[Stuart]

EDIT: for bonus points mark the point in the story where you know whats about to happen.


In the summer of 2006 we got our first (and currently only) mill. its a 10.5"^2 3 axis CNC techno Devinnci (its small its cheep but its our baby so please be kind). Well in the fall we do BEST so we used the BEST robot as a test bed for our new mill (we ended up making plywood omni wheels). So we had sent one of our mentors to training down in San Antonio and we felt OK to turn it on and start to cut. As BEST only really allows plywood and plastic, and doesn't give you much plastic, we started with plywood as our first cut. We set the mill up to how our mentor was trained and started to watch it go. Now at this time I should mention that our mentor was trained on this mill using brass and light steel, so we had the head speed turned all the way up the travel speed all the way down and were using like a 8 flute bit.

About 5 min in ( or 3 in in to the cut) the student monitoring the mill (in BEST the students have to do 100% of the work, but they do allow mentor guidance) noticed that the mill started to smell really really good like a pine forest in spring. We took a look at how the cut was going saw that there was just a pile of saw dust forming and no large chunks flinging off , it was rather unimpressive. We felt confidant enough to open the door and further "investigate" the pine fresh sent. As we opened the door a draft blew the pile of saw dust in to the air . . it was at this point as the dust mixed with the new air and aided by the very hot bit that most of the part ,as well as the aspirated saw dust, caught fire.

we have since moved to a 4 flute bit. turned the head down, increased the travel speed . . and got a vacuum attachment. We have had no further flame ups.