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What lens to get the smallest dot size possible with 405nm @ ~250mm?

Meduza

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Jun 2, 2008
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Hello

What lens should i use for 405nm laser if i am after the smallest dot size possible at 200-300mm focal length?

I am not concerned about power losses (50% would propably be OK), but i want a round small spot from a standard 405nm laser module (this is for building a galvo based SLA 3D printer)
 





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Jul 1, 2013
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A glass 3 element coated lens for 405 nm should give the smallest dot size ...why at 250mm most times i focus its about 10 ...12 cm.
 
Last edited:

NKO29

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Jun 6, 2013
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Actually i think if you get a LFL G2 lens, it will give the best dot. LFL= long focal length.
 
Joined
Jun 3, 2007
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Hello

What lens should i use for 405nm laser if i am after the smallest dot size possible at 200-300mm focal length?

I am not concerned about power losses (50% would propably be OK), but i want a round small spot from a standard 405nm laser module (this is for building a galvo based SLA 3D printer)

I believe all that you need acquire is a lens with a focal length of 200-300mm. there are some lenses here you could experiment with.
http://www.anchoroptics.com/catalog/product.cfm?id=253
 
Last edited:

cev1

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Apr 14, 2011
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At that focal length, the lens quality is virtually irrelevant to spot size assuming:
1. Your beam size at the lens is much smaller than your focal length (less than a factor of 10, say).
2. you aren't using a drinking glass.
 




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