I personally don’t use Ramps controller with my MPCNC but I have built a 3dpburner laser burner which uses Ramps controller and is designed by a bright guy name villamy on thingiverse. He has a website 3dpburner.blogspot.com where he provides a free image to gcode converter software that works very well for raster engraving . He also has a nice gcode sender app that he built that works with Ramps controller. I bought the image to gcode raster software provided by Jtech photonics also but personally found Villamy’s free version to work better.
The Jtech site is a good resource for info and I’m sure their product is great but if you’re on a budget you can find an equivalent 9mm 2.8w laser at DTR laser shop with a 3 element lens for under $100. An adjustable lens is key to ensure the beam focuses to a spot about 50mm away from the lens to prevent smoke damage to the lens from being to close. A mounted fan doesn’t hurt either. In addition to the laser/lens, you’ll need a heat sink and driver which can both be had for about $20. Then you can just follow the 3dpburner.blogspot.com site for guidance on how to connect it all to Ramps and get the software there to convert images to gcode as well.
Here’s a link to my build. It’s a nice little laser engraver but one of these days I’m ginna strip it down and mount the laser on my MPCNC. I’m confident it’ll add more precision and the work area is huge in comparison.