Prusa Nozzle Released

Me and a couple of cousins bought a sell mendel and right off the bat we ruined the first hot end(thermistor fell out) One of my cousins bought a new (PTFE )hot ends and did some really nice prints with PLA. Well once my other cousin got ahold of it he wanted to try ABS and melted. He then bought a S.S one off of ebay and it kept plugging up and he ended up bending it. So now I am trying to do some research on what would be the best and what really works.
I wouldnt mine switching back and forth useing PTFE hotend for PLA and a S.S for PLA. I am just looking for one right now that will do ABS real well. What i have been reading here the Prusanozzle seems to be a good one. Just a little on the hesitant side $91+$25 shipping. I want to make sure I spend that kind of money wisely. Does everyone here give this a thumbs up? I would like to hear how it works for you.

I'm printing with PLA, and I'm obtaining great results after running Marlin auto PID and using the suggested Kp, Ki and Kd: since then, with a fan directly on the hot end, I'm not having anymore hot end clogs.

This nozzle is great: I manage to achieve great levels of details and reliability, even if I agree with the ones saying that the learning curve is quite steep: it took me several days to tune it properly, and even 2°C on extruding temperature can make the difference between a perfect print and a clog.

Just when I thought I have got the hang of it, I could no longer extrude ABS for more than 10 minutes without ending in a jam. Josef told me to use the fan on the top half of the extruder and mounting plate and that completely fixed the issue as I've got two-hour prints.

I used a single zip tie to fix the fan to the bottom of compact extruder.

what temp were you printing at?

290-310C works for my ABS, 280C or lower ends up in chewed filament.

wow that seems awfull hot. That sure would melt the ptfe hotend. Thats cool though that you are able to go that hot without melting anything else. The other night me and my cousin got his ebay all metal nozzle printing we had them temp up to 270C and we kinda melted the plastic where it mounts into.
Any of you try any other all metal hot ends?

Read the rest of this thread and the E3D thread for more info on the differences between an insulated hot end and and all metal hot end. The heat transfer properties between the two designs are the cause of the temp difference even with identical material. The melting you are experiencing could be due to the printed parts being PLA and not being able to withstand the heat. That's not uncommon and has happened to me as well.

i understand because of the heat transfer of the materials but 310c thats enough to melt my printer just thinking about it lol
Yeah your probably right about it being PLA, I'm not sure what it is

Please note that 300C is the measurement of the thermistor, located next to the heat cartridge. However, the filament won't reach such a temperature nor other metal parts of the extruder. The cooling plate on the top is around 50C at the same time without active cooling. Remember that stainless steel has poor thermal conductivity.

etkoehn Wrote:
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> wow that seems awfull hot. That sure would melt
> the ptfe hotend.

>pfte where



Thats cool though that you are
> able to go that hot without melting anything else.
> The other night me and my cousin got his ebay all
> metal nozzle printing we had them temp up to 270C
> and we kinda melted the plastic where it mounts
> into.
> Any of you try any other all metal hot ends?

I Should have said
That sure would have melted a ptfe hotend

Well I have to say that although this is a good all metal design, it really needs to be shipped with a fan and fan mount that attaches to the nozzle.

misan it looks like your using the I3EXT extruder the same as me.

with my prusa nozzle iv found a few things while printing ABS.

1. PLA extruder you can forget about it the top metal plate gets so hot with no fans that it will soften the extruder mount holes.

2. Having a fan using the standard I3 Fan mount blowing on the hotend sorts the above problem to a point but will cause a lot of ABS Warp. just a matter of turning fan speed down until you get best of both worlds.

3. With the I3 EXT iv found with all metal hotens the amount of force needed to push the filament is massive! and the MK7 gear will work loose on the M5 bold/threaded rod (even when using a flat) this will cause lots and lots of jams 10 mins into the print. (im currently trying some thread locker to see if it will solve the problem)

All above im using the prusa nozzle on a single plate i3 with ABS at 250C (marlin setting 1) (power level set at 128 in firmware) (max temp set at 300C in firmware)

Hi Enlightx,

PLA is something I still have to try. But other people have had their share of trouble. I guess that with a fun blowing to the top part of the hotend temperature should not be a problem unless it climbs through the inside of the hotend and filament. I just do not know.

