Hi All,
While I’ve been a reasonably happy user of my X1C over the last year or so, I want to do something about the print quality in certain circumstances.
This is a simple bowl I made in Solidworks. The rough bit is where the X1C puts in a bit of tree/auto support. You can also see where it’s a bit poor at the bowl rim (bottom)
The material is PLA Matte and the settings are all standard for printing at 0.20 Standard resolution.
Any hints will be welcomed!!
Gerard
If you use adaptive layer height it will smooth out the stepping on those layers and probably wouldn’t need support.
Another tip is to avoid shallow layers by using a chamfer instead of a fillet.
Thanks for that. Yes, fillets look great in theory but printing can be something else.
I’ll look at the adaptive layer spacing and report back. Maybe it will help someone else.
Can you point me at adaptive layer height?
Thanks
Well, you’ve taken the first step in lesson #1 of 3D printing CAD design; Gravity Sucks!!! 
Two things. You can possibly “reduce” not eliminate the sagging lines by increasing the filet radius to be more gradual. So in this example(I’m using OnShape) I create an asymmetric filet(Fusion should support this feature too). Figure 1, will produce too much of an overhang. Whereas figure 2 will produce less of an overhang which allows the layers below to provide more support and therefore less droop to the layers above.
The second thing is that you can experiment with layer height as was suggested. The adaptive layer height tool will allow you to vary the layer height by region. But this is a limited tool and whenever you reduce layer height you increase print time. You may also weaken the part or in some filaments like PC that don’t like small layers, you may even weaken or make the appearance worse. So it’s a double edged sword that has to be used where appropriate and appropriate is a decision you have to make based on trial and error. You can click on the “adaptive” button and allow the algorithm to ‘guess’ at what is ideal, or do it manually. Try both.
Thanks for all of that. I made some Adaptive adjustments so we’ll see what happens. I’ve printed hundreds of prints over the last couple of years and “slump” has always been something to watch out for. With really fine work, it usually takes a couple of interations before get an acceptable result but that’s the nature of the business I suppose.
Iteration is lesson #2 of 3D printing CAD design. I’m a firm believer in taking 3 versions to get where you want to be. First is just roughing things out to find out what the major problems are. Second is where you figure out what needs refining. Third is where you finally get to add polish.
I find that the Adaptive settings don’t seem to have any effect. The print time stays the same, the quality is no different.
Edit: Finger trouble. You have to click on the LH button AFTER changing the setting! 
OK. the sphere came out pretty well. Smooth. It’s obvious which is the Adaptive one!
The fillets, not so much but an improvement!
One thing that I’ve always had a problem with is seperating the support material from the model.
Often removing it tears away the bottom layer of the model thus exposing the cross hatched internals.
The common wisdom is support or chamfer instead of fillet. This is 100% the only solution.
But wait!!! you can also do a nuanced combo if you want a more fillet-y look.
Make a chamfer that is at least 35-40 degrees from level. Have that chamfer rise to the point that an equal fillet would be curving past 40 degrees, then go into a fillet curve.
This way, it look like a fillet to a passer by when it is sitting on a surface, but has a chamfer at the very bottom that is steep enough to not need support.
Those are badly calibrated seams! 
I often find that the odd surface quality over the wide swath required for a scarf joint is more noticeable than a well tuned seam.
For sure, others may feel differently.
I’ve got to defend this notion. Scarf joints are something that still requires mastery. It’s not a set it and forget it feature… just yet. If you just flip on scarf joints with a purely tuned filament… well… garbage-in-garbage-out. However, if you first fine tune the filament for pressure advance to eliminate stringiness and over extrusion at the edges, then move onto calibrating seam gap and then finally dial-in the correct scarf joint settings, you can achieve perfection. After a while, I found it to be second nature.
I’ve said this before but it is important to repeat. Why pay for the label on the spool if you’re not getting your money’s worth? Unless you need that RFID tag.
Mastering filament calibration is the ultimate hack for every 3D printing enthusiast and a must for top results such as seam mitigation! Discover that feeling whjen you unleash the power to transform any $10 spool into a high-performing powerhouse, proving that the only difference between a $10 spool and those overpriced “premium” options is the price tag—and your calibration skills. Imagine the thrill of producing top-quality prints without shelling out for overpriced filament. And if that sense of accomplishment isn’t enough, who wouldn’t want to double their filament stash just by fine-tuning their setup? Dial it in, claim those savings, and enjoy the rush of beating the system. 
