Since 3 weeks I am trying to work with the k8200. Up till now I am unable to get proper results.
As an Industrial design engineering graduate I have been building and working with 3D printers (Ultimaker & many REPRAP variants), but never have my efforts been so frustrating and disappointing as working with the Velleman k8200.
Some of the issues encountered;
- bed is not flat due to insufficient rigidity of the aluminium base and the way it is fixed by four screws (they cause the bed to bulge when tightened) (bulging also caused by screw holes through heated bed being too small, they needed to be drilled to a larger diameter)
- bed gets even more dome-shaped when heated (as many others on this forum I too added a glass plate to overcome this problem)
- bed is unable to reach 60ºC at ambient room temperature (this causes insufficient adhesion and warping when working with ABS)
- in factory configuration the bed is hard to get level due to the placement (hard to reach, too little space) and length (too short) of screws
- screws (levelling and limit switches) have a tendency to loosen while the printer is in use, it is necessary to adjust and tighten them before every print
- wiring is insufficient to supply the power needed to heaters and motors and are a pain to strip and solder (I had to replace them)
- filament feed is not guaranteed (I replaced the bearing of the feeder assembly, but after many hours of experimentation (spring tension, increased motor amperage) it is still not trustworthy)
- the metal lip of the limit switches are so loosely fitted (they are able to rattle sideways) that the screw with which the axis limit is determined is able to miss the switch if not carefully positioned (this needs to be checked before every print to avoid scary collisions and the possibility to burn out the motors) especially the z axis is problematic, since the adjustment screw and the limit switch are not properly aligned
- screws with which the x and y axis limits are determined are very hard to reach for adjustments and tightening
- the supplied threaded bar that needs to function as a z axis lead screw was significantly bent (I had to replace it with a straight one a layered cake effect due to variations in layer thicknesses)
The design is a direct copy of the open source 3Drag design. (source: http://reprap.org/wiki/3drag) Velleman did not had to invest much in product development.
I was seduced by the sturdy looking aluminium frame and the benefit of not having to source all the components myself, but after three weeks I am having a hard time to justify my 700+ euro investment.