PTFE coupler - Theory and practical details

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Re: PTFE coupler - Theory and practical details

Post by ivan.akapulko »

LePaul wrote:
Why not to sell through the state of Delaware, or to use a shipping service was it? Afaik, companies, registrated there doesn't pay VAT. Something like this: https://qwintry.com/en
P.S. Seriously, we need another thread about VAT, or we accidentially can steel these thread :-P
In short...my buyers ask me to lie on the value of the item so they can pay less tax. I won't do that! It upsets some but sorry, I've signed my name on those forms and it could come back on me!
It speaks banal contempt of the seller. As far as I know, the US government (government of any country, probably) afraid of tax evasion more than ISIS. The punishment in this case makes you cry tears of blood. Challenge buyers to use the delivery services in the regions with the preferential taxation, or decline of the transaction. These *censored* not going to pay you a penalty in case if it got out.
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Re: PTFE coupler - Theory and practical details

Post by Anders Olsson »

So, as I promised earlier, now when the Ultimaker 3 is official.

The Ultimaker 3 approach is PTFE lining which has proper cooling and then a very short and efficient heat break zone.
I should not share accurate drawing of it, but here is approximately how it looks:
2016-10-05-8975.jpg
It is basically the same concept as the I2K-washer, but with proper cooling for the PTFE.
Or one can describe it as a properly engineered version of the E3D hotends, like version 10 or something.. :-)
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Re: PTFE coupler - Theory and practical details

Post by Iltacitoduca »

Anders Olsson wrote:So, as I promised earlier, now when the Ultimaker 3 is official.

The Ultimaker 3 approach is PTFE lining which has proper cooling and then a very short and efficient heat break zone.
I should not share accurate drawing of it, but here is approximately how it looks:
2016-10-05-8975.jpg
It is basically the same concept as the I2K-washer, but with proper cooling for the PTFE.
Or one can describe it as a properly engineered version of the E3D hotends, like version 10 or something.. :-)
the nozzles is still made of brass... really a poor choice IMO
and the white sealing washer on the nozzle... hummm... allumina? PTFE/TFM/PI?? withstand up to 280°C? so it's not PTFM/TFM...
contacts for heat cartridge power made on sliding contacts? at the first speck of dust will give a lot of problems (
especially when it considers that flows a constant current of 1.5 A)... without talk about the thermal sensor! the worst choice ever for it...

The shape of the metal hot end (the brass part I mean), finally have a decent design, at least the heat cartridge is on the side of the nozzle!!
But that heatsink along the "PTFE lining" with the rear part obstructed by the mounting itself... cannot be seen! really this hot end is nice to view... but is not engineered well, not at all...

without talking about that the PTFE is a thermal isolator, so, putting a heatsink along it will not affect the internal heat that someone here in the forum say climbing along the filament... ;)

at this point they could use the hotend of E3D.. instead of bring life to this abort LOL! (ok too much sarcastic?... but come on! who thinks it's a good design or fails to predict how an object will behave in the real world or is just a bit naive... (or just trying to sell something claiming to be innovative or better letting the potential customers get blinded by an object worthy of note at first sight...)

no, really... this is the innovation? :( :( so sad about it... and disappointed!
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Re: PTFE coupler - Theory and practical details

Post by drayson »

Thanky for explaination...

In short, to check if I got it correctly:
- there is a thin tube of PTFE (Teflon) which sits in an alu housing with lot of cooling rips to make sure it will kept below ~200°C.
- this is supported by a very thin stainless tube which acts as a heat break - small/thin area for heat transition so less heat will end at the PTFE

similar to this: http://i.stack.imgur.com/WiRIv.jpg

The rest I can roughly imagine... Maybe there is a way to port the main concept to UMO :-)
The only thing I´m a bit struggling is, how the nozzle/heater/stainless tube is crewed together? it shall be tight fit to prevent leaking... ??
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Re: PTFE coupler - Theory and practical details

Post by Meduza »

There was actually a video of the print core internal design at the launch yesterday, i dont know if i can share it, but i will check!
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Re: PTFE coupler - Theory and practical details

Post by drayson »

Thank you, that would be great...
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Re: PTFE coupler - Theory and practical details

Post by Anders Olsson »

I guess there is a risk this becomes a UM3 print core thread now, but anyway.. :-)

Anyway, regarding the lifting mechanism, the circuit board is stationary and the cables between circuit board and heater/sensor are flexing, so the contact surfaces are not going to wear much.

When I say well engineered I don't mean that the design is the most simplistic possible.
I mean that Ultimaker actually made something that prints well, which is not what I can say about E3D hotends
(I can not tell you how much I dislike the E3D-design after spending way too much time fixing it at our delta printer. I have a hard time understanding how something that primitive, inconvenient and unreliable can be that popular)

The PTFE lined E3D hotends either have a too long or a too short distance between the PTFE and the hot part, which means they don't take advantage of the benefits with a metal heat break zone.
The metal zone has to be short enough for the plastic to be properly melted but long enough for the PTFE not to overheat, which is exactly what Ultimaker did on the UM3.

