304ss facemill help

I’m cutting a rectangle aprox 9x7 inches with a 6fl Mitsubishi facemill.

My inserts are lasting aprox 4 parts cutting .05 inches deep. Only taking 1 pass.

Scale has been cut in a previous op so it’s clean 304.

S850 F50.

My inserts look like this. They start throwing mild sparks and glowing metal. Cutting dry

I haven’t cut stainless in a while and work an off shift with some help but not a ton of knowledge.

All numbers are in inches.

Trying to get some better took life.

Thanks.