(Sorry if i'm in the wrong place)
Thanks for your reply ! This might be filament related, but I already printed some models with that filament before, without any issue. Strange
I can try to increase the flow, but I fear that this will alter the model dimensions, as multiple parts must join together
No need to dry PLA. I have 5 year old PLA that prints fine. PVA and Nylon however get "ruined" just be leaving out in the open for a day.
Do you have this issue with other types of PLA?
9 hours ago, neoweiter said:I can try to increase the flow, but I fear that this will alter the model dimensions, as multiple parts must join together
Just a little bit! Like maybe 102%, definitely not more than about 105% (which is what I use when printing a bottom layer anyway to aid adhesion and it doesn't affect the dimensions.
As is usually a good idea, unless you've got a few hundred kilos of filament to spare, test small scale first.
On 10/11/2023 at 3:35 PM, gr5 said:No need to dry PLA. I have 5 year old PLA that prints fine. PVA and Nylon however get "ruined" just be leaving out in the open for a day.
Do you have this issue with other types of PLA?
Disagree, some PLA seems to miraculously avoid moisture uptake or at least seem not to suffer from it, but generally it needs to be kept dry. Poor bed adhesion, extrusion blobs, stringing and inconsistencies all things being equal are usually down to water in the PLA.
32 minutes ago, mrender said:Disagree, some PLA seems to miraculously avoid moisture uptake or at least seem not to suffer from it, but generally it needs to be kept dry. Poor bed adhesion, extrusion blobs, stringing and inconsistencies all things being equal are usually down to water in the PLA.
I don't think this forum software has polls, but this might be an "agree to disagree" moment. I'm with @gr5, I've found spools of PLA which I forgot existed that have just been sitting around in the same spot for years and print fine first time.
PLA is basically chemically inert - it doesn't really interact with anything. That's why some other kinds of filament, you can smooth surfaces or basically temporarily melt it so you can glue things on using chemicals like acetone or methyl ethyl ketone, but with PLA, you're stuck with good old cyanoacrylate (superglue) for sticking things back together. A lot of this is because PLA is derived from plant starch (often corn starch) - it's extremely stable chemically, so it won't react with almost everything.
However, some companies make filaments with names like "PLA+". They might be slightly more reactive if they've added other ingredients (because those other ingredients might not be as chemically stable).
Edited by Slashee_the_Cow24 minutes ago, Slashee_the_Cow said:I don't think this forum software has polls, but this might be an "agree to disagree" moment. I'm with @gr5, I've found spools of PLA which I forgot existed that have just been sitting around in the same spot for years and print fine first time.
PLA is basically chemically inert - it doesn't really interact with anything. That's why some other kinds of filament, you can smooth surfaces or basically temporarily melt it so you can glue things on using chemicals like acetone or methyl ethyl ketone, but with PLA, you're stuck with good old cyanoacrylate (superglue) for sticking things back together. A lot of this is because PLA is derived from plant starch (often corn starch) - it's extremely stable chemically, so it won't react with almost everything.
However, some companies make filaments with names like "PLA+". They might be slightly more reactive if they've added other ingredients (because those other ingredients might not be as chemically stable).
Think you are going off on a tangent here, PA is as chemically inert as PLA and doesn't chemically react with water. Both are hygroscopic, PA more so than PLA. Processing either with a significant water content will have issues.
I manly use PLA+. I have a rather dry environement, and I avoid leaving the window open, especially when it's raining.
I don't think I have big moisture issue with my filaments, but sometimes I can hear some bubbles popping when printing. Not sure if this affects my prints though, and I don't think this is the issue of my post above.
I also try to store my spools in sealed bags as much as possible
3 minutes ago, neoweiter said:I manly use PLA+. I have a rather dry environement, and I avoid leaving the window open, especially when it's raining.
I don't think I have big moisture issue with my filaments, but sometimes I can hear some bubbles popping when printing. Not sure if this affects my prints though, and I don't think this is the issue of my post above.
I also try to store my spools in sealed bags as much as possible
Doesn't look like wet filament is the issue at all in your prints, looks like wall settings or retract.
11 minutes ago, mrender said:Think you are going off on a tangent here, PA is as chemically inert as PLA and doesn't chemically react with water. Both are hygroscopic, PA more so than PLA. Processing either with a significant water content will have issues.
Straight PLA isn't exactly hydrophobic, but it's about as hygroscopic as anything you'd find sitting on your desk. And I've never found my mousepad damp after a few straight days of high humidity.
7 minutes ago, neoweiter said:I manly use PLA+. I have a rather dry environement, and I avoid leaving the window open, especially when it's raining.
I don't think I have big moisture issue with my filaments, but sometimes I can hear some bubbles popping when printing. Not sure if this affects my prints though, and I don't think this is the issue of my post above.
