I’m having a lot of trouble with the BBL Silk + Silver filament. I’ve waisted a full spool trying to finetune it. I’m getting closer but other problems start to appear along the way.
I think it’s important to mention that i’m printing on a X1C printer which is just over a month old. I haven’t printed any abrasive materials yet.
Edit: I dried the filament per Bambu’s recommendation with no improvements so i won’t bother with drying the second roll of filament since they are from the same batch.
When printing at the normal BBL profiles there are no problems except no Silk/Shiny finish, so i lowered the outer wall speed to 35mm/s. The picture with number 1 is the result of that. Blobs and zits. Solved this by lowering the retraction speed to 0.2 and increasing nozzle temp from 230 to 235°C.
Then i get the shiny result that i want. Mostly. Other problems started to appear. I get these overextrusion lines which are visible on the left side of picture number 2. Solved that by increasing the K factor from 0.020 to 0.034. I also did the second calibration. The only problem left are these underextrusion lines on the outer wall which are visible on the right side of picture number 2. These underextrusion lines happen when the printer prints the horizontal lines on the inside of the object which are visible in picture number 3. I also see a slight discoloration on these layers from the outside.
The current print profile is:
0.4mm Hardened Steel nozzle,
0.2mm layer heights, i also tried 0.16,
35mm/s outer wall speed,
300mm/s inner layer speed,
Prints outer walls first. (Underextrusion lines on the right side of the second picture is exactly where a new layer starts printing the first outside wall.
0.2mm retraction distance,
235°C nozzle temp,
K factor of 0.034,
Auxiliary fan turned off,
Nozzle flow at around 0.94,
Edit:
Acceleration Speeds:
Normal printing 2000 mm/s²
Movements 10000 mm/s²
Initial layer travel 2000 mm/s²
First layer 500 mm/s²
Outside wall 2000 mm/s²
Inside wall 2000 mm/s²
Hey there. I did dry the first roll of filament. No improvements. That was 12 hours at 70°C i believe. Basically the stock drying settings of the X1C for PLA with the box it came in to cover it. I’m having the same issues with the second roll of filament so that one didn’t dry. I was thinking the improvement for my case could be to lower the acceleration speeds
On the page for the silk+ they do say to slow down the outer walls for best lustre but not sure if that’s not already done for you in the RFID settings. I would think so but haven’t compared to other filaments to know.
About drying - moisture has to be able to get out of ant drying enclosure and that is a problem even with commercial (low end) filament dryers.
Since you are using the printer to dry, I’d put a few 1/4” or so holes in the top of the box you use to cover the spool. Humid air is less dense than dry air so humidity will move towards holes in the top surface. And I’d leave the door open to help circulation.
Last, 70C is too hot for PLA. Recommended drying temp is 55C. At 70, you could even see warping of the spool depending on its temperature rating. (As an aside, there are multiple different plastics used for spools with different ratings).
But I fully agree with @MZip . Silk is more susceptible and sensitive to moisture and benefits from being dried. Preferably at lower temps though. Just to be on the safe side, you may want to check if the filament diameter is (still) within tolerances and round rather than oval. Once or twice around the spool at 90° intervals should be enough.
I know there can be batch differences between filament lots of the same type/color but I’ve had great luck with the original silk PLA and now with silk PLA+. I’m using stock settings for them as set by the RFID identification. No changes to flows or temperatures and they print fine here.
There is a difference though and it’s how I dry my filament. Any other techniques/circumstances that dry to the same extent should get similar results.
Drying is a semi-complex topic and may not even be what’s causing the issue. I think a partially-clogged nozzle can also dork up prints something like what you show.
Also, just FYI, filament can arrive with all sorts of water content levels. The plastic bags they ship in are probably semi-permeable or maybe the spool just wasn’t dried that well to begin with. Either way, new filament may or may not print properly thanks to moisture content.
There’s a number of threads here on drying filament and if you take some time and dig in you can see what a topic it is. And dealing with water isn’t that hard once you sort out how to tell and how to fix water issues - if what you are seeing is water.