I am using Josef's drive gears which are smaller diameter than MK7 (in fact you have to if using original extruder from vanilla repo as there is no room for thicker drive gears) with a flat in the M5 and a tight grub screw, that still has to fail its grip.

However, even with a fan, ABS extrusion finds a point from time to time where it needs more torque and the gear may end up chewing the filament (or the stepper skipping, but that is not causing a permanent fault).

Conversely to what seems intuitive to me, these moments where more torque seems to be needed happen at low extrusion speed instead of when speed is higher (infill in my current setup), so this has me puzzled.

I do use marlin too, config set to 1 too, power level set to 100. I can print a part flawlessly and then I may have one episode where extrusion starts to fail (I guess do to excessive extrusion force needed) that I may overcome just pushing the filament with my hand or that may end up in the gear chewing the filament (which would be a game over for extrusion).

All this happens with hotend temp at 300C, lower than 280C will be a no go in my setup (some pictures of it: [www.flickr.com] ) and my version of the compact extruder: [www.thingiverse.com]

Just when I am getting confident in my setup, a new chewing incident makes me wonder what I am doing wrong.

Edited 1 time(s). Last edit at 06/17/2013 02:32PM by misan.

jzatopa Wrote:
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> Well I have to say that although this is a good
> all metal design, it really needs to be shipped
> with a fan and fan mount that attaches to the
> nozzle.


Prusa includes a fan in the kits. The issue with including a mount is the variety of carriages and extruder designs. For example an i2 mounts the fan differently than an i3. I'd suggest the fan mount be included as a basic part of any printed kit as the design of the RP parts will largely dictate the mounting method.

For ABS Josef suggested me to blow air to the top half of the hotend and cooling plate, which I did and posted the zip tie method above. This way top half is below 30C.

I do not know if there is a better way but while helping it does not seem to rule out ocasional failure when extruding. I guess there is something else like retract speed/length, extruder acceleration or else that is causing trouble.

I would appreciate that any of you having a trouble free operation with the nozzle to share your configuration details.

misan with the vanilla extruder can i ask which driver pulley / gear you are using to grip the filament?

i printed the vanilla extruder but the MK7 gear does not fit. iv also see in the 3D assembly video made that it uses M4 threaded rod / bolt ??

it seems extruders are the main thing letting down the I3 at the moment i believe.

iv been thinking of going back to a gregs design but the newer i3ext style suits this printers layout so much better.

Since going to all metal hotends (prusa and E3D) iv found my extruder motor runs much hotter then before as it requires much more torque

also what retraction settings are people using ? im starting to think the nozzle may need no were near as much retraction of other hot ends ? im currently running 0.8mm @30mm/sec

Edited 1 time(s). Last edit at 06/17/2013 03:50PM by Enlightx.

Hi Enlightx,

The variant I mentioned above [www.thingiverse.com] should allow an MK7 gear drive. Same as sgraber's i3ext does.

With the vanilla extruder I am using a brass drive gear I sourced from Josef Prusa (10.18mm external diameter).


However, I did modify the vanilla part first so I can fit the new symmetrical mount. Next I did the other change so larger gear drives would fit too.

It uses M5 threaded rod (66m is what I have) with an M5 lock-nut (or a regular one with one drop of superglue) and two press-fit 625 bearings for holding the rod, plus one 608 for the idler.

Nozzle fixing screws are M3x12mm and idler screws are M3x40mm (four M3 nuts are needed too, plus a couple of springs, sourced from Ikea PRESSA for example).

I created a variant of Greg's extruder that have worked nicely for me: [www.thingiverse.com]

I am running 0.3mm at 15mm/s (but I feel 0.3mm might be a bit short but no significant stringing is happening on my prints).

Edited 1 time(s). Last edit at 06/17/2013 04:21PM by misan.

Thanks ill give that a try tomorrow .

i normally cut the back out of the extruder with a dremel and use a M5 nut to hold it all together.

Has anyone printer nylon with the prusa nozzle

Im trying to print for a few days with the prusa nozzle. No succes. Constant the extruder keeps slipping. Im at 300 degrees now rediculous temperature and still its getting stuck. I have the fan blowing at the mounting plate. On prusanozzle.org i see ABS is 260 degrees but even when I feed the fillament per hand its almost impossible to get it trough.

