Teflon insulator / nozzle head

[kometen]

Hi,

How far down in the nozzle head does the 2 tubes go?
All the way or should there be space a reservoir of filament in the nozzle head?

I have now had 3 incidents where the inner tube get smaller and squeze the filament.
Do you think that this can happen when the printer are doing many retractments due to friction between the filament and the tube?


/ Poul

[mhackney]

I have a new Rostock - received this week - and the hot end is different than I recall on the H-1-1. Let me show you what I have and then describe the other. In this new model, the smaller diameter inner tube slides into the nozzle. The inner tube protrudes from the outer tube by about 5mm:

[img]http://mhackney.zenfolio.com/img/s2/v73 ... 4072-3.jpg[/img]

Inserted the outer tube abuts agains the nozzle:
[img]http://mhackney.zenfolio.com/img/s8/v81 ... 4166-3.jpg[/img]

I recall on the H-1.1 nozzle that both the outer and inner tube slide into the nozzle and the tubes are the same length. Which version do you have?

[geneb]

I've got the same issue - old style nozzle.

Every time I change filament, I have to change the inner liner as well because the portion that's inside the nozzle has been necked down sufficiently to prevent filament from moving through it.

g.

[mhackney]

Gene, just to be clear - is your nozzle like the one I photo'd?

I think I've seen every permutation of SeeMeCNC's hot end and nozzles! I have all 3 printers and extra nozzles and hot ends as they were developed. This one I photo'd above is much more elegant and should be trouble free - especially coupled with the insulated PEEK design.

cheers,
Michael

[kometen]

Thanks for your answers.

I got the old type, then. So both tubes go down the nozzle then.

/Poul

[mhackney]

Yes, that's correct.

If I recall, if you make the inner tube a little longer it will create a better seal since the inside of the nozzle is a cone.

Michael

[geneb]

I've got the old style nozzle. The new on is on its way.

g.

[dbarrans]

I have the old style also, and it's already causing me calibration issues. I got my printer calibrated, then realized the nozzle was a bit loose and that if I moved it I'd have to calibrate again.

I wonder what specific problems the new nozzle was designed to fix. I can think of a few:

1) It allows a metal-to-metal contact for tightening it into the hot end, which means no recalibration is needed because it was removed for cleaning and reinstalled.

2) It has a different internal temperature gradient for better extrusion.

Any other speculation? Can SeeMeCNC add some insight here?

- dan

[Polygonhell]

The original allowed a metal to metal contact, if the liner was the correct length.
If I had to guess looking at it (and I don't have mine yet) it likely has a longer melt zone and possibly a shorter nozzle orifice this would reduce the force necessary to extrude and probably make fast retraction easier.

[Highcooley]

This is Steve Wygant's answer to my question about the benefits of the new nozzles and what influences the different changes in the design have:

"The benefit of the new no22le is that there is almost no ooze after retraction. It works so well, I decided to get them out to everyone who has supported us. The new nozzle has been shipping with Rostock MAX's since January 15th, 2013."
Thank you again, Steve! You guys are awesome!

Having the one of my new second extruder in hand, I can clearly see a longer melt zone but am not sure about a shorter nozzle orifice. What is obvious from the outer shape is, that the orifice is closer to the heating block and probably helps for a faster heat transfer. I can also imagine, that retraction through the longer melt zone works better, as no air can get sucked in from the side.

[kometen]

It would be nice to have one of those new nozzles. How do you communicate with Steven, I am not familiar with the organization at seemecnc?
/Poul

[Highcooley]

go to shop.seemecnc.com and see the top right informatiom.

[barnett]

I just ordered the new no22le.

Highcooley, do you think this new no22le will be too short for the LED light ring or is there enough room still?

[Highcooley]

I just ordered the new no22le.

Highcooley, do you think this new no22le will be too short for the LED light ring or is there enough room still?

With the LED ring alone, it will work, but not with the fan duct.

[barnett]

aw shucks! Your new duct design was on my project list for this weekend's blizzard. Maybe I'll do it anyway.

[Highcooley]

Don't have any good idea how to design another duct with this limited space. It needs about 1-2mm distance from the heating block in order not to melt. Maybe a solution could be, to build the ring larger to fit around the heating block. But then, it would have to be a closed ring design with holes to supply air to the other side of the ring. Or we could substitute the LED ring completely with a fan duct/LED combination. Inputs welcome...

