Sourcing parts for new 3d printer

Discussion
1

Any recommended places to purchase parts for a 3D printer? I use eBay quite a lot, however for some of the more specialised items required, eBay doesn’t have some parts (or the quality of parts is questionable).

2

I use there ramps boards and stepper drivers.
And they sell the very good hexagon hot end.

But for cheaper stuff you cant beat ebay or aliexpress but be prepared to wait for stuff to be delivered.

Gordon

3

@gordonendersby Did you get your stepper motors from there? What model of stepper do you recommend?

4

I got mine from a german seller on ebay. Theyve performed without fault so far.
Ill probably do the same again. They are cheaper in bulk if you club together.
Long time since i got them so no idea who the seller was now.
Ill need 5 more at some point for my next machine.

Nema 17 at least 13.7 N·cm holding torque is recomended for most reprap machines.
Reprap wiki stepper motors

Gordon

5

Thanks Gordon, I’m looking into a way of making a 3D printer that uses 4 stepper motors (Rather than 5) and not a delta design.

6

If your trying to do 1 instead of 2 on the z axis.
Its been established that the gearing or belt and guides needed to link 2 z axis screws is both more complex and just as expensive as 2 stepper motors to get it right.
Like the prusa i2 or i3.

There are other designs using one lead screw but the bed is usually supported on just one side of the rectangle, which is very difficult to stabalise and lift cheaply. Needs expensive guides and bearings for strength and accuracy.

Some have tried a scissor mechanism with a screw and motor but its non linear and the firmware needs modifying to handle it. Lots of pivot points to get sloppy.

Its a difficult design problem which i think is why so many low cost designs usually end up with 2 motors and lead screws for z axis.

There

7

Do you think 1 z motor would be achievable if the extruder was mounted on the frame, so only the hotend would need to go across. But still have two metal guides on both sides of the print bed, with one threaded rod or belt to make the hot end go up/down

8

Printrbot Simple has I think 4 motors…

9

Have you had a look at this lot.
Reprap printers

Theres a few good designs of every type in that list.

Gordon

10

There are a few designs that have the x axis as a balanced arm reaching out across the bed.
But again its got to be very stiff to not wobble and the materials to do that get more expensive to give the same rigidity as a gantry held at both ends.