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Heat Staking
Staking is the process of connecting two components by creating an interference fit between the two pieces. One workpiece has a hole in it while the other has a boss that fits within the hole. The boss is very slightly undersized so that it forms a slip fit. A staking punch is then used to expand the boss radially and to compress the boss axially so as to form an interference fit between the workpieces. This forms a permanent joint.Degarmo, pp. 415–416. Thermoplastic staking Thermoplastic staking, also known as heat staking, is the same process except that it uses heat to deform the plastic boss, instead of cold forming. A plastic stud protruding from one component fits into a hole in the second component. The stud is then deformed through the softening of the plastic to form a head which mechanically locks the two components together. It is a versatile technique benefiting from being quick, economical and consistent. Unlike welding techniques, staking has the capacity to join plas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Interference Fit
An interference fit, also known as a pressed fit or friction fit is a form of fastening between two ''tight'' fitting mating parts that produces a joint which is held together by friction after the parts are pushed together. Depending on the amount of interference, parts may be joined using a tap from a hammer or ''pressed'' together using a hydraulic ram. Critical components that must not sustain damage during joining may also be cooled significantly below room temperature to shrink one of the components before fitting. This method allows the components to be joined without force and producing a shrink fit interference when the component returns to normal temperature. Interference fits are commonly used with aircraft fasteners to improve the fatigue life of a joint. Introducing interference between parts These fits, though applicable to shaft and hole assembly, are more often used for bearing-housing or bearing-shaft assembly. Tightness of fit The tightness of fit is con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boss (engineering)
In engineering, a boss is a protruding feature on a work piece. A common use for a boss is to locate one object within a pocket or hole of another object. For instance, some motors use a precisely machined boss on the front face to locate it on the mating part. Like a process on a bone, bosses on castings can provide attachment points or bearing surfaces. The term 'boss' when used in engineering can also relate to a finishing edge around (usually) a circular opening that allows the opening to locate onto, or within another opening thus locating or joining two items together with a view to the location or joining being temporary or semi-permanent. A common everyday example of a boss is the housing of the rotation spindle in a washing machine drum, or on a cylinder lawn mower at the end of the cutting blade cylinder which may house a bearing set to allow the cylinder to rotate through one plane, but held firm in another plane. A boss can also be a brass eyelet on a sail. It is a gener ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Slip Fit
Engineering fits are generally used as part of geometric dimensioning and tolerancing when a part or assembly is designed. In engineering terms, the "fit" is the clearance between two mating parts, and the size of this clearance determines whether the parts can, at one end of the spectrum, move or rotate independently from each other or, at the other end, are temporarily or permanently joined. Engineering fits are generally described as a "shaft and hole" pairing, but are not necessarily limited to just round components. ISO is the internationally accepted standard for defining engineering fits, but ANSI is often still used in North America. ISO and ANSI both group fits into three categories: clearance, location or transition, and interference. Within each category are several codes to define the size limits of the hole or shaft - the combination of which determines the type of fit. A fit is usually selected at the design stage according to whether the mating parts need to be accur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cold Forming
In metallurgy, cold forming or cold working is any metalworking process in which metal is shaped below its recrystallization temperature, usually at the ambient temperature. Such processes are contrasted with hot working techniques like hot rolling, forging, welding, etc. The same or similar terms are used in glassmaking for the equivalents; for example cut glass is made by "cold work", cutting or grinding a formed object. Cold forming techniques are usually classified into four major groups: squeezing, bending, drawing, and shearing. They generally have the advantage of being simpler to carry out than hot working techniques. Unlike hot working, cold working causes the crystal grains and inclusions to distort following the flow of the metal; which may cause work hardening and anisotropic material properties. Work hardening makes the metal harder, stiffer, and stronger, but less plastic, and may cause cracks of the piece. The possible uses of cold forming are extremely v ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plasticity (physics)
In physics and materials science, plasticity, also known as plastic deformation, is the ability of a solid material to undergo permanent Deformation (engineering), deformation, a non-reversible change of shape in response to applied forces. For example, a solid piece of metal being bent or pounded into a new shape displays plasticity as permanent changes occur within the material itself. In engineering, the transition from Elasticity (physics), elastic behavior to plastic behavior is known as Yield (engineering), yielding. Plastic deformation is observed in most materials, particularly metals, soils, Rock (geology), rocks, concrete, and foams. However, the physical mechanisms that cause plastic deformation can vary widely. At a crystalline scale, plasticity in metals is usually a consequence of dislocations. Such defects are relatively rare in most crystalline materials, but are numerous in some and part of their crystal structure; in such cases, plastic crystallinity can res ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Softening
