Under-Extrusion ... but in only one spot on the plate?

Hello, 

I'm having a problem with my new Zortrax M200.  I've had the machine for a few weeks and it is totally awesome, but I'm starting to get some print failures. It started with a problem loading my third roll of filament (only using z-ultrat) and the extrusion motor started catching. I fixed this by cleaning the nozzle and cleaning the filament pathway.  However, I'm now starting to see underextrusion ... at only ONE spot on my printbed (see pictures). 

The entire print bed seems to be printing fine, except for this one spot? You can even see the spot in the raft picture (using a brand new nozzle). Does this sound like a cable problem to you fine folk?  Is the cable twisting in a certain way when traveling over this area? Or am I missing something?  

Thanks so much! Here are the pictures (hope I attached them properly). 

-Tim

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If I'd seen only the raft photo I'd suspect a high spot in the bed, which would be easy to check with a straightedge. But after seeing that last photo - yikes. Something's going on. How exactly did you clean the nozzle? There are places in there that can accumulate gunk that are not obvious. Just running a 0.35mm wire through the orifice doesn't clean the 1.8mm melt chamber behind the orifice.

could be ribbon cable / contact also. Probably filament drag on a certain angle caused by the feed tube

Please, to to print [url=http://library.zortrax.com/project/ribbon-cable-tester/]Ribbon cable tester[/url] and get back with results. 

Julia: The print failure happened with the original nozzle. I then removed the nozzle and dunked it in acetone for several days, cleaning it with the little wire.  I wasn't sure about my cleaning job, so I bought a new nozzle and installed that instead.  The raft failure photo is using the brand new nozzle, so I don't think the nozzle is the issue. I'll try the straight-edge check. thanks.

Countdigit: I hadn't thought of filament drag. I don't think that is happening, but I'm very much a neophyte to this process, so what do I know?  My money is on the ribbon cable, as the sticky holders keep coming off the back of my machine. I'll order a new one and try installing it I guess.

Marcin: Will do!

Ok ... the ribbon-test print just started, but here's a preliminary picture. The raft didn't print in one spot. I checked the platform with a straight edge, and there is a TINY bit of central bowing over the whole platform (the auto-calibration picks up 0.02) but not anything strange about this one spot. 

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So ... what do you think? Ribbon cable? 

Ok ... the ribbon-test print just started, but here's a preliminary picture. The raft didn't print in one spot. I checked the platform with a straight edge, and there is a TINY bit of central bowing over the whole platform (the auto-calibration picks up 0.02) but not anything strange about this one spot. 

attachicon.gif5.jpg

So ... what do you think? Ribbon cable? 

Most likely ;) 

Yeah ... I'll try ordering and installing a new one. If that doesn't work, it might be a filament feed problem. Watching the extrusion motor gear, I can see it hanging up when printing at these spots.  Unclear if electrical connection to motor or filament feed problem (though it's not making that knocking sound it makes when filament get's stuck during loading).

Thanks for the help everyone. I'll post my results here