Anyone had a succesful (large 30 minutes or more ) print?

seems like no one wants to help you

I'm finally getting some consistant printing with the new Prusa hotend. I saw in other threads that all metal hotends DO NOT like to idle at all. I'd have to say that I agree. At present I'm printing ABS, and get the hotbet up to temp before I start the nozzle heating. I've wrapped the heater cartridge with ceramic tape, which is probably overkill, but we'll see.

If my parts come out this run I'll be working on going to dual extrude on Prusa nozzles. :-)

So if you are not printing, let the nozzle cool to ambient. Then bring it back up to print temp and try extruding 5mm. Btw, you might actually try backing the temp off a bit. With the ceramic tape I'm down to 260c from 270c. I still need to rerun the layer bonding test and see what temp this filament likes to run at.

Hope that helps!
Mike

mpandrex Wrote:
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> all metal hotends DO NOT like to idle at all.

yes and no, this is something that seems to be more common in 3mm than in 1.75mm, it is also comes down to the filament itself the color and how much starch has been added to it to bulk it up,

there are other considerations like speed at which the pla or abs runs through the hotend, any polymer starts to degrade while in it's molten state, which is why plastic in general can only be recycled so many times, so ideally you want to be pushing the filament through as fast as your printer can handle reliably,

ironically the tendancy for most people which experience problems with these all metal hotend seem to be to slow down, which can be counter productive

this is where the ultimate argument to 3mm vs 1.75mm starts ... but i digress ....

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-=( blog )=- -=( thingiverse )=- -=( 3Dindustries )=- -=( Aluhotend - mostly metal hotend)=--=( Facebook )=-

100% agree with the dont let is sit. I use 3mm and i have a nightmare with PLA or ABS if i let it sit. i now let it cool down and star the print when its ambient temp and its much better.

Iv got the new prusa fan mount blowing direct across the nozzel head now and its helps a fair bit with prints but i will still get skips during a print now and then for no reason due to high pressure in the nozzle.

Been playing again tonight with the nozzle.

iv had a temp coupler 1cm above the heater block measuring temps etc.

i find that i get jams when temp here goes above 60C

again if i let the hotend idle with pla in i cannot push filament when above 60C

iv just added a little ram heatsink and cable tied it to the lower of the hotend which im hoping should help.

Plan is to run some test prints over the weekend to see if it helps and also leave the couple attached so i can monitor the shaft temp while printing.

other then this i can see the problem being retraction speed as iv noticed if i retract 5mm then try to extrude 5mm i get jams.

Closing in on stable printing...

I had bumped up the print speed to 70mm/sec. Started getting jams again. :-(

I have dialed it back down to 50mm/sec and it seems to be stable. The variable of quality filament should be addressed in the next week or two when I get some new material. Can't wait to be printing with something that "didn't" come from China.

Running ABS at 260c. I'm not doing any retraction, which means I've got a bit of drool thread. I'll try dialing that back in over the weekend.

I was also getting stable printing with PLA at 220c at 50mm/sec. If I have a successful weekend printing I'll get more detail posted.

I setup a fan pointing at the barrel and now I have had 2 really good prints. I went to start a large print just now and got a jam. The key for my setup has been pointing a fan right at the barrel and making sure I set the right fan speed settings in KISSlicer. I think the jam was because I tried to slow down the fan and it didn't have enough airflow.

I now have what looks to be stable system. Still some work to do, but the nozzle seems to be happy.

What I have is an aquarium pump running into two hoses that have small tips inserted to direct the air in a small stream at the base of the nozzle just above the heater cartridge. A small fan is ziptied above that moving more air across the stainless steel higher up.

Originally I was using these to jet air at the nozzle on our J-head extruders. I haven't played with moving one back down to hit the material as it leaves the nozzle yet. I'll work on that later this weekend if I get the time.

I have retraction set at 0.5mm at 70mm/sec speed. This really cleaned up the drool and doesn't seem to lead to jams.

I have also noted that I'm not seeing the jams if the machine sits for very long like I was before. The caveat is that I'm printing ABS at the moment and not PLA. Again, I'll try to get to the PLA later this weekend if I have a chance.

Hope this helps.

Thought i had mine sorted but just failed around 10 mins into a single wall print i thought my main problem was retraction but with no retraction on a vase print (const rising Z) retraction is not my problem.

I seem to have trouble just using this nozzle slowly again heat creep around 10mm up from heater block. Really hope we can get it reliable as its so detailed a print that comes from it.