Hello Everyone!
My name is Jethro Hazelhurst. I would like to ask some specific questions regarding the optics required to focus a high wattage laser diode.
To give some background to the question: I started an open source initiative to design and prototype what is known as a 3D Metal Printer.
here is the wiki: http://www.metalbot.org/wiki/index.php?title=Main_Page
The machine we are designing will use a powerful laser beam to melt very thin layers of metal powder* untill the object is materialized layer by layer. Simple.
*For reference, the powder layers are 50-30um in thickness
Reasons for a Very Tight Focus: To melt the metal powder the laser beam has to reach a critical energy density. This depends on two things:
* (1) The wattage of the laser
* (2) The area of the laser spot on the surface of the powder.
To give an idea of the energy levels required to melt metal powder, current 3D Printers use 200W Fiber Lasers with a focus of 500 microns down to 100 microns.
The single biggest challenge for us is the sheer cost of a high wattage laser like that, so our solution is to go smaller.
Here is the logic: Instead of using a 200W Fiber laser with a focus of 500 microns, why don't we use a 20W laser with a focus of 50 microns? We will have the same critical energy density needed to melt the powder, but use a laser a fraction of the cost.
Questions:
* What is the best focus you can expect to achieve from a high wattage (20-50W) 'laser diode'. for example this fiber coupled one: http://bwt-bj.en.alibaba.com/product/387532406-213054480/976nm_25W_Fiber_coupled_Laser_Diode_Module_K976DA3RN_25_00W.html?edm_src=sys&edm_type=fdbk&edm_grp=0&edm_cta=read_msg&edm_time=realtime&edm_ver=e
From what I have read, high power laser diodes have some pretty bad beam quality.
* What lenses will we need in order to get the best focus possible out of the diode.
Keep in mind that the laser beam will travel through a laser scanner.
From my limited knowledge, the raw laser beam goes into a beam expander then into the scanner where it is reflected off the two galvo mirrors then down through the F-Theta lens which focuses the expanded beam down to the work surface.
This part of the project is very similar to a laser engraver.
We have a budget estimate of $3000.
Many thanks in advance :yh:
Jethro.
My name is Jethro Hazelhurst. I would like to ask some specific questions regarding the optics required to focus a high wattage laser diode.
To give some background to the question: I started an open source initiative to design and prototype what is known as a 3D Metal Printer.
here is the wiki: http://www.metalbot.org/wiki/index.php?title=Main_Page
The machine we are designing will use a powerful laser beam to melt very thin layers of metal powder* untill the object is materialized layer by layer. Simple.
*For reference, the powder layers are 50-30um in thickness
Reasons for a Very Tight Focus: To melt the metal powder the laser beam has to reach a critical energy density. This depends on two things:
* (1) The wattage of the laser
* (2) The area of the laser spot on the surface of the powder.
To give an idea of the energy levels required to melt metal powder, current 3D Printers use 200W Fiber Lasers with a focus of 500 microns down to 100 microns.
The single biggest challenge for us is the sheer cost of a high wattage laser like that, so our solution is to go smaller.
Here is the logic: Instead of using a 200W Fiber laser with a focus of 500 microns, why don't we use a 20W laser with a focus of 50 microns? We will have the same critical energy density needed to melt the powder, but use a laser a fraction of the cost.
Questions:
* What is the best focus you can expect to achieve from a high wattage (20-50W) 'laser diode'. for example this fiber coupled one: http://bwt-bj.en.alibaba.com/product/387532406-213054480/976nm_25W_Fiber_coupled_Laser_Diode_Module_K976DA3RN_25_00W.html?edm_src=sys&edm_type=fdbk&edm_grp=0&edm_cta=read_msg&edm_time=realtime&edm_ver=e
From what I have read, high power laser diodes have some pretty bad beam quality.
* What lenses will we need in order to get the best focus possible out of the diode.
Keep in mind that the laser beam will travel through a laser scanner.
From my limited knowledge, the raw laser beam goes into a beam expander then into the scanner where it is reflected off the two galvo mirrors then down through the F-Theta lens which focuses the expanded beam down to the work surface.
This part of the project is very similar to a laser engraver.
We have a budget estimate of $3000.
Many thanks in advance :yh:
Jethro.
Last edited:
