Induction heater From what I can tell hot end design have not progressed much, especially on hobby printers. I think inductive heater would increase precision, control and maybe speed of melting filament, especially for multicolor printing, but I don't see any development in this area. Here's an interesting induction heater used for FDM: [url=https://youtu.be/im-OYObxMdM]https://youtu.be/im-OYObxMdM[/url] https://reprap.org/forum/read.php?1,766463,766463#msg-766463 Mon, 09 Mar 2026 14:20:05 -0400 Phorum 5.2.23 https://reprap.org/forum/read.php?1,766463,775538#msg-775538 Re: Induction heater https://reprap.org/forum/read.php?1,766463,775538#msg-775538 3d print metal? why not?]]> prot0typ1cal General Thu, 29 Jun 2017 11:59:59 -0400 https://reprap.org/forum/read.php?1,766463,775519#msg-775519 Re: Induction heater https://reprap.org/forum/read.php?1,766463,775519#msg-775519
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newbob
..........................

How wide was your coil and what was the distance between thermal break and the nozzle? I'm looking into localizing the induction heating in the nozzle, far away from the heat break...

The length of the ferromagnetic part between the 316 stainless steel (non-magnetic) heatbreak and the brass nozzle was 16mm, the diameter of the coil was 14mm od made of 10 turns of flat 0.95mm x 2mm silver plated copper wire. The ferrite flux concentrator to keep the HF files away from the heatbreak was 15mm od, 8mm id and 2mm thick placed at the beginning of the ferromagnetic part. The concentrator worked, but not great. The other significant problem was self heating of the capacitors at about 40 degrees above ambient. If there was some way of getting a flexible hotend without having a very short transition zone I might still explore, but at the moment I have other fish to fry

Mike]]> leadinglights General Thu, 29 Jun 2017 10:30:37 -0400 https://reprap.org/forum/read.php?1,766463,775516#msg-775516 Re: Induction heater https://reprap.org/forum/read.php?1,766463,775516#msg-775516
A hotend idea that may still be feasible is sensing the temperature with the same wire as the heater is made of [forums.reprap.org] Running the numbers for thermal resistance of the parts and the electrical characteristics of pure nickel wire seem to indicate this may work - not one of my priorities at the moment though.

Mike]]> leadinglights General Thu, 29 Jun 2017 10:17:24 -0400 https://reprap.org/forum/read.php?1,766463,775515#msg-775515 Re: Induction heater https://reprap.org/forum/read.php?1,766463,775515#msg-775515
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leadinglights
I have managed to confirm that it is possible to get a short thermal break . This required a HF "soft" ferrite washer to localize the magnetic field and prevent induction into the thermal break area. Having said than, I can now see no good engineering reason to use induction heating as it is unlikely to be lighter or cheaper or less complex than the resistive options. Geek factor B)- and general coolness B) are good but must always give way to good engineering. :D

I can now use the time saved on several other projects

Mike

How wide was your coil and what was the distance between thermal break and the nozzle? I'm looking into localizing the induction heating in the nozzle, far away from the heat break...]]> newbob General Thu, 29 Jun 2017 10:07:07 -0400 https://reprap.org/forum/read.php?1,766463,775495#msg-775495 Re: Induction heater https://reprap.org/forum/read.php?1,766463,775495#msg-775495
So you are satisfied that it is not an road worth investigating any further?
We were looking into it and thought it might be a nice idea.
So your personal opinion would be to look for something else?

Lykle]]> zestytechnology General Thu, 29 Jun 2017 07:07:40 -0400 https://reprap.org/forum/read.php?1,766463,775488#msg-775488 Re: Induction heater https://reprap.org/forum/read.php?1,766463,775488#msg-775488
I can now use the time saved on several other projects

Mike]]> leadinglights General Thu, 29 Jun 2017 06:11:59 -0400 https://reprap.org/forum/read.php?1,766463,773197#msg-773197 Re: Induction heater https://reprap.org/forum/read.php?1,766463,773197#msg-773197
[attachment 95289 SectionedHeater.jpg]

Some trials that I have just made with 4mm diameter 316 stainless steel tube look a lot more promising as it heats up very little. Also the aluminium of the heatsink neither heats up nor seems to steal any power.

