What's happening here?

[joewino]

This weekend I was cutting some shapes out of .75" MDO with a .25" mill end bit. There were six identical sign panels to be cut from a 4' x 8' sheet. The ShopBot was to cut down .25" on each pass.

The first panel went just fine (three passes) and so I went about doing something else. Suddenly I could sense that the spindle was overloading. As the second panel was being cut out the bit suddenly began to cut deeper and deeper into the MDO (on the first pass) and then into the sacrifice board underneath, and was not following the outline of the panel - all within just a few feet...and then the bit broke.

I stopped the machine, put in a new bit, loaded the tool paths again and restarted the whole process. It cut everything to perfection, with no more problems.

Any ideas of what happened and how I can avoid the mistake in the future? The ramaining part of the bit was still tight in the collet, so the bit was not coming loose.

[paco]

I recently got pretty weird behavior from static arcs; I was vacuuming around the machine, here and there getting snapped by electrical arcs from statics, when I was ground on the table from, the machine would just stop but the DRO kept going on with the file processing. Every time that happen, I had to reset EVERY THING.

SB3, sure need some fix as for error and miscommunication issues...!