Hello - many times my solid color prints are unusable because of a darker filament strand from filament that was used prior.
Ideally having a paint pen that matches this color would be ideal. See my other post here.
Are there any steps I am overlooking to avoid this from happening? I have a number of prints where something like this occurs and simply can’t use them.
The calibration steps, prior to printing, the sample test print lines, I even use a skirt multiple times - and yet this random strand manages to find it’s way. It’s like the nozzle is not fully cleaned or the extruder still has something in it.
If printing black that is usually not a problem, because I can cover the colored strand easily with a black paint pen.
I was printing black PETG for a bit and then switched to yellow. if I print multiple batches of a color, usually the next batch of that color will be fine.
The bed and nozzle were clean before the print - but I am baffled what I missed - or if there are any extra steps I can take to avoid this from happening?
You said the magic word, PETG. It’s sticky, likes to get all up in the nozzle and sleeve, maybe even just a chunk stuck in the heating chamber too.
You can do your best to mitigate issues by manually or otherwise extruding extra filament when you are making such a change, double check the nozzle and the sleeve and get it nice and clean (take the sleeve - silicone sock - off, then put it back on after cleaning of course).
If that’s not enough then I guess a cold pull in an attempt to dislodge anything stuck in the heating chamber.
Also, I was getting lots of blobbing on the nozzle with PETG-HF so I went from 245 nozzle temp to 260 and the blobbing is gone. I’m only saying this because I think that is the main contributor to such issues as evidenced here.
The first thing to do is always wipe your print bed with a lint-free cloth, microfibre ones work well.
This removes anything deposited on the surface between prints.
If you have printed something dark before you print something light you really need to fenperfect, it is time to clean the build-plate.
Dish soap (nothing fancy) and warm water. Thoroughly rub the surface making sure to hold it by the edges, a complete rinse and a total dry.
In the slicer you can make a change to limit contamination between the colours you have chosen within your model.
The first one is to add the filament colour choices in the filament selector from light to dark, leaving 5he selection of black as the last one added.
This should influence the print order of colours.
However, this isn’t always practical and isn’t always honoured.
You can ensure the order the colours will print by pressing the cog icon on the right of the build-plate and down the bottom you can turn on the filament order for the first layer and also for subsequent layers.
You grab the swatches and drag and drop them, these weirdly swap positions rather than inserting into the gaps, it can take a few moments to shuffle them into the order you prefer. Again, light first, then going to the darkest.
This should stop any black being deposited before white (for example) contaminating the model’s appearance when the print has completed.
You could try using the printer menu to do an additional load/unload of the subsequent color before cleaning out the chamber (again) and then starting the print.
Are you suggesting the nozzle remained perfectly clean until it made it to the centre of the build-plate before or during the printing of the first layer?
I’m not sure that is a reasonable explanation of your problem.
You clearly are not if you believe that imperfections are coming from the nozzle.
Filament doesn’t wait until later to melt and appear within the model.
At best, your nozzle could have some contaminants you didn’t clean off which gets disposed of in the build plate during the levelling process.
You can give the build-plate a quick wipe after the levelling process and before the actual print begins.