In physics and astronomy, an ''N''-body simulation is a simulation of a dynamical system of particles, usually under the influence of physical forces, such as gravity (see ''n''-body problem for other applications). ''N''-body simulations are widely used tools in astrophysics, from investigating the dynamics of few-body systems like the Earth-Moon-Sun system to understanding the evolution of the large-scale structure of the universe. In physical cosmology, ''N''-body simulations are used to study processes of non-linear structure formation such as galaxy filaments and galaxy halos from the influence of dark matter. Direct ''N''-body simulations are used to study the dynamical evolution of star clusters. Nature of the particles The 'particles' treated by the simulation may or may not correspond to physical objects which are particulate in nature. For example, an N-body simulation of a star cluster might have a particle per star, so each particle has some physical significance ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Economical
An economic system, or economic order, is a system of production, resource allocation and distribution of goods and services within a society or a given geographic area. It includes the combination of the various institutions, agencies, entities, decision-making processes, and patterns of consumption that comprise the economic structure of a given community. An economic system is a type of social system. The mode of production is a related concept. All economic systems must confront and solve the four fundamental economic problems: * What kinds and quantities of goods shall be produced: This fundamental economic problem is anchored on the theory of pricing. The theory of pricing, in this context, has to do with the economic decision-making between the production of capital goods and consumer goods in the economy in the face of scarce resources. In this regard, the critical evaluation of the needs of the society based on population distribution in terms of age, sex, occupation, an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Welding
Welding is a fabrication (metal), fabrication process that joins materials, usually metals or thermoplastics, by using high heat to melt the parts together and allowing them to cool, causing Fusion welding, fusion. Welding is distinct from lower temperature techniques such as brazing and soldering, which do not melting, melt the base metal (parent metal). In addition to melting the base metal, a filler material is typically added to the joint to form a pool of molten material (the weld pool) that cools to form a joint that, based on weld configuration (butt, full penetration, fillet, etc.), can be stronger than the base material. Pressure may also be used in conjunction with heat or by itself to produce a weld. Welding also requires a form of shield to protect the filler metals or melted metals from being contaminated or Oxidation, oxidized. Many different energy sources can be used for welding, including a gas flame (chemical), an electric arc (electrical), a laser, an electron ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metal
A metal (from Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts electricity and heat relatively well. Metals are typically ductile (can be drawn into wires) and malleable (they can be hammered into thin sheets). These properties are the result of the ''metallic bond'' between the atoms or molecules of the metal. A metal may be a chemical element such as iron; an alloy such as stainless steel; or a molecular compound such as polymeric sulfur nitride. In physics, a metal is generally regarded as any substance capable of conducting electricity at a temperature of absolute zero. Many elements and compounds that are not normally classified as metals become metallic under high pressures. For example, the nonmetal iodine gradually becomes a metal at a pressure of between 40 and 170 thousand times atmospheric pressure. Equally, some materials regarded as metals ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Printed Circuit Board
A printed circuit board (PCB; also printed wiring board or PWB) is a medium used in Electrical engineering, electrical and electronic engineering to connect electronic components to one another in a controlled manner. It takes the form of a Lamination, laminated sandwich structure of conductive and insulating layers: each of the conductive layers is designed with an artwork pattern of traces, planes and other features (similar to wires on a flat surface) Chemical milling, etched from one or more sheet layers of copper Lamination, laminated onto and/or between sheet layers of a Insulator (electricity), non-conductive substrate. Electrical components may be fixed to conductive pads on the outer layers in the shape designed to accept the component's terminals, generally by means of soldering, to both electrically connect and mechanically fasten them to it. Another manufacturing process adds Via (electronics), vias: plated-through holes that allow interconnections between layers. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rivet
A rivet is a permanent mechanical fastener. Before being installed, a rivet consists of a smooth cylindrical shaft with a head on one end. The end opposite to the head is called the ''tail''. On installation, the rivet is placed in a punched or drilled hole, and the tail is ''upset'', or ''bucked'' (i.e., deformed), so that it expands to about 1.5 times the original shaft diameter, holding the rivet in place. In other words, the pounding or pulling creates a new "head" on the tail end by smashing the "tail" material flatter, resulting in a rivet that is roughly a dumbbell shape. To distinguish between the two ends of the rivet, the original head is called the ''factory head'' and the deformed end is called the ''shop head'' or buck-tail. Because there is effectively a head on each end of an installed rivet, it can support tension loads. However, it is much more capable of supporting shear loads (loads perpendicular to the axis of the shaft). Fastenings used in traditional w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Screw
A screw and a bolt (see '' Differentiation between bolt and screw'' below) are similar types of fastener typically made of metal and characterized by a helical ridge, called a ''male thread'' (external thread). Screws and bolts are used to fasten materials by the engagement of the screw thread with a similar ''female thread'' (internal thread) in a matching part. Screws are often self-threading (also known as self-tapping) where the thread cuts into the material when the screw is turned, creating an internal thread that helps pull fastened materials together and prevents pull-out. There are many screws for a variety of materials; materials commonly fastened by screws include wood, sheet metal, and plastic. Explanation A screw is a combination of simple machines: it is, in essence, an inclined plane wrapped around a central shaft, but the inclined plane (thread) also comes to a sharp edge around the outside, which acts as a wedge as it pushes into the fastened material, and th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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