these are all switch mode supplies. Group regulation has nothing to do with transformers or the number of secondaries, that's not a simplification, it's confusion. Group regulation is simply the rails being regulated as groups rather than being monitored independently, eg one regulator with multiple outputs, the clue is in the name "group REGULATION" .The cost saving is in regard to the number of regulator circuits, not transformer secondaries, these aren't linear psu's.
He explained that sometimes uses different voltages ratios between outputs to bring the voltages, and because of that, the use of only one transformer with this different ratios is used. Obviously, this is not ideal for many voltages, but is cheaper.
The SMPS uses transformers, but not to step down the voltage. Is for induct high voltage low current from the primary to the secondary, and in this manner induct low voltage high current in the secondary, that is rectified and filtered to give the desired output voltage.
He is correct you are wrong. Switch mode supplies are regulated by PCM on inbound side. So if you have one transformer you can only regulate all outputs at once. To regulate them individually you need separate transformers to have separate PCM modulation for separate output voltage.
m3chanist - Sorry you're incorrect.
Vyacheslav Kononenko PWM. PCM is Pulse Code Modulation.
Your wrong. Unlike a linear power supply, the pass transistor of a switching-mode supply continually switches between low-dissipation, full-on and full-off states, and spends very little time in the high dissipation transitions, which minimizes wasted energy. The first block is used to rectify and filter the input making the power draw more "stable"as in so its more of a straight line on the graph.The second block in an (smps)is a chopper which makes pulsating dc waves and the biggest ones go through the transformer.
I've been through pretty much all the options;
12 V cheap PSU that came with the printer
12 V ATX (Noise)
12 V ATX with Boost Converter (TMC drivers)
24 V ATX in series (faster bed heating times)
24 V Meanwell (less cable clutter)
24 V ATX in series (that Meanwell is stupidly loud)
24 V ATX in series with a 12 V buck converter (lights would flicker when loading the 24 V rail)
With the 12v atx supplies that also provide - 12v can you connect across +12v and - 12v to achieve 24 volts?
That does give you 24V. However, (a) they share a ground with whatever else is connected, such as the controller board. That ground is in the middle of the 24V, rather than the negative side of the 24V. Hence the controller will not be able to switch this "24V" like it normally would. And (b) more fatally, the -12V supply in an ATX PSU generally has a very low current capability. So it would not be able to supply loads like the bed or hot-end or motors.
I tried using the 5v standby for my Pi2 + PiCam + Arduino Mega + Ramps 1.4 + backlit large LCD & SD card controller setup, wasn't sufficient, the temperature values kept fluctuating and had some other odd behavior (it worked though, but I didn't like the jumping temp readings), I instead added a separate 5v supply. This is an Antec ATX PSU I used to use in a gaming PC.
What do you think about using a ZU-550W-24V ? It is what ReliaBuild printers use.
12 floppy drives 😂😂😂
The games install quicker this way. Especially now, that they are all dozens of gigabytes
.
I built my printer mostly out of bits I had lying about, so I went with a Maxpower 300W ATX. I run the electronics on the 5v line to prevent auto-shutdown during hot end heat-up. I don't have a heated bed, and at 12v my motors are more powerful than the wooden frame can handle so 24v isn't required. I also don't use the standby power as I run direct from my PC with Repetier.
why cant you use the -12v and +12v from an atx to achieve the 24v for the printer?
I'm really hoping for anaswer to this as well. Seems like a simple solution to me.
use the -12v and +12v to get 24v just saying
My very first printer back in 2014 was a fairly cheap (for the time!) Kit build and uses a ATX PSU with a couple of Resistors, it works fine and vecro keeps it from diving off the table (yup that happened, vibration from the printer made it walk since its not attached!) It still works fine, and I used the 5v to run a Pi with octoprint for quite a while. Ultimately though 24v and not having to deal with a rats nest of chopped up atx power leads has meant i've not really looked back. Nice Video Tom!
12V->24V DC-DC 10A boost converter? DAFAQ!!
The emphasis is on 10A.
I used 2 ATX power supplies for my first 3d printers but they seemed not very reliable, I had rare shutdowns while printing. Probably some voltage spike or other things happening, since there is lots of unregulated stuff going on. I then used switch mode power supplies for LEDs and never had any problem since.
