Hi all - thanks for the many suggestions to help me fix this! 
After a lot of diagnostics, I believe I finally have solved the mystery. I’m now waiting on a replacement head from Pete, but he did authorize me to open mine up. I’m pretty skilled at such things so I didn’t see it as a huge challenge to perform.
Turns out my head had a “special” feature - there was a large glob of glue entirely covering one of the magnets at the top of the heat sink. This was not just a film but a rather thick piece that took some work to remove. Looking at the tight clearances, I think this restricted the head movement and at least at some point might have been stuck to the stop screw in the shell. No wonder why turning the cam by hand didn’t change the game! Once reassembled, and the cam at its far travel, I got a nozzle to work! And moving the cam completely in the other direction (after cooling/powering down/etc.) I got the other one extruding. But the motor drive that shuttles them back and forth is still unresponsive. My theory - the stuck head or restricted travel damaged the driver chip or the motor by overstressing them.
@Rudy The packing clips are printed at the end of the line on each machine using a sacrificial test bed as a test of all functionality after a commissioning process - this includes firmware flash, motors, heaters, electronics and valve tests, calibration and finally the assignment of a serial number. The clips themselves are printed on the default draft profile using the stock white PLA and its default profile.
On a side note, some of you may have noticed that the blue strapping tape used to secure the bed for shipping can sometimes stretch after a bit of a bump in the right direction, causing the door to be locked when unboxing, making it sometimes difficult to remove the tape. We’re planning to rectify this by modifying the PLA head securing clip to also secure the bed at the same time, removing the need for tape. It also needs to be printed as quickly as possible to test all functions in a minimum time… it sounds like another competition might be in order…
@clarkegn: How about heating up the head, and then, while still hot, remove the head with protection gloves and trying the hot needle trick again?
Hi @ijprest, I guess you’ve figured already but just trim off the filament back to the area where the extruder marks start, should solve the feed issue. As for the flow stopping, it may be worth manually purging the pla through the head a few 100 click to remove any bits of ABS that may be stuck in the head and attempting it again. Could potentially be some stray filament in the extruder (feed device) but that hasn’t been the case when I encountered the problem. Other than that I guess raise a ticket and see what Cel have to say on the matter, I’d be interested to hear what they suggest if it works
OK… I switched back to PLA, and ran a short job (about 1.5 hr on ‘normal’ profile). Same symptoms as before.
- The flow-rate was spotty by the half-way point, and stopped completely at about 70% completion (whatever was left in the heat chamber would ooze out and get pushed around, but no new filament was being introduced into the heat chamber).
- Removed the head; no apparent blockages.
- Could not advance the filament with the buttons in AutoMaker. Could retract and then go forward again, but couldn’t get past the point where it stopped.
- No skipping noises.
- With filament ejected, the “stripping” artifact was apparent on the filament (about 12-16″ from the head… presumably where the extruder gear makes contact with the filament).
-
This reply was modified 3 days, 9 hours ago by ijprest.
Attachments:
You must be
logged in to view attached files.
To disassemble the head enough to clear that would be a total strip-down… I really wouldn’t even consider doing that unless recommended by CEL, and that’d probably be only as a last resort.
I’d recommend getting some extra-fine needle-nosed pliers (as used in jewellery-making) and try again to remove that while the head’s hot. You should be able to get some that’ll fit in the hole, and they’ll have a lot more pulling power than tweezers. It might take a number of goes though.
If the filament snipping fixes it temporarily, it may be worth trying ABS if you have some @ijprest, just make sure you run a couple of purge cycles to completely remove all remnants of the PLA, bits can hang around in the heat chamber for a while and once its brought up to ABS temps it will be much more difficult to remove.
I can’t be sure as I haven’t used PLA much, but the odd time it happened to me it was as if the filament had bulged from the pressure and warmth if the head clogs temporarily (haven’t noticed it with ABS) . . just a theory though.
Tom: one more thing - when the filament is loaded, it comes out the right port (looking into the head mount, with the head removed). I’m assuming that is correct? - Eric
Just got my Robox. Followed the setup guide to the letter. Automaker installed OK, ran fine, found printer. It did not ask me for registration info on first run as the setup guide showed, but otherwise everything seemed OK.
So I loaded some filament - the white PLA that came with printer. When spooled to the head, it recommended a purge. I accepted this option. But no material ever came out of the nozzles. I know material was in the head, as I was able to eject the filament and see that the end was melted somewhat. I then tried the nozzle select buttons. I understand there is a motor inside the head that tilts them back and forth and adjusts the valves too. But no response was had - no motor noise, no nozzle movement. I powered down and removed the head. Clearly no white PLA ever was in the nozzle tips. I put the head back in, powered up, and manually heated the head to 215C. Tried the nozzle select again - nothing.
Any suggestions? I believe the head is defective, or at least the internal motor or controls to it. I did put in a support ticket, but this looks like a hard failure requiring a replacement head.
I’m experiencing something similar (filament not feeding), but I’m not sure it’s the same problem. Using the supplied PLA reel (haven’t tried ABS yet), I’ve had multiple prints “run out” of material half-way through because the filament wasn’t feeding into the head.
The first time it happened I assumed it was a blockage in the head, and went through all the purge & manual purge steps without success. It was only when I had the head removed that I noticed that my unit wouldn’t feed the filament far enough to reach the heating chamber! When I used the feed buttons in AM, there were never any skipping sounds (just the regular feed motor sounds), but the filament just stopped coming out. It would retract OK… hitting -20 or -100 would retract an appropriate amount of filament. Subsquently, hitting +20 or +100 would bring it back out to the same spot, at which point I couldn’t coax it to go any further. Even a complete eject/reload wouldn’t feed past this point.
I solved it the first time by ejecting the filament completely, trimming off the filament back to “virgin” material (i.e., without any of the little grooves from the feed mechanism… about 16″ I suppose), and reloading it. That seemed to solve the issue, and I got through 1.5 prints (about 3 hours) today before it happened again! Again, I remove the head and find that the filament just won’t feed any further. Same symptoms. No “skipping” noises.
I haven’t tried the eject/trim/reload trick again (I’ll do that tomorrow night)… but something about this seems wrong. I don’t believe the tube is blocked (the filament is already all the way through the tube anyway), so why does it just stop feeding in the middle of a print?
Not too sure if this is a beta only issue or not, but thought its worth suggesting that people fully power off the unit and remove the USB before removing or re-applying the head. It has caused a number of issue with Betas and it looks like other backers may also be experiencing issues which may have been caused by this.
ahh, an obvious thing to suggest, I presume you’ve tried already, but power off fully & unplug USB, remove and replace the head, you should hear a nice click when its in place, before tightening the screw.
It possibly sounds like a blown head mofset . . . . most important to fully power off the unit and remove the USB before removing the head otherwise it can get damaged . . . hopefully its something simple. . . ticket time I’m afraid, if the above hasn’t worked.
