Building a cheap 3d printer with DC Motors?

Question

Because I do not own a 3d printer I am searching a way to build an affordable 3d printer. But paying a 200Euros for one seems too much for me.

So in my search for affordable 3d printer I thought to build one out of legos (for example this one) that I can find in bulk at reasonable price.

As for rods I can use out of old printers and skim them down to 8mm at a machine shop (at worst case).

But as for motors DC ones are easier to find/scavage that stepper ones but:

• Is it possible to build a 3d printer that uses DC motors instead of stepper ones and what kind of firmware is needed?

Answer 1

To use DC-motors instead of stepper motors, you would need to have some sort of encoder that tells the controlling machine where the printhead has moved.

On the arduino Forums they have discussed the problems and difficulties. The main problem is, that currently, there is little firmware for Arduino or similar chips that can do this. Another big problem is, that such a machine might need a different type of G-code, unless well done.

That is not to say that there is no firmware that does control DC motors via an encoder. Printers do so since ages. But to reverse engineer printer firmware is really really hard. It took a pair of hackers the better part of a half year to dissect the printer & Fax firmware for one printer, and they had mainly looked to dissect the fax protocol and had not looked at all at the motor control^{Defcon talk about it}.

Luckily, as the RepRap tells though, somebody did hack together a DC motor control: Miguel Sanchez has a GitHub about it. You DO need proper encoders though.