power supply for 3d-printer application

Hi guys,
i’m a student and i have never get involved with sush thinks again, but i had to do a project in the university. The idea is to built a 3dPrinter.
i have choose the electronics but i have to select the power supply. I’ll use an arduino mega2560, a RAMPS shield (is a shiels for RepRap 3dprinters) , A4988 pololu stepper dirvers, and 3 of these linear stepper motors.

how can i select the power supply that i need? if i have understand well the suplly for the arduino will be different from the supply for the drivers and the steppers.

Yes, the power supply for the Arduino should be separate from the motors.

Those motors seem to require .4 amps per coil or about 0.8 amps per motor - so a 4 amp supply should give you plenty of headroom and 3 amps would probably be OK.

For best performance use a high voltage supply - the A4988 can accept up to 35v. You can adjust the A4988s so that they limit the motor current to protect the motor. This is explained on the Pololu webpage.

If you have a suitable (large) capacitor on the power supply then you won't need the full 3 amp supply with higher voltages - see this Thread


Thanks for the answer. May i ask one more newbie question , the ramps shield , does it need any supply?

Note that the maximum speed of the motors will be limited by the voltage to the Pololu drivers - its worth checked whether 12V is enough for your requirements (experiment with one driver and motor). You'll then know if 24V might be a wiser choice. Actual performance depends on the motors and mechanical load so you can only really tell for sure on the complete rig.

See what other people have achieved on similar setups - there are various 3D-printer forums out there to ask this kind of question on.

12V is probably needed anyway for heaters/fans etc, of course, so an ATX style supply is a solid starting point.

chernobill: Thanks for the answer. May i ask one more newbie question , the ramps shield , does it need any supply?

I don't know but it probably requires a 5v supply which may be able to come from the Arduino 5v pin if the required current is not too large.

Have you looked at the RepRap forum. It has a huge amount of advice.

I was at the Midlands Model Engineering Exhibition in mid October and a man gave a very interesting lecture about his experience building a 3D printer from a kit. He got it to work after remaking some of the plastic parts in laser-cut aluminium. His end conclusion was that it is much more sensible to make the drawings of your object and send them to someone with a £100k printer to do the actual printing. Having seen some printers in action - they are very slow - I agree with him and I have given up my own plans to make one.