[truenorthtrader]

I have the older cone nozzle it's oozing bad.

After every large print I have to take it out while hot and clean it out, it's driving me nuts as it's getting in the threads and I have to get up there with needle noze pliers and pull melted plastic out.

I tried lower flow rate but my prints are ratty and unuseable, when set to about 105 even it comes out the extruder.

[geneb]

It sounds to me like your temperatures are way too high. Have you double-checked the hot-end temperature with a standard temperature probe to see how it compares to what the firmware is seeing?

g.

[truenorthtrader]

No I don't have a temp probe I'll look into getting one.

I had it set to 240 for first layer and 225 for others and 70 first layer bed temp, 60 others as I was having problems with it sticking and tried everything, ABS juice,hairspray ( best so far ) even Stick glue.
I have the .365 nozzle.

Just lowered to 220 / 210 and it seems much better increased Fill Density to 0.3 from 0.2 and seems better already thank you!

[Highcooley]

aw shucks! Your new duct design was on my project list for this weekend's blizzard. Maybe I'll do it anyway.

Good news! Upon closer inspection, I figured out that the teflon tubes for the new nozzle are cut exactly the right length by default (on the add-a-struder). So the nozzle sticks out of the heating block for the same length as the old one did. This means, the new nozzle is intended to stick a few threads out of the block. If you manage to cut the tubes correctly, the fan duct will still work together with the LED ring.

However, I already managed to rip my fan duct off during bed leveling in positions close to the rim of the bed. It got caught in the extruder construction.It is reattached meanwhile but hangs a bit to one side Well, I guess in the end, we need a complete other soltuion together with the dual heads anyway.

[kometen]

Hi,

I found out that the inner tube must fit exactly in the length so it cannot move together with the filament.

I have fine result with hairspray. And it smells much better than ABS juice.

/Poul

[Highcooley]

Over the weekend, I switched over to the new nozzle. So far, I only had bad print results. The lines look all jittery and the infill is sparse.
The filament (PLA) sticks to the nozzle tip a bit more and gets dragged along the bed. So, perimeter start and end points sometimes don't connect (gap of about 0.5 - 2mm), so gaps start to form and get bigger and bigger. Probably that's also what makes the infill look bad.
I figured out, that the nozzle tip has a flat area around the hole. This is probably causing the drag.

Despite installing the new nozzle, I reset Z level (first 0.2mm layer is about 0.17 thick, like the old setting) and autotuned the PID settings. They turned out about the same. But the the hot-end temperature oscillates for about one minute after a temperature change (e.g. after the first layer is printed and I turn down from 205°C to 195°C). After messing with the I and D parameter for a while, I gave up for the moment. During my test prints, I manually lowered temperature by 1°C per minute to avoid the oscillating. Still, the results are pretty bad.

I figured out, that the new hot-end probably needs a higher temperature. At least, the results @ 200°C look a little bit better. However, the finished parts are useless due to all the gaps.

What are your results after switching to the new nozzles? Any other experiences with PLA in comparison to the old nozzle?

If I hadn't cut the two inner tubes, I would switch back to the old nozzle. But maybe I am just doing something wrong. THX for sharing your thoughts.

[dbarrans]

I installed the new nozzle at the same time as the Onyx, and I'm now struggling with making the first layer stick. I'm also getting more buildup on the nozzle causing problems.

- dan

[mhackney]

I found that the low curvature of the new nozzle makes it more apt to snag the layers at it moues around. See my build thread for more details but basically, add some Z Lift in slic3r (or whatever you use) to raise the nozzle before moving. Do this before spending time on the "stick" problem as drag may very well be what's causing that.

I started with 3mm and that works fine, I intend to decrease that until I find the minimum Z Lift needed.

cheers,
Michael

[Highcooley]

I'm working with Z lift in slic3r, which really helps a lot. Unfortunately, Kisslicer still doesn't support it. It was announced one year back. On the other hand, I love the way Kisslicer moves back a couple of mm along the last print path before moving fast. Unfortunately, the drag I am observing happens at the beginning of a new path and not at the end. And it starts to happen and increases after a couple of short parts with retraction in between (the filament looses pressure). With 7 mm retract, I am already at the lowest level before I get stringing. I think about priming the nozzle a little bit, but this would cause blobs in the cases where no drag would happen.