Velleman K8200 - optimizations

Hi again,

time flies. Over a year ago, I've bought the Velleman K8200 3D Printer Kit.
It took several nights to assemble carefully (the manual was not always correct), wire, adjust the mechanics and electronics, then tweaking the software and facing some bugs. Making designs with SCAD, Blender and tinkercad. I've learned a lot since then and many printed parts aimed to improve the 3D printer itself - A 3D printer creates problems you did not have without them :-)

Today, I want to share an overview of those mods/improvements I've applied to the printer over time and which turned out to be useful. Others I have removed again.

The general objective of the mods:
A good ratio between the achieved improvement and the effort for a mod (e.g. different heat bed, power supply, double-axis/trapezoid Z-axis designs where not considered)
Simple to print and/or rather inexpensive.

I have to say, when comparing early prints with the most recent ones, those changes could have been provided by Velleman at probably not much extra cost.

Let's start with a little overview:

All those changes are available via thingiverse - either provided by myself or by others:

K8200 Z-axis Backlash eliminator
One of the best replacement parts as it boosts the Z-Axis precision and prevents the "wobble" along the prints z-axis. A little metal spring is required, though. I was lucky and found one as part of the spray mechanism of  an almost empty window cleaner bottle.

Better Z-Axis adjust for K8200
Makes leveling the print bed easier as you do not have to keep the nuts tight while adjusting.

Flex coupling: Try to straighten the Z-axis rod first: use a permanent marker and slightly touch the Z-axis while the motor spins. you should be able. Either bend the rod carefully or disassemble it and us a vise with three nuts (around the rod) to carefully correct the imbalanced stretches.
Additionally, get a metal flex coupling (I tried a 3D printed plastic one first, but these are better!) to compensate for little bumps.

K8200 improved Z-Axis holder
Using the flex coupling, I needed to lower the axis, so I needed another holder on top.

New z-Motor-Holder for the Velleman K8200 or 3Drag
This motor holder does a better job than the original one.

I've used the original controller case provided at Vellemans support page.But I disliked that the board was diectly attached to the frame. It might easily break.
So, I've added a plate under the board just to be on the safe side:
K8200 cover bottom plate

y-axis cable bridge
Looks nice and reliable :-)

K8200 simple Filament Roll Holder
I wanted to move the printer into a cabinet with less space, so I needed to compact the printer dimensions a bit by moving the roll holder from the side to the center and also adding a simple filament holder to make it easier for the printer to feed the filament.

K8200 Reset Button Extender
I've used an old Windows Netbook with Repetier at the beginning as a printer controller. Sometimes the serial communication got stuck. Never found out why. But the reset button turned out to be reeeeally useful in such situations. 

Currently I'm using OctoPi on a Raspberry Pi to control the printing. So I can use any browser (also on tablets, phones) to control the printer.
Also connected an old webcam and an USB-LED to the Raspberry.I can really recommend this setup.
I use Repetier Host and/or Slic3r on my workstation to generate the gcode-files first.

Meanwhile, I've ordered the "GP8200", the glass plate for the heat bed. Before, I made good experience with capton tape to allow for ABS printing (they already stick at 55 Celsius to the tape).
Now, with the glass plate, I started experimenting with hairspray. Seems to work nicely.