I have an issue with an 0.2mm height difference between the left & right side nozzles. I’d appreciate your feedback on this.
Recently, my right side nozzle was clogged up so severely, I had to disassemble it in order to get the mess properly cleaned. In itself, that worked perfectly, no problem there.
However, after re-assembling, I now find that the nozzle end of the right side nozzle ended up 0.2mm higher than then the i[/i] left nozzle. And - to be honest - I can’t see how that could be, as the components all have fixed lengths?
Now, there always had been a very minor difference in height between the nozzle ends - but that never was an issue - the printer worked perfectly. Now, however, when I have the correct height set for the left nozzle, the right hand side’s PLA isn’t sticking to the bed: it’s too high.
As a result, I now tried to middle the nozzles out, where both nozzles are 0.1mm off their optimal height of 0.35mm:
Left side nozzle height = 0.25mm
Right side nozzle height = 0.45mm Heights measured with feeler gauges, with 0.05mm increments.
This is giving me an acceptable result, when using the heads seperately - but I am yet to see how this might affect a dual head print job. After all, a height difference of 0.2mm is 2 “normal” layer heights: so it’s fair to expect that this would have a negative impact.
Does anyone have experience with this? And is there a way to solve it?
I guess, in the worst case, I could use a whetstone (manual grinding tool for knives & such) to grind the left side head back for 0.2mm, but that might call up other problems…
I had a lot of problems with a clogged nozzle. Trying to fix it, I’ve found a deformed plastic washer which moreover caused different nozzle height.
I replaced all washers and tightend the screws very slightly. After that there were no problems with clogged nozzles anymore and the height of both nozzles ist perfect.
to my experience a height difference in the nozzles can be caused by uneven tightening of the screws(hotend1 vs hotend 2). But even more important is the length of that inner tube to be cut identical. each nozzle can be tightened untill it touches the inner plastic tube (can’t be tightened all the way).
You need to have equal length (up to 5/100 of a millimeter) of this inner tube by using sandpaper and caliper.
Just an update on this issue, of the different nozzle heights… It’s good news!
I’ve given this a lot of thought & finally found that I could only conclude that the difference as measured now must have been in the build since I first assembled it.
I tried to disassemble the nozzle & peek element, to verify the length of the tube inside, but the components are very resistant to disassembly attempts. Persisting to disassemble them would probaby only cause unacceptable damage.
Hence, I finally resolved today to take the whetstone to try & very carefully bring the nozzles to the same height, by grinding the longer one back. I figured, that if this wouldn’t work, I’d need to replace them anyway.
The brass nozzle grinds back really fast, so I quickly went a little beyond the 0.2 limit I had set out to grind off the longer assembled nozzle: so, I had to grind the other nozzle back something like 0.05mm too. But now, they’re both dead on: with the feeler gauge, I can’t determine a difference anymore.
I made 2 quick tests prints with both nozzles & both turned out just perfect: there is no quality loss.
So far, so good.
P.s.: As I noticed that - near the tip - the wall of the nozzle was really thin, I used the whetstone on the nozzle while the (cold) filament was still loaded. In this way, the filament would support the thin wall & prevent that it could collapse as a result of the grinding friction.
There isnt that much trouble to take it fully apart. I had ~0,05mm difference between mine and re did everything. You need a good grip on the isolater, i used a pipe wrench with rubber protectors and a used a spanner to undo the nozzle without problems. I made a jig for the PTFE tube so i could cut it in identical lengths. I also did thighten my hotends to hard first time i did assemble it so my plastic spacers lost its shape. I got a few extra with my second nozzle set so exchanged them. After this i cant tell any difference with a feeler gauge.
I also noticed that unscrewing the nozzle from the isolator requires a lot of force; which could damage or break the isolator. It’s mainly due to sticky resin from filaments that came between the threads.
remove the nozzle/isolator assembly but leave the heater and sensor wires attached so you can still heat the nozzle, when it’s hot you can easily unscrew the nozzle from the isolator (resin on the threads becomes soft again)
So, disassembly is possible after all - after experiencing how tight the components were “bound”, I didn’t dare to risk it. That’s good feedback, guys - thanks.
And you’re right - getting the heights of the nozzle assemblies correct is key: there should be no height difference. A jig is a good idea: at least, the both tubes would be the same, leaving no room for difference if tightened.
