[Arm-netbook] a designing a low-cost decent 3d printing board

[Luke Kenneth Casson Leighton]

On Tue, May 30, 2017 at 10:05 PM, David Niklas <doark at mail.com> wrote:

> Remember that as the weight and speed of the hot end increases the load
> on the z-axis motors and gears also increases (if temporarily), leading to
> (temporary), inaccuracies when using multi motor setups.

 but you don't print at the time when z-axis motors are in motion:
they're there purely to move the bed up (or down) for the next layer.
thus the important thing to have for z-axes is precision and fine
tolerances.  fine tolerances can be achieved on lead screws with
double nuts and a spring to prevent backlash.

 ok so on to the next issue:

> If I were to use multiple motors I'd not do it like this:
> M == motor
> H == Hot end
>
> TOP       SIDE
> M----M    +-----+
> |    |    |H    |
> |H   | -> |     |
> M----M    M-----M
>
> But rather like this:
>
>
> TOP       SIDE
> +----+    M----+
> |    |    H    |
> |    | -> |    |
> M----+    M----+
>
> Assuming I understand you rightly.

 so you're advocating 3 lead screws instead of 4   i considered this
as well, however i realised that if the printbed has even the
slightest amount of twist it becomes impossible to correct that: you
literally have to throw out whatever metal plate is being used and
replace it.

 if you have 4 lead screws, they may be used to place a twist on the
plate to return it to dead-flat.

l.