“Prometheus Hot End”: New Customizable All-Metal Hot End! [Many Pictures]

Ok guys,

Earlier on people were having some difficulty visualizing the various zone lengths in the pictures in my original post. I decided to annotate them to illustrate this concept. Here are the pics:

CZ = "Cold-Zone" Length
TZ = "Transition-Zone" Length
MZ = "Melt-Zone" Length
TP = Thermistor Position








Just let me know if anything is still unclear

Eric

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RP Iron Man
EDIT: It looks like the Ultimaker thermocouple also uses an M3 thread. I just need to find out where they source their thermocouples...

Shenzhen. Any sort of electronics parts you could every need or want can be found in the markets there at prices much better than Alibaba or Taobao.

Eric: Those pictures you posted above really help with understanding the different zones in a hot-end. What would be the best set up (using the pictures from above as reference) to ensure no jamming or other common hot-end issues?

The Megatronics board from RepRapWorld has got 2 thermocouple inputs. That's also where E3D's adapter board and thermocouple originates from, seemingly.

About the additional costs of thermocouples: that's also bugging me, but I think the best solution would be to have a way to choose during purchase. People who are willing to put in more money can while the ones who like thermistors more are equally well served.
The Ultimaker thermocouple is custom-made if I remember correctly. Don't know about the cost of doing that, but they are generally selling stuff with quite a markup.

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vegasloki

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RP Iron Man
EDIT: It looks like the Ultimaker thermocouple also uses an M3 thread. I just need to find out where they source their thermocouples...

Shenzhen. Any sort of electronics parts you could every need or want can be found in the markets there at prices much better than Alibaba or Taobao.

Are you talking about the city in China, or is there a market similar to Alibaba that is called Shenzhen?

---

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vegasloki

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RP Iron Man
EDIT: It looks like the Ultimaker thermocouple also uses an M3 thread. I just need to find out where they source their thermocouples...

Shenzhen. Any sort of electronics parts you could every need or want can be found in the markets there at prices much better than Alibaba or Taobao.

I agree with Greg. I am not sure sure if you are talking about the the City or an online marketplace. I live in Toronto, Canada so I don't think it would be practical to fly across the world to hunt for some thermocouples in the streets of Shenzhen

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NewKidOnTheBlock
Eric: Those pictures you posted above really help with understanding the different zones in a hot-end. What would be the best set up (using the pictures from above as reference) to ensure no jamming or other common hot-end issues?

I am glad the pics were useful

General speaking, a short TZ will prevent jamming as it reduces the length of the soft rubbery plastic "plug" in the TZ and thus reduces the friction in the hot end. Most of the above pics illustrate this short TZ.

As for clogging and leaking, my 1-piece nozzle already takes care of those issues (of course there is nothing stopping a clog being caused by filament impurities).

The length of the MZ is really dependent on your application. In general, shorter MZ means less "ooze", quicker extrusion response times and more effective retractions (due to less pressure hysteresis in the MZ) at the cost of a lower maximum feed rate. On the other hand, longer MZ means more "ooze", slower extrusion response times and less effective retractions (due to increased pressure hysteresis in the MZ) but you can sustain a higher maximum feed rate.

The thermistor position (TP) is also dependent on your application as the TP within the MZ dictates the accuracy of the temperature reading and the thermal response of the hot end. Generally, there are a few causes of heat loss in the MZ: heat loss due to thermal radiation of the aluminium parts occurs over the entire length of the MZ; heat loss through the TZ to the actively cooled CZ and heat used to melt the plastic entering the MZ drains heat from the top of the MZ; heat transferred to the extruded plastic at the nozzle tip drains heat from the bottom of the MZ. Most of the heat is dissipated at the top of the MZ so it is a good idea to configure the TP at the top of the MZ to ensure that the temperature is sustained especially at high feed rates. However, if you are printing very detailed items at low feed rates and you are more concerned with very accurate temp readings at the nozzle tip you may want to configure the TP at the bottom of the MZ. The entire MZ is aluminium (highly thermally conductive) so the thermal hysteresis within the MZ is not much of an issue at all.

For optimal reliability, I am going to recommend a 2-3mm TZ. For starters, I am going to recommend a medium length MZ (about 14-16mm) and the TP at the top of the MZ. The CZ is fixed and remains actively cooled in all applications.

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uGen
The Megatronics board from RepRapWorld has got 2 thermocouple inputs. That's also where E3D's adapter board and thermocouple originates from, seemingly.

