I had a lot of issues during printing, and I'm also making a video about that to give more insight in the problems and solutions that I made up for it. But there is also a lot I can discuss in a written post:
First, I misjudged the time required to print all the parts quite severely. I did expect that it would take some time but just as you guys I was also a bit suprised when I got to hold the actual parts in full size in my hands (its a larger build than I imagined). The final print time for all the cage parts is:
6x ring section (Total 18 hours)
6x Arm 3 parts (Total 24 hours)
1x Motor mount (Total 9 hours)
1x Adapter block (total 4 hours)
All added up to: 55 hours (excluding prep and finishing time)
The high print time (and slow printing) is partially my own fault. Because of the printer I choose to use I needed to dail back the print speed significantly because of the flimsy frame. At higher speeds the forces on the frame will have a serious effect on the print quality. I used this printer:
Wanhao i3
The first prints came off the machine in decent shape (nothing special but also nothing to be worried about and re-do) but that changed quickly in the prints that followed up to the point that I just needed to stop and figure out what is wrong.
The last print before the I changed things up:
Please note that this picture can give an exaggerated idea of how bad it was. Please remember that the layers are only 0.3mm
Most important things to see:
1 - At the start of about half of the outer perimeter extrusions the actual extrusions starts about 10 to 20mm after its intendedstart. And the other half of the layer starts where it did extrude from the start there is a severe overlap and over extrusion that oozes out of the side.
2 - Layers are not aligned in a nice manner.
What I did to fix this:
1 - This is primarily an oozecontrol issue. Some of these settings I set correct before but for an unknown reason they were reset.
I changed the following parameters:
- Retraction distance from 2.00 lowered to 1.00mm
- Extra restart distance from 0.2 to 0.1mm
- Coasting set from 0.05 to 0.1mm
- Only retract when crossing open spaces (now activated)
- Force retraction between layers (now activated)
- Retraction during wipe move (now activated)
- Only wipe at outer perimeter (now activated)
- Avoid crossing outline for travel moves (max 3mm detour) (now activated)
2 - Mostly caused by too high of a printing temperature. I did set it above average to compensate for the lack of extrusion strength of the printers extruder but lowered it as a test (from 215C to 205C) and besides that I changed the layer height from 0.3 to 0.25mm to compensate for the more viscous material as the change in layer height would directly affect the force required from the extruder.
After these changes the prints got way better but there was still the issue with inconsistent extrusion due to slipping of the extruder. its drive gear outer surface is not concentric with the axle when fastend correctly giving uneven pressure on the filament. I got annoyed by this and decided to "just pull it all out" and I replaced the extruder and hotend with an E3D Titan extruder and E3D V6 hotend that I had laying in my drawer. After this (and some tweaking to get the new extruder dialed in) the printquality got a lot better:
Please note that this picture is also a macro and, remember that the layers are only 0.25mm