I'd watch my prints (or set up a camera) and try and determine the cause of the bubbles. Damp filament might be a primary cause of that sort of thing, but it's not the only one (e.g. if it's not extruding properly, air pockets can get inside your hot, not-yet-set filament).
7 minutes ago, neoweiter said:I also try to store my spools in sealed bags as much as possible
Bonus points if there's also a sachet or two of silica gel (or other desiccant) in there. I don't store my PLA in sealed bags (mainly because they didn't come with them and I CBF finding some big enough for them). Same with my ABS, never really had a problem with either. I do however keep my TPU and PETG in sealed bags (they came with them!) and have a filament dryer I stick them in for a couple of hours before I print
13 minutes ago, mrender said:Doesn't look like wet filament is the issue at all in your prints, looks like wall settings or retract.
Retraction is set to default :
3mm
speed : 40mm/s
I also tried retract less and more quickly :
1.5mm
speed : 45mm/s
Same random holes issue
Did you try increasing the material flow a smidge?
2 minutes ago, Slashee_the_Cow said:Straight PLA isn't exactly hydrophobic, but it's about as hygroscopic as anything you'd find sitting on your desk. And I've never found my mousepad damp after a few straight days of high humidity.
I'd watch my prints (or set up a camera) and try and determine the cause of the bubbles. Damp filament might be a primary cause of that sort of thing, but it's not the only one (e.g. if it's not extruding properly, air pockets can get inside your hot, not-yet-set filament).
Bonus points if there's also a sachet or two of silica gel (or other desiccant) in there. I don't store my PLA in sealed bags (mainly because they didn't come with them and I CBF finding some big enough for them). Same with my ABS, never really had a problem with either. I do however keep my TPU and PETG in sealed bags (they came with them!) and have a filament dryer I stick them in for a couple of hours before I print
Hygroscopic materials are not going to feel damp precisely because there are hygroscopic.
33 minutes ago, Slashee_the_Cow said:Did you try increasing the material flow a smidge?
not yet. I'll make some new tests soon
22 minutes ago, mrender said:Hygroscopic materials are not going to feel damp precisely because there are hygroscopic.
I'd love to write a witty retort, but I don't want to derail this thread any further.
Based on the pictures, it looks very unlikely to be a moisture issue, so we can drop the matter.
31 minutes ago, Slashee_the_Cow said:I'd love to write a witty retort, but I don't want to derail this thread any further.
Based on the pictures, it looks very unlikely to be a moisture issue, so we can drop the matter.
- You should only have to increase Material > Flow > Outer Wall Flow since that seems to be the problem part.
- Just to check, you don't have Experiments > Enable Coasting turned on, do you? That would definitely explain some underextrusion.
- You could also try setting Walls > Outer Wall Wipe Distance to maybe 4mm-ish (it's basically the opposite of coasting).
Agreed, no worries apology accepted:)
3 hours ago, Slashee_the_Cow said:I'd love to write a witty retort, but I don't want to derail this thread any further.
Based on the pictures, it looks very unlikely to be a moisture issue, so we can drop the matter.
- You should only have to increase Material > Flow > Outer Wall Flow since that seems to be the problem part.
- Just to check, you don't have Experiments > Enable Coasting turned on, do you? That would definitely explain some underextrusion.
- You could also try setting Walls > Outer Wall Wipe Distance to maybe 4mm-ish (it's basically the opposite of coasting).
Thanks mate, i'll try this
But no, I don't have coasting enabled :)
I have some interesting results with other prints I just made:
I printed some parts, with another filament (Black PLA+), with pretty standard slicing settings, and there again, I notice holes.
Then, I decided to print a super basic calibration cylinder (no top, no infill, even at 200% print speed), and this one came out FLAWLESS all the way around🤔 I really don't understand.
I tried again with my silk filament, with 10% gyriod infill... and came out perfect too 🫠
I'll make some further tests, but this is really driving me crazy
I get holes and bumps but barely notice them as I don't care about them. I'm not sure if I get barely any or lots as I really don't pay much attention.
But when I *did* pay attention, like 5 years ago, I seem to remember that if I printed slower they went away. Very slow, like 25mm/sec and also I think possibly thick like 0.2mm layers.
8 hours ago, neoweiter said:I'll make some further tests, but this is really driving me crazy
Most people don't have 2D printers any more, so something had to come in and fill the void of working properly depending on how many butterflies within 100 metre radius of the printer have flapped their wings within the past 73 seconds.
Although it is worth noting that your test prints are entirely, 100% round. Test a rectangular prism or something with straight walls and see if it shows up then.
8 hours ago, Slashee_the_Cow said:Most people don't have 2D printers any more, so something had to come in and fill the void of working properly depending on how many butterflies within 100 metre radius of the printer have flapped their wings within the past 73 seconds.
