Started getting strange small gaps on the outer walls, but only on one side  

Re: Started getting strange small gaps on the outer walls, but only on one side

Is the "one side" the side away from the cooling fan ("!HOT!")? (e.g. the back)
Or is it a left or right or the front?

Is the filament free to spool to the extruder? Might the location (the one side) cause the filament to bind or have extra resistance?

Re: Started getting strange small gaps on the outer walls, but only on one side

Is the "one side" the side away from the cooling fan ("!HOT!")? (e.g. the back)
Or is it a left or right or the front?

Is the filament free to spool to the extruder? Might the location (the one side) cause the filament to bind or have extra resistance?

Thank you for some good ideas.

Yes, it is on the back, but I forgot to mention in my post that the cooling fan is turned off entirely for this particular piece. Now, the "back" side is facing the window, but it''s not particularly hot outside and the sun isn't shining on the printer.

I'm using a filament holder with bearings, so it's turning very smoothly. I'm not sure about it bending too much though, I wasn't paying attention to that so I'll check it. It did print the same gcode perfectly fine last week though, so I'm guessing if this was the problem, it would be evident in the first print already.

Re: Started getting strange small gaps on the outer walls, but only on one side

The only other thing I can think of is an intermittent connection in your wire bundle (kink at a zip tie) that triggers at certain bend radiuses of the extruder cables. Thus certain positions trigger it but it goes away quickly. If this is the case, it will get worse - and then be much easier to find. 😯

Are you running in "silent" mode? Some people have found that the power in that mode is marginal, and sometimes the motors skip steps.

Re: Started getting strange small gaps on the outer walls, but only on one side

The only other thing I can think of is an intermittent connection in your wire bundle (kink at a zip tie) that triggers at certain bend radiuses of the extruder cables. Thus certain positions trigger it but it goes away quickly. If this is the case, it will get worse - and then be much easier to find. 😯

Are you running in "silent" mode? Some people have found that the power in that mode is marginal, and sometimes the motors skip steps.

That's a very interesting theory. I've looked at the cables and they appear ok on the outside, but you never know. I'll try and make a couple of test prints at the back of the bed and see if it's repeatable. If nothing else, I hope it fails as you've mentioned, so that I can at least have something to fix.

Do you think using a cable chain would be better than the stock solution?

No, I'm never using silent mode.

Re: Started getting strange small gaps on the outer walls, but only on one side

I think you may want to try a couple of "cold pulls" and also check that the filament drive pulley is clean.

Maybe even a nozzle change.

Temps? Material? Speeds? Always helpful...

Ambient temp is now lower than it was a couple of weeks ago, so you may want to increase bed temp by 5 degrees to compensate.

Peter

Re: Started getting strange small gaps on the outer walls, but only on one side

I think you may want to try a couple of "cold pulls" and also check that the filament drive pulley is clean.

Maybe even a nozzle change.

Temps? Material? Speeds? Always helpful...

Ambient temp is now lower than it was a couple of weeks ago, so you may want to increase bed temp by 5 degrees to compensate.

Peter

Hey Peter,

I've never heard about the cold pull before, but the internet has plenty of info about it, so I'll give it a try, thanks for the idea.

The nozzle is only a few months old and I've been printing nothing but PLA and PETG, but I don't mind replacing it if I can't solve it otherwise.

I've posted the temps/material info in my first post (PLA@215/60), but forgot to mention the speed which was set to 50mm/s.

Re: Started getting strange small gaps on the outer walls, but only on one side

I've never heard about the cold pull before, but the internet has plenty of info about it, so I'll give it a try, thanks for the idea.

Pull at about 95 degrees, preferably with a light-coloured filament. Check for any burnt filament bits on the end and repeat until the filament comes out clean.

The nozzle is only a few months old and I've been printing nothing but PLA and PETG, but I don't mind replacing it if I can't solve it otherwise.

I tend to replace nozzles every few weeks; it's a lot easier than messing around trying to clean them...

I've posted the temps/material info in my first post (PLA@215/60), but forgot to mention the speed which was set to 50mm/s.

Sorry, I missed that...

Peter

Re: Started getting strange small gaps on the outer walls, but only on one side

To summarize your post, that the rest of the model looks fine, and this artifact only occurs on the back part, from a gcode that previously worked well. All of the normal nozzle clogged, filament not feeding issues should not be position dependent, but would occur all over the model at random.

Does this occur only at specific heights? (E.g. the bottom of the model is fine, but only at higher Z values?)

Is there anything different about that part of the model? Thinner wall? More or less inflil behind it?

Re: Started getting strange small gaps on the outer walls, but only on one side

Prusa Mk2S, PLA@215/60, Simplify3D.

I've been using the same gcode to print a certain part multiple times. I have not changed the settings or the gcode in anyway and yet I've started getting these strange artifacts/tiny gaps on my prints. The funny thing is, they only appear on one side of the model and the rest is fine. I printed this model (from the exact same gcode) last week and there was nothing there, the entire surface was fine.

Here's a photo of what it looks like:

The spool is brand new from last week, so that's probably not the reason.

Suggestions or tips much appreciated.

Please explain the orientation of this picture. I think I see the layers going top to bottom. Does that mean the RIGHT side of the image is UP (increasing Z)?

IF the above is correct, it seems you have a sputtering line just AFTER each of those rib features. This might be caused by your retraction settings. If there is a retraction around those features.

Re: Started getting strange small gaps on the outer walls, but only on one side

To summarize your post, that the rest of the model looks fine, and this artifact only occurs on the back part, from a gcode that previously worked well. All of the normal nozzle clogged, filament not feeding issues should not be position dependent, but would occur all over the model at random.

Does this occur only at specific heights? (E.g. the bottom of the model is fine, but only at higher Z values?)