Mike]]> leadinglights General Tue, 13 Jun 2017 11:53:06 -0400 https://reprap.org/forum/read.php?1,766463,770698#msg-770698 Re: Induction heater https://reprap.org/forum/read.php?1,766463,770698#msg-770698
Please feel free to try developing and selling hot-ends and let me know how it works out for you.

I've made hot-ends since around 2008 or 2009 and literally been told to create new designs so that people can buy chinese knock-offs. The J-Head Mk 9 is only a prototype because of this reason and the fact that china can sell hot-ends for around the price of the raw materials and include free shipping. The majority buy on price alone.

Personally, I could envision a proper hot-end with induction heating and a thermocouple. Throw in a quick-change mount (another design I haven't marketed because of my above reasons.) and a bowden configuration and it would be fantastic. But, once china would sell it, all of the sales of the original developer would dry up quickly.

I have no way of knowing the numbers. However, I suspect that E3d has lost millions of dollars in sales to chinese knock-offs. I have no way of knowing how much business I have lost due to the same issue.

Best Regards,

Brian



Quote
Lykle
Quote
reifsnyderb

Given that the induction heater requires more electronics, people aren't going to want to pay for it, either.

If there is a clear benefit sure they will. And the costs can come down by quite a bit after the initial experimentation.
As to the clones, that should not be a reason to stop developing. E3D do it very successfully. Yes they are cloned, but I will still buy original.
Until we develop a better one.

I like the idea of induction heating. Makes sense. Put the energy where you need it, heat only that part you want hot. It is not a magical cure all, for sure, but it does need investigating.
]]> reifsnyderb General Sun, 28 May 2017 15:53:20 -0400 https://reprap.org/forum/read.php?1,766463,770669#msg-770669 Re: Induction heater https://reprap.org/forum/read.php?1,766463,770669#msg-770669
  • Can the oscillator be relied to start each time the MOSFET is switched on. If it cannot, can the design be made safe against thermal runaway and all of the heartbreak, homelessness and fire brigade involvement that goes with a bad failure
  • Can the part of the hotend that is heated by the high frequency induction be made in such a way as to allow a short transition zone in the filament path.
  • Can the design be simple enough to be made by greengrocers, lawyers, midwives and others who start from a position of not knowing which end of a soldering iron to hold.

It does seem a bit strange to me that a community of makers, geeks and others who DO know which end of a soldering iron to hold seems so adverse to any new or novel ideas.

Mike]]> leadinglights General Sun, 28 May 2017 12:00:13 -0400 https://reprap.org/forum/read.php?1,766463,770661#msg-770661 Re: Induction heater https://reprap.org/forum/read.php?1,766463,770661#msg-770661
Quote
reifsnyderb

Given that the induction heater requires more electronics, people aren't going to want to pay for it, either.

If there is a clear benefit sure they will. And the costs can come down by quite a bit after the initial experimentation.
As to the clones, that should not be a reason to stop developing. E3D do it very successfully. Yes they are cloned, but I will still buy original.
Until we develop a better one.

I like the idea of induction heating. Makes sense. Put the energy where you need it, heat only that part you want hot. It is not a magical cure all, for sure, but it does need investigating.]]> Lykle General Sun, 28 May 2017 10:54:34 -0400 https://reprap.org/forum/read.php?1,766463,770209#msg-770209 Re: Induction heater https://reprap.org/forum/read.php?1,766463,770209#msg-770209
The best chance for new hot-end technology, such as by using an induction heater, is in the hands of the hobbyist. The problem is that if somebody develops a new hot-end, it is copied by the chinese. Then, most people buy the cheap chinese copies. So, there is no incentive for a company to create an induction heater hot-end to add to china's profit margin. R&D costs money.

