For the past years I have used a spoil board on my CNC Router and it worked very well for plate material as you can fasten everything directly onto the board. Lately I do more and more work in aluminum and have to use coolant. The MDF spoil board is not ideal for that as it absorbs any liquid and swells, so I decided to make a new fixture plate from cast aluminum. As always if you have any questions I be happy to answer in the comments.