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What laser to use?

Posted by Noz 
What laser to use?
October 17, 2012 12:00PM
Hello all

So I've got my carteasen robot up and going, and the powder bed etc. However im unsure what type of laser I need, many companys keep trying to change my decision. Firstly I wanted to be able to print with metal and plastic, however metals need special gases to be used so they dont ignite or possibly explode. Thus im going to keep with plastics for the moment.

Ideally I would like a fibre laser, however they cost around 20k according to my research and thats alot of money when it seems laser diodes seem feasable. However no one can tell me what kind of output power I would need for sintering (maybe cutting,scribing and welding as well) with a laser diodes or even which wavelengths are better, although I would hope for a small wavelength to keep printing accuracy.

I know I can go onto the CO2 lasers, but i beleave there lifetime is less than others and are more prowne to catastrophic failures (ie blowing up).

Any advice would be appriated, and if anyone has any good supliers for turnkey solutions (so i dont need to build the laser from parts on my own) would be really really nice.

Thanks in advance to any advice given, lasers are really outside my expertise and hurt my brain quite alot,

Thanks again

Re: What laser to use?
October 17, 2012 04:32PM
Hi Noz,

IR-laserdiodes can only handle dark powders, as the light will pass through translucent or reflect from bright materials - here you can start with fibercoupled IR-diodes with 9 Watts of power, wavelengths of 808nm or 975nm with prices of around 300 Euros.

CO2-lasers can handle all sorts of organic material, glass or ceramic powders but will be reflected from shiny metal sheets - tubes with powers from 20Watts to 130Watts and estimated lifetimes of maybe 200 hours can be bought for some hundred Euros from Chinese vendors over ebay ...

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Re: What laser to use?
March 29, 2013 08:37AM
I've written a simple document about what I'm thinking about this issue. I've not experimented with everything as of yet, besides using a laser and a lens to create a small focussed point. It's not sure if this will fly, but if this work it might make way for cheaper alternatives than lasers. Maybe some of you have ideas about this as well?
open | download - thinking-about-sls-printing.pdf (201.4 KB)
Re: What laser to use?
April 11, 2013 07:19AM

Build Speed Calculator Laser 808 <!-- "this" is just the selectbox alert('titanium'); -->
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StainlessSteelTitaniumTungstenPrg Test 1Kg 1K Titan. How much money should you spend on; Power Supply? Deflection Mirror drive circuits? Digital to Analogue converter?

Final printed object size: x y z cm    
Layer depth defining final print resolution: m      
Fill: %

Initial Room Temprature in Kelvin: K  
Metal preheat temperature ( normally 20C below melt tempreature ): K

Wall plug efficiency: %  
Beam to metal absorbtion efficiency: %

Wall socket power:: W 
laser voltage : V  
Laser current: A  
Beam power entering metal: W 

Maximum hardware speed Mirror Scan Rate Mirror Scan Rate: Hz ( typical ? 64000)    

Maximum beam speed used when skipping nonpart areas: m/s    
Constants; Solid density: kg/m3    <!--change 'text' to hidden to hide text on simple version -->
Melting point: K    <!-- -->
Boiling point: K    <!-- -->
Solid specific heat capacity: J/kg/K
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Liquid specific heat capacity: J/kg/K    <!-- -->
Latent heat of fusion/melting: J/kg    <!-- style="font-size:50%;color:grey" -->
Latent heat of Fusion/boiling: J/kg
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Thermal Conductivity : W/m/K    <!-- style="font-size:50%;color:grey" -->
Thermal Diffusivity: m2/s    <!-- to get rid of text -->
Table output Format definition, Time step: s  <!-- -->
number of Steps:
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