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Home build induction heater


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The knife makers and tech geeks might jump all over me for saying so, but bells and whistles, ramp up or down, sending commands, etc, are a waste of time and money for me.  As an architectural/hardware guy I want a forge that heats my stock as fast as efficiently possible , and as soon as that workpiece is too cold to hammer back in the forge it goes for as fast a reheat as possible.  

 

That's what makes me money so that is what I will spend money to achieve.  

 

Analyze your market.  I would suggest a basic robust all or noting system that is economical for you to produce, AND a more elegant system that commands a premium price that can do what a high end gas forge, pyrometer, and thermocouple struggle to achieve.  

 

You have 2 distinct types of smith interested in your product.  There have been different types of forges for different kinds of work since they invented blacksmithing, so it's logical to have diverse types of induction forges.

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The knife makers and tech geeks might jump all over me for saying so, but bells and whistles, ramp up or down, sending commands, etc, are a waste of time and money for me.  As an architectural/hardware guy I want a forge that heats my stock as fast as efficiently possible , and as soon as that workpiece is too cold to hammer back in the forge it goes for as fast a reheat as possible.  

 

That's what makes me money so that is what I will spend money to achieve.  

 

Analyze your market.  I would suggest a basic robust all or noting system that is economical for you to produce, AND a more elegant system that commands a premium price that can do what a high end gas forge, pyrometer, and thermocouple struggle to achieve.  

 

You have 2 distinct types of smith interested in your product.  There have been different types of forges for different kinds of work since they invented blacksmithing, so it's logical to have diverse types of induction forges.

 

Very good point, although at this point I think it would take more work to not include those features. Josh only has to do the programming once, then it can be used on every one we build. Each system will have a display and features to monitor system/water temp, power, ect… The programing for the more detailed controls will just be part of that same system, if you wish to use it.

 

The prototype model I've been using is a simple on/off with a foot pedal, its nice in some ways but it will melt anything if I leave it in for long. With the controls on the new versions you could have a larger oval coil with a few things heating while you forge and be able to limit to power so that it won't go past forging temps and start to burn or melt completely. Great for architectural work, doing multiples of the same thing, allowing non stop forging when rotating a few pieces in a large coil. 

 

There will be at least 3 different models as well, more info on that later. 

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it does have health risks...    you have to be in good shape to use it...     your forge cycles are fast and it seems like you have to hammer like a mad man to keep up !

 

and you become impatient ..    gas forges seems so sloooooooow, you've got lots of time to pick your nose and day dream

 

i can say that having 1 induction unit is not enough...  i'd like to have more for different things .   i can firmly say that i have a fear !  that if my induction unit was to fail/break down, i'd be racing to get another quickly as its turned into one of the most valuable pieces of equipment i use

 

even forging damascus

20140501_150127_resized_zps64b017f1.jpg

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I want a forge that heats my stock as fast as efficiently possible , and as soon as that workpiece is too cold to hammer back in the forge it goes for as fast a reheat as possible.  

 

Analyze your market.  I would suggest a basic robust all or noting system that is economical for you to produce, AND a more elegant system that commands a premium price that can do what a high end gas forge, pyrometer, and thermocouple struggle to achieve. 

The programing for the more detailed controls will just be part of that same system, if you wish to use it.

Judson,

You really hit the nail on the head, and as Daniel explained that is exactly what we set out to do and that is what we have now (a basic, simple to use high reliability model). 

However that basic model will soon have the capability to do so much more, if you so wish. I have completed years of testing and been through nearly 100 different revisions and system configuration combinations so I have the data I need to complete the "extra features" in programing but that will come last. We are proceeding with final preparation to get the basic model to market yet will continue to add value to it virtually, hardware additions will obviously be an extra cost. 

 

Make no mistake, at the core of our values in this venture is not to become another high priced induction heater manufacturer but to bridge the gap between real people and fast efficient heat! Of course any business has to turn a profit to survive, and with recent advances is processing and high power electronics, we believe we can do that while staying true to those goals.

 

 

Is there any health risk with prolonged exposure to an induction coil like this?

  • Don't wear metal jewelry, especially rings near the work coil. Heating can occur a few inches from the coil depending on its geometry.
  • Be cautious if you have metal implants, they too could heat up if brought within the coils field.
  • As JNewman mentioned, if you have a pacemaker or defibrillator never use or be near this machine when it is in operation.
  • Be prepared to work harder and faster than you ever have as dimenickel brought up!
  • Never touch the coil, particularly where it exits the machine. Although it is isolated from dangerous mains current (like a welder) there is still high energy RF present, you could get an RF burn or a painful jolt. Holding metal that touches the coil or even shorts it out is NOT dangerous.

