Cutting is the separation or opening of a physical object, into two or more portions, through the application of an acutely directed

force In physics, a force is an influence that can cause an Physical object, object to change its velocity unless counterbalanced by other forces. In mechanics, force makes ideas like 'pushing' or 'pulling' mathematically precise. Because the Magnitu ...

. Implements commonly used for

cutting Cutting is the separation or opening of a physical object, into two or more portions, through the application of an acutely directed force. Implements commonly used for wikt:cut, cutting are the knife and saw, or in medicine and science the sca ...

are the

knife A knife (: knives; from Old Norse 'knife, dirk') is a tool or weapon with a cutting edge or blade, usually attached to a handle or hilt. One of the earliest tools used by humanity, knives appeared at least Stone Age, 2.5 million years ago, as e ...

and

saw A saw is a tool consisting of a tough blade, Wire saw, wire, or Chainsaw, chain with a hard toothed edge used to cut through material. Various terms are used to describe toothed and abrasive saws. Saws began as serrated materials, and when man ...

, or in medicine and science the

scalpel A scalpel or bistoury is a small and extremely sharp bladed instrument used for surgery, anatomical dissection, podiatry and various handicrafts. A lancet is a double-edged scalpel. Scalpel blades are usually made of hardened and tempered ...

and

microtome A microtome (from the Greek ''mikros'', meaning "small", and ''temnein'', meaning "to cut") is a cutting tool used to produce extremely thin slices of material known as ''sections'', with the process being termed microsectioning. Important in sc ...

. However, any sufficiently sharp object is capable of cutting if it has a

hardness In materials science, hardness (antonym: softness) is a measure of the resistance to plastic deformation, such as an indentation (over an area) or a scratch (linear), induced mechanically either by Pressing (metalworking), pressing or abrasion ...

sufficiently larger than the object being cut, and if it is applied with sufficient force. Even liquids can be used to cut things when applied with sufficient force (see

water jet cutter A water jet cutter, also known as a water jet or waterjet, is an industrial tool capable of cutting a wide variety of materials using an extremely high-pressure jet of water, or a mixture of water and an abrasive substance. The term abrasive je ...

). Cutting is a compressive and

shearing Sheep shearing is the process by which the woollen fleece of a sheep is cut off. The person who removes the sheep's wool is called a '' shearer''. Typically each adult sheep is shorn once each year (depending upon dialect, a sheep may be sai ...

phenomenon, and occurs only when the total stress generated by the cutting implement exceeds the ultimate

strength Strength may refer to: Personal trait *Physical strength, as in people or animals *Character strengths like those listed in the Values in Action Inventory *The exercise of willpower Physics * Mechanical strength, the ability to withstand ...

of the material of the object being cut. The simplest applicable equation is: :

\text =

\tau=\frac

The stress generated by a cutting implement is directly proportional to the force with which it is applied, and inversely proportional to the area of contact. Hence, the smaller the area (i.e., the sharper the cutting implement), the less force is needed to cut something. It is generally seen that cutting edges are thinner for cutting soft materials and thicker for harder materials. This progression is seen from

kitchen knife A kitchen knife is any knife that is intended to be used in food preparation. While much of this work can be accomplished with a few general-purpose knives — notably a large chef's knife and a smaller serrated blade utility knife — there ...

, to cleaver, to axe, and is a balance between the easy cutting action of a thin

blade A blade is the Sharpness (cutting), sharp, cutting portion of a tool, weapon, or machine, specifically designed to puncture, chop, slice, or scrape surfaces or materials. Blades are typically made from materials that are harder than those they a ...

vs strength and edge durability of a thicker blade.

Metal cutting

Cutting has been at the core of manufacturing throughout history. For metals many methods are used and can be grouped by the physical phenomenon used. It is the process of producing a work piece by removing unwanted material from a block of metal, in the form of chips. * Chip forming (material removal processes) – sawing,

drilling Drilling is a cutting process where a drill bit is spun to cut a hole of circular cross section (geometry), cross-section in solid materials. The drill bit is usually a rotary Cutting tool (machining), cutting tool, often multi-point. The bit i ...

milling Milling may refer to: * Milling (minting), forming narrow ridges around the edge of a coin * Milling (grinding), breaking solid materials into smaller pieces by grinding, crushing, or cutting in a mill * Milling (machining), a process of using ro ...

turning Turning is a machining process in which a cutting tool, typically a non-rotary tool bit, describes a helix toolpath by moving more or less linearly while the workpiece rotates. Usually the term "turning" is reserved for the generation of ...

etc. *

Shearing Sheep shearing is the process by which the woollen fleece of a sheep is cut off. The person who removes the sheep's wool is called a '' shearer''. Typically each adult sheep is shorn once each year (depending upon dialect, a sheep may be sai ...

– punching, stamping, scissoring, blanking * Abrasive material removal – grinding,

lapping Lapping is a machining process in which two surfaces are rubbed together with an abrasive between them, by hand movement or using a machine. Lapping often follows other subtractive processes with more aggressive material removal as a first ste ...

polishing Polishing is the process of creating a smooth and shiny surface by rubbing it or by applying a chemical treatment, leaving a clean surface with a significant specular reflection (still limited by the index of refraction of the material accordi ...

, water-jet * Heat –

flame cutting Principle of burn cutting Oxy-fuel welding (commonly called oxyacetylene welding, oxy welding, or gas welding in the United States) and oxy-fuel cutting are processes that use fuel gases (or liquid fuels such as gasoline or petrol, diesel, bio ...

plasma cutting Plasma cutting is a process that cuts through electrically conductive materials by means of an accelerated jet of hot plasma. Typical materials cut with a plasma torch include steel, stainless steel, aluminum, brass and copper, although other ...

laser cutting Laser cutting is a technology that uses a laser to vaporize materials, resulting in a cut edge. While typically used for industrial manufacturing applications, it is now used by schools, small businesses, architecture, and hobbyists. Laser cutt ...

* Electrochemical –

etching Etching is traditionally the process of using strong acid or mordant to cut into the unprotected parts of a metal surface to create a design in intaglio (incised) in the metal. In modern manufacturing, other chemicals may be used on other type ...

electrical discharge machining Electrical discharge machining (EDM), also known as spark machining, spark eroding, die sinking, wire burning or wire erosion, is a metal fabrication process whereby a desired shape is obtained by using electrical discharges (sparks). Material is ...

(EDM), electrochemical machining (ECM) Every method has its limitations in accuracy, cost, and effect on the material. For example, heat may damage the quality of heat treated alloys, and laser cutting is less suitable for highly reflective materials such as aluminum. Laser cutting sheet metal produces flat parts and etches and engraves parts from complex or simple designs. It is used over other cutting options for its quick process and customizable abilities.

References

External links

*
How stuff works – Handsaws

Etching vs. traditional metal machining
{{Authority control Suicide methods de:Zerspanen

Metal cutting

See also

References

External links