First layer of print being destroyed by 2nd layer

pandelume · Post by **pandelume** » Fri Jun 05, 2015 10:11 pm

It's hard to tell what's going on in the picture - it's a touch on the blurry side. That being said, if what we're seeing is layer 1 and part of layer 2 on top of a raft then I think your issue is starting below layer 2. Just looking at the picture, it looks like layer 1 is not properly adhering to the raft or to itself - it looks like in the center of the print layer 1 is just a set of unconnected parallel strings when is should be a contiguous surface. It also looks like layer 2 may be dragging across layer 1 and pulling the unconnected strings up. Is that correct? I mean, is that what it looks like in person?

The odd thing is that it seems to combine two fairly common issues - bad adhesion on layer 1, which is often caused by underextrusion (or potentially by too tall a layer height), and dragging on layer 2, which is often caused by overextrusion (or too short a layer height). Maybe you have a loose drive gear or an issue in the extruder gearbox, which is leading to inconsistent extrusion. Or maybe after releveling the initial z offset has changed, leading to weirdness between the raft and layer 1. If it were me, I'd take a look at the extruder drive gear and gearbox, and if that looked fine I'd try printing without a raft to see if layer height issues appear in that case.

Redwizard000 · Post by **Redwizard000** » Sat Jun 06, 2015 1:45 am

pandelume wrote:It's hard to tell what's going on in the picture - it's a touch on the blurry side. That being said, if what we're seeing is layer 1 and part of layer 2 on top of a raft then I think your issue is starting below layer 2. Just looking at the picture, it looks like layer 1 is not properly adhering to the raft or to itself - it looks like in the center of the print layer 1 is just a set of unconnected parallel strings when is should be a contiguous surface. It also looks like layer 2 may be dragging across layer 1 and pulling the unconnected strings up. Is that correct? I mean, is that what it looks like in person?

Yeah that is exactly what it looks like.

I am going to try a few suggestions from here and repost the results.

Thanks all!

Redwizard000 · Post by **Redwizard000** » Sat Jun 06, 2015 1:50 am

pandelume wrote: The odd thing is that it seems to combine two fairly common issues - bad adhesion on layer 1, which is often caused by underextrusion (or potentially by too tall a layer height), and dragging on layer 2, which is often caused by overextrusion (or too short a layer height). Maybe you have a loose drive gear or an issue in the extruder gearbox, which is leading to inconsistent extrusion.

It always messes up in exactly the same way in exactly the same place. Even AFTER messing around with the bed level.

Another point of note, I am noticing a soft "clicking" noise when the machine is printing. As of now I haven't been able to pinpoint what part of the machine it is coming from. I don't know if it is related or if it was doing it before and I am just now noticing it.

I will take some better pictures

PcS · Post by **PcS** » Sat Jun 06, 2015 2:38 am

Check the extruder closely.

Redwizard000 · Post by **Redwizard000** » Sat Jun 06, 2015 2:42 am

OK I looked at the extruder. There is some plastic stuck around the nozzle, but it isn't obstructing anything. There is also a bit of plastic from the melted plastic spaghetti incident on the side of that silver part that is covered by the cloth. It also is not obstructing anything. I took the cloth off and under the cloth is perfectly clean. I moved the fans over and looked at the driver. The little grey plastic gear is in good shape and rotates smoothly if I extrude filament through it.

I cleaned the glass and I lubricated all the rails and the jackscrew. It seems like the parts are moving a little smoother now. I am going to try again...

jimc · Post by **jimc** » Sat Jun 06, 2015 3:31 am

extruder clicking is from:

temp too low
clogged or semi clogged hot end
extruding too fast
bed gap too tight.
filament dia too large and or tension bolt too tight squishing filament out of round.

if its clicking then its not putting out enough filament because the extruder is skipping steps. it cannot push the filament through the extruder. when the print fails is it printing a bottom layer or is it printing infill?

Redwizard000 · Post by **Redwizard000** » Sat Jun 06, 2015 3:36 am

Well this time it printed a small corner of the 2nd layer before it went to hell.

The first layer must be not printing correctly. It is all stringy instead of being solid. If I run my thumb down it all the loose strings move.

I don't know why it is suddenly doing this or how to fix it... I am getting really frustrated... I want to punch a kitten in the face!

Another perfect raft though. Tested it with a micrometer and it is the same thickness in all four corners.

I have attached a copy of the factory file I have been using. Maybe somehow something got changed in it. I have pulled one from a backup and it does the same thing though.

Redwizard000 · Post by **Redwizard000** » Sat Jun 06, 2015 3:38 am

jimc wrote:extruder clicking is from:

temp too low
clogged or semi clogged hot end
extruding too fast
bed gap too tight.
filament dia too large and or tension bolt too tight squishing filament out of round.

if its clicking then its not putting out enough filament because the extruder is skipping steps. it cannot push the filament through the extruder. when the print fails is it printing a bottom layer or is it printing infill?

I found the clicking.

The clicking sound is coming from a small washer on the horizontal motor belt thing. The one on the far left hand side. When the extruder assembly moves back and forth rapidly it makes the washer click. I don't know if it has always done it or if I am just now noticing it.

jsc · Post by **jsc** » Sat Jun 06, 2015 4:02 am

You said you attached a factory file, but I don't think you did....

Did you see if the extruder rotates at all in its mount? A cracked mount is a common failure mode.

Redwizard000 · Post by **Redwizard000** » Sat Jun 06, 2015 4:29 am

jsc wrote:You said you attached a factory file, but I don't think you did....

Did you see if the extruder rotates at all in its mount? A cracked mount is a common failure mode.

Must not have attached correctly. The mount is fine, I checked.

Anyways... I think all this drama has been caused by my inability to properly level a bed. 19th time might have been a charm. I am doing a test print just hard on the glass with no raft and it is printing fine so far. It is certain to warp in a corner after a few layers but if it gets that far I am going to try it again with the raft and see.

I think when that first print failed in such a spectacular fashion it must have driven one of the bed leveling screws back into its hole or something which caused the failure of subsequent prints. I must not have done a proper job of correcting it when I re-leveled after moving the printer.

I am going to be upset and extremely happy if after all this that is all it was. And it is nice to know that after a month, checking all the parts shows that my maker gear is in very good condition

I have such a hard time with bed leveling.

I am not calling the problem "solved" just yet, but I think I am getting there. This thread will hear from me again if the issue persists. Probably in an hour or so.

I would like to thank everyone for responding so promptly and trying to help me with my issue.

Also, can someone recommend a really good guide to easy bed leveling? I... really hate doing it and as it seems I am not very good at it.

First layer of print being destroyed by 2nd layer

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