I previously posted about poor K2 Plus prints vs K1c prints–which is still an issue. It is a bit better at times after optimizing filament settings, but I am still getting frequent poor prints. The two pictures below are from within the same prints of identical cloned models– Print settings include slow layers 1-3 (0.2 mm layers, speed 20-30 mm/sec). I just checked my bed flatness and it is generally within <0.06 variance for the bulk of the print bed space.
What am I missing that is giving such erratic prints?
Elegoo PLA+ rapid for all but the skin color–which is Creality (HyperPLA non-RFID). I’ve been battling it for a while–but within the same print runs it doesn’t make sense to be so varied. I’m trying to avoid the black line prints until after the first layer print on the next run to see if it makes a difference. I have no idea what would be causing most of them as the bleeding-through black should be tightly confined to its spaces (eyes and nostrils, which I actually shrunk down in size relative the the holes in the lighter filament part of the model).
This looks like a purge issue. If the last filament is not purging completely, when the next filament starts to print, the remnants of the previous color will still be in the nozzle.
You’ll be provided a table whereby you can increase the multiplier between colors. This table below is what pops up and it will be different depending on what colors are in your CFS. You want to increase the number which increased the volume of filament that is purges between the two colors. So as an example, the default algorithm would make the purge less between red and black because black is darker and red bleed wouldn’t be noticed as much. Goin the other way from black to red, the purge value is higher for the opposite reason.
To test this, what you would do is to create a simple model with different color layers and flipping it on it’s side. You can do this by stacking some cube primitives at different colors, then flip it on its side to get the stripe between black and white.
Thank you for the info. I put in flush volumes of 1200 for anything related to black with implement but still some stuff still obvious. It seems to be in the same spurts in general. The top set : same as the last posting. 2nd row: with high flush volumes and print tower 120, last one I corrected the model before printing in case that’s an issue.
The increased flush volumes has helped but still has sine artifact and it’s always at the same parts of the print.
Could it be that the lighter filament is dragging in from the outer black line? Should I try printing from the inner to outer wall? What else might I be missing?
That said, you could try a different white filament to determine whether greater opacity reduces the bleed-through. Unfortunately, opacity is not usually a published specification, so you will need to compare filaments experimentally.
This is one of many models designed to show filament transparency and compare the relative opacity of different filaments:
Here is a search for additional transparency-test models:
You could also try this purge calculator. I have not tested it, so I cannot comment on its effectiveness:
Unfortunately, you’re situation requires trial and error experimentation, I don’t know of a magic bullet that will address this.
My only other thought at the moment is the nozzle staying clean during the print? Or is it picking up random bits of filament during the first few layers? and randomly redistributing them during the print? I’ve had that happen with softer filaments requiring extra tweaks..
I’ll try a higher number. I didn’t know I could go above 1200 lol. Why would the bleed through occur at precisely the same spots in each case within that print run? If it were only bleed-through, wouldn’t it be more random?
I don’t think that the printhead is getting contaminated, but hard to tell for sure. The model parts are directly abutted without space, so there may be some possible overlap–although I optimized pressure advance, flow rate for all the filaments I use. I wonder if the reproducibility of the effects suggests touching the black line as it progresses around at specific parts? It is printing outer wall first.
what did you do to fix that when using softer filaments?
Thank you for all the thought & effort in your response! I wondered about more opaque filaments–that would definitely make my life easier for this model anyway. I was unaware of how big a problem bleeding could be–and assumed it was just my printer. The kicker: for a different model that printed poorly on my K2 plus, it prints nearly perfectly on my K1c. I tried using all the same speeds, jerk, etc that the K1c uses but still got poor results. I don’t know why my K1c prints so much cleaner still.
It might be worthwhile to check if your K2 is doing a clean cut before retraction. To do this you only need to remove the filament roll from your cfs and inspect the cut end. It should be a clean cut, If not there is a small mod you can do by printing a spacer for the blade actuator to give the blade more travel. This was a problem for me and once I did this mod it solved a number of issues. You will need to check different filament types and select a spacer thickness for the worst case until you get a clean cut on all filaments.
It appears a lot of people have had this issue with the K2 machines,Another tell tale sign is if the CFS unit giving a squeal when it starts to retract.
and let the community know how you faired so others can benefit.