About the additional costs of thermocouples: that's also bugging me, but I think the best solution would be to have a way to choose during purchase. People who are willing to put in more money can while the ones who like thermistors more are equally well served.
The Ultimaker thermocouple is custom-made if I remember correctly. Don't know about the cost of doing that, but they are generally selling stuff with quite a markup.

Yeah, newer controller boards are starting to support thermocouples. Later on, will try to offer thermocouples as an optional add on, with an additional optional add on of an extension board for people who do not have thermocouple capability built in to their board.

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valimai
I'm new to reprap so I would like to ask if hot end have same function as megatronics board.

I am not sure what you mean by this? The Megatronics board is an electronics board that controls your 3D printer, while a hot end is mounted to the 3d printer extruder and melts the plastic to be extruded through a small nozzle orifice.

Eric

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RP Iron Man
Yeah, newer controller boards are starting to support thermocouples. Later on, will try to offer thermocouples as an optional add on, with an additional optional add on of an extension board for people who do not have thermocouple capability built in to their board.

Eric

I've got a Panucatt Azteeg X3 controller with the expansion board. It supports thermocouples, but there's zero documentation and my requests for info on implementation and how to set it up in firmware have gone unanswered...

I'm looking for someone with some info on how to implement.

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3DogNate
I've got a Panucatt Azteeg X3 controller with the expansion board. It supports thermocouples, but there's zero documentation and my requests for info on implementation and how to set it up in firmware have gone unanswered...

I'm looking for someone with some info on how to implement.

You should probably start a thread about this as there are probably other people who have figure it out.

Eric

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RP Iron Man


I agree with Greg. I am not sure sure if you are talking about the the City or an online marketplace. I live in Toronto, Canada so I don't think it would be practical to fly across the world to hunt for some thermocouples in the streets of Shenzhen

You asked where to get them. It's up to you to decide how.

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vegasloki
You asked where to get them. It's up to you to decide how.

Lol, I just wish there was an easier way...

Then again, another option may be a higher temperature thermistor. The PICO guys on Kickstarter are now offering a 500C thermistor as an add on for their hot end. This would be much easier to support in place of a thermocouple but I have not heard anything about the specs of this thermistor. If it is an NTC thermistor I imagine the reading would be quite inaccurate at such high temperatures. Besides I have no idea where they managed to find a thermistor that can read up to 500C

Eric

You might want to ask the E3D guys about the 500°C thermistor. IIRC, they also found one for a reasonable price or something like that.

Edited 1 time(s). Last edit at 03/13/2014 08:46PM by uGen.

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RP Iron Man

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vegasloki
You asked where to get them. It's up to you to decide how.

Lol, I just wish there was an easier way...

Then again, another option may be a higher temperature thermistor. The PICO guys on Kickstarter are now offering a 500C thermistor as an add on for their hot end. This would be much easier to support in place of a thermocouple but I have not heard anything about the specs of this thermistor. If it is an NTC thermistor I imagine the reading would be quite inaccurate at such high temperatures. Besides I have no idea where they managed to find a thermistor that can read up to 500C

Eric

Once you get the hang of sourcing overseas you'll find it easy. Here's a small trading company on Alibaba that's a good place to start. I know nothing about them and looked them up when I was making an order from another vendor.

[www.alibaba.com]

A good way to start is by see who has similar items and contacting them about what you want. The messaging software translates fairly well and some places have english speakers. That can get you started.

Another place to look closer to home for specialized thermocouples are process and industrial control suppliers. Digikey and the like have regular K type but the instruments specific to process control, like the threaded thermocouple are likely best from a specialist.

A quick Google turned this up for a high temp thermistor [www.shibauraelectronics.com]

The info is out there, it just needs to be retrieved.

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vegasloki
Once you get the hang of sourcing overseas you'll find it easy. Here's a small trading company on Alibaba that's a good place to start. I know nothing about them and looked them up when I was making an order from another vendor.

[www.alibaba.com]

A good way to start is by see who has similar items and contacting them about what you want. The messaging software translates fairly well and some places have english speakers. That can get you started.

Another place to look closer to home for specialized thermocouples are process and industrial control suppliers. Digikey and the like have regular K type but the instruments specific to process control, like the threaded thermocouple are likely best from a specialist.

A quick Google turned this up for a high temp thermistor [www.shibauraelectronics.com]

The info is out there, it just needs to be retrieved.

