Wikipedia:WikiProject Metalworking/Main page
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Metalworking is the craft and practice of working with metals to create individual parts, assemblies, or large scale structures. The term covers a wide range of work from large ships, bridges and oil refineries to delicate jewelery. It therefore includes a correspondingly wide range of skills and the use of many different types of metalworking processes and their related tools.
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[edit] General Metalworking Processes
Metalworking generally is divided into the following categories, forming, cutting, and, joining. Each of these categories contain various processes. Forming is a process wherein the metal is moved to a specified geometry by:
- heating until molten, poured into a mold, and cooled,
- heating until the metal becomes plastically deformable by application of mechanical force,
- is caused to deform by the simple application of mechanical force.
Casting is an example of achieving a specific form by pouring molten metal into a mold and allowing it to cool. Hot forging is an example of moving heated metal into a specific form by deforming it with tools such as hammers or hydraulic presses while the material is at forging temperature. Drawing copper wire to a specific size is an example of forming by the use of mechanical tooling and mechanical force.
[edit] Milling
Milling is generally done on a milling machine, which is a power-driven machine used for the complex shaping of metal (or possibly other materials) parts, by removing uneeded material to form the final shape. Its basic form is that of a cutter that rotates about the spindle axis (like a drill), and a worktable that can move in multiple directions (usually three dimensions [x,y,z axes] relative to the workpiece, whereas a drill can only move in one dimension [z axis] while cutting). The motion across the surface of the workpiece is usually accomplished by moving the table on which the workpiece is mounted, in the x and y directions. Milling machines may be operated manually or under computer numerical control (CNC), and can perform a vast number of complex operations, such as slot cutting, planing, drilling, rebating, routing, etc.
[edit] Turning
A lathe is a machine tool which spins a block of material so that when abrasive, cutting, or deformation tools are applied to the workpiece, it can be shaped to produce an object which has rotational symmetry about an axis of rotation. Examples of objects that can be produced on a lathe include candlestick holders, table legs, bowls, baseball bats, crankshafts or camshafts.
The material may be held in place by a chuck or worked between one or two centers of which at least one can be moved horizontally to accommodate varying material lengths. In a metalworking lathe, metal is removed from the workpiece using a hardened cutting tool which is usually fixed to a solid moveable mounting called the "toolpost", this arrangement is then moved around the workpiece using handwheels and/or computer controlled motors.
[edit] Marking out
Marking out is the process of transferring a design or pattern to a workpiece and is the first step in the handcraft of metalworking. It is performed in many industries or hobbies although in the repetition industries the need to mark out every individual piece is eliminated.
The actual method is unique for each field of expertise, some common areas and their needs are listed below as examples of the variation in an otherwise simple process.
In the metal trades area, marking out consists of transferring the engineers plan to the workpiece in preparation for the next step, machining or manufacture.
[edit] Drilling and threading
Drilling is the process of using a drill bit in a drill to produce holes. Under normal usage, swarf is carried up and away from the tip of the drill bit by the fluting. The continued production of chips from the cutting edges pushes the older chips outwards from the hole. This continues until the chips pack too tightly, either because of deeper than normal holes or insufficient backing off (removing the drill slightly [breaking the chip] or totally from the hole [clearing the bit] while drilling). Lubricants (or coolants) (i.e. cutting fluid) are sometimes used to ease this problem and to prolong the tools life by cooling, lubricating the tip and improving chip flow.
Taps and dies are tools commonly used for the cutting of screw threads in metal parts. A tap is used to cut a female thread on the inside surface of a predrilled hole, while a die cuts a male thread on a preformed cylindrical rod.
Die head · Drill · Drill bit · Drill bit shank · Drill bit sizes · Drill and tap size chart · Drilling · Jig borer · Pin chuck · Screw thread · Taps and dies · Tap wrench
[edit] Welding
Welding is a fabrication process that joins materials, usually metals or thermoplastics, by causing coalescence. This is often done by melting the workpieces and adding a filler material to form a pool of molten material that cools to become a strong joint, but sometimes pressure is used in conjunction with heat, or by itself, to produce the weld. This is in contrast with soldering and brazing, which involves melting a lower-melting-point material between the workpieces to form a bond between them.
Many different energy sources can be used for welding, including a gas flame, an electric arc, a laser, an electron beam, friction, and ultrasound. While often an industrial process, welding can be done in many different environments, including open air, underwater and in space. Regardless of location, however, welding remains dangerous, and precautions must be taken to avoid burns, electric shock, poisonous fumes, and overexposure to ultraviolet light.
[edit] Hand fabrication
A wide variety of hand and small power tools are often used for metalworking, and an experienced machinist can fabricate almost any part using only hand tools, although it may not be as efficient (time wise) as with advanced machinery. Many types of hand tools are used, including cutting and scraping tools to remove metal, impact tools to reshape metal, and a wide variety of tools for marking, positioning, or otherwise assisting the fabrication process.
Automatic center punch · Ball-peen hammer · Burr (cutter) · C-clamp · Clamp · Combination square · Die grinder · Drift pin · F-clamp · File · File card · Hacksaw · Hammer · Hand scraper · Machinist square · Magnetic base · Needlegun scaler · Pliers · Power tool · Punch · Rotary file · Rotary tool · Saw piercing · Scriber · Tap and die · Throatless shear · Tongs · Tube and pipe benders · Vise · Workbench · Wrench
[edit] Grinding
Grinding uses an abrasive process to remove material from the workpiece. A grinding machine is a machine tool used for producing very fine finishes or making very light cuts, using an abrasive wheel as the cutting device. This wheel can be made up of various sizes and types of stones, diamonds or of inorganic materials.
