Challenge: To improve the hole-making process in composite materials in the aerospace industry using portable machines.

Solution: New cutting tools that meet the variations and demands experienced in portable applications.

The very nature of operations with handheld tools leaves them prone to instability and even inconsistency. The performance of the equipment being used and the operator’s experience directly affect the quality of holes and productivity.

If hole-making with handheld tools is hampered by grab effect from the drill, and a high thrust force is needed to penetrate the hole, then levels of quality, efficiency and operator fatigue will be negatively affected. Operators have to concentrate more on countering the effects of the portable tool and are more likely to make mistakes, with scrap as a result.

Handheld tools are also greatly affected by how well the cutting tool functions. Cutting action, size and direction of cutting forces, possible cutting data and achievable tool life are cutting tool factors that very much determine the quality and economic outcome.

Portable handheld drills need more toughness, due to the inherent instability of the operation. For this reason, an uncoated cemented carbide drill and reamer is the best solution, as the balance of toughness and wear resistance has to be strength-oriented.

CoroDrill 452 drills for high tolerance hole making in composite materials.

The CoroDrill 452 standard drill range has been designed to optimize composite applications and composite metal-stacked applications that are performed with hand tools. On the composite drill, combinations such as the left-hand helix and right-hand drill point promote smooth cutting action with minimized or no grab effect. Only a low level of feed force is needed, and the drill makes a smoother, nondestructive exit from the material.

For the metal-stacked version there is a choice between a drill with or without a pilot incorporated in it, to reduce differences in thrust effect between the materials and to provide high hole accuracy and finish. The hole-size difference between the materials is then minimal, and exit burrs are eliminated. The nonpiloted drill has a double margin edge for stability, which further improves performance and results.

Originally published in Metalworking World 2.2011, a business magazine published by Sandvik Coromant.

Text: Christer Richt