Prusa Nozzle Released

Very hard to say which is the best nozzle because they all have different strengths and weaknesses and people give different weights to those. Very few people own more than one or two different types and everybody uses different plastics at different speeds on different machines, so hard to get any true comparative data.

This one has the advantage of handling very high temperatures (when fitted with a thermocouple) but it doesn't look like the easiest to push plastic through.It also looks like it would be very reliable as there is nothing to wear or leak, etc. It is also very expensive compared to say the E3D one, which is also all metal.

The Archol one prints very well by all accounts but is a bit fragile.

Edited 1 time(s). Last edit at 05/15/2013 09:25AM by nophead.

---

[www.hydraraptor.blogspot.com]

Quote
eikgnum
Where is arcol nozzle information?

Ever heard of Google?

---

Bob Morrison
Wörth am Rhein, Germany
"Luke, use the source!"
BLOG - PHOTOS - Thingiverse

Yes, 280 is hot. I started a print overnight at that temp. It held up about a quarter of the way through before stripping the filament. But before that I ran a few experiments.

First, I set the nozzle to 260 and extruded 100mm of filament at 2mm/sec. This went as planned, but as I stepped up the extrusion rate to 3 and then 4mm/sec the filament would strip. I repeated this process several times, cleaning out the hobbed bolt between temp changes. So I finally arrived at 280C which allowed me to extrude very quickly, which was nice. So that's where I settled. Granted, I could probably get away with 265 or 270, but I decided to go with a big print - Dizingof's dragon bowl. This probably wasn't a good choice, but we learn more from our failures than successes. So I sliced and printed it then went to bed. But before I did that I decided (stupidly) to gamble and turned my machine speed up to 150%. This was a mistake. Shouldn't have introduced the extra variable. Live and learn. Needless to say I woke this morning to a failed print which was sad, but not all that unexpected.

So why is the filament stripping? I've insulated the block to prevent heat from creeping out and up the barrel to the extruder. I'm using the supplied mounting flange, so any excess heat that makes its way up the barrel is sunk there. There is no visible deformation of either the carriage or extruder at this point. Also went and replaced my broken extruder to one that has two bolts instead of one, so there is plenty of pressure on the filament at the hobbed bolt. Ambient temp is ~ 40C, but this has never been an issue before.

So my next steps are:
1.) choose a suitable test object
2.) begin changing variables, starting with
- ambient temp (turn off heated chamber)
- clamping force at hobbed bolt (right now close max - too much? maybe I'm deforming the plastic?)
- hotend temp

Making progress!

---

- akhlut

Just remember - Iterate, Iterate, Iterate!

[myhomelessmind.blogspot.com]

Looks like you found the max feed rate by trial and error but perhaps didn't run it long enough for it to reach thermal equilibrium. My early experiments with stainless barrels taught me it takes a long time for the heat to propagate in SS.

I have to say I am surprised it works at all with no obvious sharp thermal transition. Presumably it is because the inside is highly polished.

---

[www.hydraraptor.blogspot.com]

Quick note so far:
VERY different nozzle than what we are used to. Ours was a brass body with nicrome wire wrap. We had a fairly large melt zone. A PEEK insulator was used and our top end we limited to 250C. Removing filament was done when the nozzle was hot.

With this one, I need to remember to let the nozzle cool before trying to remove the PLA.

Right now we are mostly running PLA, though I'll be trying some ABS shortly. First pass at cooling the body was not enough and we had some extrusion challenges (filament stuck in barrel). I think I have that sorted out and will try another print.

Other than that, looking forward to seeing how fast we can push the machine. :-)

akhlut Wrote:
-------------------------------------------------------
> Yes, 280 is hot. I started a print overnight at
> that temp. It held up about a quarter of the way
> through before stripping the filament.