Im using ATX psu salvaged from some older gaming pc. Thanks for the info on marlin being able to turn my psu on and the standby line. But my raspi is very picky and screams undervoltage constantly, so i don't think hooking it up to the standby line will work
I have customized a 3d printer for a Friend.
5vSTB to the RPI running Octoprint.
The PI is able to turn on the printer. By switching on the ATX PSU!
I'm running two ATX supplies for 24v and it works great, but you have to do some hacking to make it work.
Fundamentally, the power supply creates a *difference* of 12v between its low and high outputs. We call them ground and 12v, but they're really more like x and x+12. So if you connect the low output to 12v, the high output will be 24v - easy! Unfortunately the low output is already internally connected to the earth pin on your power plug. This is for safety: if you let x just float around with no specific value, who's to say it couldn't end up at 240v and shock you when you touch it? However, it's possible to mod the power supply so that the earth is still connected to the case, but not the low output, leaving it free to be connected to the 12v of another (identical) supply.
There's a video by Neilgn called "Isolate negative terminal from ground on ATX supplies" that shows how to do it (though he isolates both supplies and you only need to isolate one of them). It's not that difficult, but I wouldn't attempt it without at least a multimeter and a knowledge of how to discharge the big input capacitors.
Who among us does not have a rig that rocks 12 floppy drives? XD
Most recent ATX power supplies have a single 12V rail again, but it's good to know they exist, especially on cheaper or older designs that you might repurpose from an old computer.
Server power supplies are often superior to both in most aspects. They can be a bit loud, but are often autoranging for mains power. Laptop power supplies can also be useful too. There are mods that 'float' ground to gang multiple power supplies together for 24 volts as well.
Why not just use a standalone 5V supply, and use a SSR to turn on and off the main 24V supply?
using 2 x 12V30A wired together to get 24V30A for heatbed & mainboard and 36V10A for motion system (Nema 23) - sounds way too much, but i have a gigantic corexy mashine for 3d printing (40x40x48cm buildplate) and cnc routing (48x45cm wasteboard) on linear rails. and yes tom, it's working freakin' great! :)
A lot of system integrators (Dell, HP, Lenovo etc) use 12v only PSU's that are proprietary versions of the ATX12V standard (ATX12V is an old variant of ATX that only supplies 12v). If you want a cheap 12v PSU wthout 5v and 3.3v, cannibalise a Dell, HP or Lenovo desktop PC. A lot of us PC nerds can get them basically free. These PC's have 3.3v/5v regulators on the motherboard, same as their laptops, and the small form factor PC's have physically small PSU's.
24V industrial type, with a relay switch controlled by a raspberry pi that is on with another insdustrial supply of 5V (i have one for 35W on 5V) - those 5V comes in handy for lots of sensors and actuators (relays and stuff.. the RPI GPIO is 3.3v, but with a npn transistor i give the 5V to whatever amps the relays need (which is much more than the max 60mA GPIO pin should be used, and also it's 3.3V. I like to transistorswitch all gpio outputs for turning on a fan, a led strip, the PSU, etc)
Worth noting - EU rules (EN61000-3-2) require power factor correction (PFC) on such equipment, which improves power output and reduces load fluctuation on the power network. Cheap import printers rarely have PFC - of course the Prusa printers do as they're built in the EU. Here's what Meanwell say for their LRS range (common in cheap printers) that don't have PFC:
"This power supply does not meet the harmonic current requirements outlined by EN61000-3-2. Please do not use this power supply under the following conditions:
a) the end-devices is used within the European Union, and
b) the end-devices is connected to public mains supply with 220Vac or greater rated nominal voltage, and
c) the power supply is:
- installed in end-devices with average or continuous input power greater than 75W, or
- belong to part of a lighting system"
Seeked out an ATX PS with a 5V standby that can handle over 3A to power a R PI and re-arm when it was off. I found the PS for a Dell Optiplex 3010 or 9010 has a 5Vsb at 4A. It is a small form factor 240W and goes for about $35 USD on Amazon. I have the 5V Standby powering a the RPi with its USB connected to and powering re-arm with ramps. the PS on turns on the ATX PS to provide the 12 V to the ramps for motors and hot end. I have the PWR OK signal from the ATX PS trigger a Solid State relay to turn on a 24V 480W PS for the heated bed. The ramps is connected to a MOSFET to control the 24V to the heated bed. I added the plugin to octoprint for power on the PS and power down the PS after some time. I just send a job to octoprint and the printer powers up and shutsdown after cool down.
