Printing inconveniences that ask for explanation  

RE: Printing inconveniences that ask for explanation

Hi there and welcome to the 3D printing community!  I know when I was getting started that printing issues could become discouraging and frustrating quickly, so here's a few tips I'd try for the issues you're seeing and my reasoning why I came to that conclusion.

Issue #1

Cause: Under- or over-extrusion
Recommendation: Try the 0.20mm STRUCTURAL profile, double-check the filament profile, check for nozzle clogs
Explanation:

Overall, that cup holder print is in pretty bad shape for a relatively simple print.  The inconsistency of extruded layers leads me to think you're experiencing severe under-extrusion and the printer can't produce the print in a dimensionally exact way, which is a catalyst for many other weird behaviors and issues.  I've found using any speed-oriented profiles without the use of high-speed filaments can cause me issues with under-extrusion, so I would advise trying to re-print the cup holder with the 0.20mm STRUCTURAL profile and see if that comes out better.  I've provided a bit more context for how I've encountered this issue before and my reasoning in a reply to a forum post a while back here: https://forum.prusa3d.com/forum/english-forum-original-prusa-i3-mk4-hardware-firmware-and-software-help/my-mk4-is-very-noisy-vibration-in-x-direction-for-large-flat-pieces/#post-712104

Next, I would double-check your filament profile and ensure you're really using the old, "Made for Prusa" silver.  While your pictures look right and it's probably one of my favorite grey/silver PLAs that I got back with my MK2, these filaments are harder to get ahold of these days and most folks newly entering 3D printing will only know of the Prusament filament line.  If did manage to get your hands on some Made for Prusa silver the filament profile you've selected is correct (and congratulations on the find).

Finally, if the change in print profile doesn't help and the filament profile is correct, double check that the filament isn't hanging up/dragging somewhere and that the nozzle isn't clogged.  If you've used a fibrous or abrasive filaments, consider doing a cold pull to extract burnt fibers stuck in the hotend.  The latest firmwares have a guided procedure in the settings, but the full document can be found here at the knowledge base: https://help.prusa3d.com/article/cold-pull-mk4-xl_445071

Issue #2

Cause: Thermal stability
Recommendation: Use an enclosure or minimize drafts, resolve previous issue
Explanation:

Ultimately, I think printing this file with the standard .02mm layer height and structural print profile will fix a vast chunk of your issues.  If the print profile change didn't fix it, then this warping may be more problematic to resolve.  Prints with parallel features that jut away from the print bed are some of the hardest prints to avoid warping on.  Having an enclosure around your printer (even if it's a cardboard box) can help prevent drafts, which cause uneven cooling and in turn promote warping.  Additionally, you might slightly increase z-hop to give your nozzle more clearance to bridge the gap without crashing into a warping part.

Finally, while maybe not exactly applicable to this part, do know that cleaning your print bed with mild dish soap and water will make a world of a difference.  Some folks here will explain that isopropyl alcohol kinda seems to just push around oils and other residues, so soap and water is really necessary when the plate gets dirty.  If you encounter any warping of large parts at sharp corners, it's best practice to clean the bed with soap and water and try using mouse ears or support discs around the corners to keep everything adhered to the print bed.

Issue #3

Cause: Under-extrusion
Recommendation: Try the 0.20mm STRUCTURAL profile, double-check the filament profile, check for nozzle clogs
Explanation:

This one is similar to issue #1.  While yes, the overhang is somewhat a complicating factor, your major issue is the lack of consistent filament layers along a path.  Here's a simplified example to explain:

Imagine a circle with 100 dots evenly spaced along the circle's path.  These dots are representing the coordinates that the printer's nozzle is going to use to draw the circle.  Now imagine randomly selecting only of 80 percent of the dots and connecting them as the printer would.  This would lead to weird flat spots and sharp corners.  Finally, imagine this process is happening on top of one another with a different random selection of dots each time.  This leads to a highly inconsistent and mess of a cylinder wall.  That's in essence what I'm seeing in your cup holder print photos.

Finally, in response to your comment about cleaning up the bridge edge with an Xacto blade, this cleanup is still sometimes necessary when things go right.  Bridging is one of the hardest things our printers try to do and any additional small complications can result in a failed print.  The major purpose for the MK4 to MK4S upgrade was to improve the cooling such that bridging and overhangs are better.  While fixing all your other issues here will help this, just know that bridging is just hard and problematic sometimes.  Perhaps someone else posting will have some better tips or techniques, but even after working with 3D printers for several years, failed bridges involving tall, thin structures is the number one cause of death for my prints.

Issue #4

Cause: Slight under-extrusion
Recommendation: Consider the 0.20mm STRUCTURAL profile over the SPEED profile
Explanation:

While some of the zits on the top may be helped by the extrusion speed of the structural filament profile, my recommendation is more that overhangs are handled better by slower speeds that allow for more cooling from the part fan.  The rest of my explanation would be rehash from earlier in the post. 

As far as the horizontal line, I don't find that to be too egregious of a blemish.  It could just be a slight step out as a result of the changes in the inner structure.  When I downloaded and sliced that model, it appears the interior conical structure starts forming around layer 22 - which is around the layer where you start seeing the change in seam location.  If it's a major bother for you, some folks have had success with having outermost perimeters printed first instead of interior perimeters.  This checkbox setting can be found under "Print Settings" > "Layers and Perimeters" > "Advanced" section > "External perimeters first".