You are much braver than I am. I don't think I could sleep next to a brand new hotend running at 280C. Or at least have nightmares of the heater screw working itself loose and the heater dangling around on a couple pieces of wire. I'm only printing PLA at max 200C, and the hotend can leave a nice burn mark in the painters tape if I park it at z=0 for a couple seconds. Please be safe.

nophead,

yes, that was my goal. I'm not a programmer or engineer, but I do like to move in a methodical manner when approaching new things. I would have liked to collect the data from pronterface (length, rate, temperature) for each extrude, but didn't want to invest the time in doing so. Would the arduino serial monitor have worked to collect that data?

lajos Wrote:
-------------------------------------------------------
> You are much braver than I am. I don't think I
> could sleep next to a brand new hotend running at
> 280C. Or at least have nightmares of the heater
> screw working itself loose and the heater dangling
> around on a couple pieces of wire. I'm only
> printing PLA at max 200C, and the hotend can leave
> a nice burn mark in the painters tape if I park it
> at z=0 for a couple seconds. Please be safe.



Not to worry. I've got a smoke detector installed in the cabinet, and the entire setup is on a kill switch. Add to that it's in a fairly well sealed box, so a fire might snuff itself out once it runs out of oxygen. Also, the only thing in the cabinet that's combustible is the cabinet itself.

What bothers me at night is the noise.

---

- akhlut

Just remember - Iterate, Iterate, Iterate!

[myhomelessmind.blogspot.com]

akhlut Wrote:
-------------------------------------------------------
> nophead,
>
> yes, that was my goal. I'm not a programmer or
> engineer, but I do like to move in a methodical
> manner when approaching new things. I would
> have liked to collect the data from pronterface
> (length, rate, temperature) for each extrude, but
> didn't want to invest the time in doing so. Would
> the arduino serial monitor have worked to collect
> that data?
>
> lajos Wrote:
> --------------------------------------------------
> -----
> > You are much braver than I am. I don't think I
> > could sleep next to a brand new hotend running
> at
> > 280C. Or at least have nightmares of the heater
> > screw working itself loose and the heater
> dangling
> > around on a couple pieces of wire. I'm only
> > printing PLA at max 200C, and the hotend can
> leave
> > a nice burn mark in the painters tape if I park
> it
> > at z=0 for a couple seconds. Please be safe.
>
>
>
> Not to worry. I've got a smoke detector installed
> in the cabinet, and the entire setup is on a kill
> switch. Add to that it's in a fairly well sealed
> box, so a fire might snuff itself out once it runs
> out of oxygen. Also, the only thing in the
> cabinet that's combustible is the cabinet itself.
>
> What bothers me at night is the noise.

Same here, I cant run a print at night while im sleeping, i just keep getting up to watch it haha. perhaps there is a good way to insulate the box, by using sound absorbing foam. it would probably also make the build chamber more insulated heatwise.

akhlut Wrote:
-------------------------------------------------------
> Yes, 280 is hot. I started a print overnight at
> that temp. It held up about a quarter of the way
> through before stripping the filament. But before
> that I ran a few experiments.

Can you post a pic of the setup, can the air flow under the carriage? That is kinda needed if you want passive cooling.
If not, try experimenting with the included fan.

I print here at 245°C. But as I stated, heat was somehow misteriously travelling to the hobbed bolt, so I cool the bolt.

Also I noticed It doesnt like extremely quick retracts. Which isnt big of a problem as I noticed, the nozzle doesn't really ooze that much. Try setting your retract to 8mm/s and 0.2mm lenght.

Cheers
Jo

nophead Wrote:
-------------------------------------------------------
> Looks like you found the max feed rate by trial
> and error but perhaps didn't run it long enough
> for it to reach thermal equilibrium. My early
> experiments with stainless barrels taught me it
> takes a long time for the heat to propagate in
> SS.
>
> I have to say I am surprised it works at all with
> no obvious sharp thermal transition. Presumably it
> is because the inside is highly polished.