I’ve been looking for an excuse to use more Seasonic products :-)
Lol kidding, the ‘industrial’ type just make so much more sense. I’ll just slap a Noctua fan on one if it needs cooling. Did it for my Ender 3 Pro’s Meanwell unit and it made a ridiculous difference in noise. Been running for 2.5 years with the fan swap.
DON'T JOIN RAILS TOGETHER !!!!!! This is such a common mistake in non-electronic major peoples.
If u join both 12V rail together, they could back feed eachother, wasting a lot of energy and might desotry your power supply as well. This is due to the fact that they are not prefectly at 12V, any tiny difference will start back feeding eachother. And powersupply has tiny internal resistance, small voltage difference still generate lots of current. You might get lucky that the two rail are actually the same internally, then you are fine.
But, don't put any two power supply directly in parallal !!! or even two channles in the same powersupply.
A third option would be that the 3D printer manufacturers get together and do a SPEC similar to ATX for 12V, 24V and 48V - including 5V standby, electric on/off,... They could come up with their own set of connectors or simply reuse some old PRE-ATX mainboard connectors. They would be free to change the size etc.
And the result is a fixed form factor and a spec people can produce or order. Just look at the stepper motors for size and layout. It might even be better to look for other applications as well. E.g. getting the LED guys on the boat - 5v standby for remote access and cloud snooping and 12/24V for light action.
I am using a HP DPS-460 Server Power Supply on my 3D printer. It has a lot of power, is silent, can be also switched by marlin, uses high quality longlife components, is very compact in size and you can buy it on ebay for less than 15 Euros. It is still 12V but thats fine for my me even though I have a 200W/12V Heatbead.
I'm custom building my CR-10 with Duet2 wifi and a super cheap used HP server PSU. Very happy with it. High efficiency, doesn't even get warm when printing with heat bed on. With a buck converter to convert 12vsb to 5v for Duet2 board and a PS_ON pin connected, I can keep the board always on while turning the main rail on / off with a single line of gcode and from GUI.
Turing printer on/off using OctoPi is a neat feature and quite easy using ATX power supply. However I will stick to industrial PSU - 24V is much "better" feature. To turn the printer on off I plan to use relay on 230V side, I am going to power Raspberry Pi and relay from separate 5V power supply. Both connected to the same UPS, so I can switch them manually on/off there.
so you didn't mention that with an ATX PS: if you use the -12v output (as positive) and the +12v output (as ground) you get +24V... would that not suit the needs of the required 24V in a newer system (My Ender3 for example)... THNX :)
I've recently remade all the electronics of my Anet A8 upgrading it to TMC2130s and I've used an 875W computer PSU. I know that that is overkill however I didn't go out of my way to buy it, I found it in an old Aurora R2 which is a rebuilt computer and the manufacturer made the PSU slightly larger (not longer, larger) so that it couldn't fin in any standard case.
Basically, I had this PSU laying around that I couldn't use and the choice was pretty clear.
"500W" (actually 300W)
also actually a fire hazard, speaking from (school) experience.
Also, higher-end ATX PSUs have been increasingly single-rail for years now.
ATX supplies have in the past led to ground loop issues. However if you look at buying new -- a quality ATX supply vs even a set of quality meanwell (or comparable) industrial supplies -- 24v, 12v and 5v -- 3 pack -- if you want to avoid using boosters or drop down converters, you still come out ahead using industrial supplies. Considering getting 24v out of an ATX supply requires extra circuitry, it's a bit of dead topic. The only valid argument is if you have a free ATX supply recycled from a PC tear down or just in general, and if you don't care about the benefits of 24v -- quieter, smoother steppers, faster heat up times, etc. You have to deal with multiple 12v rails, ganging them up to create any decent current output of an ATX supply -- but if it's free and you're on a budget -- why not.
Great info video! I've swapped the original power supply of my MK2.5S with an ATX. The man reason was to have a stable 5V for the Raspberry Pi with OctoPrint running. Also, for the printer and the Pi have the same gournd level, I think the USB connection between them is much more stable.
I have a question connected to E3D (I'm sorry, it's not about PSUs):
- guarantee services are considered a service.
