Fine horizontal lines on exterior when an internal feature ends, how do you get rid of this?
I don't know where to post this. The root cause could be many things. Anyways I see a fine line on the exterior perimeter of my parts. This fine line on the exterior is at the same height as the interior of the part. I printed a cap, and a threaded bottom to make a screw top container. For the cap, the fine line is at 4 mm. For the base, the fine line also occurs at 4mm height, and guess what, that's the thickness of the base. It mars the appeal of the printed product.
What causes this artifact? How can it be reduced or eliminated? In all fairness, the parts were printed in structural mode. Would the line effect be reduced in quality mode? Or are there other things to look at?
Overall, I like the print quality. But the fine line artifact is there. For what it is worth, it was also present with an MK4S, and I never figured out how to get rid of it.
What would you like to see? I need daylight to get a good photo, it's night now. I can supply the project files. Looking at the parts closely, there's actually a double line artifact, separated by a layer, so about 0.6mm high, on both parts. The artifact is not circularly symmetric, although the basic parts are. Some sides are worse than others.
RE: Fine horizontal lines on exterior when an internal feature ends, how do you get rid of this?
Here's a picture. Not the greatest, but shows the dual lines on both parts. I don't know how to make the picture show in the post, but I have attached it.
RE: Fine horizontal lines on exterior when an internal feature ends, how do you get rid of this?
Here's a picture. Not the greatest, but shows the dual lines on both parts. I don't know how to make the picture show in the post, but I have attached it.
It's would be easier to diagnose if you attached your zipped 3MF project file. Otherwise, I can only guess that at those layers there is either a change to the flow rate, part cooling or both.
RE: Fine horizontal lines on exterior when an internal feature ends, how do you get rid of this?
Pardon my inexperience, do I have to zip the 3mf file? Or just send the 3mf?
RE: Fine horizontal lines on exterior when an internal feature ends, how do you get rid of this?
The forum only allows you to attach files with a zip extension. So first zip the 3mf and then attach it. Ironically 3MF itself is already a zip file so you could just change the file extension. However that could confuse people so it's best to zip it first. So a zip of a zip...
RE: Fine horizontal lines on exterior when an internal feature ends, how do you get rid of this?
Hmm, even compressed it is over 10MB. Heck, the zip file is only 100kB smaller than the original at 11.9MB.
RE: Fine horizontal lines on exterior when an internal feature ends, how do you get rid of this?
Yes, but the zipped file is 11.8MB, or nearly 20% greater than allowed. Now what?
RE:
Put it on google drive/dropbox etc and post a link.
Otherwise, slice it then when on the Preview view, select Fan Speed (%) from the drop down. Check if the fan speed shifts dramatically where your layer shows this ridge. Also do the same for Volumetric flow
RE: Fine horizontal lines on exterior when an internal feature ends, how do you get rid of this?
I made a simple cylinder with a pocket, and although I can see traces of the transition, they are a lot more subtle. I can barely see it, unlike the photo I posted. That 3mf was only 39KB. Let me see what I can do for the larger file. Think it will be tomorrow, unless I get lucky.
RE: Fine horizontal lines on exterior when an internal feature ends, how do you get rid of this?
Here's the link to both 3mf files for the top and bottom. https://drive.google.com/drive/folders/1qOAHCr_bbyZ7sgonvBUTNsB8jYzHgH9H?usp=sharing
Hope that works.
RE:
OK. If you look at the sliced preview and switch to layer time you can see that the color change corresponds to where you are seeing the ridge. Means that the fan will ramp up quickly at that layer. If you slow the fan down, it should get rid of the ridge. Also, I would recommend printing it in the center of the bed.
So under Filaments -> Cooling -> Fan settings, try setting the Min and Max to 25% and set the "Full fan speed at layer" to 3
RE: Fine horizontal lines on exterior when an internal feature ends, how do you get rid of this?
Its basically the benchy hull line problem. There are loads of existing threads on here (and elsewhere) about the same basic issue. Unfortunately the forum search function sucks but you could use a google search with the site: delimiter to find them.
RE: Fine horizontal lines on exterior when an internal feature ends, how do you get rid of this?
@hyiger Just so I understand, changing the fan like that will also modify the cooling of the printed threads, yes? At one point I had troubles with printing the female threads and and reduced the Max Volumetric speed down to 6. The filament wasn't sticking, and pulled away when it cooled.
RE: Fine horizontal lines on exterior when an internal feature ends, how do you get rid of this?
Its basically the benchy hull line problem. There are loads of existing threads on here (and elsewhere) about the same basic issue. Unfortunately the forum search function sucks but you could use a google search with the site: delimiter to find them.
From my quick look, there is no real solution to the benchy hull line problem. At least one that is automated at the slicer level. Lots of conjecture, but even the Prusa knowledge base article comes up short of a solution. It's 5 years old, but I haven't seen anything else jump out at me.
You'd think this was deterministic, not random. And being deterministic implies some strategy could be deployed, like smoothing out any abrupt changes, like in cooling...
RE:
@hyiger Just so I understand, changing the fan like that will also modify the cooling of the printed threads, yes? At one point I had troubles with printing the female threads and and reduced the Max Volumetric speed down to 6. The filament wasn't sticking, and pulled away when it cooled.
There is two ways I can think of. In the slicer preview you can use the right scrubber to select the first layer where the bulge is happening then set the fan speed to 25% using M106 P0 S64. Where M106 is the fan speed command, P0 is fan 0 (part fan) and 64 is 25% of 255. Or in the before layer change section, do something like (set N to the start layer and change the +5 to where you want it to stop).
{if layer_num >= N and layer_num <= N+5}M106 P0 S64{endif}
Or perhaps can play around with the dynamic cooling settings
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@hyiger, In this particular case, I could find the layer and make some hack. Does the suggested code fragment restore the fan setting if the conditional is not met?
Not sure what the dynamic cooling can accomplish. Don't know what the term overlap means for this context. But conceptually, dynamic cooling is very likely a possible solution, if it had the proper controls, perhaps change rate limiting. Here's my whole set of settings for cooling.
RE:
The g-code inside {} are macros, it's not executed by the printer. The slicer expands the macro into g-code/m-code statements.
So in this example:
{if layer_num >= 6 and layer_num <= 9}M106 P0 S64{endif}
For layers 6,7,8,9 in the g-code file, the part fan is set to to 25%. For the other layers the fan is set to whatever the slicer chose for that layer.
RE:
A somewhat heavy-handed thought, can you disable the print fan completely? I usually turn it off (with ABS/ASA, to err on the side of caution as cooling means warping means catastrophic head crash). It's probably suboptimal but might still be an improvement. The object in the picture looks quite robust, no bridging or the like.
Or a compromise, set a fixed fan speed min=max?
If the ridge is still there, it's not the fan...
RE: Fine horizontal lines on exterior when an internal feature ends, how do you get rid of this?
A somewhat heavy-handed thought, can you disable the print fan completely? I usually turn it off (with ABS/ASA, to err on the side of caution as cooling means warping means catastrophic head crash). It's probably suboptimal but might still be an improvement. The object in the picture looks quite robust, no bridging or the like.
Or a compromise, set a fixed fan speed min=max?
Heavy handed, yes, but simple to implement. Yes, this is a simple part. Definitely worth a try.
Wish there was a general solution, rather than hacks like this.