Perçages

Perçages is the term used in machining to describe the process of creating holes in a workpiece by removing material with a rotating cutting tool, typically a drill bit. The term is of French origin and is used to encompass a range of hole-making operations, from simple through-holes to precise blind holes that may require subsequent finishing steps such as reaming or tapping.

Common tools include twist drill bits for metal and wood, brad-point bits for woodworking, and center drills for starting holes. Drilling is performed on manual machines such as drill presses and on CNC mills. Bit materials vary, including high-speed steel, cobalt, and carbide, often with coatings to reduce wear. Hole diameters range from fractions of a millimeter in micro-drilling to several centimeters in general-purpose work.

Process considerations include selecting the appropriate drill size, applying lubrication or cooling for metal work, and controlling speed and feed to minimize deflection and heat. Peck drilling helps clear chips, while proper clamping and center punching improve accuracy. In many applications, drilling is followed by countersinking, spot drilling, reaming, or tapping depending on required finish and tolerance.

Hole types include through-holes, which pass completely through the workpiece, and blind holes, which terminate before the far face. Quality factors include diameter tolerance, perpendicularity, straightness, and burr control. Finishing steps such as deburring or reaming improve roundness and surface finish.

Safety concerns emphasize secure workholding, appropriate personal protective equipment, and correct speeds to avoid tool breakage. Perçages remain a fundamental operation in manufacturing and fabrication, enabling reliable creation of holes in metals, wood, and plastics.