Do you have some time to test the nozzle? I can send you some goodies ;-) If so send me an email to info@prusaresearch.com

Jo

prusajr Wrote:

> Can you post a pic of the setup, can the air flow
> under the carriage? That is kinda needed if you
> want passive cooling.
> If not, try experimenting with the included fan.
>
> I print here at 245°C. But as I stated, heat was
> somehow misteriously travelling to the hobbed
> bolt, so I cool the bolt.
>
> Also I noticed It doesnt like extremely quick
> retracts. Which isnt big of a problem as I
> noticed, the nozzle doesn't really ooze that much.
> Try setting your retract to 8mm/s and 0.2mm
> lenght.
>
> Cheers
> Jo


Received mine today (0.4).

Very nice part but the setup is not easy. Unlike a J-head who will print badly, but will print, this one seems to work only in
a narrow range.

Dont like at all to run too slow, which makes slowing for small layers akwards.

Now, the PLA i tested ooze really a lot at 230°C. The same plastic dont ooze at all with a J-head at 215°C.

tested extrusion speeds in air north of 180 mm/min (3mm/s !) without problem, and this with translucent PLA which is one I was slowing my normal settings for. Backpressure is high though, you need a lot of pression and a good hobbed bolt.

Results are very promising so far.

Bought that hotend for nylon, need to order some quickly

alj_rprp Wrote:
-------------------------------------------------------
>
> Received mine today (0.4).
>
> Very nice part but the setup is not easy. Unlike
> a J-head who will print badly, but will print,
> this one seems to work only in
> a narrow range.
>
> Dont like at all to run too slow, which makes
> slowing for small layers akwards.
>
> Now, the PLA i tested ooze really a lot at 230°C.
> The same plastic dont ooze at all with a J-head at
> 215°C.
>
> tested extrusion speeds in air north of 180 mm/min
> (3mm/s !) without problem, and this with
> translucent PLA which is one I was slowing my
> normal settings for. Backpressure is high though,
> you need a lot of pression and a good hobbed bolt.
>
>
> Results are very promising so far.
>
> Bought that hotend for nylon, need to order some
> quickly

What machine do you run it on?

Jo

prusajr Wrote:
-------------------------------------------------------
> Can you post a pic of the setup, can the air flow
> under the carriage? That is kinda needed if you
> want passive cooling.
> If not, try experimenting with the included fan.
>
> I print here at 245°C. But as I stated, heat was
> somehow misteriously travelling to the hobbed
> bolt, so I cool the bolt.
>
> Also I noticed It doesnt like extremely quick
> retracts. Which isnt big of a problem as I
> noticed, the nozzle doesn't really ooze that much.
> Try setting your retract to 8mm/s and 0.2mm
> lenght.
>
> Cheers
> Jo

I had thought about this today as well. I've lowered the jerk and accel on E to see if that helps. 0.2mm retract set at 7mm/s.

[i.imgur.com]

There is little air flow, so that may be an issue, but then again...

I took some measurements. @ 265C the top of the SS barrel reads a comfortable 46C, @280C I get 51C. With the ceramic insulation the heater block is *almost* cool enough to touch at 280C, which is kind of crazy.

I've also moved the heater block down so that the bottom rests on the tip chamfer. Now that the melt zone is closer to the tip I may get better results (hopefully).

[i.imgur.com]

[i.imgur.com]

[i.imgur.com]

Printing reliably at 270C now. 260C was a little too cool.

We'll see in a few hours.

---

- akhlut

Just remember - Iterate, Iterate, Iterate!

