Ditto, E3D have informed me that they are sending replacements, and would like to see the others back for checking. I can't fault their service, given that I only sent them an email asking them to investigate, I did not ask them to do any more than that. And that is why I go with them for my hotends, not clones
Hi Mike, To be honest, and given the advice by E3D about the possible impact that the lower thermal conductivity of steel nozzles might have versus the wear resistance, I actually didn't notice any difference in the way it behaved against it's brass counterpart on the printer. I swapped the nozzles across extruders and hotends - no difference in the way they behaved, both feedpaths (filament > extruder > bowden tube > heatsink/heatbreak/nozzle) suffered exactly the same issues. Interesting to see that the later versions of Marlin now allow you to enable a hotend temperature increase to allow for increased flow rate, to compensate for the heat removed by the filament. Just finished crashing my aluminium bed several times trying to upgrade to Marlin 1.1.1 and auto-bedlevelling. "Hey, but that's part of the learning curve for 3D printing" - Ohhhh Yeahhhh!!!! in spades
I might have spoken too soon... Still no further word from E3D, and no nozzles, nothing further on the process of getting them exchanged either. So, fed up with having to run all my prints at extended print durations, I decided to drill out the suspect nozzles to 0.4mm. The brass nozzle was no problem. I figured it would probably work if I used the hardened guitar string as a drill. I filed the tip of a section of the 0.4mm wire to a wedge shape, stuck it in the drill, and voila, 30 seconds later it opened out the nozzle diameter to 0.4mm. The hardened steel nozzle was going to take a bit more finessing. I heated the nozzle to cherry red, and let it cool slowly to anneal it. A fresh bit of guitar wire, some filing to make it a pseudo drill, and the application of some jewellers rouge polishing paste, plus a lot more time did the trick. So now I have 2 nozzles at 0.4mm, how did they print? Great, all my problems with them before had gone - the extruder jamming, under-extrusion, failed prints - all disappeared. I can now print with the nozzles at 0.25mm layer height (actually recommended by the Reprap Calculator https://nathan7.eu/stuff/RepRapCalculator/RepRapCalculator.html#PrintSetup), print quality is good, and print times are now back to sane. If E3D want these nozzles back for testing, that's kinda tough, but I have proved, to myself at least, that there was a problem with them.
UPDATE: Lawson contacted me, it looks like the order went astray. Lawson has subsequently sent out replacement nozzles, which arrived in quick time. Just have to find some time during the day to replace what is on the printer, and give the new nozzles a run Thanks E3D and Lawson for the Customer Service
