i did a search and found some other instances of this.. and am wondering if theres a work around.or fix..
the zits are happening at the outer perimeter, when the nozzle steps out from the inner perimeter of a 2wall outer wall ..
im printing INSIDE-OUT outline direction..... they are also present on the inside perimeter where the inside perimeter ends and the second starts.. so its definitely being caused by the 90 deg turns being made during this transition.
i have tweaked my coast, extra restart distance, nozzle temp.. to the point where they are almost non existent but when they happen for every single layer..its not that hard to spot the pattern..
the only things that help are slowing the print wayyyyy down to 10-12mm/sec from my normal of 30-85mm/sec.. and decreasing flow in the tuning menu..but i have to decrease the flow to almost 70(my extrusion multiplier if 91 in software with a .4 nozzle) then i get sever under extrusion everywhere else..
from what i can tell, what is happening is the zit forms during that 90deg outward step to start the outer perimeter when it comes back round after completing the first inner perimeter..its cause both by the nozzle having to micro pause to make that 90deg degree turn to start that outer perimeter loop..and by the whipping being introduced into the x and y axis (cr10s-4 and 5 are heavy build surfaces) when those 90 deg turns are taking place at higher velocities.(taking into account the mass of the build surface /glass keenovo bed heater etc etc.. plus the weight of the stuff on the z axis as well .i know were not talking about massive weight but this tuff starts whipping back and forth at 50mm/sec with accelerations added in.. you get the idea(i will be doing a brace mod to see if it helps or eliminates the problem)
i cant print at 10mm / sec,, way to slow...
1. what might be a fix for this when the machine starts the second outer perimeter loop... have it do an angled approach to the beginning of the second perimeter loop ..instead of complete 90deg turns..so the transition is smooth and not jerky like it is now.. there will be a small tiny gap where the first perimeter ends and the second begins.. ( it will be on the inside of the model, but using a sweep/angle during that movement will help to almost eliminate the 2 micro stops the nozzle has to do to make those 2 90 deg bends when starting the second outer perimeter.. maybe give a setting where we could tweak the angle of the start of the second perimeter ..
i have also printed x and y axis tensioners.. and i have experimented by tightening both belts to the point that the creepy Deliverance guy could have a banjo duel with them.. while the tensioning did help but not eliminate the zits.....there is a point where its just too tight and bad for the stepper bearings.. and not a good long term solution.
2. another fix is a setting to be able to decrease feed rate (extruder would have to slow down with it) during those 90 degree transitions onto the outer perimeters only.. so it doesn't affect infill print speed and other stuff..)
3.another is a setting to be able to apply a COAST to the outer perimeter beginning during those 90 degree transitions onto the outer perimeters only..to extrude just a bit less for a small amount of time.. when its making those 90 deg turns and avoid zits on outer permiters
i know i can print outside in.. but that creates another problem where no it cant print overhangs as well and requires more support that is not needed when printing with inside out mode
anyway i hope i didn't just waste you guys time .. i know there are other mentions of this but they were not quite identical to mine
Rick
