Ideally, one needs to have two teeth of the blade contact the metal to be cut in order to prevent chattering.
You need 18+ teeth per inch blade at a minimum. If you see the teeth being worn away, you need to verify whether you have a quality blade (bi-metal, etc) that is designed to cut metal.

Thanks....

I'll look for 18+ teeth blade. Would this prevent the machine randomly shutting down?

Thanks.

Is the motor shutting off or just bogging down? If it's shutting off it may be an electrical problem with the saw itself.