Several tool manufacturers have once again check the indexable insert drills, seeking to overcome the shortcomings of the cutting force imbalance inherent in their design. The CoroDrill 880 one of the most recent research and development in these products series launched by Sandvik Coromant (Fair Lawn, New Jersey). According to the the Sandvik product experts Bruce Carter, this can be transferred bit drill designed to avoid the problems generated by the unbalanced cutting force, thus improving the productivity and the quality of the hole, while maintaining the economy of a blade has a cutting edge of the four available .
The key is the company referred to as a "step-by-step technology concept. This phrase describes a blade cutting edge "progressively" access to the workpiece, and said to greatly reduce the past indexable drill associated radial cutting force. This concept involves two different angles of the blade and the cutting characteristics. The center blade has an obvious irregular shape of the cutting edge, the outer edge of the blade combined with a Wiper geometry.abrasive wheel The first step into the workpiece, the outside corner of the center blade contact with the workpiece. This makes the drill bit to begin cutting a relatively low radial force to the drill pipe skew minimization. In the second step, the outer corners of outer edge of the blade contacts the workpiece. This balances the force generated by the center blade. In the third step, i.e. the final step, the remaining part of the center insert start cutting. All the three steps that are in (above) illustrations.grinding wheel