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Induction brass annealer redux

I should add that I think, all else being equal, you want to deliver power in the shortest amount of time. I turned my limiter off to deliver the maximum power my 48V 750W psu could deliver. For most of the anneal time the load (case in coil) is the limiter but as the brass heats it can pull more power. You want to deliver power in a short sharp jolt to the area in question rather than a slower delivery.

Remember also that brass thickness will impact how far down the case wall heats. The cylindrical work coil is efficient but not particularly concentrated. I think it pointless to chase a colour change too far down the case wall if it means you are cooking the neck.
 
thanks for the suggestions, i think that by increasing the copper tubing to 3/16" the height of the coil also increased and having the shelf at 1/2" thick makes the 308 case mouth a couple coils below the top with the shelf at the bottom of the coil. i guess i might change back to the 1/8" tubing but it almost seems like you need a super pump to push water through it because my current brushless pump is rated at 380GPH with about 11ft of lift and it barely pushes any water through the 3/16" tubing. what pumps are good to push water through the 1/8" tubing?

thanks
James
 
It doesn't take much water flow to keep the coil cool. Sometimes I wonder if my pump is actually moving any coolant.

Push the shelf snug with the bottom of the coil.
 
success :D. So i decided to change the coil to the 1/8" tubing and it worked fine even though the flow was just a trickle. I ran 25 pieces of .308 brass and the coil did get a little warm not not enough to not hold the coil but it cooled off within a couple minutes. The amp draw also was the same so looks like all is good.

Thanks
James
 
I have to smile... Hollywood did put a lot of time and work in getting the right the coil size. And yes maybe the flow of coolant is not much through that 1/8" tubing, but it works. Never hurts to try different things, that is what this thread is about.
 
I think the coil as recommended is far from ideal for this application but it is one that is easy to make and the ability to trickle coolant though it allows for a relatively high duty cycle (whether you take advantage of that duty cycle is another matter).

A coil structure such as one using an air-gapped ferrite core is going to be much better. (The flux pattern is concentrated in the air gap into which the case is inserted.) The challenge with these is finding a suitable air gapped ferrite, winding around it vs retaining cooling (if that is desired) and supporting the coil structure.

The cylindrical coil fits the easy peasy lemon squeezy criteria.
 
I think the coil as recommended is far from ideal for this application but it is one that is easy to make and the ability to trickle coolant though it allows for a relatively high duty cycle (whether you take advantage of that duty cycle is another matter).

A coil structure such as one using an air-gapped ferrite core is going to be much better. (The flux pattern is concentrated in the air gap into which the case is inserted.) The challenge with these is finding a suitable air gapped ferrite, winding around it vs retaining cooling (if that is desired) and supporting the coil structure.

The cylindrical coil fits the easy peasy lemon squeezy criteria.

SGK

Well said.
 
@KeeWay
Dont know much about 40A & 100A ebay Fotek SSR's.
Could you please give a link to the correct ones as i am not sure which to buy.
Also. i have a Arduino Mega, will it work.
 
@Rover when you buy from ebay and China ya throw the dice and take your chances. There are batteries sold on thier advertising 6000mAH the technology is only up to 2600-3000 mAH and what is often inside the very real looking packaging might only be a watch battery.

The flip side is I have bought some really great stuff from china that has been good quality, great technology and a fantastic price.
 
Fotek SSR-40DD 40A Solid State Relay
This is the one I got about a year ago, as David101 says, its luck of the draw. I found a diagram that shows the inside schematic for the relay and based on that I didn't need any extra resistors, etc. for the Arduino 5VDC output.

The solid state relay input "-" goes the common on the Arduino. The solid state relay input "+" goes to the Arduino input pin that you want to use. The positive of your power supply goes to the "+" of the relay output. The "-" of the relay output goes to the induction board "+" input. The "-" of your power supply goes to your "-" of the induction board.

Someone correct me if I got anything backwards. Perhaps someone has a drawing.
 
the below link is where i learned how the Fotek SSR is connected and once i did this it worked fine. The other problem i had was they are kind of cheap and overly rated for the AMPs stated so i just went as high as i can. i tried both 25A and 40A and they all blew with my 20A power supply that i was switching so i finally got a 100A SSR and it seems to be working fine so far.


thanks
James
 
IMHO, there is no more comforting music than the clap of a relay or a contactor. The SSRs are great, provided they DO deliver their label claim. Unfortunately, it appears that most of them don't.
 
I wanted to go for the SSR's as we are talking about short switching times and the resolution or steps in time that we adjust by can be small. No point it having a timer that can time down to a hundredth of a second if the contractor is only goof for a tenth. In my machine with the work coil a tenth of a second in most cases is not a problem. But Still I would like to switch it faster.

The price advantage of the SSR really goes out the wind if you have to buy something 5 times the size you need and even then your not guaranteed anything. Like I said I have seen a 18650 battery advertised as a 6000mA the technology only goes up to 3000 mA and then what is inside the case may be a watch battery.

If you have the money and time to experiment with these and get a good working one I thnk it is the way to go otherwise the old school relay will get the job done.
 
Vf for these things is 1.6V. Are you sure you guys are heat sinking them appropriately?

Wow, is that the forward voltage drop across the output terminals when 'closed' (conducting across outputs)?

Thassalotta voltage drop.

I question the need for precision timing, SSR's switch in the uS range, mechanical relays in the mS area. Even if a EMR (electromechanical relay) takes 50 mS to switch it won't effect anneal quality.

I just looked up the on/off time specs for the EMR I use, on time is 7 mS, off time is 2mS. So in theory you could cycle it 100 times per second. I'd consider this more than adequate timing precision for what we are trying to accomplish.

Breathing on a case getting annealed probably has a much higher effect than a 2mS variation in on time. I've never seen a need to get more annealing time resolution than 0.1 seconds.
 
Here's the updated drawing per my "as built". PM me if you'd like the TinyCad file. I'm also working the final parts list and can include that when complete. Still working on the hopper; need to machine a few parts on my mini CNC.

View attachment 1001018

Hello,
Amazing work, I'm really impressed by your skills.
I'd like to build the same but not sure how to program it. If I build the same Should I have to program the ACE 11 PLC with a computer.
If I undersatnd well the ACE 11 PLC, the TB06 and TBR 06 are piloting the solenoids. So regarding annealing time you must modify the programming for the solenoids work at the right time, no?.
Thanks so much for your help
Have a good day
Regards
Patrice FRANCE
 
Having finally waded through this wealth of information, I'm getting ready to start my build. I already have a home-built annealer using a propane torch, but this will be so much more accurate.

@KeeWay , do you have a wiring diagram for your design? I've built a 3D printer and a laser engraver using Arduino and Nema17 motors and would love to base my annealer off your design.
 

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