Today, I finally have the guts to trying to cut using the 3mm endmill that I bought from Eric.
First, I created the work using MasterCam and generated the G-Code. Feed rate is set at 60mm/min in MasterCam. During cutting, I increased it to 300mm/min and then to 600mm/min. I also increased the spindle rpm to match the feed rate. I also set the MasterCam toolpath to "roughing then finish" and 3 times cut per roughing and 3 times cut for finishing. The only mistake was, I did not reduce the feed rate when finishing.