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penarichard53
(@penarichard53)
Active Member
Problems with top layer on prints

Reveal problem with top layer print Reveal problem with top layer print

Reveal problem with top layer print

Hello all,

I've recently built my Prusa 3MKS+ printer and have been printing/calibrating in all directions. I will make another post regarding my stringing problems 🙁

 

First, I have a calibration print (thingiverse link). As you can see, reading the text is quite difficult on the "bottom" of the print and the degrees on the overhang are basically impossible to read. What is going on here?

 

Next, looking at the reindeer model (prusaprinters link) you can see a nice top layer on the bigger piece and nasty lines/buildup on the smaller piece that looks like a "W". Looks like my printer is struggling when doing the top layer on small pieces, it looks like the z height is changing during the small areas.

 

Things I've done so far:

- print temp tower, nothing alarming

- bed adhesion is perfect, haven't had a problem with warping

- just calibrated z height, my eye calibration performed very well only 0.04mm variance

 

Please help me get rid of my headache, thank you

 

 

 

Posted : 01/12/2021 2:11 am
sylviatrilling
(@sylviatrilling)
Reputable Member
RE: Problems with top layer on prints

Please run a first layer calibration and post a pic of the results. Also with issues like this, it is useful to post pix of the bottoms of your prints.

Mk3S+,SL1S...
Posted : 01/12/2021 1:00 pm
penarichard53
(@penarichard53)
Active Member
Topic starter answered:
RE:

Hi @sylviatrilling

 

Thank you for your response. Please see the pictures. Excuse the apparent warp in the first photo, it was a little tricky to peel off the bed lol. I printed the first layer calibration gcode file found here.

There was an odd piece of filament that was stuck onto the print which is pictured 2nd. 4th is the bottom of the multi-calibration square print. 5th is the underside of the overhang test. 

 

Curious - how will the bottoms of the print reveal issues with top layers?

 

This post was modified 2 months ago by penarichard53
Posted : 01/12/2021 6:33 pm
sylviatrilling
(@sylviatrilling)
Reputable Member
RE:

Thanks for the additional pix. I suspected that your z-offset is too high and that is easier to see looking at the bottom of the print. It does look like it is too high.  When your nozzle is too high, the lines of extrusion don't squish together enough to make a firm flat foundation. Although the z-offset only affects the first layer, that first layer is crucial for a successful print. Because your lines of extrusion are too round, the second layer doesn't have a good flat platform to adhere to and so on right up to the top layer. 

Look at the bottom of the elk model where the parallel lines meet the perimeters. There are gaps. You want those lines to be nice and tight up against the perimeters as in the benchy below. You will have some gaps because those perimeters are curving lines, but they could be tighter.

Mk3S+,SL1S...
Posted : 01/12/2021 10:41 pm
penarichard53
(@penarichard53)
Active Member
Topic starter answered:
RE: Problems with top layer on prints

 

Hello again

 

Pictured is my latest print with an adjusted offset. I lowered the offset from -1.200 to -1.250 (made the z offset more negative) and the bottom layer looks like there are less gaps, but the top layer looks worse. I also had a failed print using offset -1.300 but had to stop it early because it was clobbering the print. What are your thoughts?

Posted : 02/12/2021 1:34 am
sylviatrilling
(@sylviatrilling)
Reputable Member
RE: Problems with top layer on prints

Good, we have more data points. Try -1.225.

Mk3S+,SL1S...
Posted : 02/12/2021 2:05 am
penarichard53
(@penarichard53)
Active Member
Topic starter answered:
RE: Problems with top layer on prints

Here is the latest -1.225 offset

 

Not much progress on the top layer and bottom layer has the gaps you mentioned before. I know there is a "this is as good as it's going go get" but I image the mk3s+ would consider this a "simple" print.

Posted : 02/12/2021 3:29 am
sylviatrilling
(@sylviatrilling)
Reputable Member
RE: Problems with top layer on prints

Excellent work. The 'W' piece and the antlers look much better to my eye. The -1.225 offset is very close to your optimum. It occurs to me to step back a bit and help you rethink the calibration prints. There are limitations to filament printing. The point of those calibration prints is not to get every part of them to print perfectly. The point is to understand the limitations of your printer so you can be aware of those limitations when you design your models.  These calibration prints are a bit of a challenge to print and that is their point. Overhangs are going to be tricky. I would not consider the reindeer to be a simple print either because of its smallish pieces with convoluted perimeters.

I suggest that you move forward and start printing items that you want to print. When you run up against trouble spots, post your pictures and a ZIPPED .3mf file so we can see your model and your settings. There are amazing people on this forum who are generous with their time and will be glad to help you get the best quality print from the model you are trying to print. 

Mk3S+,SL1S...
Posted : 02/12/2021 4:10 am
RandyM9
(@randym9)
Trusted Member
RE: Problems with top layer on prints

Greetings and welcome to the forums.

I’m no expert and there are many options to investigate but I will offer a couple things to start with.

First, I highly recommend the “life adjust z, my way” by @jeffjordan to actively and accurately tune your z value. You can find the files near the bottom of page 42, here:

https://forum.prusaprinters.org/forum/original-prusa-i3-mk3s-mk3-assembly-and-first-prints-troubleshooting/life-adjust-z-my-way/paged/42/

But go back to page 1 to learn how to properly use the calibration prints. This has been a godsend to me and many other “new to 3D printing types.”

Second, change your top infill pattern to “monotonic” for a cleaner finished look. It looks like you’re using “rectilinear” which gives you the parallel line looking finish. You may need to be in advanced or expert mode in prusaslicer to see the top infill options.

There is lots more to learn and tweak to improve your prints. Hopefully this gives you a bit more direction to start with. Best of luck.

Posted : 02/12/2021 5:39 am
sylviatrilling
(@sylviatrilling)
Reputable Member
RE: Problems with top layer on prints

Great idea from @Randy. You could try different top layer patterns. Concentric might be good too for the reindeer. 

Mk3S+,SL1S...
Posted : 02/12/2021 12:45 pm
RandyM9
(@randym9)
Trusted Member
RE: Problems with top layer on prints

Thanks @sylviatrilling! 

Your post reminds me that the bottom infill can be changed as well as the top infill so you can get a “cleaner” print all around. I typically stick with monotonic top and bottom (boring, I know) but your idea about experimenting with different top infill patterns is a good one. I don’t always think to try that. Thanks for the reminder!

Posted : 03/12/2021 12:52 am
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