48V mini 5+

Aurimas

Are there any plans to make it happen?
Same system on mini 5+ I was limited to 300mm/s and 5000 acceleration
With 6HC and 48V it was cruising at 400 and 10000. And still it wasn't the limit

dc42

@Aurimas the TMC2209 drivers used on the Duet 3 Mini are limited to 29V so we can't make a 48V Duet 3 Mini with those drivers. The TMC2240 drivers that we could consider using instead are limited to 36V. So unfortunately it's not possible to make a 48V version of Duet 3 Mini.

Right now the only realistic option for 48V drivers is to use TMC2160 or TMC5160 drivers as we do on the 6HC. These drivers require 8 external mosfets each, plus some resistors and diodes to keep EMI under control. This of course increases costs and the board size. We've thought about making a lower-current version of the 6HC but the cost saving wouldn't make it worthwhile.

All this means that we can't make a smaller and lower cost board than the 6HC that has low enough EMI to make compliance with EU and FCC regulations practical, until Trinamic releases a 48V-capable driver with integrated mosfets.

To get the best speeds for a particular supply voltage, use low inductance motors, because they have lower back EMF than high inductance motors so they need less voltage to drive them at speed. Use our tool at https://www.reprapfirmware.org/emf.html to do the calculations. There is a tradeoff between inductance and required current when choosing stepper motors, so you also need to ensure that the chosen motors don't draw more current than the stepper drivers can provide without overheating.

HTH David

Aurimas

@dc42 thanks a lot for detail explanation.
In my particular application 7 drivers is really handy since I use it on 600x600 and bigger machines with 4x z motors, 2x Y motors at least X and also U axis for idex. Not to mention 2 extruders sitting on 1lc
So realistically I have to either use 6hc +3hc or use 4x1lc for Z and ready of the drivers for the other axis.
Current for me is not an issue. My motors are only 2A rated
It's getting pretty complicated.
When you look at smaller Steppers you have lots of options. When you step into high torque 60mm long Steppers options become limited

dc42

@Aurimas what size motors will that machine use? For a 600x600 machine I would have thought that at least the Z motors would be Nema 23, perhaps also the X/Y/U motors. In which case, 2A is rather low for that motor size and you would get better speed with lower inductance/higher current motors.

We don't currently make a 8HC board but we may do so in the future.

Our closed loop EXP1HCL board and M23CL motors are also 48V capable.

Aurimas

@dc42 z motors are 40mm Nema23 - got no issues with them at all.

Y motos right now are 60mm Nema17 with 80Ncm torque, 2 ohms and 3.3mH
calculator with 24V tops out at 330mm/s and that is exactly what I have obeserved.
with 48V I can go all the way up to 700mm/s before it will top out.
I cannot use Nema23 since the motors move with the axisis and thus they would be way too heavy.

T3P3Tony

@Aurimas one option is to use a mini5+ for Z and then 3hc for XY for a large idex maybe using closed loop becomes sensible for XYU

Aurimas

@T3P3Tony said in 48V mini 5+:

@Aurimas one option is to use a mini5+ for Z and then 3hc for XY for a large idex maybe using closed loop becomes sensible for XYU

thanks Tony, but it would not work. I need more than the 3 drivers - I need 2 x Y + X + U - so 4 higher voltage motors for the motion, then 4x Z motors and then 2x extruders.

So I think the most cost effective option would be to go with 6HC + Mini +2x 1LC.
Complicated - isn't it. Don't do simple

fcwilt

@Aurimas said in 48V mini 5+:

So I think the most cost effective option would be to go with 6HC + Mini +2x 1LC.

Have you taken into the cost of filament?

I know that for my work saving some $130 (Mini instead of second 6HC) doesn't really cut the cost of ownership.

Best of luck.

Frederick

Aurimas

@fcwilt having 6HC instead of the Mini ads no extra benefits. I could go even with 4x 1LC - but what is the point?

T3P3Tony

@Aurimas I meant for the non index version a 3hc was sufficient. For the idex version maybe it's worth using closed loop control and use 1HCLs.

Aurimas

@T3P3Tony Nema23 ad additional 750-1000g to the weight
when the motors are mounted on the axis and they are moving together it is a lot of weight
I was considering using 42mm servo motors with intehrated drivers.

T3P3Tony

@Aurimas the 1HCLs allow you to use a range of stepper motor + encoders

Yes you could use servos with integrated drivers and then use a 6XD to drive those 4 motors