Bizarre: cracking all along a layer, exactcly where I have a construction plan

[lucagiorcelli 0]

My print cracks at the 100th layer, exactly where I have placed a construction plan in Fusion 360 (my modelling software). The second photo shows the 100th layer surface, that is more similar to a top layer, than a cracked layer.

It seems like my model had been sliced into two parts exactly where I've placed the construction plan.

What's the problem? Bad export from Fusion? Bad gcode? What else?

Edited March 20, 2016 by Guest

[gr5 2,210]

Did you look at the part in slice view? In fact could you upload your gcode file somewhere - I want to look at it. STL also if you can.

if indeed it skipped a layer (it happens) look at the part in xray view and if you see *any* red - even a tiny spot - that's probalby the problem - either a missing wall or extra wall.

[neotko 1,417]

If it isn't the print object try to print 2-3 times tall test cubes like 10x10x50mm tall and check if the error repeats.

[lucagiorcelli 0]

Did you look at the part in slice view?  In fact could you upload your gcode file somewhere - I want to look at it.  STL also if you can.

if indeed it skipped a layer (it happens) look at the part in xray view and if you see *any* red - even a tiny spot - that's probalby the problem - either a missing wall or extra wall.

 

Thanks GR5,

You can download the exact gcode of the broken print here:

https://www.dropbox.com/s/7exesss8awitbzp/aecc71be-ef68-4ffa-bc0d-ce4c2bb293cf.gcode?dl=0

I'm not able to reproduce STL because meanwhile I've changed the model. Opening the new model in Cura x-Ray at very large zoom, I can see red parts that could match with other construction planes, see below:

[gr5 2,210]

That red is normally a problem but it doesn't seem to affect your part so I guess you got lucky this time.

[gr5 2,210]

So I looked at the gcode in repetier-host (awesome free software) and there is nothing wrong with the gcode. Would have been nice to know 4 days ago.

So that layer underextruded. it's just a coincidence that it's on the layer with the hole in it.

It could be a filament tangle. That happens a lot to some people. Or it could be the Z stage is somewhat defective and fell more than it should. This happens to a lot of people who have both a bad Z nut and extra friction on their Z stage. If it's the Z stage it will probably happen at similar heights each time whereas a filament issue would be more random. So that might help you diagnose. Many people end up spending the bucks (4€ ?) to get a new Z nut with less backlash/play. Other's just put a weight on their Z stage to eliminate backlash. Consider cutting power and pushing the stage up and down many times and feel for irregularities. Don't oil the rods - but you can use oil and a rag - or wd40 and a rag to clean them if they are dusty. The z screw should have a lot of green grease on it hopefully already.

Some people loosen the 4 screws that hold the vertical bearings on either side of the screw and move it up and down a few times and re-tighten.

Sometimes simply moving the bed up and down 10 times is all you need to do to remove friction there.

[gr5 2,210]