Nema 34 steppers for 3d printer questions

I am building a 3d printer and would like to use nema 34's.
What is the best option for electronics for these motors?
1. Industrial motor drivers and ramps or rumba? Not sure if these can be used together.
2. Powerlolu motor drivers and ramps or rumba?

Thanks!

Nema 34 is a motor frame size. The drivers care very much about the electrical input your particular motors are looking for. There is a wide range of torque available in any basic frame size. As the torque goes up, the energy required goes up as well. That energy can be delivered as any of a wide range of current and voltage combinations.

How much torque do you really need? Do you have a specific motor already in hand?

Most of these printer designs (as opposed to CNC's - a very different animal) wind up with motors that are way bigger than what they actually need. Some derating on a motor is a fine idea. As you go past 4:1 towards 10:1 it gets a bit expensive. The cost isn't just in dollars, it's also in the weight of the motor and the weight’s impact on the design. The cost / benefit simply stops making much sense.
If you are going to derate the motors (say) 4:1 that directly impacts the drivers. The solid state “stuff” in the drivers is likely to do quite well at a much lower derating factor.

That’s one layer. There are others. The faster the motor needs to go, the more involved the driver gets. On a big heavy printer, things may (or more likely) may not move very fast. Moving heavy stuff quickly generally means things bend. There’s no real static force on the print head in a normal design (again, unlike a CNC where the tool does have force on it). The drive needs are mainly all weight related (you need to accelerate and stop it).

Running at > 10,000 rpm on the motors and >3,000 mm / second motion will be a very different design than something a bit more normal. It’s not just a motor question, it’s a system design issue. If you want big and fast, then the only way to go are high voltage / high current / high power industrial controllers. You also will need some pretty high torque motors unless you have a very light weight load.

Thank you for the response! I am looking at using two 1600oz nema 34's for the z (vertical axis). I am looking to use smaller nema 23's to move the x and y axis. The reason for this is that this will be a really large printer (4ft^3 build area) and I want to be sure I can support the weight on the build platform. (I have found that the powerlolu stepperdrivers will work with the ramps or rumba controller for this. I have also found cnc kits with the motors and industrial drivers. Just not sure if this would work with a 3D printer controller like the ramps or rumba controllers. Just not sure what direction would be best. Any input would be appreciated. Thanks again!

How fast will your print head be moving / is there only one print head / how heavy is the print head?

On some of these designs a print speed in the range of 100 to 300 mm / sec is about as fast as they can push plastic through the head. On a larger machine you may not be as able to hit the high end of that range. Multiple extruders is one solution. If you are headed that way it’s a consideration in the printer controller boards.

In a normal setup the Z does not move a lot and it's a fine resolution step. That means you can get away with a "low power" Z axis. Put another way, the Z axis is geared way down compared to X and Y. (usual disclaimer – on typical designs, done the normal way, most of the time, from what I’ve seen in my sheltered life…)

With some effort, any stepper controller that will accept signals to step forward and step backward can be made to work with the basic printer controller boards. That may not be ideal for other reasons, but it can be done. I would want to be sure that any controller for a printer would do micro stepping at some level. Don’t get too excited about 1/32 vs 1/8 steps at this point.

A lot of this depends on the specifics of your design. All I'm trying to do is keep you from over spending on the steppers and drivers. I'm by no means trying to change your basic design.

Great Feedback! I am looking to use two extruders. Total weight of the head will only be 1 to 1 1/2 lbs. We are looking to print at about 150mm / sec max. I am looking to use smaller nema 23 frame motors to drive the head. You are correct that the z will only move very little at a time. I was looking to use the rumba controller due to multiple extruder capability. The thought was that due to the large build area, that a large motor would be needed to support the weight on the z axis. Perhaps that is not the case. The printbed would start at about 4 feet in the air and would move downward as the object is printed, increasing the weight to be supported. Perhaps smaller motors could do this? Again, Thanks for all the help!

The real question is weather to support all the weight on the motor bearings. If you support the Z weight on conventional bearings, there is no real need for big motors on the Z. I'd bet you a beer that a pretty normal nema 17 with full drive current could handle the Z axis.

At a rational speed (150 mm / sec should be rational) you don't need super drives on the X and Y motors. You may not get away with Ramps 1.4 plug in modules, but you should not need some sort of fancy 400V drivers. I'd probably look at 24 V into something fairly conventional. You would have to match the motors to the drivers. If you don't already have the motors that should not be to hard.

Understand exactly. Thank you very much for all your help! Great insight on the use of bearings to support the weight!!!