Twist drills have some important features in the hole-making procedure. They normally have two cutting edges and two flutes which are actually grooves formed in the body of the drill to provide the cutting lips and permit the removal of chips while allowing the cutting fluids to reach action. The twist drill is the most important among allied drills and it is gaining quite a lot of importance for critical hole-making applications in the metalworking industry. Every shop and plant that intends to maximize its productivity and improve quality almost always has a twist drill. The trend today is towards the high performance of twist drills particularly those that are made from tungsten carbide and other premium materials that have been combined with innovative geometries, tighter tolerances and more advanced coatings.
Workpiece materials today are becoming more difficult to machine because they are harder and their geometries have become more complex. As a result, the design of allied drills has evolved towards new base tool materials, new geometries, tighter tolerances and modern coatings. New emerging designs for allied drills can be called high performance drills because they are mostly configured from base materials that include cobalt, cobalt with coolant holes, solid carbide, solid carbide with cool and holes and carbide tipped and coolant holes.
The purpose of using premium materials on the high performance drills is to improve its ability to withstand the higher temperature that is generated at higher surface footage rates while allowing for shock resistance during the drilling process. Premium tools materials and advances in coating systems have increased surface speeds and have reduced drilling time. This has resulted into a trend towards premium materials like solid carbide in order to enhance productivity. Solid carbide became the choice to optimize drilling performance due to the following reasons:
- Solid carbide has improved metallurgical properties that provides the foundation for superior performance
- Due to the toughness of carbide, special drill geometries were created.
- Enhanced thin film technology has provided coatings that have the capability to reduce friction better so that tool can last longer.
- Solid carbide fully exploits the higher accuracy and rigidity of this generation’s CNC machine tools.