The test files with Orca prebuild and even an excel worksheet can be found here.
The models that Teaching Tech provides are here.
For me personally, I take his standard model and only print the first to geometries on top for calibration purposes which does good enough for my purposes.
but you know what? Cylinder primitive does just as well…
If you can upload the 3MF for this model I’d be willing to look at the settings. I always love a challenge. 
From what I can see, there are extrusion issues at the bottom which could be improved–not eliminated–by modifying temps and and/or flow rate. The model orientation may have more influence. Also, don’t expect great results from Bambu Matte PLA, as I’ve stated in other posts, on a scale of 1-10 for model fidelity, it is about a 3. I’ve had much better results with Overture, Jayo and 3DHoJor Matte filaments, 3DHoJor usually being far less expensive($13 or $0.37/oz).
I also see evidence of the walls being too thin. But I would be guessing without direct access to the model.
However, at the end of the day, you may be expecting too much of the technology if you feel your overhangs should look like your walls… gravity sucks and it is very egalitarian… it sucks equally for everyone… filament and people alike. Why do you think that Resin prints looks so great? They print them in a liquid bath hanging typically upside down at resolutions that are 4-8x than that which can be achieved with FDM technology without the sag. So why doesn’t everyone use resin? Because it’s got really bad fumes and must be used in a well ventilated area, it’s messy, more expensive, a whole lot sloooower and the prints are best suited for smaller objects–not functional parts–that one paints afterwards. In other words, Dungeons and Dragons figurines or artistic pieces. You can do some very cool thing with resin that you just can’t do with FDM but on balance, FDM is much easier to use in my limited experience.
See if his makes sense…
Feeder Bowl.3mf (149.8 KB)
In terms of moisture control, I use pre-dried dessicant bags liberally within the printer. The moisture metre reads about 3 currently (out of 5).
Edit: I’m not wedded to using PLA Matte, it was just to hand.
Thanks for uploading the file, this really helps cut to the chase and eliminates all sorts of back and forth speculation. It took me two seconds to spot the problem.
Unfortunately, this is about as 3D Printer-unfriendly a shape you can get. This is an important lesson of starting off with an optimal model. It’s easy to get caught into visualizing a piece of plastic that we may have seen as a piece of pottery or a molded piece of plastic in the supermarket but unlike pottery and molded plastic, with FDM, we have to deal with gravity and that where you’re seeing filament sag and supports producing a print that is not ideal.
If I were designing this type, I’d keep it simple.
No lips or edges.
Here’s a side by side using admittedly a very quick and dirty approximation of your object which I did quickly in a few minutes in OnShape, this is not optimized by any stretch but it shows what just a few simple changes can make. This was a shape set 156x156x39mm, which was the gross dimensions of the original model.
Here’s what it slices to. Notice that the slicer did not see the need for supports. Please note that I have not printed this, there may be more tuning but the shallower lines will already produce a no-support print.
And just by adding a 3mm fillet to the bottom of the bowl causes the slicer to want to add one layer supports which will mess up the smoothness.
Now if you still want to get that “Injection molded-like” appearance. Then you can either reduce the layer to something finer at the cost of triple the print time. Or simply use variable layer height and only focus the finer filament layers to the top and bottom curves.
Also, note the difference in time and filament between the original model and the simplified model. This is because supports require a lot of time and filament.
I’ve added and uploaded these examples into your file. Note that I have not printed them as stated above.
Feeder Bowl - simplified examples.3mf (3.6 MB)
Thanks for that. I’ll give it a try out.
Reason for that shape is that it’s what the customer brief states. There’s several parts to this whole contraption but I have a few days until I have to show a prototype. I have a company in Shenzhen that I use and if I paid him about A$8k, he’d injection mold them for me by the thousands!!!
I’m a Design Engineer, BTW. To me the Bambu is a tool of the trade but, having said that, it’s vital it understand what/how the tools work. Off topic, if you were choosing another printer (apart from Bambu), what are your thoughts?
Gerard
Ah… that makes total sense now. Thanks for sharing that info and adding clarity.
Yeah, this is the reason I choose not to do this for a living. It’s a lot like software coding, once I started collecting a paycheck and having to meet deadlines, it lost all of the fun and became work. I choose not to spoil this with 3D printing. I have fun now, especially when folks in this forum present “Stump the band” challenges like this one. It’s always fun solving problems when you don’t have a deadline or commitment to make. Not so much when you have folks relying on you.