Given that the induction heater requires more electronics, people aren't going to want to pay for it, either.

Best Regards,

Brian


Quote
newbob
From what I can tell hot end design have not progressed much, especially on hobby printers. I think inductive heater would increase precision, control and maybe speed of melting filament, especially for multicolor printing, but I don't see any development in this area. Here's an interesting induction heater used for FDM:

https://youtu.be/im-OYObxMdM
]]> reifsnyderb General Thu, 25 May 2017 20:59:06 -0400 https://reprap.org/forum/read.php?1,766463,770199#msg-770199 Re: Induction heater https://reprap.org/forum/read.php?1,766463,770199#msg-770199
[attachment 94569 MOV_2.mp4]]]> newbob General Thu, 25 May 2017 18:14:58 -0400 https://reprap.org/forum/read.php?1,766463,769772#msg-769772 Re: Induction heater https://reprap.org/forum/read.php?1,766463,769772#msg-769772
Coil is 14mm OD, 10mm ID and 12mm tall. Wound with 2mm x 0.9mm silver coated copper wire from The Scientific Wire Company

Mike]]> leadinglights General Tue, 23 May 2017 10:25:12 -0400 https://reprap.org/forum/read.php?1,766463,769760#msg-769760 Re: Induction heater https://reprap.org/forum/read.php?1,766463,769760#msg-769760
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leadinglights
@newbob,
Thanks for the pointers to the inductance calculators, I found they gave a different value to the one that I had used. Your one was right and the inductance now comes out at 0.77microhenries - the other one (allaboutcircuits I think) said 1.92microhenries.
I have spend a bit of time browsing the web and even joined another forum [highvoltageforum.net] to get more background. The biggest worry is that the common circuits are all capable of stalling on power up - not a good thing if the is powered directly from the output of a controller as it may give several opportunities per second for the oscillator to stall and burn out.

Mike

Looking at reference designs for induction stoves they all use microcontroller/IC to regulate power and to keep heater working within design parameters. I think it would be best, once nozzle is proven to work, to have an induction circuit with a IC that can vary heater output power (instead of bang bang control) which would allow higher safety, very fast heatup times and lower temperature fluctuations.

I see many circuits using IRS2453 IC, such as this one

What are the dimensions of your coil?]]> newbob General Tue, 23 May 2017 09:01:34 -0400 https://reprap.org/forum/read.php?1,766463,769719#msg-769719 Re: Induction heater https://reprap.org/forum/read.php?1,766463,769719#msg-769719 Thanks for the pointers to the inductance calculators, I found they gave a different value to the one that I had used. Your one was right and the inductance now comes out at 0.77microhenries - the other one (allaboutcircuits I think) said 1.92microhenries.
I have spend a bit of time browsing the web and even joined another forum [highvoltageforum.net] to get more background. The biggest worry is that the common circuits are all capable of stalling on power up - not a good thing if the is powered directly from the output of a controller as it may give several opportunities per second for the oscillator to stall and burn out.

Mike]]> leadinglights General Tue, 23 May 2017 05:12:32 -0400 https://reprap.org/forum/read.php?1,766463,769573#msg-769573 Re: Induction heater https://reprap.org/forum/read.php?1,766463,769573#msg-769573
[attachment 94474 20170523_0948191.jpg]
(Not the one I weighed as no dog-leg on one lead, but the other one was ugly)

Mike]]> leadinglights General Mon, 22 May 2017 11:48:13 -0400 https://reprap.org/forum/read.php?1,766463,769565#msg-769565 Re: Induction heater https://reprap.org/forum/read.php?1,766463,769565#msg-769565
Air coil calculator: [electronbunker.ca]
[www.tesla-institute.com]

Coil that comes with the heater:

]]> newbob General Mon, 22 May 2017 11:04:50 -0400 https://reprap.org/forum/read.php?1,766463,768844#msg-768844 Re: Induction heater https://reprap.org/forum/read.php?1,766463,768844#msg-768844 It may not add anything, this is only a guess as it is too early to get more than a feel for it but I think the total weight would be somewhere between the weight of a hotend with an aluminium block and one with a brass block.

