Patent ID: 7909545

Claim:
A ballnose end mill having a diameter and a central rotational axis about which the end mill is to be rotated, said end mill comprising: a shank portion being configured to be held by a tool; a fluted portion connected to said shank portion; said fluted portion comprising a rounded, semispherical tip portion disposed opposite said shank portion; and said fluted portion comprising: a first chip flute and a corresponding first cutting tooth; a second chip flute and a corresponding second cutting tooth; said first cutting tooth comprising a first flank surface; said second cutting tooth comprising a second flank surface; said first chip flute being disposed to intersect with said first flank surface to form a first cutting edge; said second chip flute being disposed to intersect with said second flank surface to form a second cutting edge; said first cutting edge being disposed to extend along the length of said first chip flute and across a portion of said rounded, semispherical tip portion; said second cutting edge being disposed to extend along the length of said first chip flute and across a portion of said rounded, semispherical tip portion; said first flank surface merging with said second flank surface on said rounded, semispherical tip portion to form a continuous flank surface extending continuously along the length of said first cutting tooth, across said rounded, semispherical tip portion, and along the length of said second cutting tooth; said first cutting edge comprises a first cutting edge end section and said second cutting edge comprises a second cutting edge end section; said first cutting edge end section is disposed to run on one side of the central rotational axis and said second cutting edge end section is disposed to run on another side of the central rotational axis; said first cutting edge end section and said second cutting edge end section are each disposed on said tip portion and a distance from the central rotational axis; said first cutting edge end section is disposed opposite said second cutting edge end section about the central rotational axis and at least substantially parallel to said second cutting edge end section; and said continuous flank surface comprises a smooth, uninterruptedly curved, rounded surface portion disposed between said first cutting edge end section and said second cutting edge end section and which said rounded surface portion passes through the central rotational axis.