The UM3 hotends prints everything from PLA up to polycarbonate without feeding issues and will need no regular maintenance, which is something rare (or even previously unheard of) among 3D printers in this price range.

That said though, things can still be improved, for example by fitting a ruby nozzle to the print core :-)
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Re: PTFE coupler - Theory and practical details

Post by ivan.akapulko »

This suggests that Ultimaker may in thermodynamic modeling, in contrast to the colleagues from Albion XD
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Re: PTFE coupler - Theory and practical details

Post by Iltacitoduca »

Anders Olsson wrote:I guess there is a risk this becomes a UM3 print core thread now, but anyway.. :-)

Anyway, regarding the lifting mechanism, the circuit board is stationary and the cables between circuit board and heater/sensor are flexing, so the contact surfaces are not going to wear much.

When I say well engineered I don't mean that the design is the most simplistic possible.
I mean that Ultimaker actually made something that prints well, which is not what I can say about E3D hotends
(I can not tell you how much I dislike the E3D-design after spending way too much time fixing it at our delta printer. I have a hard time understanding how something that primitive, inconvenient and unreliable can be that popular)

The PTFE lined E3D hotends either have a too long or a too short distance between the PTFE and the hot part, which means they don't take advantage of the benefits with a metal heat break zone.
The metal zone has to be short enough for the plastic to be properly melted but long enough for the PTFE not to overheat, which is exactly what Ultimaker did on the UM3.

The UM3 hotends prints everything from PLA up to polycarbonate without feeding issues and will need no regular maintenance, which is something rare (or even previously unheard of) among 3D printers in this price range.

That said though, things can still be improved, for example by fitting a ruby nozzle to the print core :-)
Yes, should be better have a new 3d (thread ;) ) for UM3

Well engineered doesn't mean, for me at least, that the design is the most simplistic possible... for example a DELL or HP workstation have both well engineered internal design ;) (but they are anything but simple IMO)

I never bought a hotend from E3D for the simple reason that I never thought that an interchangeable nozzle as proposed by E3D could work without leaks...besides the fact that achieve the precise connections between the steel part and the aluminum side and the nozzle side of so reduced size, it would result in a high precision mechanical processing. and from the proposed price I highly doubt that this is the case
For the same reason I never purchased an Olsson block, no offense, but I really don't like your solution, which more than anything else is a compromise to have an interchangeable nozzle

I not even take into account the ruby nozzle ... in the printing of thermoplastics I do not see the use of nozzles Sapphire / Ruby, and certainly not for the cost since the synthetic rubies cost nothing (more than anything else could be costly one initial investment to get a custom made ruby) nor for the dimension or anything else ...
So all I see behind the use of the nozzle with ruby is unconvincingly ...

Instead, it would be helpful to draw experience from what already exists in the field of injection molding... don't you guys?
Regards
Claudio
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Re: PTFE coupler - Theory and practical details

Post by LePaul »

I spent a long time looking at the new print head with Siert explaining all the testing that went into it.

If Meduza can find the video that shows the exploded view, that will explain a lot.

When I asked about changing nozzles, I'm not sure I got an answer I completely understood....I also still wonder what the white ring is around the nozzle?
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Re: PTFE coupler - Theory and practical details

Post by drayson »

.. that question (white ring) also came into my mind...

@ Meduza, any news regarding the video?
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Re: PTFE coupler - Theory and practical details

Post by gudo »

Iltacitoduca wrote:
I not even take into account the ruby nozzle ... in the printing of thermoplastics I do not see the use of nozzles Sapphire / Ruby, and certainly not for the cost since the synthetic rubies cost nothing (more than anything else could be costly one initial investment to get a custom made ruby) nor for the dimension or anything else ...
So all I see behind the use of the nozzle with ruby is unconvincingly ...

Instead, it would be helpful to draw experience from what already exists in the field of injection molding... don't you guys?
Regards
Claudio
Hi Claudio
Without trying to enter into a controversy,
we play with tolerances of 0.1mm or even less and precise temp for quality prints, maybe what already exists in standard appropriate to the greatest users number, that does not stop trying to improve, " who can do more can do the least " ;-) .
After using a full spool of CFT filament, I doubt the brass nozzle or even steel is still in its exact original size, I think you'll be glad to use a brass/ruby nozzle just for his life time, there is the titanium or other steel which can be used but not highly compatible to the nozzle well heat diffusion.
And I have no doubt, because it is obvious that any serious 3D printer designers in their research have certainly taken a share of experience in the field of plastic injection molding.
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Re: PTFE coupler - Theory and practical details

Post by drayson »

drayson wrote:.. that question (white ring) also came into my mind...
After viewing some pictures and taking into account a sentence somebody wrote abount 300°C with core and a "silicon seal" I assume this white ring is something like a seperator between the nozzle and the front fan bottom cap/closure...