Mike]]> leadinglights General Fri, 19 May 2017 03:46:48 -0400 https://reprap.org/forum/read.php?1,766463,768817#msg-768817 Re: Induction heater https://reprap.org/forum/read.php?1,766463,768817#msg-768817
Any ideas of the weight it would add?]]> briangilbert General Thu, 18 May 2017 21:43:36 -0400 https://reprap.org/forum/read.php?1,766463,768708#msg-768708 Re: Induction heater https://reprap.org/forum/read.php?1,766463,768708#msg-768708 The biggest problem at the moment is that few of the manufacturers of polyester capacitors give important data for this sort of use. It looks like a bit of "suck it and see" will be needed.
The size at the moment is under 30mm across the transistors and 35mm long from the end capacitor to the end of the coil - this will obviously increase with metalwork, tubework and connectors but feels to be a good start

[attachment 94285 Newhotend4.jpg]

Upside down view showing only the principal electronic parts and nozzle.

Also needed will be things like a PEEK coil support to stop the coil being squished and possibly some form of thermal insulation to lessen the work of the water cooling.

Mike]]> leadinglights General Thu, 18 May 2017 07:11:48 -0400 https://reprap.org/forum/read.php?1,766463,768594#msg-768594 Re: Induction heater https://reprap.org/forum/read.php?1,766463,768594#msg-768594
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newbob
............. I ordered the same induction heater board. This board has two chokes, later I saw video where presenter claims that boards with single choke with midpoint are more stable. .............

Possibly true, but on the two choke circuit I think the chokes can be at some distance from the oscillator and tank circuit so reducing moving weight at the hotend.

Quote

............ Analog is a cheap way to start testing but ultimately I think digitally controlled heater would be the way to go. From what I understand, in the video in my original post, author is using micro controller for the heater, probably similarly to this doc . Using uC has it's advantages as one can vary power by changing frequency of the circuit which should be much more precise and quicker.

I have often used small 6 or 8 pin PIC microcontrollers to replace things like 555 timer ICs where they are more accurate, cheaper and waaaaay cooler but I don't think that they offer any advantage over analogue techniques for hotend control - I may be wrong though.

Mike]]> leadinglights General Wed, 17 May 2017 15:04:01 -0400 https://reprap.org/forum/read.php?1,766463,768559#msg-768559 Re: Induction heater https://reprap.org/forum/read.php?1,766463,768559#msg-768559
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leadinglights
That is an instructive video but with care an inductive heater can be made with only a modicum of electronic knowledge. The main "gotchas" are that the Royer circuit needs a fast switch on and that the the type of capacitor is very important. Having said that, for hotend use in a 3D printer it would be nice to drive it with the same PWM input as used with a resistive heater. To use a PWM, or even a bang-bang control will need the the oscillator to be switched on and off up to several times a second without locking up and may lead to white smoke, tears and the gnashing of teeth. To work with while I am evolving a circuit, I have ordered two of these from Amazon [www.amazon.co.uk] They are 120W which is two or three times more than a hotend needs but I will copy and modify shamelessly. More importantly they are only £5.38 each so if I fry them there will be little moaning.

Mike

...I ordered the same induction heater board. This board has two chokes, later I saw video where presenter claims that boards with single choke with midpoint are more stable. If you're looking for circuit diagrams - there's one in that video.

Analog is a cheap way to start testing but ultimately I think digitally controlled heater would be the way to go. From what I understand, in the video in my original post, author is using micro controller for the heater, probably similarly to this doc . Using uC has it's advantages as one can vary power by changing frequency of the circuit which should be much more precise and quicker.]]> newbob General Wed, 17 May 2017 12:13:55 -0400 https://reprap.org/forum/read.php?1,766463,768450#msg-768450 Re: Induction heater https://reprap.org/forum/read.php?1,766463,768450#msg-768450 Induction heating for 3D printer]]> MattMoses General Tue, 16 May 2017 18:41:58 -0400 https://reprap.org/forum/read.php?1,766463,768419#msg-768419 Re: Induction heater https://reprap.org/forum/read.php?1,766463,768419#msg-768419 www.amazon.co.uk] They are 120W which is two or three times more than a hotend needs but I will copy and modify shamelessly. More importantly they are only £5.38 each so if I fry them there will be little moaning.

