I was thinking about this the other day. How is mdf different than just thick, solid cardboard?
My guess would be the binding agent used and MDF being formed with high heat/pressure that I don’t believe is the case with cardboard.
One thing that seems consistent is the mention of nasty dust by anyone who’s cut MDF.
MDF is a wonder material, and it’s pretty much the same as cardboard - just a bunch of wood fibres and glue really, If you glued your cardboard together under the same pressure you could probably call it MDF.
It does generate rather fine dust. Having said that and notwithstanding the carcinogenic effects of breathing formaldehyde long term, it’s not really any more harmful than lots of other kinds of wood dust.
Wood dust generally should not be inhaled! I could write a thesis about how I’m a bit paranoid because my brother-in-law died of mesothelioma, or my father’s asthma or even my own sinus reactions to the stuff, but others have done a much better job. Besides, I’m more paranoid about wood dust because my workspace has two rather large doors opening into a living area of the house, and letting any dust escape would lead to a painful if not lingering demise!
For a real good time, go here: http://billpentz.com/woodworking/cyclone/index.php
Don’t be alarmed, just take as many precautions as you can - electricity and lasers and fast spinning things are dangerous too.
Mine looks exactly like yours minus the enclosure and the drag chains. 
MDF is similar to chip board, except chip board is made from larger bits and will fracture… MDF is very solid and pretty strong… the only problem is its dust from cutting is so fine it goes everywhere and is not very good for your lungs, hence the full enclosure with dust extraction…
GREAT looking set-up you have there!
Curious what you’re using for dust collection?
I want to build an enclosure for mine but it seems I’d need a taller enclosure to allow a hose connected to a dust shoe enough slack to reach the full range of movement without dragging on anything.
for my shed i have a dust extractor mounted outside in a little shed… there are 2 100mm pipes coming in to my work shop part, in the top corner… i will be connecting 1 of these to the top of the enclosure to keep it negative pressure… i will also do a dust shoe the connect my vacuum up directly… will take some pics when i complete it… will route the router power cable up in a similar fashion… i will also be cutting some vents in at the front to draw the air and dust from the front to back…
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Very nice! I look forward to seeing it completed and dirtied up. 
Thanks. Liking that box, that foam seal looks promising. Really starting to consider one myself.
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Great setup, and you’ve got pretty much the same sort of space for the machine as I have!
I think “negative pressure” is a bit of a Furphy. If you don’t allow air in, you won’t have airflow and the dust won’t move. I’d bung a vent on the opposite side of the box equal to the area of the dust inlet, and then you’ll see airflow and dust flowing with it.
The LR enclosure is a bit problematic, but I’m working on that, which is to say I’m not doing anything at all.
Yeah negative pressure is miss leading, positive airflow through the box to the dust extractor… I have just fitted gas struts and a latch to the front… with the latch released it creates a gap of 15mm about 40mm higher than the spill board so it should draw dust away… worst part is I have built all this, no idea on the programming yet… and still waiting for my control board to arrive via snail mail…
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Looking at the quality of your build I look forward to seeing your future projects! 
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The firmware will be smooth. Which brain did you buy?
RAMBO V1.4… Electrical box all done… each stepper wired back to a 9pin serial plug with limit switches… Estop kills power to steppers and tool via a relay… z axis has a led strip light at bottom of tool clamp… have a bag of T nuts to put in the bottom of spill board hopefully use the mpcnc to cut these… still need to make the tool zeroing plate and wire back to box… have wired a plug socket just need to make lead/plate/clamp… and then drill in 100mm dust extractor tube and 40mm vacuum hose line… I machined up a collet for 1/8" bits but will play with the 1/4" bits I already have…
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Oh, dang, classy stickers. Is that CF background with the red on top?
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Good Eye! 
Only carbon vinyl… partner has a cricut and she was kind enough to cut them… hope you don’t mind… I liked the “MARLIN” LOGO to so thought why not…