Why does my top layer look like this?

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nolebotic
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Why does my top layer look like this?

Post by nolebotic » Thu Jul 03, 2014 10:41 pm

Hi All,

I'm having lots of fun with my new M2, it's quite an upgrade from my printerbot simple. I'm really close to getting it completely dialed in, my prints look great and are accurate. There is a weird quirk though that I can't seem to figure out after lots of tinkering with S3D settings and searching this forum and others. When printing medallion type prints (large, flat type objects like badges, logos, etc.) the top layer(s) look really rough and kind of burnt like. I'm using the supplied black PLA at 215c and have S3D set to high quality. It's not due to the head dragging, because when I printed the example below that has a flat platform and then objects on top of it, the base platform's top layer is nice and smooth but the final layers don't look nearly as clean. Your thoughts and tips are GREATLY appreciated.

Nole
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top layer.png
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jimc
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Re: Why does my top layer look like this?

Post by jimc » Fri Jul 04, 2014 5:05 am

Hmm well its hard to tell really but it does look like your underextruding a bit. Even around the outside where it looks better the lines arent touching so the with of the line being extruded isnt what the slicer is expecting. In the boxes the underextruding is probably causing the infill to be a little broken so the top layers arent bridging it. Measure your filament and make sure the dia is set right in the slicer then turn up the multiplier a little bit. For proper extrusion the edges of each line should just touch.

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Tim
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Re: Why does my top layer look like this?

Post by Tim » Fri Jul 04, 2014 3:16 pm

But if it's underextruding, shouldn't that apply to all layers? Only the top layer looks bad; the surface halfway down looks great.

215C is a bit high for PLA; I usually do about 200 to 205C.

Otherwise, the top layers can be affected by speed. . . the slicer will slow down the printing to force a minimum amount of time spent on each layer. That combined with too high a temperature might cause that effect. Otherwise, check all the conditions that are different between printing the lower (good) surface and the upper (bad) surface. Is the fan speed different? Print speed? How about the number of solid layers printed under the surface (I doubt that makes a difference but I can't tell how thick the piece is)?

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jimc
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Re: Why does my top layer look like this?

Post by jimc » Fri Jul 04, 2014 3:41 pm

i dont know. the surface around the blocks that looks better still looks underextruded to me. none of the top surface lines are touching on the edges. they are close but not quite touching. if the infill gets all broken apart with holes then the top surface will be very hard to get right. broken infill usually comes from underextrusion and as you mentioned tim, too high a temp. in s3d there is a setting "use random infill placement". turn this off. your parts will be stronger and infill will be less likely to break since each strand is supported 100 as its laid down. it likeS to break from trying to print over a mesh. im not saying this is whats happening but it does kinda look that way. if you notice in his print, judging by it sitting on his hand the part that looks good appears to be very thin so there is probably no infill being put there. they are probably a few solid layers then it does the blocks, adds the infill and then everything gets screwy. tim remember he has a new m2 as well so 215 is fairly normal i think with a v3b but i dont print pla either so who knows. i somehow remember 210-220 being about right. so if that were my print my next moves would be this.

1: uncheck use random infill placement
2: reduce temp 5 deg
3: increase # of top layers
4: increase infill density
5: measure filament and check filament dia settings are ok. if its right then bump up the mulitplier 3-4 points. if dia is off leave multiplier alone and correct dia setting

i would run the print at that point and see what happens. to the op, let us know how it works out
Last edited by jimc on Fri Jul 04, 2014 5:01 pm, edited 1 time in total.

Toby
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Re: Why does my top layer look like this?

Post by Toby » Fri Jul 04, 2014 4:52 pm

Can you post the .factory file? That would help troubleshoot the problem.

The .factory file is what you get from File->Save (or ctrl-s) in S3D. Also, you'll have to put it in a zip file in order to post it on the board.

nolebotic
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Re: Why does my top layer look like this?