Mike]]> leadinglights General Tue, 16 May 2017 16:15:14 -0400 https://reprap.org/forum/read.php?1,766463,768403#msg-768403 Re: Induction heater https://reprap.org/forum/read.php?1,766463,768403#msg-768403 What most people miss is that current coils are built to deliver over 1000 degrees C. Totally over-kill for melting filament.
Smaller, lighter weight coils, with smaller capacitors could be used to produce 500 degrees C or less, and offer more control over selected melt temperatures.
More experimentation and prototyping may result in a favorable solution applicable for 3d printing.
Using single piece nozzle, like the Prometheus, would be a good choice to start with, and help isolate the melt zone, and create a more compact assembly.
Would be a fun project.]]> prot0typ1cal General Tue, 16 May 2017 15:15:53 -0400 https://reprap.org/forum/read.php?1,766463,768366#msg-768366 Re: Induction heater https://reprap.org/forum/read.php?1,766463,768366#msg-768366 youtu.be] I decided against assembling my own circuit.]]> newbob General Tue, 16 May 2017 11:43:56 -0400 https://reprap.org/forum/read.php?1,766463,768340#msg-768340 Re: Induction heater https://reprap.org/forum/read.php?1,766463,768340#msg-768340 I will try to give a bit of background heat from an induction heater in the hopes that this will reduce the end load from friction but that will need something a touch more powerful than my first assay at making a Royer oscillator. To this end I have sent for a couple of 120W induction heaters from Amazon.
It would be philosophically satisfying to use the same induction heater both to make its own (insert name for heater tube bit) and then do the heating for printing; but at the moment I am "Plan B"ing and back-peddling at the same time.

Mike]]> leadinglights General Tue, 16 May 2017 10:21:34 -0400 https://reprap.org/forum/read.php?1,766463,768313#msg-768313 Re: Induction heater https://reprap.org/forum/read.php?1,766463,768313#msg-768313
Will not necessarily make it lighter, but will make it better to control.
And generating the heat exactly where we need it is perfect. I can see a whole range of experiments opening up, like, what is the optimal distance from the nozzle tip to put the heat. Things that are not possible with a heating element.

Composite nozzles, made of different materials to focus the heat and the cooling to where it is needed.
Lykle]]> Lykle General Tue, 16 May 2017 07:57:47 -0400 https://reprap.org/forum/read.php?1,766463,768191#msg-768191 Re: Induction heater https://reprap.org/forum/read.php?1,766463,768191#msg-768191
Quote
newbob
I've done some more reading and I think I'll go with horseshoe inductor positioned on two sides of the nozzle instead of trying to squeeze enough coil around it. I'm also looking at ways of focusing the magnetic flux to direct it precisely at the end of the nozzle where I think it should be (I maybe wrong and may get oozing and not enough melting speed but I'm curious the outcome).

I will be interested to see how that comes out, I have seen similar inductors for heating frozen bolts and for induction hardening instrument components.
I am presently exploring a possible answer to joining a high permeability mild steel heatable part to a very low permeability austenitic stainless steel part by friction welding. A good demo on [www.youtube.com] This may give us the ability to have the needed short transition between the hot and cold sides of the hotend.

Mike]]> leadinglights General Mon, 15 May 2017 12:32:48 -0400 https://reprap.org/forum/read.php?1,766463,768168#msg-768168 Re: Induction heater https://reprap.org/forum/read.php?1,766463,768168#msg-768168 newbob General Mon, 15 May 2017 11:16:02 -0400