Finally, if you want to better align the seams to aid in visual appeal, you can choose "rear" in your seam alignment settings or even use the seam painting tool to choose a preferred location and alignment of your layer seams.

Anyhow, I hopefully some of this is helpful.  I tried to be a bit verbose to help walk you through the troubleshooting a bit since you mentioned you're new the the space.  Best of luck getting your prints to come out better, and again, welcome to the community!

Don't print torture tests in the first month, it's pointless.  Newly built printers are all fractionally different and prebuilt ones have been shaken up in transit.  During the first month the printer will settle into a stable state and the working parts will run-in, even if perfectly calibrated on day one the settings will drift - but after a month and the first maintenance session the machine will be much more stable.   https://help.prusa3d.com/article/regular-printer-maintenance-mk4_419000

when printing the grid infill the nozzle starts to grind the on the print

I'm not sure why Prusa continue to default to grid, historically it was the first and only fill but it's rarely the best, for your part I would use cubic fill.

When printing something with edges, they warp 1-2 mm upwards.

It's in the nature of FDM printing for steep overhangs to lift as the extrusion cools and contracts, it's something experienced designers factor into their designs - usually by avoidance...

closing the arches

... such as either flattening the top of an arch or coming to a point to avoid overhangs in the critical range ...

an issue while printing the outside curved base

... and never taking a steep overhang close to the build sheet where there is no room for supports, never convex fillet a base, use chamfers.

There's also a horizontal "line"

The vertical line is your seam, the horizontal one is at the point where your curving overhang passes the point at which each layer is mostly supported from below and instead must be supported by horizontal adhesion to the adjacent extrusion on the same layer.

some (minor?) imperfections which are driving me nuts

Yes, you need to dry your filament.  As moisture boils-off the uneven steam pressure messes with the extruder pressure.

0.40mm HF nozzle

0.10mm FAST DETAIL profile

0.20mm SPEED profile

There is nothing in the cupholder to justify 0.1mm layers, use 0.2mm.

It is in the nature of FDM printing that anything that increases speed reduces quality, it's a trade-off and you have to pick the point that is acceptable to you.  Try the same prints in one of the slower, higher quality profiles.

There are a lot of users who are impatient, own micrometers and can't be bothered to post process their prints; they will never be satisfied.

Most of the issues with the cupholder relate to beginner design errors and a low resolution .STL file - a huge proportion of the files on printables are a waste of filament as there are no quality metrics and anyone can post untested designs.

Unlke @forbiddenphoton I can see no extrusion issues that wouldn't be addressed by drying the filament; there are slight verical wall imperfections that suggest you need to check belt tesions at your maintenance session.

Within the limits above, I would rate those prints as 'Good enough for the first month.'  Now it's time to start designing your own parts bearing in mind the design constraints you have just discovered.

Cheerio,

RE: Printing inconveniences that ask for explanation

Thank you @forbiddenphoton  and @diem for your responses 😊

@forbiddenphoton

double-check your filament profile and ensure you're really using the old, "Made for Prusa" silver.

This is what I got (both Grey Silver and White):

• Made for Prusa Filament:
  • 
• Filament Profile in PruisaSlicer:
  • 

Prints with parallel features that jut away from the print bed are some of the hardest prints to avoid warping on

Noted.

If you encounter any warping of large parts at sharp corners, it's best practice to clean the bed with soap and water and try using mouse ears or support discs around the corners to keep everything adhered to the print bed.

I haven't encountered it yet, but will keep an eye out for it just in case.

cleanup is still sometimes necessary when things go right. 

I agree/know... I've appropriated my girlfriend's blade to remove brims and supports. The bridges and that overhang made me panic as:

1. I built the printer from the ground up, as it was a kit. So, it being the first 3d printer that I've (literally) touched (not to mention... build), I got the sense that something might have probably gone wrong, such as loosened bolts, belts, etc...
2. I haven't used supports. Well as I've started printing some stuff with supports... I believe now I know a little more on how and what type to use.

choose "rear" in your seam alignment settings or even use the seam painting tool to choose a preferred location and alignment of your layer seams

I already tried that on different models and it was ok. On the Scandic Plate, I was referring to the horizontal line... not the vertical "interrupted" line which is indeed the seam. But yeah... I can live with it on this Scandic plate.

@diem

Don't print torture tests in the first month, it's pointless.

I see your point on having the build do a run-in and get itself into a stable state. However, the torture test can be somewhat used as a baseline for future tests. At least that's how I look at it.

I would use cubic fill

Yes sir, captain sir! 🫡

It's in the nature of FDM printing for steep overhangs to lift as the extrusion cools and contracts, it's something experienced designers factor into their designs - usually by avoidance...

Dully noted.

you need to dry your filament.  As moisture boils-off the uneven steam pressure messes with the extruder pressure.

I'd argue here that while moisture might be a cause, the imperfections seem to be in the same places which makes me think that the underlying layer was off for some reason, as they go outward from the plate's center (as same as the seam):

All in all, THANK YOU both for sharing your wisdom and experience with me in trying to make sense of things🫡.