Waterjet cutting machines
Introduction
Cutting is a subtractive manufacturing process that involves removing material from a workpiece using a cutting tool to achieve a desired shape, size, or surface finish. It is one of the most common methods in mechanical engineering and production, where excess material is sheared away in the form of chips, typically through relative motion between the tool and workpiece.[1]
The process encompasses a wide range of operations, including turning, milling, drilling, and grinding, applied to materials such as metals, plastics, and composites. Cutting tools vary from traditional edged implements like knives and saws to advanced technologies such as lasers, waterjets, and electrical discharge machining, enabling precision in industries like automotive, aerospace, and electronics.[2]
While essential for creating complex components, cutting requires careful consideration of factors like tool wear, cutting speeds, and coolant use to optimize efficiency and minimize defects. Modern advancements continue to enhance accuracy and sustainability, reducing waste and energy consumption in manufacturing.[3]
General Principles
Definition and Fundamentals
Cutting is defined as the process of separating a material or object into two or more parts by applying compressive and shearing forces that exceed the material's tensile or shear strength, typically using a sharp-edged tool to create new surfaces along a controlled plane.[4] This separation occurs when the localized forces induce failure in the material, resulting in a clean division rather than random degradation.[5]
At its core, the physics of cutting revolves around the generation of stress in the material. Stress is mathematically expressed as the force applied per unit area, given by the equation σ=FA\sigma = \frac{F}{A}σ=AF, where σ\sigmaσ is stress, FFF is the applied force, and AAA is the cross-sectional area over which the force acts.[6] In cutting, the tool's edge concentrates the force over a very small area, producing high localized stress that surpasses the material's strength threshold, leading to shear failure or fracture along the intended path.[4]
The origins of cutting trace back to the Paleolithic era, with the earliest evidence of stone tools appearing around 2.6 million years ago in the form of Oldowan flakes and cores used for cutting and scraping.[7] These rudimentary implements evolved over time; by the Bronze Age (circa 3000 BCE), metal alloys like copper-tin bronze were cast into sharper blades and axes, enhancing cutting efficiency for tools and weapons.[8] Further advancements occurred in the Iron Age (starting around 1200 BCE), where iron's superior hardness allowed for more durable cutting edges that displaced many stone and early bronze variants.[9]