To be verified... Nallath?? Daid?? Meduza?? :-)
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Re: PTFE coupler - Theory and practical details

Post by Anders Olsson »

Iltacitoduca wrote: I never bought a hotend from E3D for the simple reason that I never thought that an interchangeable nozzle as proposed by E3D could work without leaks...besides the fact that achieve the precise connections between the steel part and the aluminum side and the nozzle side of so reduced size, it would result in a high precision mechanical processing. and from the proposed price I highly doubt that this is the case
For the same reason I never purchased an Olsson block, no offense, but I really don't like your solution, which more than anything else is a compromise to have an interchangeable nozzle

I not even take into account the ruby nozzle ... in the printing of thermoplastics I do not see the use of nozzles Sapphire / Ruby, and certainly not for the cost since the synthetic rubies cost nothing (more than anything else could be costly one initial investment to get a custom made ruby) nor for the dimension or anything else ...
So all I see behind the use of the nozzle with ruby is unconvincingly ...

Instead, it would be helpful to draw experience from what already exists in the field of injection molding... don't you guys?
Well, the E3D design certainly has it issues, technically it works but I much rather change nozzle on my own heater block than on the E3D.
The E3D hotend appears mainly to be designed to be cheap to manufacture on simple machines with cheap labor, that is my opinion.

My "Olsson block" on the other hand is a rather complex product, as I had no budget to change the printer or to manufacture my own nozzles and as I never thought we would make more than 200 pieces in total :-)
When I only had the prototypes Ultimaker were not interested. When we had sold a few hundred we had done all the R&D, testing and lots of marketing and it was for that reason suddenly hugely interesting for Ultimaker and they did not want to change a thing on it as it was working good enough. And luckily this rather complex block can still be manufactured relatively cheaply using complex machines and well paid labor.

It is often like this in product development, things are rarely optimized but there are often various unpredictable chain events, sourcing issues, assembly considerations and random things that ends up forming a product that is good enough for a particular task.

The ruby is mainly a project for my boron carbide filament, which requires something of that magnitude to be printable at all.
It has advantages for more common filaments too though and I am hoping that solving the wear issue once and for all will have other effects. For example filament manufacturers might start selling more interesting composite filaments if they know there is a nozzle that surely can handle it.

The PBI that gudu used is a typical example of injection molding materials, but you can not always compare injection molding with 3D-printing.
You for example get a much more challenging wear issue on the tip of a 3D-printer nozzle than inside an injection molding machine.
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Re: PTFE coupler - Theory and practical details

Post by Iltacitoduca »

gudo wrote:
Iltacitoduca wrote:
I not even take into account the ruby nozzle ... in the printing of thermoplastics I do not see the use of nozzles Sapphire / Ruby, and certainly not for the cost since the synthetic rubies cost nothing (more than anything else could be costly one initial investment to get a custom made ruby) nor for the dimension or anything else ...
So all I see behind the use of the nozzle with ruby is unconvincingly ...

Instead, it would be helpful to draw experience from what already exists in the field of injection molding... don't you guys?
Regards
Claudio
Hi Claudio
Without trying to enter into a controversy,
we play with tolerances of 0.1mm or even less and precise temp for quality prints, maybe what already exists in standard appropriate to the greatest users number, that does not stop trying to improve, " who can do more can do the least " ;-) .
After using a full spool of CFT filament, I doubt the brass nozzle or even steel is still in its exact original size, I think you'll be glad to use a brass/ruby nozzle just for his life time, there is the titanium or other steel which can be used but not highly compatible to the nozzle well heat diffusion.
And I have no doubt, because it is obvious that any serious 3D printer designers in their research have certainly taken a share of experience in the field of plastic injection molding.

Hi Gudo,
I do not understand what you are referring to when you talk of 0,1 tolerance to the printed part or to the pieces that are part of the hot end? Because 0.1 tolerance for a small part, like the hot end/nozzle, is a BIG tolerance IMO (for example I don't admit tolerance above 0.01-0.015mm on my prototype)

And why you talk about brass or titanium? when I never write that those metals could be used instead? I have no doubt that a ruby nozzle will be more durable instead of brass or titanium because both cited metals aren't sufficiently hard to withstand the wear (again we can just take a look at industrial molding nozzles to realize that no one (NO 1 LOL) uses the simple brass or titanium to create nozzles! )

And, just because you (rightly) mention the heat diffusion, you should agree that using a piece of brass in contact with the heat cartridge bring a loss of heat power... but we still see hot end made of cheap brass on a serious (at least for the price) machine like UM!

Always to be clear the thermal conductivity of Ruby is 36W/mK (and will drop as low as 20 when temperature is 300°C), Steel (generic, but can be 45 on nichel alloy or manganese and some alloy increase when temperature increase)17W/mK, Brass(generic) 100-150W/mK, Titanium 21,9W/mK
and so on.. but this is only literature already known from the ancient of molding LOL

So, I have doubt about that "serious 3D printer designers" are looking at consolidated experiences in other application fields :D

Kindly regards
Claudio
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