Increased voltage to make stepper motors more “strong” and fast - is it really worth it? Sometimes in the Internet I see this suggestion - increase main voltage source from 12V to, say, 14-16V, and this will allow you to increase printing speed and quality. But does it really safe for motors? Somebody actually does try this? I’m using MKS Gen-2 board, which allow up to 24V input voltage, so it seems safe, but…
You adjust the stepper by changing the voltage on the stepper driver potentiometer. But to much will overheat the motor too little will skip steps. Depending on the setup it’s between 0.4v and 0.65v
Steppers are constant current devices. It is safe to run them at higher bus voltages, the stepper driver limits the current. Running at a higher voltage just gets them to the current limit faster, which improves torque at high speed.
Also it is good for heating bed, right?
@Vladimir_rvo_va_r , running heated beds are higher voltages means less current draw for same heater power, allowing you to use thinner and more flexible wires (important for moving beds) and allows for less losses in wires; running a bed at mains voltage can completely eliminate the need for a bulky, expensive, and inefficient bed power supply
I have come to the conclusion that all 3d printers should run at 24 volts. Thinner gauge wires are needed for the power supply and heaters, the motors will have higher torque, and there are less losses al around.
The only reason why we still use 12v is the antiquated idea of using a PC power supply.
@Stephanie_A Thats why! Exactly! It all comes from oldschool using ATX-power supplies.
I have build 2 Printers on my own, now on my third, I resolderd a RAMPS-board to make it 24V-ready, I even did documentation of my experience with the SAME printer at 12 and then 24V.
24V is better in EVERY way but two: You cant use cheap 12V-PC-fans any longer, you either have to buy 24V-ones or step-down-converter and second: the motors get louder. In EVERY other category 24V is the winner. And if you use stepperdriver like TMC2100(16th interpolated to 256th-stepping) or Silenciosos (raw 128th-stepping) the loudness is no issue.
I use 12v for one reason: low cost. Oh, and it works. 24v is easier, but 12v is possible and forces us to make really efficient hardware.
Brook
After having my printer catch on fire because the wiring, mosfets, and connectors couldn’t handle the 15+ amps, I don’t think the ease and cost are worth your house burning down.
Trace routing on the board is easier, connectors can be cheaper, wires can be thinner, the power supply can be cheaper and smaller.
if you add everything up and spec it right, the cost difference is negligible.
you can even add a 12v regulator on board that can handle fans and accessories. The hardware will be even more efficient.
Nope. you realize that as voltage goes up, amperage goes down. For a 12v 25A supply, it’s 300 watts.
http://www.circuitspecialists.com/12-volt-25-amp-power-supply-PFC.html
a 24v 13A supply, it’s 312 watts.
http://www.circuitspecialists.com/320watt-24v-output-with-pfc.html
this was a 20 second google search, but you get the idea. Same wattage, same power, same cost. supply and demand doesn’t affect the cost that much.
@Stephanie_A at first 24v PSUs are cheaper, now they’re the same price?
I’ve done a lot of sourcing at the bulk quantity level, and I’m afraid @Mark_Rehorst is correct: 24v power supplies are more expensive for a given wattage. I wish that weren’t the case!
It’s crazy how nonchalant people are about >20A circuits in 12v systems. The average hobbyist is not qualified to work on >20A circuits. It’s terrifying how many people don’t check the capacity and de-rating factors for connectors, wiring, etc. I see too many stories about burned-out connectors, HBP wiring scorching under load, and other NEAR-MISSES for houses burning down. 24v is safer, that’s all I need to know.
I’ve bought around 40,000 power supplies. I can tell you definitively that 12v 5 amp power supplies are the cheapest option for non-heated bed printers. Legitimate CE testing is a must.
Even the 12v ATX supplies I use for printers with a heated bed (300+ watts) are way way cheaper than a 24v power supply.
The other benefit is accessibility. If someone burns out their ATX, they can drive to get a replacement anywhere in the world. And the plug will fit.
We will eventually move to 24v for several reasons- Cnc requires it due to higher motor requirements… And I hate how big and bulky the ATX cases are.
We are considering breaking out a 24v “power board” to directly power the heated beds - noise in the electronics is a huge factor. If we did this, I could just send 12v to the printrboard. Benefits are getting some more life out of the printrboard and not having to retool the hotends. I want to avoid the confusion of needing to know if you have 12v or 24v before buying a hotend. 24v hotends are on the roadmap, so I guess having that first would ease the strain from switching over.
Brook
I’ve thought about moving the voltage regulators off-board, with the heaters powered by 24v, and the rest receiving 12v, but the cost of manufacturing a 2nd pcb isn’t worth it.
Custom power supplies aren’t worth the cost either - off the shelf is the way to go. There are plenty of low cost 3-5 amp 24v supplies, but the 15 amp ones are not so common. If you look at the smoothieboard and other next gen electronics, they’re made for 24v supply.
24VDC power supplies aren’t terribly expensive. Only a tiny bit more expensive than an equivalent 12VDC PSU. Still, I understand it’s more than a “found” PSU.
The drivers are good for something like 35VDC, and the motors operate in current limit mode. For low performance motion, 12V is fine. where 24V can be an advantage is when a stepper is moving faster, it has a higher back EMF. So you need even more voltage to counter the back EMF.
I would agree that reducing the amperage for same bed power would help the bed heater. Too many boards have questionable traces, FETS and fuses for the bed.