Rough Top Surface When Printing with Wood Filament
Howdy All,
I'm trying to print with some wood filament, but I'm getting a rough top surface in one part of the print, as shown in the following photos:
As the photos show, the surface looks nice and smooth on the right, but on the left side (near the hole), it's rough.
The filament I'm using is from Sain Smart. (Click here for their posting.)
I designed the model myself in TinderCAD. I sliced it with Prusa Slicer, using the default Prusa PLA settings and the layer height set to 0.15mm. The only setting I changed was to bump up the infill percentage to 20%. I've printed this exact same gcode with a number of different brands and colors of PLA (including Sain Smart's own silver PLA), but I haven't had this same problem.
I didn't watch the entire print, but I did watch the beginning and the end. The first layer was close to perfect. The problem didn't seem to be only with the top layer but instead started with the last few layers. This problem is very consistent - This is the third print that's had the same problem in the same area.
Any ideas?
Thanks,
A.J.
P.S. My only thought is that there's some kind of problem bridging across the infill, but I don't understand why it would only occur near the hole.
RE: Rough Top Surface When Printing with Wood Filament
It looks like the part is warping and lifting off the bed, which compresses the upper layers at that end of the part. Raise the bed temp 10c and try again. If that doesn't help, then try washing the bed with dish soap and hot water, rinse well, use only paper towels to wash and dry - and never touch the print surface with your fingers.
RE: Rough Top Surface When Printing with Wood Filament
I know it looks like it's warping, but it's really not - that's the way I designed it. The sides and corners are rounded up. I'd attach the .stl file, but I guess that's not allowed in these forums.
A.J.
P.S. Also, I cleaned the print surface with 91% isopropyl alcohol just before this print.
RE: Rough Top Surface When Printing with Wood Filament
Anything but images must be zipped ... and alcohol - well, a cap full of alcohol is a poor substitute for gallons of water to rinse the bed.
This bed was cleaned in alcohol, too... and see where it got me:
ps: there are a couple of threads going discussing the PC sheet needing soap and water to get PLA to stick.
RE: Rough Top Surface When Printing with Wood Filament
filament getting wet from room humidity? - wood filament is moisture sensitive because of the wood fiber in it
RE: Rough Top Surface When Printing with Wood Filament
And back to the over extrusion. Unless your filament is getting thicker at that point, there's really no mechanism for the extruder laying down more material in corners or just one edge of a layer. So lift is still the most obvious and likely cause. That or the mesh leveling is failing.
Try rotating or moving the part to remove bed issues.
RE: Rough Top Surface When Printing with Wood Filament
Well don't I look like a newbie - and I've had my MK3S for a full three weeks. Attached is the .stl and the gcode.
As for cleaning, I'm just doing what Jo Prusa suggests. Besides, the print happened the same way three different time, with lots of other prints in between.
I don't think moisture is the culprit. The first time I printed it, the filament was fresh out of the box, and the same thing happened.
A.J.
RE: Rough Top Surface When Printing with Wood Filament
Other than asking for problems by using a radiused rather than chamfered edge, the part is a part. Since the nozzle is moving X-Y in a plane parallel to the bed, it really can't pile more filament up in a corner. Only if the part warps and lifts off the bed or mesh calibration is broken will you see this. And your photo shows what appears to be warp and I'd bet you can slide a piece of paper under that end of the part.
The extremely odd case would be print through or whatever it's called, where your bed is not level and the first layer is totally messed up and that furball causes the layers above to be distorted. But this usually only affects a few layers, not 25.
Try remaking the part with square edges instead of a radius. Square edges will make part lift easier to see. surface.
Or - you can just be confident the part isn't warping and write the oddness off to the mysteries of 3D printing.
RE: Rough Top Surface When Printing with Wood Filament
[...] The first layer was close to perfect. The problem didn't seem to be only with the top layer but instead started with the last few layers. This problem is very consistent - This is the third print that's had the same problem in the same area.
I'm assuming you've done several prints and are getting the same results. A quick test would be to rotate the part and print again. Also move the part around to different parts of the bed in your slicer. If the distortion stays on the same physical area of the bed, that gives you a strong hint that it's a mechanical issue of some sort. If it's warping, it should move about as you move the part. Warping will happen wherever there's a stray fingerprint on the PEI surface. If the distortion stays in that part of the print, it's something you can look at in your slicer settings. One note: You mentioned that the distortion is greater around the hole...