[myhomelessmind.blogspot.com]

akhlut Wrote:
-------------------------------------------------------
> prusajr Wrote:
> --------------------------------------------------
> -----
> > Can you post a pic of the setup, can the air
> flow
> > under the carriage? That is kinda needed if you
> > want passive cooling.
> > If not, try experimenting with the included
> fan.
> >
> > I print here at 245°C. But as I stated, heat
> was
> > somehow misteriously travelling to the hobbed
> > bolt, so I cool the bolt.
> >
> > Also I noticed It doesnt like extremely quick
> > retracts. Which isnt big of a problem as I
> > noticed, the nozzle doesn't really ooze that
> much.
> > Try setting your retract to 8mm/s and 0.2mm
> > lenght.
> >
> > Cheers
> > Jo
>
> I had thought about this today as well. I've
> lowered the jerk and accel on E to see if that
> helps. 0.2mm retract set at 7mm/s.
>
> [i.imgur.com]
>

Is the mounting plate completely hidden? Can you put it under, so its exposed? I should put on the website that it acts as heatsink o.O

That will move the melt zone bit lower and make it more reliable. Also try to use fan, just for fun sake, you carriage looks like it traps all the heat in nice pocket under the carriage :-)

prusajr Wrote:
-------------------------------------------------------
> alj_rprp Wrote:
> --------------------------------------------------
> -----
> >
> > Received mine today (0.4).
...
> > Now, the PLA i tested ooze really a lot at
> 230°C.
> > The same plastic dont ooze at all with a J-head
> at
> > 215°C.
> >
> > tested extrusion speeds in air north of 180
> mm/min
> > (3mm/s !) without problem, and this with
> > translucent PLA which is one I was slowing my
> > normal settings for. Backpressure is high
> though,
> > you need a lot of pression and a good hobbed
> bolt.
> >
> >
> > Results are very promising so far.
> >
> > Bought that hotend for nylon, need to order
> some
> > quickly
>
> What machine do you run it on?
>
> Jo


Beta prusa ( an i2 variation). I Know that one wont be able to move fast enough for this extrusion, but I'm designing an extremly sturdy xy table actually.

well...i am waiting for plans, then i will try to make one

is it known when the plans will be relased?

woo Wrote:
-------------------------------------------------------
> well...i am waiting for plans, then i will try to
> make one
>
> is it known when the plans will be relased?


he has released a rough drawing on his site, however if anything i would urge him not to release it at all, given that the moment he does every clone shop will be in on it to make a quick buck with no actual contribution to the reprap community,

i gotta ask though why on earth would you try and make it? why not just buy one, even reprapdiscount.com has them

---

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thejollygrimreaper Wrote:
>
> he has released a rough drawing on his site,
> however if anything i would urge him not to
> release it at all, given that the moment he does
> every clone shop will be in on it to make a quick
> buck with no actual contribution to the reprap
> community,
>
> i gotta ask though why on earth would you try and
> make it? why not just buy one, even
> reprapdiscount.com has them


1) Polishing a small hole inside SS is not trivial. Polishing a blind hole is a mess, for average hobbist.

2) The forums will be flooded by "I am trying to make a prusa nozzle but it doesn't work - help".

3) If Prusa himself took months to find an acceptable quality finish... the average mee-too will take years :-)

4) Given correct tools and knowledge it can be made. But even at industrial level it is not cheap...

5) Moral: DON'T think to buy/make a CHEAP prusa clone. It will ruin your day :-). Buy the real one, or any other design that has a REAL knowledge built-in.

Bye
Davide

---

==============================
no toys here...sorry

thejollygrimreaper Wrote:
-------------------------------------------------------
> woo Wrote:
> --------------------------------------------------
> -----
> > well...i am waiting for plans, then i will try
> to
> > make one
> >
> > is it known when the plans will be relased?
>
>
> he has released a rough drawing on his site,
> however if anything i would urge him not to
> release it at all, given that the moment he does
> every clone shop will be in on it to make a quick
> buck with no actual contribution to the reprap
> community,
>
> i gotta ask though why on earth would you try and
> make it? why not just buy one, even
> reprapdiscount.com has them


because i have acess to few manual and cnc lathes so why not try, material isnt so expencive, few usd, so i cant loose even if i fail

its always easiest way to buy...

also i am interested about thickness of wall in the heater-nozzle area

if nozzle wall in this area can be thinner, then its possible to have better heat conduction, better temperature reading..

