Wanted to share an interesting diagnostic path I’m on with my Replicator 2:
- Started a high quality (default “high” settings in MW) print on a print surface that was a bit torn up from use.
- Three tries in a row, the print nozzle clogs / stops and I have to run the setup script to re-seat the filament in the extruder.
- Replaced tape + printed a lower res (15 infill, .27 height, 3 shells). The extruder is working fine.
I should have tried low res first then the tape, I guess. I will update as I learn more. This might be obvious common knowledge but I figured since I’m working through the issue I’d post the story for newbies.
Happened quite a bit for us in the beginning, and was largely due to levelling issues in our case
@Funbie_Studios Thanks for the suggestion! I’ll add that to my list. After this print I’m going to try a high-res print again. If it clogs up again, I’ll re-level. Did your clogs come from too little gap?
If you look around one of the upgrade parts for mb’s is a rather expensive glass bed, because the material used in a stock mbr2 is in most cases warped from the factory, if not it warps with N number of heat cycles. Imagine the stock piece you have as a bowl. That is what you are trying to level. Keep in mind I dont have a mbr2. But I read allot.
@Paul_Donovan - yep, when we had the build plate too high, sometimes it cause the nozzle not to be able to extrude properly and jams up the whole thing, leading to the need to unload and reload the filament. In extreme cases, we had to open the extruder mechanism to clear any pesky bits of filament left behind.
Now we always make sure to watch for the first 1,2 layers of print to be fine before we let the machine chug along…
@Addidis_no Yes you’re right, the default build plate being acrylic did warp for us, making the extreme left and right sides noticeably lower than the middle portion, leading to printing problems when it comes to the larger models.
To remedy that, we actually cut up a mirror (as a substitute for glass) and mounted it as a flatter replacement and it has been working great so far - http://funbiestudios.com/2013/03/mirror-build-plate-for-replicator-2/ … We’re still using tape on it though 
The first two layers are vital for any 3D printer. This is often why you would print with a raft.
The extruder has an immense pressure built up in there, and if the nozzle is too close to the platform (essentially it’s closed off) for too long, something will fail. This usually ends with the teeth digging a groove into the side of the filament, or “stripping out.”
PLA is another beast, and adds to the problem. Because if PLA’s low liquefying temperature, and large difference between the temperature where it starts to liquefy and where it’s actually soft enough to extrude, it will react to back-pressure more that ABS. Often, the heat will propagate back up the filament, making the inside of the extruder like a honey bear, and the pressure required to extrude at that pointy is impossible.
The best solution to this is the actually back the plastic out while it is molten, snip the gooey end off, and run fresh plastic through. Run a noodle for a few seconds, and you’ll be back up and running.
Never let the extruder stay heated too long when it’s “empty,” or it will solidify and truly clog.
Tram the platform carefully. Run a large print or a test print that covers most of the platform, watching the first layer carefully. You’ll see where it’s too close pretty easily, and you should be able to gently adjust the tram as it prints (carefully.)
@Rob_Giseburt Yup, this is becoming clearer with time. Thanks for the tip.
I ran a spool out mid-print so I’m going to load a new spool and run some more trials, but I think the issue may have been a small layer height (.1) + a print surface set too close. Therefore the first layer places the extruder too close to the surface. Does that sound right?
I think part of the issue is that the print surface is either warped or unstable (when the extruder is near the center during calibration, it is closer to the build plate than when the extruder is toward the outside).
Thanks very much for the tips, everyone. More details to follow later, in case anyone is interested.