Is there anything different about that part of the model? Thinner wall? More or less inflil behind it?

Hey aaron, sorry for taking a while for a reply. I'll answer both of your posts here.

No, it wasn't occurring at a specific height, but it affected the entire side of the part. It might be more pronounced at the middle, but not by much.

The entire model is a single extrusion wall, so there is nothing different as it goes up. There's no infill except some support structure that's part of the model.

You are correct, the image is rotated and the right side is up. I've taken three new photos. Here's a combined one; the top model is the one I've printed last week and came out fine. The bottom one is the latest with artifacts. The arrow indicates up direction. If you look closely at the bottom print, you can see those little gaps all over the surface, beginning almost as soon as the print started (bottom left corner) and going almost all the way to the top. Again, this is on this side only, the remaining three sides are fine.

Here's a close up of the good print that shows the entire height of the model:

And here's an entire close up of the bad print:

What baffles me the most is that both models are printed from the exact same gcode, so they should be identical. The only difference is that they were printed a week apart.

Re: Started getting strange small gaps on the outer walls, but only on one side

I've never heard about the cold pull before, but the internet has plenty of info about it, so I'll give it a try, thanks for the idea.

Pull at about 95 degrees, preferably with a light-coloured filament. Check for any burnt filament bits on the end and repeat until the filament comes out clean.

The nozzle is only a few months old and I've been printing nothing but PLA and PETG, but I don't mind replacing it if I can't solve it otherwise.

I tend to replace nozzles every few weeks; it's a lot easier than messing around trying to clean them...

I've posted the temps/material info in my first post (PLA@215/60), but forgot to mention the speed which was set to 50mm/s.

Sorry, I missed that...

Peter

Peter, thanks for your reply. I did a cold pull as suggested, using white filament, but it showed no burned marks or something similar. I've tried again and nothing. Either I'm doing it wrong or there's nothing there.

What are your thoughts on the ruby nozzle? Do you feel it could work indefinitely and eliminate the need to replace the nozzles every few weeks? I've been thinking of buying it, but it's hard to justify the price.

Re: Started getting strange small gaps on the outer walls, but only on one side

What are your thoughts on the ruby nozzle? Do you feel it could work indefinitely and eliminate the need to replace the nozzles every few weeks? I've been thinking of buying it, but it's hard to justify the price.

I have the Ruby installed, and like the "not having to think about it". It has been reliable and no changes. I periodically do some modestly abrasive filament (Glow or CF), it it is nice to just keep going and print it without changing anything.

It is hard to justify the price, but it has been good for me.

Re: Started getting strange small gaps on the outer walls, but only on one side

No, it wasn't occurring at a specific height, but it affected the entire side of the part. It might be more pronounced at the middle, but not by much.

The entire model is a single extrusion wall, so there is nothing different as it goes up. There's no infill except some support structure that's part of the model.

You are correct, the image is rotated and the right side is up. I've taken three new photos. Here's a combined one; the top model is the one I've printed last week and came out fine. The bottom one is the latest with artifacts. The arrow indicates up direction. If you look closely at the bottom print, you can see those little gaps all over the surface, beginning almost as soon as the print started (bottom left corner) and going almost all the way to the top. Again, this is on this side only, the remaining three sides are fine.

What baffles me the most is that both models are printed from the exact same gcode, so they should be identical. The only difference is that they were printed a week apart.

The fact that things could have changed doesn't bother me, but all the things I can think of would affect all four sides of the print, not just one.

I would focus on thinking about that geometry and what is different? Cable management? Some form of cooling or heating focused there? Something different in how the filament bends? Something different in the model?

For example, if while printing that side, there is more heat back there, the heat break might be warming up where the filament gets softer, and starts to clog. In other areas there is better cooling, so the filament does not clog. Is it warmer now than a week ago?

Is this a Spiral Vase? E.g. printed as one long continuous string.

Since we can't see your set up, I would think about the geometry, and what might be different on that side.

Re: Started getting strange small gaps on the outer walls, but only on one side

No, it wasn't occurring at a specific height, but it affected the entire side of the part. It might be more pronounced at the middle, but not by much.

The entire model is a single extrusion wall, so there is nothing different as it goes up. There's no infill except some support structure that's part of the model.

You are correct, the image is rotated and the right side is up. I've taken three new photos. Here's a combined one; the top model is the one I've printed last week and came out fine. The bottom one is the latest with artifacts. The arrow indicates up direction. If you look closely at the bottom print, you can see those little gaps all over the surface, beginning almost as soon as the print started (bottom left corner) and going almost all the way to the top. Again, this is on this side only, the remaining three sides are fine.

What baffles me the most is that both models are printed from the exact same gcode, so they should be identical. The only difference is that they were printed a week apart.

The fact that things could have changed doesn't bother me, but all the things I can think of would affect all four sides of the print, not just one.

I would focus on thinking about that geometry and what is different? Cable management? Some form of cooling or heating focused there? Something different in how the filament bends? Something different in the model?

For example, if while printing that side, there is more heat back there, the heat break might be warming up where the filament gets softer, and starts to clog. In other areas there is better cooling, so the filament does not clog. Is it warmer now than a week ago?

Is this a Spiral Vase? E.g. printed as one long continuous string.

Since we can't see your set up, I would think about the geometry, and what might be different on that side.

Well, I think I've finally solved it. I was using one of those printed vibration dampers. After you've mentioned the geometry, I went and checked them and indeed the back one was a lot "softer" than the rest. I guess this was causing more vibrations/wobbling when printing on the back side? I've replaced the damper with a new one and the problem seems to have gone away. I've only printed 2 more pieces, but they were both without those gaps.

I really appreciate you taking the time to offer your suggestions and helping me out and I'm glad we've been able to solve this issue.