Layer Offset Fail  

Re: Layer Offset Fail

Have you tried a demo model like the Prusa Logo since this print?

It looks like there are a couple of problems...

looks to me like under extrusion, and misalignment of upper layers probably due to the nozzle catching on filament already on the build-plate...

was this sliced with Prusa Slic3r? was it set for the correct Filament type?

regards Joan

Re: Layer Offset Fail

Definitely looks like under extrusion. Is this the first model you've sliced yourself? Check the filament diameter setting in your slicer is set to 1.75mm.

Re: Layer Offset Fail

I would go first and check on the layer shift. Then you can check slicer settings and extrusion. The shift is most likely not caused by them.

Is the X belt tight?

I would check the X-Motor: It might be that when you tensioned the belt, you did mount the motor correctly. That can happen easily due the tension. It fells tight but the the motor is no not correctly aligned. (I did this once ...)

The next thing is the X Pulley check if it is tight and in correct position (flat of the shaft).

There might be plastic in the X printed parts check them all if something is catching the belt.

Re: Layer Offset Fail

I bought this printer assembled, so chances are that it's not a problem with the X-axis stepper or belt tension - though you never know. I might check that later. But first, I think I might see the issue. This is the second model I sliced myself, but I noticed the one before this catastrophic fail looked kind of sparse compared to the models I'd printed off the included SD card, which were flawless. I used Cura, with the built in settings for the Prusa i3 MK2. But looking more closely, I see that the material diameter comes set at 2.85 mm.

Re: Layer Offset Fail

Use the Prusa edition of Slic3r

Prusa have invested a lot of time and money improving it for their own printer...
there are two configurations, one for the Mk2 and Mk2S
and a different one for the multi media version...

make sure you choose the correct one.

best wishes, Joan

Re: Layer Offset Fail

Thanks, everyone. It was the filament diameter setting in Cura. I had assumed that the Prusa i3 MK2 presets would be just right for my machine and hadn't even lanced at them. Serves me right. I took your advice and used the Prusa edition of Slic3r, and now it's printing perfectly.

Re: Layer Offset Fail

Uh oh - not so fast. After switching to the Prusa edition of Slic3r, I had one flawless print. Then came this one:

https://drive.google.com/open?id=0B0h8tuF7pBGyakxQc2xmQnVxSm8

The first layer went down well, and many more before I left it for the night. This morning it looks like this. I does seem like both the x and the y axes somehow got shifted a couple of times during the print, giving this sliding-apart sandwich effect. There was also a big pile of spaghetti bhind the printer. But after the offsets, it seems like the printer went on to put down decent layers, ending with a fairly nice top layer, just about a 3/4" south and west of where the first was put down.

Again - I bought this assembled, so I'm confident it was put together properly. Does anyone have a suggestion of what to check?

Re: Layer Offset Fail

Is the cable bundle that comes out the back of the extruder being held level with the extruder, or does it sag down?

Mine came loose a bit, and at higher Z values, would catch on the print below causing it to shift in either X or Y depending on what movement was happening when it caught. I simply attached it better and check on it. Hasn't happened again.

Re: Layer Offset Fail

Also check belts and motor as mentioned above. Even thought you purchased it assembled, sometime things shift in shipping.

Re: Layer Offset Fail

Thanks for the advice. Belts look good, and the bundle of cables reaching the bed and the extruder don't seem to bump each other too awfully much. I watched very closely this time, and I think I see the problem. I had a gear with a little inner flange that I had accidentally put face down on the bed when was plating the parts in Slic3r. It was such a tiny little lip, I hadn't noticed it, and I thought I had a ice flat surface on the bed. Instead, that little inner flange laid down just fine, but the whole rest of this fairly large gear was overhang with no contact with the bed. I'm sure it had warped up and caught the hot end on several occasions during the last print, making for the staggered layers.

Or so I hope. Again, thanks for the input. Signing off, at least until I find the above wasn't he reason...

Re: Layer Offset Fail

Just had this exact problem with layer shifting this morning. I've had my printer since April and printed lots of things succesfully but I've never had one fail like this. This was the second time printing this model, first attempt had to be cancelled as the model began to lift on the corners. I was able to get further along in the first attempt before I cancelled it.

First attempt:

Layer shifting on second attempt:

Both sliced with Slic3r 1.34.1 Prusa edition. Both were printed at 175% speed, successfully printed lots of things at 150% but I may have pushed it too far.

I'm hesitant to start it up again to waste the PLA and time until I know why it went wrong.

Re: Layer Offset Fail

That looks like the same problem, but maybe a different cause. In both cases, though, something seems to have caught the extruder momentarily and pulled it out of its orientation. In my case, I'm pretty sure it was a curled-up edge of one of the pieces on the bed that didn't adhere But your part doesn't look the same. Are your belts tight? By the way - I'm not really one to give advice. I'm quite a newbie myself.

Re: Layer Offset Fail

Thanks, any advice welcome.

I did notice on my first print that a small piece curled up and made a little noise when the extruder passed by it, I inspected the second failed print and there is nothing stick up that would likely catch it. Did a different print yesterday evening and it completed fine so I've started this one again at a lower speed. It's getting to the point where the second print failed so i've got my fingers crossed and I'm watching it closely.

Re: Layer Offset Fail

But wouldn't whatever pulled he extruder out of whack have been buried under the subsequent layers? Since your print ended up with the top layer intact, whatever caused the offset if probably pretty hard to spot, underneath everything that came later. That's why you're doing the right thing to stay really close and watch for clues as it happens. Hard to be there constantly for an eight hour print, though.