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1w 808nm burns less then LOC

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LuxIgnis

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Hello, I have built this 1w 808nm laser tonight, it has no FAC lens, and no Cylinder lens, yet. The focus is down to 0.3-0.4mm while on a regular LOC with aixiz I can get below 0.1mm.

The laser dose very well on black plastic, and dark objects, much better then a loc, only problem there is that the dot is bigger.

The real problem I have with it is that on light wood it doesn't seem to have any oomph at all. The LOC diode is able to finely etc a line, while the 808nm takes forever to start the burn and then once there is the black color underneath, it starts burning faster (and wider) line then the red. It does take 5-6 times as long though to start the whole process.

Now my question is, will a Cylinder lens allow me the same dot size as the single mode red? Will the laser still have problems with the light wood and white stuff (harder time then the red at 1/4 its power) ?

thanks for the answer.

Tony
 





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LuxIgnis

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Forgot to add a couple pics of diode and build.
 

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Asherz

Asherz

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I would put it down to it not being focused, the more concentrated the power is on a smaller area, the greater amount of burning ability you have.

If you slightly unfocuse the LOC, it won't burn at all. Just get a decent lens for the IR diode, or try and run it through an aixiz lens and it will burn much better.

Either that or you are under driving the diode, nice host setup btw, looks great :)
 
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maxh

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As a workaround for the poor performance on light colored wood, perhaps you could darken the wood first, do your etching, then lightly sand to remove the pre-darkening agent.
 
LarryDFW

LarryDFW

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LuxIgnis;

You must get the focus down to a smaller diameter.

A FAC lens will help equalize the two diverging angles.
It is a cylinder-type lens.

Then a larger plano-convex lens will allow you to focus down to the point you are looking for.

LarryDFW
 
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maxh

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BTW the math on your numbers supports your results. 1W at .4mm diameter focal point is 1/4th the power density of 250mW at .1mm. 4 times the diameter is 16 times the area...
 
RA_pierce

RA_pierce

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Near IR is reflected by some organic materials like light wood, paper, cardboard etc.
If you look up IR photography you will see what I mean.

And as others have said- higher power density will make it easier.
 
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LuxIgnis

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Thanks guys,
good! I will def buy this famous although not easily found cylinder lens.
If you do have suggestions on where to find a decent quantity of these (5), at a decent price, please post.
Now it makes sense , I really didn't think of the fact that it's 4 times less concentrated then LOC, being the area 0.4x0.4mm hence 1.6 mm/sq
The diode is being driven conservatively at 1100ma, I know it can take 1300 but I'd probably need copper heatsinks for that, since it does get warm on 1 minute + cycles.
 
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LuxIgnis

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Thanks,
I have found the lens at 5$ a pice, bought 6 of them.
that's a great price, I hope they do their job right.
 
lasersbee

lasersbee

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How about linking to where you got them and which ones...:whistle:

Other members may be looking for a source of these lenses..


Jerry
 
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LuxIgnis

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I thought that using the negative cylindrical lens would be better so I would spread out the slow axix and then use a aspheric very close to this lens to focus the dot.
The other way I guess would be to tighten the fast axis, with a positive cylindrical,
in which case then I thought of using these long 4" lenses, cut up every half inch.
It would make 8 nice cylinder lenses for 4$ total, that's .50 a piece.
CYLINDRICAL LENS, PCX - 4" LONG x 1/8" WIDE x 3mm FL - Surplus Shed
 
HIMNL9

HIMNL9

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Someone know what is the shipping fees for surplusshed, for Italy ?

They have nothing in the FAQ, nor seem that there's a way to check this without first subscribe and order .....



Edit: by the way, a negative (SAC) is usually better for focus at distance, a positive (FAC) is usually better when you want to focus it close for burn .....
 
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HIMNL9

HIMNL9

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Lombardia ..... grazie per la cifra.

But is better to continue with visitors messages, in Italian, cause this is, after all, an English forum, and i don't want to spam it (well, not too much more than the usual :D)
 
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