The hazards are similar to that of Induction Cooktops: http://theinductionsite.com/radiation.shtml

 

 

i can say that having 1 induction unit is not enough...  i'd like to have more for different things .   i can firmly say that i have a fear !  that if my induction unit was to fail/break down, i'd be racing to get another quickly as its turned into one of the most valuable pieces of equipment i use

I've heard that before, Daniel wants an array of 3-5 to meet his high paced needs. Nice damascus btw, I like how every piece is unique, like a finger print.

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The addition of thermal couple input to control heat would be great!  A simple moltent salt bath heat treat rig would be a snap to make, and the control would probably be as good as you could get within the temp range of the salt being used in regard to ramp up and down times. :wub:

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The addition of thermal couple input to control heat would be great!  A simple moltent salt bath heat treat rig would be a snap to make, and the control would probably be as good as you could get within the temp range of the salt being used in regard to ramp up and down times. :wub:

 

Hey that would be cool! I hadn't though of using it to heat up a salt bath, very doable.

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there are probably so many more things this machine can do it will take a lifetime to discover them all.
hope it is not to long before we can get our hands on the basic machine so the rest of us can have a play too


have read the link above concerning health risks and it brings up another question.

is using this likely to damage a mobile phone in your pocket, should it be left further away?

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While I am by no means an expert on induction heating... I was a RADAR Technician in the Navy. High frequencies can "induce" a voltage in conductive materials within the field they produce, so there is a CHANCE it could damage them. The best practice is to play it safe and keep them away. Not necessarily across the room, but don't set it on top of the machine.

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have read the link above concerning health risks and it brings up another question.

is using this likely to damage a mobile phone in your pocket, should it be left further away?

 

While I am by no means an expert on induction heating... I was a RADAR Technician in the Navy. High frequencies can "induce" a voltage in conductive materials within the field they produce, so there is a CHANCE it could damage them. The best practice is to play it safe and keep them away. Not necessarily across the room, but don't set it on top of the machine.

 

LastRonin is correct, both in the fact that voltage is induced in a conductive object with in the work coil's field (that is key to the entire process) and in the safe distance.

 

I have shot many videos with my phone and digital camera some no more than a couple inches from the work coil. The shielding in most modern electronics, especially in RF based products like phones, is usually pretty good. But one second to close and your sensitive electronics could be fried.

 

Maybe down the road I'll do some destructive tests to see just how far different items can go, sort of like the "will it blend" videos but with less blending and more melting.

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any idea of pricing yet either as a raw kit or an ARU for the basic one.

what would you get in either?

raw kit = pcb's and instructions maybe?

I know it will cost more here because of import duty etc, anything over about $50 US is subject to a lot of extra costs here

 

Quick and dirty explanation:

Raw Kit = Bare PCBs, components, fabricated/machined parts, raw materials, manual (requires soldering, assembling raw materials and components, etc.)

ARU Kit = Populated PCBs, assembled modules, manual (only requires mounting modules and plugging in cables) If you can turn an allen wrench and match colors you can assemble this in just a couple hours.

 

Pricing will be released soon but our goal has always been to keep the machine under $2K. We also have in the works, a smaller 120V model. 

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I am looking forward to seeing the completed kits.  How many KW will these unit's be?  They seem to be able to go to a lower frequency than the Chinese machines?  I heat a lot of 1"-3" round and from what I understand the lower frequency is better for heating the center of heavier bars. 

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from what I know.

lower frequency means less skin effect so deeper heating

chinese IH often are measured in chinese kw which may be a bit different to other kw, seen one which according to  V and A in was about 6kw but was quoted as being 15kw output which if it was right would solve the world energy problems.

from what I can see the current IH here is 15KW 220v

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Something is wrong with the forum!

 

I can save this sentence:

The actual input power in volt amps is about 7-8KW or

However I can not save if I type 208 directly after "or". It seems to fail with some other text as well, numerical or not.

These are the errors in the web console when I hit save changes while there is any number after the "or" in the above sentence:

Failed to load resource: the server responded with a status of 403 (Forbidden) : http://www.iforgeiron.com/index.php?s=4873ae5f5cb422c66e74a632c5414bcb&app=forums&module=ajax&section=topics&do=editBoxSave&p=397404&t=28193&f=66

I have tried on Chrome, FireFox and Safari. Already tried logging out, clearing browser data, restarting and logging back in. Looks like a string sanitizing issue.

