Unintended Lip on Vertical Holes

See how each hole as a little lip around it? It's like a little build up of filament. This photo makes it look like it's as pronounced on the right as it is on the left, but it's really not. I would say the right is only 10% as high as the left. You can barely feel the lip on the right one. Is this maybe caused by over extrusion?

The echo of crickets in here is awful.

it's a hit and miss community. I've asked questions that have gone unanswered.

Do you have extremely low acceleration? Maybe none at all? Are you belts tight? It couldn't be from too much weight, else there would be ghosting. Are you printing PLA without a fan?
Help is better given when more details are available.

Edited 1 time(s). Last edit at 08/12/2014 04:00PM by MrDoctorDIV.

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Realizer- One who realizes dreams by making them a reality either by possibility or by completion. Also creating or renewing hopes of dreams.
"keep in mind, even the best printer can not print with the best filament if the user is the problem." -Ohmarinus

Do you have extremely low acceleration? Maybe none at all?
I haven't ever turned it on.

Are you belts tight?
There seems to be differing opinion and lack of specification on belt tightness.

It couldn't be from too much weight, else there would be ghosting.
Carriage + hot end + extender + motor + fans?

Are you printing PLA without a fan?
Yes, I'm printing PLA. I have one fan blowing on the upper part of my j-head and one of those doughnut ducts that goes around the hot end with a 40mm high velocity fan out of a server that blows on the part. That fan is triple thick and will take your finger nail off. (Found this out the hard way. Had to print a protector for it.) Surprisingly not as much air comes out as one would expect with such a high CFM fan. I think it has to do with the blade angle on the fan not playing nicely with being compressed into the doughnut. It blows out and away more than straight ahead. However, I believe it's putting as much air down there as normal size 40mm fan would.

So I'm guessing that 1, 2, and 3 have to do with the inertia of the print head and everything attached to on the X carriage; when the direction changes the inertia carries it past the end of the line. Now that I think about it I really have this on any outside corner. It's just more pronounced on the holes for some reason. My belts might be loose by some peoples definition; should I give tightening them a go first?

Hm, I would skip on the belts for now, so long as you don't see any out-of-axis movement [bouncing, moving of the idlers, etc] and so long as your printer is basically tuned. Loose belts, in my experience, offer uneven walls that are irregularly jagged. A different issue.
I would start by turning on acceleration, you do have enough weight and at a second closer look you also have ghosting that proves it is inertia. People typically start at 9000mm/s², but if you're anything like me you should start at 5000mm/s².

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Realizer- One who realizes dreams by making them a reality either by possibility or by completion. Also creating or renewing hopes of dreams.
"keep in mind, even the best printer can not print with the best filament if the user is the problem." -Ohmarinus

And if it's in the budget and mechanical inclination, an upgrade to bowden would rid of ghosting almost indefinitely [it's still possible, but I have never seen, nor heard of a case of ghosting with a bowden setup.

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Realizer- One who realizes dreams by making them a reality either by possibility or by completion. Also creating or renewing hopes of dreams.
"keep in mind, even the best printer can not print with the best filament if the user is the problem." -Ohmarinus

I would start by turning on acceleration, you do have enough weight and at a second closer look you also have ghosting that proves it is inertia.
So the idea here being that it slows down when it get to the edge of the layer, which will reduce the inertia to help mitigate the overshot?

Loose belts, in my experience, offer uneven walls that are irregularly jagged.
If you mean each layer being offset from the others, yes I do have just a touch of this left. You can see it in the pic. It looks like a changing gradient over length of the whole part. Various improvements in the printer over time have removed 70% of it.

And if it's in the budget and mechanical inclination, an upgrade to bowden would rid of ghosting almost indefinitely
I have been looking at the bowden since just after I got my Prusa i2 built and started trying to tweak it in. I never have liked all that weight moving around. I'm in the process of building an i3 now and was really considering it, but didn't want something new to deal with while trying to get it running. I think I will switch over after I get it running at least as well as the i2.

Are you calling those lips ghosting or can you see an impression of the hole echoed on the flat of the part. I can't really see the echo in this pic, but on some other wider ones I have observed it.

Edited 2 time(s). Last edit at 08/12/2014 05:35PM by appdev007.