Post by nolebotic » Fri Jul 04, 2014 9:38 pm

jimc wrote:i dont know. the surface around the blocks that looks better still looks underextruded to me. none of the top surface lines are touching on the edges. they are close but not quite touching. if the infill gets all broken apart with holes then the top surface will be very hard to get right. broken infill usually comes from underextrusion and as you mentioned tim, too high a temp. in s3d there is a setting "use random infill placement". turn this off. your parts will be stronger and infill will be less likely to break since each strand is supported 100 as its laid down. it likeS to break from trying to print over a mesh. im not saying this is whats happening but it does kinda look that way. if you notice in his print, judging by it sitting on his hand the part that looks good appears to be very thin so there is probably no infill being put there. they are probably a few solid layers then it does the blocks, adds the infill and then everything gets screwy. tim remember he has a new m2 as well so 215 is fairly normal i think with a v3b but i dont print pla either so who knows. i somehow remember 210-220 being about right. so if that were my print my next moves would be this.

1: uncheck use random infill placement
2: reduce temp 5 deg
3: increase # of top layers
4: increase infill density
5: measure filament and check filament dia settings are ok. if its right then bump up the mulitplier 3-4 points. if dia is off leave multiplier alone and correct dia setting

i would run the print at that point and see what happens. to the op, let us know how it works out
I really appreciate you taking the time to analyze this for me! I followed your directions exactly as listed above and I beleive it solved the problem. Top layer is much cleaner now. before and after pics below. (stl is different this time around because I felt that this batman logo illustrated the burnt looking top layer better than the previous picture). Thanks again for the help.
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after jimc settings.png
after jimc settings.png (146.63 KiB) Viewed 8849 times
before jimc settings.png
before jimc settings.png (182.04 KiB) Viewed 8849 times

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jimc
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Re: Why does my top layer look like this?

Post by jimc » Fri Jul 04, 2014 9:44 pm

ahhh good. that looks much better. just now it looks like there may be a hair too much plastic. its close though. maybe bring the multiplier down 1 or 2 notches. it does look good though. i just notice your nozzle dragged across the surface so that can be a indication of a little too much plastic. also in s3d retraction control add .2 to the z-lift. it will keep it from dragging.

tomlombardi
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Re: Why does my top layer look like this?

Post by tomlombardi » Mon Jul 07, 2014 3:32 am

I set my temperatures to the minimum and turned the multiplier down and I get great prints. For me those two things fixed most of my problems. I stumbled across something that helps solve bed adhesion problems, I apply hairspray to the bed while it's warm, this makes the texture rough and makes my prints stick extra well.

rixpix247
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Re: Why does my top layer look like this?

Post by rixpix247 » Fri Aug 29, 2014 3:33 am

Guys, Great thread that helped me with my 'holey' top layer when using the default 'High' perimeters in S3D! My M2 has been popping out good looking prints until I decided to try the 'High' auto-configure for Print Quality when trying to push the envelope.

When checking my filament diameter, I don't see where this multiplier is that I need to bump up? The only multiplier I see is the Bridging extrusion and speed multiplier. Sorry, noob here. Oops.. DISCOVERY!! Just found the EXTRUDER MULTIPLIER in the Primary Extruder Toolhead TAB. SO this is what we should turn up by 3 or 4 clicks huh?

I want/need to find out which change made the difference for me. I tend to be very systematic in my discovery approach. Was it the unchecked random fill? Was it the reduced temp? Was it the total of 4 layers on top instead of 3? Was it upping the infill from 20% to 30%? My filament measured 1.77mm which is really close to the 1.75 setting. I did however reduce my default printing speed from 4800 to 3800 just for good measure since I could not find a way to increase the amount of filament extruded. (just discovered the Extrusion Multiplier after I wrote that... D-OH!)

Does anyone have a cookbook of what all these settings do? I have browsed the S3D web site but didn't find anything. Maybe I am looking in the wrong places.

BTW, thanks to all of you guru's out there that have felt our noobian pain and still answer our questions!
Rickster

jsc
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Re: Why does my top layer look like this?

Post by jsc » Fri Aug 29, 2014 4:10 am

rixpix247 wrote: Does anyone have a cookbook of what all these settings do? I have browsed the S3D web site but didn't find anything. Maybe I am looking in the wrong places.
I did write up a beginner's guide a while ago: http://jinschoi.github.io/simplify3d-docs/

Some of it is dated, as it was written against the previous version, but mostly it's the UI that has changed, and not the process settings stuff.

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