Induction brass annealer redux

[GrocMax]

Automotive type relays are already coil flyback suppressed, either a resistor or a diode, resistor is most common. I've had zero issues with a HD 12v resistor suppressed coil 24v+ contact SPST unit over 12000 cycles and the Sestos 12v-24v version timer on the gnd side of the induction board.

This is the relay I'm using-

http://www.mouser.com/Search/Produc...tualkey65500000virtualkey655-V23234-A1001X033

Normal 12v automotive relays you'll weld the contacts real quick.

Flyback suppression diode for DC goes (negative > positive), > is diode direction. Backwards is a direct short that would bypass the coil.

 

[SGK]

@GrocMax Ok so you are just breaking the +24V leg (rather than breaking both). Do you just secure it to the chassis with the tab? Cheaper than what I was thinking of using.

BTW I saw you implemented PWM fan control. I was thinking about that. I just did similar for another application. But, unlike in that case, here there is no need for keeping things quiet so I don't think I will bother.

I've received my Mean Well 48V PSU. A few more parts are expected tomorrow. (Gotta love Amazon Prime Free Delivery. It should be called Amazon Prime Free Toss-it-Over-the-Gate.)

I'm not planning an auto feeder type build. But one thing I don't like about the 'basic' build is that in cycle mode you need to keep pace with the cycle and with no interruptions unless you hit stop. So I am doing a simple circuit with the aim of automating the start feature (in one-shot mode the timer will stop by itself). The circuit will use a basic PIC12F1501 for control and an OPB819Z IR switch watching the case/inductor slot. I'm in the process of ordering some parts to breadboard test the circuit and code. I also spent an hour mapping out a little PCB for it which I will send to fab once the circuit passes testing. The PCB is 2.5cm x 4cm (roughly 1" x 1.5") and could even be affixed with (non-conductive) double-sided tape. The 15 or so components required (including connectors) cost very little and there will be no need for the momentary switches. It has on-board regulation for 5V from 12V (and supplies 5V for the Mean Well PSU current control). I hate through-hole soldering but most of the layout could be through-hole if I change the Mosfets from SOT23 to TO92. (That would leave just 1 diode, 5 resistors and 2 capacitors SMD. If one can solder through-hole you can solder SMD!) The PIC will be socketed to make things easier (flashed PICs can be transported etc).

If the circuit works as expected, I will likely panelise the board for production which means I will have extras and I will happily provide them to others at cost. I will also provide the hex file for the PIC. Let me know if anyone is potentially interested.

PS: did I have my diode orientation incorrect? Too tired to check right now.

 

[GrocMax]

SGK- the relay is between the negative leg of the induction board and the shunt on mine.

The OBP819Z should work fine, nice find, wish I had tried that one for the autofeed stop signal.

Those PWM fan control chips I used are TINY, 0.5mm pitch, 2mmx3mm, needs to be soldered to an adapter first, and that is a challenge. I ruined about 4 of them (they are like a buck apiece), but works well. Totally unnecessary, but you can use screamer fans that move lots of air without driving you crazy with noise. With a PLC or other microcontroller, fan control should be pretty straightforward, I'm an analog kinda guy, programming is not my thing, so I went all analog. I used two ring lug mount NTC thermistors, one soldered to the radiator tank, one mounted to the induction board to measure board temp, once the system is tuned it works very well, can run at full power indefinitely with screaming fans, or during normal use it is quiet.

Using the terms cathode and anode has always confused the hell out of me in DC land, so I tend to break it down into simpler terms I can understand. A battery positive collects electrons, negative provides, and those anode/cathode terms are confusing when applied to DC circuits because its the exact opposite. For a flyback/recirc diode the DC neg is the anode. You probably had it correct, I get DC dyslexic and leave out the cathode/anode terms.

 

[SGK]

I'm an analogue and digital novice! I'm using the MIC502 for PWM fan control on a linear power supply for the Oppo 203 universal disk player. Only issue is they're "obsolete" but you can still find them. Of course, a PIC could take over the whole shebang - timer, current limiting, display control, fan control etc. But programming that is beyond my skill level. The only PIC programming I have done is... for this induction project, two days ago!

PS: just looking at this Mean Well. What pin connectors are needed for the current control block. They look tiny!

 

[GrocMax]

PS: just looking at this Mean Well. What pin connectors are needed for the current control block. They look tiny!

Listed by P/N in the manual for the PS. However it will ship with the connector terminated and looped, you can cut and splice.

 

[SGK]

 

[SGK]

The OBP819Z should work fine, nice find, wish I had tried that one for the autofeed stop signal.

BTW I noticed @FishinDog has 39R as the current limiting resistor for the OPB100Z. 5V/39R = 128mA which exceeds the max rating for the device.

but you can use screamer fans that move lots of air without driving you crazy with noise

Argh you've gone and made me implement fan control on my now double-the-size board. Up to 2 NTC per fan. I will program it so that if it over-temps the unit will shut down (with flashing red LED).

 

[GrocMax]

LED current calcs aren't as straightforward as that, you have to take into consideration the max forward voltage across the diode. In this case it would be 1.7v according to the OPB100Z spec sheet. Plug in 5v supply, 1.7v forward voltage, and 100mA max (one LED) into this-

http://ledcalc.com/

Then select the next highest value resistor that will handle double or more of the 100mA current. This resistor is a current limiter (ballast resistor) so it will get warm, go larger than required, SMD or thru-hole. EDIT: Dorp, the above calculator does all that for you.

NOTE: You don't have to tax your 5v supply if it is a small one, you can use 12v just calc the proper resistor for 12v supply.

BTW I noticed @FishinDog has 39R as the current limiting resistor for the OPB100Z. 5V/39R = 128mA which exceeds the max rating for the device.