- none of "deals" with UK consider to cover services area
Question:
Is it safe to buy anything from UK?
(the lawyer failed to answer that, leaning torward negative answer)
It's quite important question to consumers (even though in my case, I was considering supply contracts with couple of british companies - quite big contracts for a small company as mine is)
EDITED:
few typos
Hi Thomas, I have built my DIY 3d printer and I'm using 2 ATX power supplies 1st for the printer and 2nd for the heated bed. I used a 12 relay to on/off the power to bed. Now the problem is when the temperature is reached 60 degrees after that relay is toggling every second. Can you please help me to fix this. I'm using Ramps 1.5 and Marlin 1.1
Thanks
I fry my first atx with my diy pcb 17A 12V heated bed. Then I buy used server power supply (12V 40A). But this was long time ago. If I was building printer now I would totaly go for small 24V brick for electronics and motors and mains power heated bed.
I'm using a medium quality EVGA 500W ATX power supply, it worked for a while without any load on 5V but after a few months it started behaving a little weird (prints stopping in the middle with the ATX still on afterwards or sometimes stopping completely), I tried adding a 12V halogen light to the 5V line and now it works perfectly so even on good quality ATX think about it if you have any issue.
I am building a printer with a 24V 350W PSU that came with the kit and I am just finding out that I probably won't be heating a 300x300 24V bed with that since those beds alone require something in the neighborhood of 400 watts... :-(
On my DIY Hypercube 300 i run 2 industrial power supplys. A 24v run the 300x300 heated bed and a 12v run all the other stuff. First i build only with the 12v but the heated bed don´t achieve 100 C degrees needed to print ABS, so i buy the 24v power supply only for the heated bed and it works insanely well, it hits ABS temps in less than a minute. I know that is possible to run the ramps on 24v and maybe in the future i go for that conversion.
My Anet E10 power supply died (looks like a bulging cap on the 240watt supply) so I used a 480 watt ATX I had, after seeing this video today and it seems to be running better than before. The Y axis bed stepper sounds like it isn't struggling like before- has more zip to it. Printing now- up and running, fingers crossed :)
You can buy a small circuit board with an ATX connector on it with a selection of binding posts with different voltages. These boards can be had from Banggood or Aliexpress for less than $2 US. Makes for a clean and safe install as you can cut off all of the wires but the main ATX connector. Also, all of the Binding posts are fused. You could easily mount the breakout board to a printer with the power supply connected through a nicely wrapped ATX connector & cable.
Due to the large number of scrapped computers, used ATX supplies are readily available just about everywhere. These breakout boards make quality ATX power supplies a bargain for 3D printers as well as benchtop power supplies. As an added bonus, most ATX supplies are UL listed and less likely to catch fire or accidentally electrocute you. Not the case with most import (Chinese) supplies.
Technically all ATX PSUs only have a single 12V rail. The difference is in some models the outputs are connected to that rail in groups with independent short circuit and over current protection. Those are logical rails with individual current settings. Physically they all get their juice from the same coil/rectifier. Everything beyond that is marketing.
But it's a nice safety feature to have nontheless.
With a single-rail-psu a component could short out and draw more power than the cables can handle, but the psu won't necessarily shut off because the total current might still be within that rails limits. Result: Fire.
So for a PC build, if you don't have the budget for a fully digital psu, a "multi-rail" psu from a quality brand is a good choice. (most are made by superflower, delta or seasonic and then re-branded anyway^^)
I built a printer and added a raspberry pi zero w for running octoprint.
On one of the GPIO pins i've connected a 5V relais that switches my 24V power supply (for heated bed, hotend and steppers) on and off via Octoprint. (using octoprint plugin PSUcontrol)
Only a small power supply for the raspberry pi is hooked up which stays on (until switched off with a manual switch on the printer itself)
Protipp. Usually there is nothing to complain about Second hand power supplys and they are really, even those 80+ Got a 660W 80+ Platinum modular PSU for 20€. It wasn´t missing a cable.
Old laptop power bricks.. Lenovo has few which are rated for 8Amp at 19.8V, which is perfect for my Cetus with a custom heated bed. Heated bed is controlled by an ESP32 with own web interface.
Used cheap industrial 24V unit + heated bed powered by mains via an SSR. I use simple step-down converters to generate 12V and 5V lines for fans, LEDs and to supply a Raspberry Pi for OctoPrint.