I have dealt with many overseas suppliers over past few years. All of the ones I have dealt with actually have sales people who speak decent English, so that isnt much of a problem when you use Alibaba. I have seen the Digikey thermocouples but as you mentioned they are not suited for this purpose (they are also VERY expensive). I think that the best way to source this thermocouple would be to have it custom made to my specs by a specialist company but I should definitely do some searching first to see if there are any compatible off-the-shelf products. Custom products can be expensive if I can't order large volumes.

As for the high temp thermistors I have also found quite a few firms that design high temp thermistors, I just haven't been able to find their distributors

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uGen
You might want to ask the E3D guys about the 500°C thermistor. IIRC, they also found one for a reasonable price or something like that.

I should definitely contact Sanjay about this. I think it would be wise to ask for his feedback on this design as well in case he has any advice to give.

Eric

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RP Iron Man

As for the high temp thermistors I have also found quite a few firms that design high temp thermistors, I just haven't been able to find their distributors

Eric

Why dont you just ask them who their distributors are? Typically companies that dont sell straight to consumers will tell you who sells their products.

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greghoge.com

HUGE 3D PRINTER PARTS SALE!!!

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gmh39

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RP Iron Man

As for the high temp thermistors I have also found quite a few firms that design high temp thermistors, I just haven't been able to find their distributors

Eric

Why dont you just ask them who their distributors are? Typically companies that dont sell straight to consumers will tell you who sells their products.

I would...If they actually had any contact info in their site I am going to try looking again. Hopefully I will find something this time.

Eric

how is it going now...?

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zungmann
how is it going now...?

Sorry for being absent for so long guys.

I have been working on getting the Indiegogo campaign up for this project but the last step (confirming my PayPal account) has been taking forever It is annoying how a seemingly simple process can take soooooo long. I am trying to add my Canadian bank account to my PayPal account so that I can launch the campaign but two times in a row I entered the wrong info and the confirmation failed I just reentered the stuff today (correctly this time!) but it will take another week to confirm. I wish I had started this process a month ago but I had no idea it would take so long to get it right.

Lol, it is actually pretty embarrassing that I am having so much trouble with such a simple process. The problem is that whenever I contacted the PayPal customer support each person I talked to gave me a different answer to my questions! They were all in the US and apparently this process is different in the US than in Canada. Their answers were just wrong I finally talked to someone at my local bank branch who had been through the confirmation process and he told me exactly what I was supposed to do.

So now I am back on track! I hope to have the Indiegogo Campaign up by Tuesday or Wednesday next week Once again I apologize for the super long delay guys. I have everything prepared with my suppliers and they are waiting for me the make the first order so I should be able to hit the ground running as soon as the campaign starts

I'll let you guys know as soon as the campaign is up!

----------------------------

In other news:

I PMed Sanjay from E3D about the 500C thermistors a while ago but he hasn't gotten back to me... I assume that he is busy with his own work so I am not sure if he has actually found a supplier of these high temperature thermistors. I have also been looking at possible solutions for printing over 300C and I am currently contacting a few suppliers about thermocouples. I have been searching for high temperature thermistors as well but I haven't found any suppliers. I checked out the 500C thermistor that the PICO guys have and it turns out that they are selling it for 20USD At that price it would be a better idea to go with a thermocouple for higher temp printing as NTC thermistors are inherently less accurate at high temperatures anyway.

I'll keep you guys updated if I can find a reasonable solution for printing over 300C. I am going to start testing thermocouples soon so we'll see how that goes.

Eric

Hey guys,

Lately I have been making some last minute changes to the heater block design in order to allow for a future thermocouple upgrade. Once the design goes into production it will be a pain to change anything so I am trying to get all that out of the way now. I have been talking with suppliers about thermocouples and as I expected M6 threads seems to be the standard mounting configuration. To make a future thermocouple upgrade as trouble free as possible I redesigned the heater block to accommodate M6 threads. I also had to re-position the thermistor holes so I am now using Brian's (bstott) method of securing the thermistor leads. Thank you Brian for contributing this idea of securing the thermistor without Kapton Tape Your method turned out to suit this application better than mine. Below you can see a picture of the final heater block design.

The leads are secured by an M6 cap screw with a small OD washer, which can be replaced by an M6 threaded thermocouple for higher temperature printing.


Now all of the drawings on my Flickr here are the final production drawings.

