Hi all!
In the parts list it refers to a 2 amps, 0.9 degree Nema 17 stepper motor.
But most of the Nema 17 I find are 1.5 amps, 1.8 degree ones!
Do they work for the Lowrider 2?
Also would Acrylic plastic be good to use for the centre plate 611?
Thanks in advance for answers!
> This is high torque Nema 17 stepper motor with 1.8 deg. step angle (200 steps/revolution).
Each phase draws 2A, allowing for a holding torque of 59Ncm(83.6oz.in).
The ones I see in the parts list are 1.8. 1.8 is pretty common.
This is the info when clicked on the link to Amazon in the partslist to Lowrider 2, for the Nema 17, that’s the reason for the question on the stepper motors!
STEPPERONLINE 0.9deg Nema 17 Stepper Motor 36Ncm 0.9A 42x42x40mm 4-lead for DIY 3D Printer CNC
1. “But most of the Nema 17 I find are 1.5 amps, 1.8 degree ones! Do they work for the Lowrider 2?”
Regards,
This is the link I see on the LowRider2 Parts page points to this item:
Amperage doesn't really tell the whole story, what you need to know is the "holding torque" of the motors. If they are ca 84in-oz you are fine."most of the Nema 17 I find are 1.5 amps, 1.8 degree ones! Do they work for the Lowrider 2"
- 5pcs/ Package
- 59Ncm(83.6oz.in) holding torque
- NEMA 17 bipolar 1.65"x1.65"x1.85" 4-wire
- 1.8 deg. step angle(200 steps/rev)
- Rated current 2.0A & resistance 1.4ohms
As for the plate, I would shy away from acrylic because it has a pretty dramatic failure mode and is slightly less stiff than MDF at the same thickness.
Someone used to sell acrylic plates for the LR (the ones with the 120 logos on them). I have a piece of 1/2" I’ve been meaning to use for that purpose. I think it would be fine, but I don’t know what thickness you’d need. If you can’t afford a replacement, then stick with something we know works.
Some intresting facts re: Acrylic vs MDF!
I agree that acrylic can be a pain, I’ve snapped enough bits building mine, but I don’t think you will find MDF less prone to breaking.
From what I’ve been able to find it looks like acrylic takes almost 2,000 times more load to break than MDF while still being as stiff. The parts I broke most often were the corner blocks; MDF’s higher co-efficient of friction should result in less force being required to hold the rods, but I doubt it’s enough less to reduce the danger of over tightening.
Acrylic is also easier to put back together after breaking a part than MDF.
Ply is a much stronger alternative with a closer max load, although it is over twice as stiff. The biggest problem with it is that 5 mm Ply doesn’t necessarily mean the board will be 5 mm thick it could be 4.5->5 mm. The only parts, I can remember, where this is significant are the X carriage and the X motor mount plates. So to use ply these would need to be altered to take into account whatever size the ply actually is.
The numbers I found are:
Acrylic
3.2 GPa young’s modulus
72.3 MPa modulus of rupture
MDF
3.8 GPa young’s modulus
32.8 KPa modulus of rupture
PLY (marine ply of unspecified wood)
7.5 GPa young’s modulus
4 Mpa modulus of rupture
The difference between the modulus of Rupture of MDF and Acrylic seems very high so if anyone could check them that would be appreciated.
Not on the LR. Ryan makes them mostly thickness agnostic. Sometimes you need longer screws. Is this just from the place that you quoted this info?
Good info though.
I think that number should be MPa (not kPa). Look at Table 12-1 in this PDF. It says MDF has a Modulus of rupture of 35.8MPa which is only about 1/2 of the Acrylic number.