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Galvo assembly and controller?

Posted by MrBaz 
Galvo assembly and controller?
January 15, 2014 08:11PM
Anyone know of a readily available galvo setup and controller that could be used for rastering/drawing with a laser? Basic CNC with a laser head is extremely inefficient for SLS, whereas a laser marking head is light years faster.

A lot of the commercial units are unbelievably expensive and require their own proprietary (but yet quite awesome) controllers.


Dangit. Wrong forum. Can a mod move this to the SLS section? Thanks.

Edited 1 time(s). Last edit at 01/15/2014 08:33PM by MrBaz.
Re: Galvo assembly and controller?
May 05, 2014 02:45AM
i was just hunting for the same thing for SLS printing.

[www.ebay.com]

is this too expensive?
VDX
Re: Galvo assembly and controller?
May 05, 2014 09:09AM
... you'll need much bigger mirrors! - after wrecking two 20x20x1mm big mirrors (biggest I've got moving with a similar galvo-setup) at around 15Watts of NIR in a 8mm wide beam I've changed to 40x40x6mm big mirrors and servo-motors instead of galvos for moving the bigger masses ...


Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]
Re: Galvo assembly and controller?
May 05, 2014 09:02PM
VDX,

i may be wrong, but it sounds like the mirror coatings were incorrect for reflecting the beam wavelength you are using. or is it just the small mass of the mirrors not being able to dissipate the absorbed heat?
VDX
Re: Galvo assembly and controller?
May 06, 2014 02:31AM
... the mirrors originally used with the galvoscanners weren't usable with my 1070nm fiber-lasers (but worked good with 445nm), so I've replaced them by 20x20x1mm big 'laser-mirrors', that were maybe 95% reflective for NIR.

The not expanded laserbeam is something around 4mm in diameter, but the energy density in the center is so big, that it starts overheating the coating in a spot of maybe 1mm diameter with >4W CW (but survived 20W with 30% PWM-ratio).

My actual mirrors are from old copiers and survive until 40W CW and >120W pulsed with the beam expanded to 8mm diameter.

I have a professional galvo-head too with dielectric mirrors, where the coating looks red-translucent - but they are designed for pulsing only with 1064nm and around 45deg reflection, not for CW exposure.

There are mirrors made from metal with higher reflectivity and thermal conductivity, o they will survive much higher energy densities, but they are really expensive and much more scratch-sensitive than coated glass-mirrors ...


Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]
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