I was just trying a new type of filament my child asked me for.
Its a eSun ePLA-SILK, a PLA based filament with additions that give it a metallic look.
Up to now I only used different brands of normal PLA and PETG with no problems that could not be solved.
But this stuff is really bad. Already when I loaded it (I was using the dual extruder) I saw that it has different liquidity at 200°C compared with normal PLA. It was forming a blob at the end of the string that comes out.
OK, so I started a first print at moderate speed (40 mm/s) with the suggested temp of 210°C.
Already with this first print I had the issue that it stopped extruding after about 3 hours (and it was stringing like hell). The extruder drive rubbed away the filament and deformed it, so it was not removable anymore. I needed to cut everything out. Then I did a cold pull with normal PLA to get evrything out that could block the nozzle and tweeked the parameters a bit (I lowered the temp to the brands minimum of 190°C). With this settings my initial test object (a lizard like creature) printed very well.
So far I thought I got it working but then with my next print the problems with stuck filament reoccurred.
It was very flat hexagonal plate around 12x12cm and 7 layers high. As it consist only out of bottom layers it was a 5 hour print at 15mm/s with nearly continous extrusion.
Then after around 3 to 4 hours the filament stuck again. I tried a second time slightly increasing temp and speed to 20mm/s and 195°C but it stuck again after some hours.
As I never had such issues before I meanwhile think this could be heat creep problem connected to this problematic type of filament. How can I prove that this is the problem and notthing else (bad diameter, dirty filament)?
Silk PLAs can be a bugger to print with, the polymer blend that gives them the sheen thickens the PLA substantially. They actually like to be printed hotter than normal, I run silk filaments at about 220C. Also, slow down your retraction speed, and reduce the retraction amount. You want just enough to relieve the pressure, otherwise if it’s too fast/far, with how thick it is, the melted blob at the end detaches and oozes/strings out of the nozzle.
Also with how thick it is, a fast detract might cause the extruder teeth to grind the filament, since it can’t pull it back fast enough. Which, would make it unable to push the filament anymore and slowly bake in the nozzle.
Try 220C at 40mm/s with a slower detraction speed.
A retraction problem with to much grinding was also my thought when it happened the first time. The first print was with 210°C (that is the temp eSun suggests as optimum). So I adjusted the retraction settings (speed, length and number of retracts) already.
As it now is a part with a wide area of continuous printing I don’t expect it to be a retraction issue, because it is not retracting. In the printing result I see that it stopped in mid of filling that big area, not on wall printing or layer change. So my first reaction also was to raise temp a bit, too.
As my observations on behavior at loading with different temps showed, it is much more liquid then pure PLA at the same temp. This is why I currently tent to believe that a heat creep would effect this filament more than others.
During long continuous sections without retraction, that would make me lean toward inconsistent filament diameter or contamination. Heat creep shouldn’t happen since you’re constantly pushing filament through, which should be pulling heat away from the heatbreak to keep new filament liquified. Heat creep usually happens with lots of retractions, or fine details when you’re pushing filament too slowly, allowing the heat to slowly make its way up the filament or heatbreak.
If you’re getting heat creep during long fill/flat extrusions, check to make sure your hotend fan is running and not blocked. Might just be a bad spool, happens sometimes.