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Stepper Motors out of old printers

Posted by Benni 
Stepper Motors out of old printers
October 30, 2009 07:21AM

First of all sorry for my bad english, i'll try my best!

I would really like to build a reprap. So i looked around which materials i already got and i found three working HP 895 Printer.
I opened them up an found - beside the two smaller steppers which are needed for the paper-feeding - a bigger one (40x40x40mm). They are labeled with 1,3V / 0,3A.
I searched the web for more information about the motors like torque etc. but i didn't find anything.

Can anyone of you please tell me if these steppers are suitable for building a reprap. Or should i use gears to boost their torque a little bit?

Re: Stepper Motors out of old printers
October 30, 2009 10:07AM
It might be sufficient for the positioning system, but probably not for the extruding.
Also, if you use gears, you might get a really low maximum movement speed..
Really thanks for your reply!

I'll try to determine the specs of the steppers and compare it to the ones which are used with the "official" reprap.
Re: Stepper Motors out of old printers
October 30, 2009 05:35PM
The voltage and amperage seem quite low. I don't think they'll work. While we haven't published complete minimum specs yet for motors, compare them with these:

If we assume the stepper motor power is
P = VI, then your scavanged motors are maybe
~= 1.3 V * 0.3 A
as opposed to the makerbot's motors:
~= 14 V * 0.4 A
(assuming we were talking resistors, not a dynamic pulsing system.)

Also, expect to have little to no luck looking up the specs online; the stepper motor manufacturer probably communicated the specs directly to the printer manufacturer.

According to:
"You need approximately 1400 g.cm of holding torque or more to be safe."

You can check this with a (weightless) vice grip, 10 cm ruler and 140 g weight (e.g. 140 ml of water in a weightless cup).

I'd save the motors for a little robot or computer controlled laser pointer based 'solar' clock that did one rotation per day or something. (The good news is you can probably wire them directly up to an arduino and make them spin, so hold onto them.)

Good luck and happy hacking!
Wow thanks for you reply!

I already thougt the motors are too weak but i'll determine their actual specs with the procedure you described.

I have already ideas for using the stepper-motors in an other project but its kinda sad to hear that i have to spend money on new ones!

Thanks for all your efforts!
Re: Stepper Motors out of old printers
November 02, 2009 01:44PM
Those printer motors probably have some labeling on them that says something like PM55L-048-E. Post what is on the label and I'll see if I have the specs for them.

Typical printer motors have the following specs +2 to +24 Volts, uses 600 mA per phase, with a coil resistance around 30 ohms (unipolar) or 6 ohms (bipolar).
Holding torque is probably around 0.2 Nm for unipolar and 0.1 Nm for bipolar.
The above values can differ from printer to printer, but they are usually near these values.

Those torque values are a little low to do much with the reprap unless you design and build a custom gear train for them, which will probably cost more in parts than just buying the motors recommended for reprap
Re: Stepper Motors out of old printers
November 05, 2009 09:30AM

The stepper is labeled with:

QH4-4307 01
1.6Deg/Step 1.9V 0.7A

I could life with an slow machine but i won't start building it up until i know if i can use the steppers.
Re: Stepper Motors out of old printers
November 05, 2009 09:50AM
Hi Beni,

... the "1.6Deg/Step" should be 1.8 and the motor could be a bit underpowerded - i have some old Nema23-steppers with 3V/1A until 1.1V/3A, what will fit for this kind of mechanic, but yours could do the job too, if you reduce friction ...

Re: Stepper Motors out of old printers
November 05, 2009 03:29PM
The STP-42d265 is just barely powerful enough to be used for a reprap, brand new they can hold about 0.16 Nm (1600 g*cm). After some use they drop down to about 0.1 Nm. You are going to have to use a lot of lubricant to keep a reprap moving with that little motor. Personally, I would use a different motor for a reprap and use that little motor in a small robot or some other project.
Re: Stepper Motors out of old printers
November 06, 2009 07:17AM
Hi everyone!

Thanks to VDX and criswilson for your very helpfull answers!

I'm going to review my plans and try to use a 10-toothed and a 15 or 20-toothed crown gear to increase torque if this won't be a problem cause of the lower speed.

Nice friday everyone!
Would these 2 motors work?
March 28, 2010 11:24PM
My brother and I are working on a repstrap, then a Mendel. We have acquired 2 motors from an old printer, would they work?

#1: Mitsumi Stepping Motor M49SP-2K

Rated Voltage: DC 24V;
Working Voltage: DC 21.6~26.4V;
Rated Current/Phase: 1A(PEAK);
No. of Phase: 2 Phase;
Coil DC Resistance: 4.6 ohm;
Step Angle: 7.5 degree/step;
Excitation Method: 2-2 Phase excitation (Bipolar driving);
Insulation Class: Class E insulation;
Holding Torque: 134mN*m;
Pull-out Torque: 100mN*m/1100pps;
Pull-in Torque: 102mN*m/250pps;
Max. Pull-out Pulse Rate: 2150pps;
Max. Pull-in Pulse Rate: 430pps;

#2 Mitsumi M35SP-8

Rated Voltage DC 12V DC 24V
Working Voltage DC 10.8~13.2V DC 21.6~26.4V
Rated Current/Phase 259mA 173mA
No. of Phase 4 Phase 4 Phase
Coil DC Resistance 50Ω/phase±7% 150Ω/phase±7%
Step Angle 7.5°/step 7.5°/step
Excitation Method 2-2 Phase excitation (Unipolar driving)
Insulation Class Class E insulation Class E insulation
Holding Torque 38.2mN·m 42.1mN·m
Pull-out Torque 23.0mN·m/200pps 28.4mN·m/200pps
Pull-in Torque 22.5mN·m/200pps 27.9mN·m/200pps
Max. Pull-out Pulse Rate 580pps 610pps
Max. Pull-in Pulse Rate 495pps 520pps

Thanks for any help you all might be able to provide.

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