There is more support being printed owing to your use of filleted edges. The amount can be affected by Print Settings->Layers and perimeters->Quality->Ensure vertical shell thickness as this is telling the slicer to add more infill to support those curved walls. I suspect the root cause is over-extrusion, and those parts of the print are simply so dense that it accumulates to the point that your nozzle hits the protruding filament as it nears the top. Have you calibrated your extrusion multiplier for that filament yet? As a quick test, bump back Filament Settings->Filament->Filament->Extrusion multiplier.
As Tim notes, the use of filleted edges is making the print more difficult. If this is just a filament swatch, consider switching to chamfers, at least on the underside.
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RE: Rough Top Surface When Printing with Wood Filament
Tim, thanks for all your suggestions. I'm at work (AFP - Away From Prusa) right now so I can't try anything, but I propose doing the following when I get home tonight. 1) Redesign the part to take out the hole. 2) Print it and right after it's finished (before the bed has cooled), test your warping theory with a piece of paper. My guess is that it will pass the warping test (i.e. no warping) and the top surface will be smooth.
BTW, I totally understand why you think it's warping from the photos. When I first started printing this design, I stopped the prints multiple times because I thought they were warping. Finally, I let one finish - it printed fine and the bottom was flat.
I inspected some of my other prints (with other brands and colors of PLA) more carefully, and I think I was a bit misleading when I stated that none of them have the same problem. While it is true that none of them are as rough as this one, some of them do seem to have a slight discoloration in this area. This seems to be due to the way that the top layers are printed. Because of the hole, it can't just print the diagonal lines in one pass across the surface, starting in the upper left corner and ending in the lower right corner. Instead, it has to print the lines in 4 sections, 1) from the upper left corner to the hole; 2) from the hole to the lower right corner; 3) to the lower left of the hole; and 4) to the upper right of the hole. Some of these sections, especially the area to the lower left of the hole (where most of the roughness is in the photos I posted), seem to be a slightly different color from the rest - I'll try to post a picture when I'm no longer AFP.
RE: Rough Top Surface When Printing with Wood Filament
Bob, thanks for the interesting description of what's going on around the hole. I think you may be onto something there. I have to admit that I've never adjusted the extrusion multiplier on ANY 3D print I've ever done on ANY printer. But this is also my first time printing with wood filament.
When I do the test I proposed to Tim in my last post, I'll also print the current design, rotated and offset from the center of the print surface, where I've been doing all these prints. (I have to stay somewhat close to the center, because my heat bed is defective and only heats the center half - it doesn't heat the quarter sections towards the front or the back of the printer. RMA in progress...)
BTW, I'm not using the rectilinear infill pattern that your picture shows. I'm using the wiggle (squiggle?) pattern, because that's what Prusa Slicer defaults to.
RE: Rough Top Surface When Printing with Wood Filament
[...] I have to admit that I've never adjusted the extrusion multiplier on ANY 3D print I've ever done on ANY printer. But this is also my first time printing with wood filament.
Seeing as how this is a swatch print, is it safe to assume you've printed it in other materials? And to those prints have finished normally? If so, you could repeat again with a known-good filament. If that looks normal, you've narrowed it down to the filament or filament-specific settings.
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He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan
RE: Rough Top Surface When Printing with Wood Filament
Yes, I've printed the exact same gcode with many different colors and brands of PLA, 24 others to be exact. All these other prints were smooth, although a few have a bit of what I'll call "discoloration" in the same area. I'll post some photos later - right now I'm at work AFP. And I printed these others before and between the three wood prints that were identically rough, as shown in my initial photos. I think I've pretty well established that it's something specific to this filament, although I "smell" that it's in combination with that hole.
RE: Rough Top Surface When Printing with Wood Filament
Here are a couple of the photos I promised y'all:
These are two other swatches I printed around the same time I printed the wood swatches, all with the same gcode. You can see some "discoloration" (that's what I'm calling it) near the hole, but it's not rough like the wood swatches. I think it's mostly just due to the filament reflecting the light differently, instead of an actual difference in color, but it shows that this particular section is printed differently than the rest of the top surface.
BTW, the left filament is from Sain Smart, the same company I bought the wood filament from. The right filament is from Prusa, the filament that came with my MK3S.
More photos to come...
A.J.
RE: Rough Top Surface When Printing with Wood Filament
If it is simple over extrusion, measure the diameter of the wood filament and set the slicer filament diameter to match. This should help, but you may also need to adjust infill widths and overlaps. Printing with the same gcode has drawbacks like this - especially as you get new spools from different batches.
I'm still on the fence and think warp might be in effect... lol.
RE: Rough Top Surface When Printing with Wood Filament
Well, I was printing some of the test prints mentioned, and my nozzle got jammed. And I have to stop printing to remove my defective heatbed to send back to Prusa, so I'll have to table the experimentation for a while. I get back to you guys when my printer is "whole" again.
A.J.