 

 

I have my post saved in a text file, I'll put it up as soon as this is resolved.

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JNewman, on 20 Jun 2014 - 1:13 PM, said:

I am looking forward to seeing the completed kits.  How many KW will these unit's be?  They seem to be able to go to a lower frequency than the Chinese machines?  I heat a lot of 1"-3" round and from what I understand the lower frequency is better for heating the center of heavier bars. 

 

 

 

 

the iron dwarf, on 20 Jun 2014 - 4:16 PM, said:

from what I know.

lower frequency means less skin effect so deeper heating

chinese IH often are measured in chinese kw which may be a bit different to other kw, seen one which according to  V and A in was about 6kw but was quoted as being 15kw output which if it was right would solve the world energy problems.

from what I can see the current IH here is 15KW 220v

 

 

 

 

 

How many KW will these unit's be? - They will be marketed as a 15KW machine. That is in reference to the oscillating power in the tank circuit. It not a good rating system in my opinion but it's the one adopted by the industry (and many others). The actual input power in volt amps is about 7-8KW that's 208-240 volts @ 32-34 amps. See the two units below for reference, it doesn't mater if they are Chinese, Russian, or America, most all of them rate their machines like this. 

http://www.magtechina.com/products/234.htm

http://www.acrossinternational.com/15KW-Mid-Frequency-Split-Induction-Heater-w-Timers-30-80KHz-IH15AB.htm

(Notice the duty cycle as well on these, 80%.)

 

I prefer rating by application like Grant did with his machines, calling them 1.5" machine, 3" etc. I've seen 15KW Chinese units that could not heat a 1" bar to much past a bright red (1600-1700℉). Showing what the machine is capable of in real world applications is the only way to really know what your are getting with these things.

 

That being said, since this machine is overbuild to ensure long life and reliable performance in the face of constant use, it can be safely "over driven" to about 75 amps. Also most units have a power factor of 0.6 to 0.75, this forge however runs at a near unity power factor of 0.99. See here for a description of power factor and what it means for efficiency.

 

The forge operates best in the mid-frequency, industry term for 30-80KHz. However it's full operation range can span from audible frequencies to about 120KHz max. In the video below it is running at 50KHz. At that frequency the penetration depth of iron is about 0.009 mm or 0.000362 inches. That is amount of material on the surface of the work piece that is receiving the bulk of the energy from the magnetic field. Keep in mind that as frequency varies from 20 to 100KHz, for example, the penetration depth only fluctuates by 0.008 mm or .000316 inches. Power control can be just as important, to much power even at low frequencies can still damage the surface of the work piece.

 

Here is an application video heating 3 inches of 1.25 inch bar stock to white hot, limiting input power to 7.6KW (about 32 amps at 240 volts).

https://www.youtube.com/watch?v=4vICz4akL6k 

 

One could heat the same length of bar faster using a 2-3 turn coil then just move the bar back and forth, however I wanted to demonstrate it's capability to heat larger sections without user intervention. Handy if your working on one item and want to have the next one heating and ready to go. Plus I'm pretty sure 2 minutes is still just a little faster than a flame forge, and there are absolutely not fumes or smells (since the bar was clean). Just the smell of hot metal, which I have to admit I'm beginning to grow fond of.

 

In reference to the previous conversation about electronics and their distance from the coil; notice how close my $250 Fluke amp meter and old iPhone are to the coil, 3 inches from the open end. And keep in mind the ends are where the magnetic lines of force extend the furthest out from the coil, just like the north and south pole of a magnet are strongest at the poles. With the coil empty (no work piece absorbing the field) the major flux lines only extend about 1.5 to 2.5 inches from the poles at full power.

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i use the 3 coil for heating larger stock and move it back n forth ...   and i find if the coil size is closer to the work piece, it'll work faster

-make the foot switch on the floor a tough metal one... otherwise it may get stomped

 

-are you using big relays ?  and are they in an easily replaceable area ?

 

-i mentioned it before ... that its a good idea to be able to easily remove the cover ...so you can blow out the grinding metal dust ....   unless its totally sealed, which would be epic awesome !!

 

-i'm really digging the idea of thermocouple control...   both salt pot... and for accurate heating of work edges to be normalized and hardened ...     that is an option that would appeal to many !

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