I started with an ATX on my original REPRAP build. But purchased an industrial supply when I needed more current than 1 wire from ATX could supply. I could never trust an ATX to provide clean power when multiple rails are joined together. Internally, I don't think it's a good idea to just combine rails in parallel in hopes of sharing the current load. Strange phasing issues may cause voltage spikes or something to burn out. I'm no power supply designer, so I could be wrong, but for the cost of an industrial supply that's rated with the high current I needed on 1 rail, I wasn't going to risk it.
or you buy a modular ATX psu (+500watt) with cable managment that delivers 300watts on pcie cables and has 2 and more lines when nessasary. the good thing about PSU with brand names are if they blow up they cut the power where cheap china psu are giving a overvolt loadout throu the lines when they are giving up, what means they take mostly everything with in the grave. and if you are abolutly unsecure you could buy a thermalthake tough 1500watt goldstandard psu 80+ (300€) that beast get every job done
What about using ATX's -12 and +12V poles? I use an old ATX for galvanising/etching small stuff, and sometimes I use that 24V possibility.
Is it a bad idea to use this feature for a printer?
24 v definetely rocks. IMO 12v for printers is dead. Most connectors are rated at 30+volts and amps on connectors drives up the price and same on wire size. Even for a hotend at 40 watts you can use a jst thpe connector at 24 but not at 12. Unfortunately the ATX is very weak on the -12 so even though you can get 24 v between -12 and + 12 its usually just around 1 Amp or so on the -12 rail
I replaced my garbage chinesium power supply for my Anet A8 with a good Dell atx powersurply i had lying about. I feel a lot safer now and the short circuit protection is fantastic. I had a LED light that was short-circuiting which would instantly trip the protection resulting in no damage.
With all software safties enabled, soldered bed connections and external MOSFET, I feel somewhat safe letting it run unattended.
One could use a +12V rail for power and a -12V for ground to get 24V, if both rails have identical amp ratings, but forget about using that 5V and 3.3V if the power supply provides a common ground for all of them. One would probably be better off opening it up and implanting a 12V to 24V boost converter
Best 3D printer power supply: AGM lead acid solar battery
I'm a little surprised the xbox 360 power bricks weren't mentioned since they were pretty commonly used a while back.
Honestly I'd assume ATX PSUs went out of favor because they're just expensive (moreso for the new-ish modular ones you'd really want) by comparison and not that many of us have a ton of spares lying around anymore, though they'd have been super common among the electronics hobbyists and engineers who got the whole RepRap thing started.
ATX PSUs are fantastic and if you get a nice one at your local dump or recycling center they're great for lots of things.
But dedicated power supplies are cheap as chips and save you that effort and shed space.
When i built my first 3d printer myself i went with ATX-powersupply since i had one extra that was available. Worked fine for years until i finally bought factory made metal framed 3d-printer to replace it.
You should have mentioned used server power supplies. They are extremely low priced, efficient, reliable and easy to work with. I also wonder why so many don't take advantage of the M80 and M80 gcodes to turn the printer on and off. This is extremely easy to achieve on ATX and server supplies.
You should NOT switch the entire printer off immediately after print is complete. You should keep at least the cooling fan on, until nozzle temperatures are low enough (to prevent heat creeping to the cold end side, and melting the plastic there).
But no worries, there's GCode for that too!
M109 R60 ; switch current hotend temp to 60 degrees & wait until the temperature is reached.
After this, it should be safer to switch the entire printer off.
24V are my main reason why i will not use ATX supplies ... boost converters from 12v to 24v for high loads seem like an unnecessary complication compared to stepping down 24v to 12v for the little bit that the control electronics need (eg inductive probe) ...
Is it possible to connect the 12V rails in series?
I believe most multi-rail power supplies are so because of the voltage drop on the ground return wire. If 12V dropped to 10V it should not be a big deal because of on-board VRMs, but if ground raised to 2V then all he'll would break loose because of the communication lines.
If this is the case, grounds being separate between trails, then only protection circuits could possibly shutdown the supply.
Are you aware of a cheap industrial psu providing both 5V and 12V? This is in my opinion the main benefit of using ATX since stepping down 12V to 5V for high current loads like Raspberry Pi is not trivial