Laser Engraver - Project Idea

Last week I stumbled across the MicroSlice on kickstarter, this is a mini laser engraver and cutter made from laser cut wood, salvaged dvd drive parts and some electronics.
It looks really cool but it isn't really useful enough for me to spend £200 on, but its given me an idea for a new project.

I would love to build something like this and I think its something I can do for less than the £200 or even if I can't it should be fun.

The MicroSlice has a cutting area of 50mm by 50mm which while being small is useful; at this stage I am aiming to have a cutting area of roughly 150mm by 200mm, basically an A5 piece of paper. I want to end up with a small device that can fit on a shelf so I may revise this down if needed.

The laser which does the actual cutting is fairly easy to obtain, at least at low 200mW power levels. I striped a laser diode out of a DVD drive last week and found that if I mounted that into a housing with focusing lense I could engrave and burn dark coloured materials with ease and that was running straight from a bench power supply.
Over the weekend I received a laser driver which will allowed me to increase the power level a little more, to the point where I was just about able to cut white paper. While it's really fun holding a laser capable of cutting through things it isn't really awesome enough enough for my needs so I am exploring other options.
Light coloured or shiny materials reflect the light before it has a chance to heat up and do any damage, I need something powerful enough to burn despite the materials attempts to reflect the heat.

The MicroSlice is entirely laster cut in either wood or acrylic, whilst this is an option open to me I would like to use 3D printed parts as much as possible. By using 3D printed parts I can design and build it at home rather than having to visit the workshop every time I need to make an alteration. I may need to use a combination of both or include another build material because for the size I am after I would need a lot of printed parts spanning some wide gaps.

In addition to the frame I also need to deal with x and y movement, the MicroSlice does this with a lead screw and stepper motor from an optical drive, these are great and come as complete mechanisms but only have about 60mm of travel, I need 200mm!
I payed around recently with linear motion but for that project I used a timing belt. At the moment this seems a little extreme for something this small so I am currently looking at a carriage on guide rails driven by a leadscrew and stepper motor or possibly just a threaded rod.

I have ordered a number of parts and over the next week I will start to put some of these together and come up with a viable design.

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