Edited 1 time(s). Last edit at 05/17/2013 05:59AM by woo.

woo: i would wait for the drawings to be published, the wall thickness is anyones guess, but i would start with 0.5mm

there's much simpler hotends to build that don't required such deep drilling into stainless steel

---

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"i gotta ask though why on earth would you try and make it? why not just buy one"

So what you're saying, is stop what I'm doing and just run buy a Replicator2? Because the smart people have already figured it all out for me, and I'm incapable of making stuff on my own anyway? And in fifty years we'll all be chicks?

lajos Wrote:
-------------------------------------------------------
> "i gotta ask though why on earth would you try and
> make it? why not just buy one"
>
> So what you're saying, is stop what I'm doing and
> just run buy a Replicator2? Because the smart
> people have already figured it all out for me, and
> I'm incapable of making stuff on my own anyway?
> And in fifty years we'll all be chicks?

i don't recall actually saying "stop what you are doing" ,

here's the thing about the prusa nozzle and my reason for my question

looking at what is available drawing wise http://prusanozzle.org/drawing.pdf

the whole thing is 52.86mm long, now assuming a 0.5mm orifice length you would have to drill with a 1/8th bit ,from one end 52.36mm deep, now this is into stainless steel, a material which work hardens pretty bad as it heats up and heat up it will even with a very short peck drilling method,

this is assuming you have a 1/8th drillbit that has a fluted length longer than 52.36mm!! (most of them are barely longer than 40mm)

after that you have the tiny hole at the bottom,which is 0.4mm which is going to have to go through a now work hardened section of stainless steel , the threads and outside stuff is pretty easy to take care of no particular skill involved there,

on to the polishing, I've got my ways of polishing blind holes like this using all sorts of oxide powders and pastes, by the time you do this, you might spend what $2 $3 on polishing if that,

when you dig into the details available it quite understandable why a large percentage of the cnc machine shops out there won't touch a job like this without much convincing, and the rather cheap retail price with all things considered starts to become a little more attractive, especially if you aren't a machinist who deals with stainless steel on a regular basis

hence i ask the question

---

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Well, if I just go and buy it, that would make me stop making one on my own.

And if I don't make the hotend, but buy it, why would I stop stopping there, and not just go buy a replicator2?

I find the most valuable feature of the whole reprap movement is people making their own stuff. The self replicating printer. Going up against "the machine", and printing the broken piece in the car door opening mechanism. Making it, instead of going out and buying it.

The more "you can't make this one at home" parts introduced in printers will make it less and less compelling it for people to build them.

Then there's "don't try this at home". I can't tell you how many times I've seen on web pages and forums that drilling a .5mm hole is a major challenge even with $100k industrial machines. Well, guess what. Total BS. You can drill .5mm holes with a dremel, a $1 drill bit, and some jig made from scrap wood laying around the house. In fact you can drill .15mm into a brass block with the same setup all day.

I would not drill the 3mm hole first. I would start with the nozzle, flip it around and drill the hole for the filament. Then go back and clean up the nozzle. I was just at the mom and pop hardware store down the street, they sell ~4" long 1/4" titanium drill bit for $3.99.

Polishing stainless steel probably also doesn't need pixie dust from the Himalayas.

On the other hand, I hope Prusa sells enough hot ends to keep his business going. That's how we show our appreciation for everything he does.

Hi, guys feel free to make them. I am really working hard to get the pro drawing made. It is GPL v3.

We made a load of tweeks over the phone with my machinist, so I have to reverse engineer it myself, lol.

Inside is 3.2mm and the OD at the tip is 4.5mm.

lajos Wrote:
-------------------------------------------------------
> Polishing stainless steel probably also doesn't
> need pixie dust from the Himalayas.

I use custom made pixie dust from Asia :-)

I may have missed it, but any plans for a 1.75mm version?

