Going thru step 15 now and assembling the printhead (with 2 nozzles actually) I can not help but wonder is the nozzle supposed to be so loose fit to isolator guide? Looking at the photo in manual and according to text you are supposed to tighten the nozzle with a wrench, but I can use just my fingers to do this! After adjusting the assembly length to 47mm, it doesn’t take much to turn the nozzle back and forth causing the set length to vary, especially after you attach heater block to it. Not mentioning how much it wiggles around with block attached.
Is this normal? Am I missing something? How come can the results be precise if the nozzle wiggles back and forth about 1 mm or so in both x and y direction? Maybe it settles a little bit after there is melt plastic and pressure inside, but still it is hard to imagine that this would result to accurate, precise action.
Hmm. Thanks for input, but I doubt that. Like I said, I never used a wrench, just my fingers. Threads look ok to me on both nozzles/isolators.
The nozzle does not wiggle as long as it pushes PTFE tube into isolator guide, but if it looses up even a little (which is very easy when heater block is attached) it begins to wiggle as I described. I’m tempted to re-cut the PTFE tube longer than 23mm so it would be possible to tighten the nozzle against PTFE lining and make the wiggle stop…
And please note, this is same for both nozzles. I’m confused.
Edit: As a picture is worth of thousand words, here are some photos of threads.
They are cut to correct length. I decided to disassemble the nozzle and removed the PTFE tube. Tubes measures 22.97mm and 23.03mm so I think they are close enough.
I decided to bite the bullet and cut new pieces of tube and against the instructions I made it longer than what would fit into ±0.25mm tolerances. I made it into 23.4mm. Again, I can screw the nozzle into isolator guide using nothing but my fingers (no wrench!) but this time when correct assembly height is achieved, the nozzle seems to tighten against PTFE inlining and lo and behold no more wiggle or wobble!
I don’t know if this causes trouble elsewhere but now I’m more confident about results. It would be nice if someone from Velleman could explain cause of this.
Alright. Now it becomes reality that you really, really need the nozzle to fit tight against PTFE lining. Having dual extruder configuration, I had to unscrew slightly the second nozzle to fine-tune the height match the height of first nozzle, meaning that it no longer didn’t sit tight against PTFE tube even though I did unscrew it less than quarter turn.
Now what happens, is that plastic is leaking thru threading over the heating block slowly but eventually it ruins everything:
Am I the only one experiencing this poor fitting? Feels like the threads of nozzle and insulator (isolator guide) do not match to each other at all.
Hmm. Not much of response from anywhere. Just to pass this info, I cut the PTFE tube marginally longer so that the nozzle will fit tight against it. I assembled and disassembled it again just to see how much of damage PTFE tube gets from tightening. With correct length, it’s snug and tight fit. I also went one step further and added some PTFE tape on threads.
Now after few days and lots of printing (biggest print jobs 10+ hours) it seems to hold and work well without trouble. No more leaking, yay!
I JUST did something similar tonight while overhauling my printer (it really is like a car, needing periodic maintenance), realigning pulleys to address belt grinding, tightening belts to address ovals which should be circles, etc.
During the stripdown I broke off the end of the filament inside the extruder, and it was too heat-bulged to come out on its own. I disassembled the hot end and removed the wayward filament. I noticed the short PTFE tube was browned on the edges, so I cut a new piece which I swear on a stack of bibles was the same length as the old one. But when I pushed it in, the nozzle wouldn’t screw down all the way flush. No problem, I thought, it just needs to compress, and I screwed tighter.
CRACK.
Right where the insulator sets into its metal holder on the printend. Not all the way around, so I tried superglue. And shortening the PTFE tube by a hair or two. This time everything went together flush, I put it all back together, and now I have a slow leak of melted filament onto the hotend when I print. So much for superglue. Fortunately I have a second extruder kit that I’ve been using as spare parts…
I am about to install the 2nd nozzle and was about to start a new post when I found this one.
I remember from the first nozzle (and when I had to replace it once…) that the 47mm meant a failry ‘loose’ nozzle as described earlier. How critical is the 47mm? The instructions say
but that seemed to be quite loose. I’d prefer to tighten it further and in fact reading thru the E3D installation it even advises to heat the nozzle and tighten it a little more. I don’t think that would work with the original nozzle but does suggest it ought to be pretty tight.
I must admit I’ve had no problems (leakage etc) with the current setup but I also realise it will be quite important to get the 2 nozzles the same length.
oh6fub - do you have any updates on your longer ptfe tube?
