a laser router

[The Lightning Stalker]

Who is the other part of "we"? Do you have a partner you build with?

No, it's just me.

Can't wait to see this fired up and lpmed

Yeah same here. Today was a loss, but I'm hoping to get working on it again tomorrow.

 

[The Lightning Stalker]

I finished boring the hole out today. There is a good 0.001-0.002" press on the back of the
module (using the new thermal one) and 0.003-0.004" on the copper part. Adjustments will
be made as necessary.

I also spent some time deburring and straightening the fins, some of which were bent by the
drill bit as it went through. I don't think that could have been prevented. If anyone knows a
way, let me know. Overall, I think it looks very good.

This particular heatsink has a thick chunk of aluminum at its core, which is perfect as it will
contact the entire front of the module and part of the back. It really is an impressive looking
unit. I wish I had known where it came from, but it was purchased as scrap, so who knows.
It looks like it could have come out of a Russian Nuclear reactor.

 

[The Lightning Stalker]

Well, there has been a slight setback with heatsink #1. Fortunately, there is a plan and 3 backup
heatsinks. I'm a bit tired right now, but later on I will post a picture of it.

 

[trussmonkey25]

Turn the heatsink the other direction. And build a bigger box to hold it...the jig you have will have too much play. And you are squeezing it out of shape with just the two bolts. Two solid chunks of 4x4 and a coulple large block clamps. The drill press vice is too shallow. Or you can make a plywood box to hold the work in place and keep it from wondering. > [■]<

 

[The Lightning Stalker]

Here is what I'm talking about.

The backup is already in the works. :beer:

 

[The Lightning Stalker]

I've decided to go with a 2-piece style this time, similar to what is used in projectors. The
design dictates that the module presses into an aluminum block. The block is then stuck to
the finned heatsink with arctic alumina.

It lives!

This is just a low power test running at about 1.5A. The camera doesn't pick it up well, but
the beam is already visible. Focal point was set at about 1.5" and there is some clipping

 

[crazyspaz]

Here is what I'm talking about.

Did it come unclamped while you were still drilling?

 

[The Lightning Stalker]

No, here is the story. The quill jib was loose on the mill, so the quill was moving around when I bored
the hole and it went oval shaped. To try and correct this, I tried pressing in a piece of steel that
appeared to mic at the perfect size. It went in with difficulty and left all that flash seen in the picture. A
test fit with the module then showed it had made the hole oversize. I was tired when I miced it and it
turned out to be exactly 0.025" oversize, which is exactly one turn on the micrometer.

It's a shame really since it was the perfect heatsink with a nice chunky core. I had even polished it. It
looked so nice! You can always take more off, but you can't put more back on. Well, actually you
could if it is 6061 and you have the right welder, which I don't (yet).

 

[Sigurthr]

If I still had access to a welding shop I'd fix that sink for you pro bono. I used to repair machine shop screw ups all the time. It doesn't have to be T6 6061 either; a good TIG welder with a solid metallurgical knowledge can mix filler alloys as needed to match any grade. I used to love specialty repair jobs, they were the highlight of my career.

 

[The Lightning Stalker]

Thanks for offering. I have done a little welding in the past, but nothing that made any money. It sounds
like you are much better at it than I am.

The heatsink had to be drilled to let the wires through and for some extra clearance for the back of the
module. It was then lapped in with sandpaper to a nice finish and the two pieces were joined with some
Arctic Alumina.

 

[crazyspaz]

those heatsinks are beastly. You said you got them as scrap somewhere?

 

[trussmonkey25]

I like em THICK &#55357;&#56838;

 

[The Lightning Stalker]

those heatsinks are beastly. You said you got them as scrap somewhere?

I live about 5 miles from a scrap metal recycler. Sometimes they have chunks of Al,
including heatsinks for pennies on the dollar. Some also come from the local computer repair
place. Sometimes I might find a computer in the trash, so a few might be from that. I don't
remember exactly where this one came from.

 

[The Lightning Stalker]

I spent the past couple days making improvements on the high power test load, which I have
nicknamed the "Mother Load", since it was inadequate to measure these voltages and
currents. Now all 7 diodes are in series and there is a 100mΩ resistor at the cathode, giving
around I / 10 + 5.2V of drop. The resistor is 3W, so it should be good enough up to 5.5A.

You can see 2 of the original white solid core wires have been left in place.

 

[The Lightning Stalker]

Well, I went and got an ATX PSU from my local PC guy today, but I don't think you want one that hisses,
so I'm going to take it back. He wouldn't even test it for me. Boy am I ticked.

 

[The Lightning Stalker]

I went back and was able to exchange it for an acceptable unit. There isn't really a whole lot
of progress to report at this point. It has mostly been hacking away at the extra wires that
were in the way and soldering jumpers where necessary. The build is coming along.

There is also now a cooling fan installed on the "laser head".