I have several M6 threaded thermocouple samples on order from suppliers so as soon as those arrive I will start testing them. Using a thermocouple will raise the max printing temperature up to about 400C so uGen you may have better luck with your Chinese Polycarbonate at these higher temperatures. I am also looking into the thermocouple expansion boards, but RepRapWorld seems to be out of stock ...I don't know where else I can get them. If anyone knows of any other supplier/manufacturer of these boards please let me know. Since most boards don't have built in thermocouple support it will be essential to offer an optional expansion board.

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As a side note, I finally have all of the PayPal stuff sorted out so I am good to go with the campaign! I will likely have it up tomorrow When it goes up I am going to start another thread in the crowdfunding section where we can talk about the campaign so we don't derail this thread.

I'll keep you all posted.

Eric

Hey, this looks really nice! Good to see that you have found a solution to combine the best of two worlds.

About the Polycarbonate problems: It's not only Chinese Polycarbonate, but also an American made PC-ABS that I have had trouble with. In the end, I am not too sure about these plastics (PC) after watching a documentation called "Plastic Planet". Endocrine Disruptors, endocrine disruptors EVERYWHERE!
But in any case, it is beneficial to have higher temperature capabilities.

I'll stay tuned for your Indiegogo. Hope that shipping will not be too excessive across the Atlantic :/

Finally!

The Prometheus Hot End is now on Indiegogo! Check out the campaign page and help support this project.

I started a new campaign thread over here in the crowdfunding section so all campaign related questions should be posted in that thread.

This thread will be for all other technical discussions relating to this hot end design so please keep all campaign related discussions in the appropriate thread so we can keep this thread on topic.

Once people start receiving their Prometheus Hot Ends I think it would be a good idea to have people discuss their experiences here as it will help us understand the performance of this hot end design in various printing scenarios.

Thank you all so much for your input over the last few weeks as it really helped me shape up this design! I really appreciate your support and I am confident that this project will be a success

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**Intuitive MULTI-FILAMENT 3D Printing** -- Successfully Funded on Kickstarter!

I designed the Prometheus V2 Customizable All-Metal Hot End. Buy online
Prometheus Hot End discussion thread

Hello Eric,

I have a couple of questions about the hotend. What type of stainless steel are you using for the one piece nozzle? Have you ever used taulman T-glass with it? I would be interested in using this with T-glass because T-glass is food safe and was hoping this was too.

Thank you,

Cameron

Hey Cameron,

It's SS 304 for the nozzle. Unfortunately I only offer 0.4mm nozzles at this time and you really can't print T-Glase with anything smaller than a 0.6mm nozzle because of the insane amounts of back-pressure, really sorry about that.

Eric

Thanks for the quick response. Oh that's to bad, no one sells a SS hotend with a nozzle size of 0.6mm. Well, I definitely will be keeping an eye on this project in hopes for the larger nozzle size.

Thanks again,

Cameron

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cameronm
Hello Eric,

I have a couple of questions about the hotend. What type of stainless steel are you using for the one piece nozzle? Have you ever used taulman T-glass with it? I would be interested in using this with T-glass because T-glass is food safe and was hoping this was too.

Thank you,

Cameron

Anything that goes through the hotend is no longer food safe. Unless of course the hotend is food safe as well. But that is discussion for another thread.

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greghoge.com

HUGE 3D PRINTER PARTS SALE!!!

Is there any visual example available of bstott's solution for securing a thermistor without Kapton? I find it hard to imagine what you mean

Here it is.



Eric

I am very sorry but it is still very unclear for me?

My thermistors all have naked wires, so if they simultaneously touch the heater block, they will short.

I am asking this because there might also be more people like me that want this a bit clearer. It still feels a bit abstract. It is a very interesting feature so I think more concrete and clear explanation may help in getting the hotend a better overall judgement

Oh yeah, I forgot to mention. The thermistor wires must be insulated in Kapton Tape first. Then the thermistor is pushed into the hole and the leads are secured by the cap screw.

Eric

Less there is a film of oil that was not cleaned off from the manufacture,
there is no reason that I can see why the Prometheus hot end couldn't process food grade resins.
304 SS, and 6061 aluminum is non-toxic, and can come in contact with food.

A2,

That's pretty much what Tom said from Taulman.

Hopefully he does not mind me posting this here. He says, "Actually it does depend a bit on the type of part and how much surface area comes in contact with the food. The problem is not microbacterial, but rather a tiny amount of lead in brass nozzles. The correct nozzle is a stainless steel one, but no one makes one I know of. The amount of lead picked up in the extrusion process is extremely small, but...as it's lead....well...it's not desired".

Foodsafe and nozzles seems to be an interesting topic.

-Cameron