Its a hobby project, make it as simple or as complicated as you wish. You PLC/microcontroller types make me jealous

Argh you've gone and made me implement fan control on my now double-the-size board. Up to 2 NTC per fan. I will program it so that if it over-temps the unit will shut down (with flashing red LED).

 

[SGK]

Doof! Time to hit the sack


Fan control strictly IC driven. My programming skill isn't good enough to have the PIC do it.

 

[SGK]

Parts slowly arriving. The water pump has no documentation. Three wires. What's the third one for? Is red +, blank GND and white??

 

[GrocMax]

Parts slowly arriving. The water pump has no documentation. Three wires. What's the third one for? Is red +, blank GND and white??

Maybe RPM signal from pump or PWM signal in for a multispeed capable one. Search on Fleabay or Scamazon you'll find an exact copy that has instructions.

 

[SGK]

I've searched everywhere. Found everything except the wiring configuration. It is the same one FishingDog used, purchased on Amazon. I think it is an RPM signal back from the pump but I'm not sure. I might just have grab a power source and use trial and error.

 

[Ross Tait]

Not annealing at all. I'm assuming the meter is seeing 15v from the internal ground path but there's no ground (relay) on the induction board. Need to fix up the cooling system and get it right first. But it does work at 15A (750w) and does 223 cases in about 2 seconds or less. 15A is FAST. This PS has an externally adjustable current limit that actually works well, you can set the current limit with no case in, and it adjusts voltage to maintain your set current limit. The two knobs were for voltage and current adjustment but if both are enabled they fight each other, using just the current limit works well.

Have just found a 20a(1000w) unit that will make it all alot faster and easier as well
https://www.ebay.com/itm/142462540092

 

[Gina1]

Have just found a 20a(1000w) unit that will make it all alot faster and easier as well
https://www.ebay.com/itm/142462540092

Nice find... great price

 

[8mm]

1-5/32" should not be a problem. The original 1-1/8" coil was set up by hollywood for .308 cases. The closer the case is to the coil, more current will transfer to the case, the faster the case will heat up. (the basic GinaErick design)

Good luck on your build.

Gina

Ma'am, how close to dead center does the brass have to be held in the coil? I have a 0.472" hole 1" deep for the .470" 8mm and it's really hard to get the shell to fall in. Have not powered the coil yet.
Also, is 1-1/2" clearance around the induction board to other parts enough if air moves well?
Thank you.

 

[Gina1]

Ma'am, how close to dead center does the brass have to be held in the coil? I have a 0.472" hole 1" deep for the .470" 8mm and it's really hard to get the shell to fall in. Have not powered the coil yet.
Also, is 1-1/2" clearance around the induction board to other parts enough if air moves well?
Thank you.

Hi 8mm

If your talking about the trap door hole, I made mine .500 inches. I made it that size to handle larger cases (ie 338 Lapua). If the case is slightly off to one side of the trap door hole, it does not seem to make any difference in the annealing, In your case, with the larger hole .028"

In my write up, at the every beginning of this thread, I mentioned that the induction PCB does get warm/hot. Hence the need for a fan blowing down on the PCB. Some other builders have added insulated heat sinks on the bottom of the induction PCB. Some where in this thread, there was a write up about it.

Hope this helps

Gina

 

[SGK]

One thing that might help is to flute the opening of the hole ie wider at top. I was thinking of making mine 15mm so a bit more than 0.5 in. 338 Lapua requires at least that. I was a little concerned that the linear pull solenoids only have 1cm of travel and so the trap door never covers the full hole. Does this matter in practice? I presume not.

I’m still waiting for my induction board. The one I bought from eBay comes with a coil. Not sure if this coil is any good for our purposes or should I spin my own? How high is the coil if you make it as described in post 1?

Tomorrow I will send my PCB to fabrication. It’s compact at 5x5 cm. I decided to learn a bit more PIC coding and so the PIC will now monitor 4 NTC thermistors and PWM control two fans, increasing their duty cycle automatically as temps rise. (2 NTC per fan.) It will automate starting of the Sestos timer (in one shot mode) by watching an IR switch under the coil. So no switches. If temps rise beyond a set over-temp threshold operation will be halted and a warning LED flashed until temps cool below the limit. (Rather geekily one will even be able to add a cheap HC-05 Bluetooth card and see the temps on a computer etc as well as set certain key variables.) Of course that assumes it works. Lots of testing to be done once the boards arrive.

 

[McHaggis]

This may help some who can’t find a solenoid with enough travel. I got one with 10mm and pulled it apart for no reason other than I could. What I discovered was that by removing the “stud” that held it together from the plunger and replacing it with a longer machine screw I increased my solenoids travel to around 16mm. It’s works fine but does bang open a bit. One day I may pull it apart again and fit an o ring on the inside to reduce this.

 

[8mm]

Hi 8mm

If your talking about the trap door hole, I made mine .500 inches. I made it that size to handle larger cases (ie 338 Lapua). If the case is slightly off to one side of the trap door hole, it does not seem to make any difference in the annealing, In your case, with the larger hole .028"

In my write up, at the every beginning of this thread, I mentioned that the induction PCB does get warm/hot. Hence the need for a fan blowing down on the PCB. Some other builders have added insulated heat sinks on the bottom of the induction PCB. Some where in this thread, there was a write up about it.

Hope this helps

Gina

I have the fan w/ air control duct and sinks, but only 1-1/2" along one card edge to the PS. Just wondering about electrical noise interference.
Thank you.

 

[SGK]

I wouldn’t worry. This isn’t something like high end audio of transmission electronics where you worry about EMF from the SMPS interfering with anything.