Hypercube Evolution build question
-
Hey everybody,
so I'm in the process of building a hypercube evolution and have a few questions that I hope someone here can answer. But first things first, I'll build the 300 x 300 x 300 build volume variant with a duet wifi as a contoller and a 12v power supply. I was searching for stepper motors and quickly realized, that I had no clue which ones to choose, since this will be my first build from scratch (before I only modified my existing printer). After reading up on the subject, I'm leaning torwards buying these motors. Will they have enough torque (65 Ncm) for my printer? The weight of the stepper motors is not an issue, since they will be mounted to the frame and not moving.
Bonus question: I'll build my printer with 2 z screws. While googling I found several hypercubes with 2 z screws but just one motor, that drives these screws with a belt, like this for example. Would one stepper motor like this be enough for the aluminium bed frame and a 300 x 300 x 6 mm aluminium sheet? Would there be other downsides to this approach?
Thanks for the help!
-
Unless you will be using an AC mains voltage bed heater, I strongly advise you to use 24V power. It's usually better to use 24V anyway on larger printers, to maintain motor torque to higher speeds.
Driving 2 or 3 leadscrews from a single Z motor using a belt is a very common approach, and avoids the need to re-synchronise the leadscrews after a power cycle. Just don't use a leadscrew with a very course lead, otherwise it may not be able to lift the weight.
-
I was actually planing on using an ac bed heater with a ssr. What other benefits will I be having with 24v?
So I'm guessing the 65 Ncm stepper motors will have enough torque? Also with a single stepper motor for z?
-
Those motors look fine. Very similar to the ones I use.
The only issue with using it in a belted Z is that if the leadscrews are course (like with a standard 8mm lead) it may bind before getting enough torque to turn. The solution for a heavy bed is to use lead screws with a more shallow lead (like 2mm single start).
But really that's a quite strong motor, if you already have the lead screws give it a try. If it can't lift the bed get some new ones with a shorter lead.
In my signature you can see an example of my belted Z using three 1mm lead screws with a slightly smaller version of the motor you linked.
-
@philippth checkout http://reprapfirmware.org/ EMF Calculator to see the main difference between 12V and 24V
-
Thanks for all the replies, I'll add these to my considerations.
While thinking about the problem of asyncronised z axis stepper, I was wondering if you could set two additional endstops for both stepper motors at their max z position. Then you would have to program a macro that would go to the max z position and stop each stepper motor individually as soon as they hit "their" endstop. You could run this every time you power on your printer to syncronise minor differences and therefore could use two stepper without the risk of them bein asyncronised.
-
@phaedrux Really nice printer you have there. Why did you choose these "wheels" instead of smooth rods and bushings?
-
The duet has the ability to do auto leveling with two or more z motors so what you propose is totally possible.
I chose the DBot design because it met all my requirements for a large build volume and open platform for customization. The v slot and v wheel combination is an economical linear motion system and accurate enough for a printer.
-
Thanks, I think I already found a way to achieve this here. I'll do some more research, but I'm pretty sure I'll implement this.
-
-
@philippth said in Hypercube Evolution build question:
Thanks for all the replies, I'll add these to my considerations.
While thinking about the problem of asyncronised z axis stepper, I was wondering if you could set two additional endstops for both stepper motors at their max z position. Then you would have to program a macro that would go to the max z position and stop each stepper motor individually as soon as they hit "their" endstop. You could run this every time you power on your printer to syncronise minor differences and therefore could use two stepper without the risk of them bein asyncronised.
You could do it that way, or you could use the same approach used by Prusa. Set mechanical stops at the bottom of the Z axis that are placed so that when the bed support is in contact with them the bed is square with the Z axis, and when you power up the machine, run the bed to the bottom and a little beyond. The bed will hit the stops, the motors will stall, and will be synchronized. Then you can run the bed back up to the extruder to print. No extra hardware is required, just a simple gcode script.
