Hi all, this is P1S, 3DXTech PETG-CF. I dried at 65*C for 4 hours in the eibos cyclops and print directly from the dryer.
I have done flow calibrations for the spool from Bambu Studio and chose bed leveling before printing.
I created the preset based on Bambu PETG-CF preset and adjust the bed and extrusion temperature according to 3DXTech guidance. Last test print which was < 1 hr was good. This one is 2 hour. Below are the photos of the issues and screenshots of Bambu Studio settings
Any suggestion how I can troubleshoot this? Thank you,
Supplying a screengrab of your settings unfortunately won’t help us help you since we can’t replicate your filament conditions.
It would be very helpful if you can show a sliced version of this and zoom in on the section of the model that is giving you issues. This will help us better undestand what the slicer thinks it was supposed to do versus what your photo showed.
Also, did you know you can upload high res photos directly here? Just drag the image into the browser or hit the upload button.
However, until we can inspect what the model looks like under the slicer preview menu, in the meantime let’s assume that the problems you’re seeing are calibration issues with the filament. First advice, load Orca Slicer and use this video linekedd below to do a proper filament calibration. Bambu Studio does not have proper filament calibration tools. There is no downside to having both slicers on your machine, Orca is just better suited for this kind of work. Here’s a video that will walk you through the process. https://www.youtube.com/watch?v=5CVq6DycUOE
FWIW, this is exactly the same problem described and discussed on the very big PETG thread. Do a search on the forum. You can’t miss it. It may have the most views of any thread in the entire forum.
While this may or may not be your problem, 4 hours is nowhere near enough time for drying. You’re only really heating the outermost layers of the roll. Plastic is a good thermal insulator after all. You might get away with short drying time for a shorter print, but not for a longer print.
Others will have their opinions, but my minimum drying time is 12 hours. Load the plastic in the dryer, do my final CAD work and slice before quitting for the day, print the next day.
For some plastics, like Nylon, even in an AMS with fresh desiccant, it needs to be periodically redried. It’s hydrophilic enough it competes with the desiccant.
Drying with heating depends on “diffusion” to drive the water out of the filament. It’s inherently slow. If you want fast drying, you need vacuum.
This is also quite interesting, as it flies in the face of what some people are claiming about the AMS being virtually airtight. I do believe you. Those who claim otherwise should take note that both cannot be true at the same time, or else explain this apparent counterexample.
Thanks for posting. These images help, but they don’t reveal everything we’re looking for. But they are useful and can infer a couple of things based on what you just posted, but I’ll share that after I describe what kind of image would be more helpful.
Here is the ideal cross-section we’re looking for and what we’re trying to learn. By scaling the slider on the right side of your screen, we get a cross-section of what’s happening inside this model.
This will allow us, for example, to examine how the walls were laid down in the offending section and what the infill looked like after slicing. We’re trying to verify that what you see in the printed version isn’t caused by an anomaly in how the STL file was rendered. If the model was made in CAD using composite shapes, it can affect the nozzle’s travel, which may be causing the artifacts.
However, as I said, now that we can see how your model sliced, here’s one takeaway I can offer. If possible, always position the model so that holes are deposited vertically rather than horizontally, as in your example. This will improve the roundness of the holes. Sometimes this isn’t practical due to strength requirements, but if you can, try to orient them vertically.
Here is what I recommend: change your model’s orientation to look more like this:
Then after printing your model, what your looking for is to see if the location and form of the artifacts have changed in any way. If they appear in different spots on the model, it becomes more likely that the issue is with the orientation or filament calibration. If the artifacts remain in the same spot, it suggests a problem with the model. Posting a cross-section of the problem area using the slicer could help further understand what’s happening.
This is also quite interesting, as it flies in the face of what some people are claiming about the AMS being virtually airtight
People who claim otherwise don’t understand the physics of the diffusion process that dries out the plastic, or the concept of a “thermal time constant” (how long it actually takes to get an entire KG spool of plastic to 65ºC or higher), or the difference between a foam gasket and a hermetic seal.
An AMS leaks, no matter how good the seal appears to be. It’s not hermetic and that’s the only kind of seal that would work well enough.
I have some Sunlu S2 driers. I bought four of them last year on Prime Day. I can’t say if they’re the best or not since I have no other driers to compare with. But they work. I don’t mess with temp settings. I just run them at their 70ºC max.
Thanks all, I tried extending the drying time and also suggestions in other threads, in particular this Solution to printing Bambu PETG-CF with X1C (.4 and .6 Nozzle) - #28 by TheGunPsychiatrist. I switched to 0.6 nozzle, increased fan speeds and reduced printing speeds to 100-120mm/s. I also redid flow calibrations. The test prints are much better and there were very tiny artifacts but I can live with that for now
