From all the troubleshooting online I’ve read I believe this is a retraction issue? I’ve done lots of retractions tests etc and have checked and rechecked esteps. I changed from grey PLA to red. The first thing I printed with the red created these weird missing areas primary on the back only and in all layers of the gyro sphere. I checked the esteps and felt it was over extruding by 1mm so I adjusted that. Then I added zhop.
In between these tries I had updated my Luban which for whatever reason it wouldn’t generate the model - so I had to revert back to an older Luban. It also did something weird where it would say I set them temperature at 215 for the nozzle when I did not. Reverting back to an older Luban fixed that as well.
I have retraction at 1/40 zhop 2
First two pictures are the same - the third is older Luban and esteps changed very slightly and zhop added.
Any other suggestions to get rid of these final imperfections?
Difficult to tell, but it indeed may be underextrusion after retraction. I add an extra prime amount to retraction, i.e. after retraction and moving to the next extrusion position, it will push a bit more filament into the nozzle as was retracted beforehand. For me it helps a lot to avoid unterextrusion. In Prusa Slicer you specify extra mm (length) extruded, and I go for 0.2-0.5. In Cura you specify exta mm³ (volume) extruded, and I go for 1-2 mm³.
Ok i have changed retraction speed plus linear advance. Nothing has made a difference. However i did notice on the model in Luban when you select “travel” to see the blue lines it is exactly where the spots are on the print. I did enlarge the item 150 and then generated and I just made it larger in another program (same size) and generated it in luban and although the travel marks are present in different areas they are not where the enlarged sample luban made them. I am working on printing this sample out to see if it’s any better. However my question is now that - what exactly does “travel” lines mean? I assume this is the start stop of each line? If so I am running out of solutions as to what causes the blank spots? retracting too much? or it’s extruding too little? Anyway to narrow it down?
