CNC Annealer (Now with case feeder)

kombayotch

kombayotch

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I was going to make an annealing machine on my CNC mill, but then I thought: why not just make the mill into an annealing machine with a simple fixture. It makes it so much easier to adjust timing and such, all you need to do is change a value in the G-Code, and it's precise to the millisecond. So, now I have the CNC annealer up and running... its rough, there is some chatter in the forward direction. It's because the guide pins are both close to the front. Easy to fix. I'm going to add a case feeder at some point.

Video here:


A dedicated CNC machine would actually be pretty cheap to set-up. The stepper motor can be bought for under $50, as can the motor driver board. The control software is free (Mach 2). All you need to run it is an old PC that has a parallel port (plenty on e-bay) and a power supply. The mechanical parts could easily be made with hand tools.

Tempilaq works well for setting things up. However, as a means of process control, I have come to the following conclusions:

1) Painting the outside of the case gives a false indication, it isn't the temperature of the metal, but of the flame. This stuff should be used on the inside of the neck.

2) I don't see the need for painting 450F or 650F on the body with these machines. The danger of overheating the body is very low since the exposure time is short and controlled. Killing the brass in the neck is where the concern lies.

3) If you want to bracket a temperature, you need two points: "hot enough" and "too hot". The proper way to set up the process is to use one paint that melts at the lowest you want (750F), and one paint that melts just above the highest temperature you want (850F). I'm thinking 875F or 900F. Things should be adjusted so that the low one melts and the high one doesn't at all. I got it so that the 750F melts completely, and the 850F either doesn't melt at all or just a tiny bit at the case mouth does.

The cheapo torches are garbage. These things only have a valve (no regulator) and the pencil flame is not ideal. The Benz-O-Matic JT539 has an actual regulator (keeps the flame consistent as the tank gets lower) and the swirl flame gives better heat distribution.

I have the predecessor to the JT539, the JHT-7. It was the same torch and regulator, but with a hose in between them. It is discontinued, but a lot of places still have stock. The 4' hose is nice. Also, Home Depot has the hoses to convert these torches to BBQ tank for only $16.xx. I need to find a splitter though to connect them both to the same tank.


Update:

Completed a simple case feeder tonight:



Got the JT539 torches on order along with a Y fitting to feed them off of a bar-b-q tank.
 
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Hey Kris,
It looks like you have got it working well and most of any issues sorted.
So how much are you going to charge the CGN members here per piece to anneal their brass for them over the coming winter?:)
All shipping costs to and from plus 10 cents a case??
At 5 cases a minute x 60 at.10 is only 30 bucks a hour gross
Maybe .15 or .20 would be more reasonable. Not a bad thing to have your necks brought back to factory malleability and consistent neck tensions.
Looks Good
Gord
 
I did play a bit with direct contact, resistance annealing:



That was just a test, I know it got way too hot.

At some point I'll make my own induction generator, it isn't hard. Just time consuming... In reality, a large tank and torches with regulators will be extremely consistent and won't require a lot of babysitting.
 
You could get all of the electronics needed to build one, including the old computer for under $250. Then its just a matter of making the mechanical part, which could use a threaded rod as a lead screw and drawer slide as the linear mechanism. It's would basically be one axis of a plotter... which is pretty simple to make:
http://www.storm.ca/~rheslip/cnc.htm

Tolerances can be quite lax, I probably have 1/16" play in all of the moving parts.

My mill is a Busy Bee Tools mill that I CNC'd myself.
 
A feed on a thread cutting lathe could be used too. All we are looking for is consistent even travel past the heat source. Set up your row of brass in a modified tool holder and stand your torch(s) behind/infront of the lathe. Adjust your temp and feed rate till you get it right. Worth a try for those of us who don't have a cnc mill but do have an old southbend.
 
In that case, why not just make a small conveyor belt that runs on a DC motor? You could use some kind of drive belt as the conveyor. Have the cases travel though two plates that shield the case body from the flame.

I thought of doing something like that with this, which is why its so long. If you look closely, you can see that the cases are rotating as they move along. But, that really isn't necessary if you're hitting them from both sides.
 
I put together a Ghetto annealer this summer.

BBQ rotisserie motor from Cdn tire - $50 approx 1 rpm. The ones that are 2 to 3 rpm are too fast.
metal stove top cover - set for $10, so only $2.50
Scrap wood to build a box and cradles for the torches

Drill a bunch of holes in the cover and have at it.

I am going to have a look at the flame nozzle you are mentioning with the valves and that can plumb off a BBQ propane tank. These little propane cans (camping variety) get pricey and I have been caught be an emptying can - GRRRRRR...

I am using 750F as my benchmark. Noticing that some alloys need more and some less temp. Some need a couple of runs through the flame if they have really been work hardened.

Automating this rather tedious job is the only way to fly.

Jerry
 
I've sketched out the case feeder, just need to build it... Then it'll be even more automated.

Once I have the case feeder running good, the next fixture will be one for depriming. That's another tedious task when you have thousands of cases to do.

I'm going to automate as many steps as I can, that don't compromise the quality of the reloads.
 
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