Quote

I may have missed it, but any plans for a 1.75mm version?

Jo hates 1.75mm filament. :-)

The difficulties JGR has outlined above are magnified quite a bit when you decrease the diameter of the hole. It's not feasible to make a 1.75mm hotend of this same design in a production setting.

It is if you know what you're doing.

crispy1 Wrote:
-------------------------------------------------------
> I may have missed it, but any plans for a 1.75mm
> version?
>
>
> Jo hates 1.75mm filament. :-)
>
> The difficulties JGR has outlined above are
> magnified quite a bit when you decrease the
> diameter of the hole. It's not feasible to make a
> 1.75mm hotend of this same design in a production
> setting.

ii could be done on an edm machine, but the cost wouldn't be pretty, there are companies that specialise in drilling holes of that nature but again cost i don't imagine will be pretty

---

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lajos Wrote:
-------------------------------------------------------
> Well, if I just go and buy it, that would make me
> stop making one on my own.
>
> And if I don't make the hotend, but buy it, why
> would I stop stopping there, and not just go buy a
> replicator2?
>
why a replicator2? granted it's probably better than an up! , why stop there? why not just outsource your printing needs to shapeways... i know we can print out own lm8uu bearings but do we make our own 608 bearings and our own nuts and bolts as well?

> I find the most valuable feature of the whole
> reprap movement is people making their own stuff.
> The self replicating printer. Going up against
> "the machine", and printing the broken piece in
> the car door opening mechanism. Making it, instead
> of going out and buying it.
>
> The more "you can't make this one at home" parts
> introduced in printers will make it less and less
> compelling it for people to build them.
>
> Then there's "don't try this at home". I can't
> tell you how many times I've seen on web pages and
> forums that drilling a .5mm hole is a major
> challenge even with $100k industrial machines.
> Well, guess what. Total BS. You can drill .5mm
> holes with a dremel, a $1 drill bit, and some jig
> made from scrap wood laying around the house. In
> fact you can drill .15mm into a brass block with
> the same setup all day.
>
brass i would agree thats easy with a dremel even with my hands, stainless is a very different story drilling

> I would not drill the 3mm hole first. I would
> start with the nozzle, flip it around and drill
> the hole for the filament. Then go back and clean
> up the nozzle. I was just at the mom and pop
> hardware store down the street, they sell ~4" long
> 1/4" titanium drill bit for $3.99.
>
your probably looking at titanium coated bits, which are most likely made in china and aren't much better than straight HSS bits these days,

> Polishing stainless steel probably also doesn't
> need pixie dust from the Himalayas.
>
not sure about pixie dust , i used cerium oxide ---- try not to breathe in,

> On the other hand, I hope Prusa sells enough hot
> ends to keep his business going. That's how we
> show our appreciation for everything he does.

by all means if you have the machining capability go for it, go nuts, feel free to post pics,

---

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lajos Wrote:
-------------------------------------------------------
> So what you're saying, is stop what I'm doing and
> just run buy a Replicator2? Because the smart
> people have already figured it all out for me, and
> I'm incapable of making stuff on my own anyway?
> And in fifty years we'll all be chicks?

That's not at all what he said. If you've got the skills you should build your own if you like. While many here have the skills, facilities and means to manufacture something like this, constraints on other resources such as time and opportunity cost are bigger factors than other factors. It's great you have the time to be able to make your own hot end and there is no one stopping you from doing just that. Some of us though have other responsibilities and would rather just purchase one and get on with it. You don't seem to respect that what might be best for you is not necessarily best for everyone else. Some people just want to print, others are more into the building of the printer. The printers being used in high end applications (medical for example) can't be built at home and require specialized tools and knowledge. However, nothing stops you from from building any of the entry level printers or even coming out with a design of your own. The point, which you've missed in your responses is that for some the time and effort to build a hot end like this (or even an entire printer) isn't worth it.