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Laser CNC, engraving works, cutting doable?

Benm

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In that scenario can the 445nm diode with a good lens (glass 405 aixiz) stay under the 1mm max dot (even if not round)?

Oh, its surely possible to focus it to under 1 mm at 2 inches distance or so. I'd say you'd be looking in the order 0.1 x 0.5 mm "dot" size. With the 405 you can achieve 0.1 mm diameter round spots or something around that number.

The problem will be that the cuts or engravings will have a resolution/line width of 0.1mm in one direction, and 0.5 in the other. If you only do cuts at 90 degree relative angles (i.e. cut out rectangles), you could rotate the laser 45 degrees and get 0.35mm cut widths in both directions.
 





altera

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Well that is unfortunate. I was very excited about this 405nm diode as it was able to burn stuff real easy in my first test with the LM317 back at the office even at 140mA.

I hooked it up to the Aixiz driver and while the laser comes on it is not nearly as powerful as it was on the 317 driver before. Even at ~300mA it will not burn - at all - It can shine across the room just fine though.

To make sure I went back to the 317 driver but to no avail. The laser lights up but is not burning anymore :(

Not sure what killed it. I've been quite careful about ESD and heat. Are these diodes that sensitive?
 
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what does the output look like? and are you positive on your previous current measurements?

405s aren't as forgiving as 445's about excess current, but as far as ESD goes they aren't generally any more sensitive than any other LD.
 

altera

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The output looks like it's lasing interference patterns and all, but not much in the way of burning -at all- my lpc-815 diode is much stronger.

I'm pretty sure about the current ( i had a multi meter in line ). I'll try to be even more careful with the next one :)
 

altera

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Btw has anyone seen DrLava? I've ordered the FlexModP3 two weeks ago yet he has not shipped the units ago nor answered any emails. How do you guys get your laser drivers?
 
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I'm pretty sure about the current ( i had a multi meter in line ). I'll try to be even more careful with the next one :)

There's your problem. having anything except maybe a lasorb between the driver and the diode is seriously bad idea. The driver's current should be set using a test load and a 1 ohm shunt, then the diode connected to the driver using soldered connections with as short of leads as you can get away with.. Having stuff between the driver and the LD is just asking for trouble.
 

jakeGT

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I just got my 820mW 12x together the other day, I'm sure it could do some hella engraving, hell, it already has on my furniture. For some reason, mom and dad didn't appreciate their names being carved into their headboard?
 

altera

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820mW that's not bad. What diode was that?

Anyway after some false starts I finally have the 405nm laser cutter up and running. I've been able to cut through some thin plastic. Thicker plastic more or less melts through. I think I might have to look into combining two beams for that.

I've made a quick video showing the laser making a (PCB/SMT) stencil in some paper.

YouTube - Laser 530 paper stencil

I also tried this on some clear packaging plastic and the laser cuts that no problem. So I have good hope I'll be able to cut my own SMT stencils from now on.
 
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I think 820mW is probably a bit much to ask from a 12x and expect a long life. For this application, I don't think i'd push one much past 700mW. The problems i've seen out the 12x's I have show that much past 700mW, they get REALLY touchy about back reflections.. sometimes to the point that just changing lenses will LED them.
 

altera

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I'm not going to push this diode over 500mA. From what I've read that is considered a safe current as long as the diode has a good heatsink.
 

Helios

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I'm not going to push this diode over 500mA. From what I've read that is considered a safe current as long as the diode has a good heatsink.

That is considered "safe" for a decent lifetime in handheld laser pointers....but im not sure if you will get the lifetime out of the diode you would like if you have it set at 500mA and use it on a regular basis for cnc cutting.

if you want higher power the 445nm diode is really the best solution because it is set at 1000mA from the factory and is designed to last for the lifetime of a home video projector. The diode in a bluray burner is not set at 500mA nor is it designed to run at the duty cycle seen by a movie projector.
 
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altera

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I'll keep the current as low as possible. I had set out to cut ABS (plastic) and while it's possible, the cut is not very clean. The laser more or less melts too much of the surround plastic at this power level. The 445nm might be a better choice for that indeed. I'll keep my eye open for a deal on those diodes.

However for the SMT stencils, with their very fine features I think the 405nm will do real good. Hopefully I'll get a chance to buy some overhead projector sheets this weekend.
 

Helios

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If you can shorten the distance to the material you can get a pinpoint with the 445nm as well. Divergence is really only a problem at a distance. Will it be as tight as a single mode 405nm? No, but the difference should be negligible


I have a friend who works with automation for manufacturing and I keep trying to convince him to build one of these saying ill build and supply the laser. Yours looks like it works great!
 
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