Although it is worth noting that your test prints are entirely, 100% round. Test a rectangular prism or something with straight walls and see if it shows up then.
I printed a calibration cube. Two holes
It's on the opposite face of Y, and the lower hole matches the height of the blob you can see on the edge of Y. Pretty sure it's related.
But at analyzing that layer in Cura, I can't really understand why this happens. Any idea ?
Nothing happens on that straight line, except it's near an infill line
EDIT : Fyi, I printed a couple more cubes. The blob on Y corner seem consistant, but not the holes. They appear randomly on each print, and I had one print that came out perfectly without any hole.
Edited by neoweiter
1 hour ago, neoweiter said:Fyi, I printed a couple more cubes. The blob on Y corner seem consistant, but not the holes. I had a print that came out perfectly without any hole.
Yeah that does strike me as pretty weird. Have you tried printing your calibration cubes in different positions on the plate in case your head seems to be getting caught up in that exact spot (and therefore overextruding) for some reason (yeah, I'm starting to grasp at straws).
Thought just occurred: Have you tried replacing your printer's nozzle (same size, just swap a new one in)? If there's a little bit of a clog it could cause material to get caught and not go out the nozzle (underextrusion, hole) or it could result in a lot of material getting built up and then coming out all at once (blobs). Buuuuuuut..... that still wouldn't explain why it happens in one specific spot in a reproduceable manner.
A couple of settings you could play around with:
Walls > Optimize Wall Printing Order: If it's on, it can cause blobs in certain cases, although usually only if the flow rate (which is affected by things like printing speed) is different between wall types. There's no real harm in turning it off, anyway, Cura will just be a bit dumber slicing your model giving you a few more travels and retractions, although the effect will probably be minimal when you only have an object which doesn't have multiple walls (like if you had a hole in it, it would do an outer and inner wall around that).
Walls > Wall Ordering: I think the default is "inside to outside" which generally makes sense (outer walls will have something to grab onto when they're printed), although it can affect things like if there's much infill pattern is visible on the outside (because the infill has had a chance to push at the inner wall, and the outer wall just follows the inner wall because it adheres to it). I doubt this would be a permanent fix, but it be worth changing it to "outside to inside" just to see what happens. Outside in is more dimensionally accurate (the wall has probably set before infill could push on the wall a bit, but the main problem is with overhang - the outer wall, being first, has nothing to grab on to (as opposed inside out, which makes the outer wall grab the inner wall which is grabbing infill).
21 minutes ago, Slashee_the_Cow said:Yeah that does strike me as pretty weird. Have you tried printing your calibration cubes in different positions on the plate in case your head seems to be getting caught up in that exact spot (and therefore overextruding) for some reason (yeah, I'm starting to grasp at straws).
Thought just occurred: Have you tried replacing your printer's nozzle (same size, just swap a new one in)? If there's a little bit of a clog it could cause material to get caught and not go out the nozzle (underextrusion, hole) or it could result in a lot of material getting built up and then coming out all at once (blobs). Buuuuuuut..... that still wouldn't explain why it happens in one specific spot in a reproduceable manner.
A couple of settings you could play around with:
Walls > Optimize Wall Printing Order: If it's on, it can cause blobs in certain cases, although usually only if the flow rate (which is affected by things like printing speed) is different between wall types. There's no real harm in turning it off, anyway, Cura will just be a bit dumber slicing your model giving you a few more travels and retractions, although the effect will probably be minimal when you only have an object which doesn't have multiple walls (like if you had a hole in it, it would do an outer and inner wall around that).
Walls > Wall Ordering: I think the default is "inside to outside" which generally makes sense (outer walls will have something to grab onto when they're printed), although it can affect things like if there's much infill pattern is visible on the outside (because the infill has had a chance to push at the inner wall, and the outer wall just follows the inner wall because it adheres to it). I doubt this would be a permanent fix, but it be worth changing it to "outside to inside" just to see what happens. Outside in is more dimensionally accurate (the wall has probably set before infill could push on the wall a bit, but the main problem is with overhang - the outer wall, being first, has nothing to grab on to (as opposed inside out, which makes the outer wall grab the inner wall which is grabbing infill).
Thank you so much for your time and commitment, I really appreciate it.
I printed a new cube in lower left corner of my plate (default settings). Holes and blobs.
I also printed a benchy earlier (centered on my plate, default settings). Still horrible.
I already checked my nozzle, it seem to be really clean. But maybe it has worn out. I will swap it with a new one and see the result. I will also test your suggestions 👍
Did you try printing at 25mm/sec? Just a s a test? That's what helps these for me.
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Not sure this is really the right place to ask for help if it happens with another slicer, but have you tried increasing the material flow a bit? I know their silk filament can be a lot of hassle to work with because it can be a bit more slippery than regular PLA, so if the extruder can't grab a bit when needed it can result in underextrusion.
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