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Q & A: Dash shaped laser beam

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Most recent answer: 10/08/2009
Q:
I sent you a question a while ago about a 2.4 watt laser cutting balsa. I have tried the laser and it will cut the balsa sheet but the beam is shaped like a dash. How do I get it to be shaped like a dot? Is there a place to purchase a lens to concentrate the beam into a dot?
- vic /58
Arizona
A:
Welcome back Vic,
Many lasers have dash shaped beams.  This is due to astigmatism of the lenses in the laser.   It is possible to have an external astigmatic lens to correct this.  You have to measure the beam width,  beam length and beam divergence and then do a little calculating in order to specify the correct lens prescription.  You can buy a cylindrical lens that will focus light in only one dimension from the Edmond company.  They run about $110 each.  See:
http://www.edmundoptics.com/onlinecatalog/displayproduct.cfm?productID=2053
A cheap possibility is to orient the laser so that the wide part of the dash is aligned parallel to the direction of the cut.

LeeH
p.s. I'm glad you bought protective glasses

(published on 10/08/2009)

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