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Deburr
A burr is a raised edge or small piece of material that remains attached to a workpiece after a modification process. It is usually an unwanted piece of material and is removed with a deburring tool in a process called 'deburring'. Burrs are most commonly created by machining operations, such as grinding, drilling, milling, engraving or turning. It may be present in the form of a fine wire on the edge of a freshly sharpened tool or as a raised portion of a surface; this type of burr is commonly formed when a hammer strikes a surface. Deburring accounts for a significant portion of manufacturing costs. In the printmaking technique of drypoint, burr, which gives a rich fuzzy quality to the engraved line, is highly desirable—the great problem with the drypoint medium is that the burr rapidly diminishes after as few as ten impressions are printed. Types There are three types of burrs that can be formed from machining operations: ''Poisson burr'', ''rollover burr'', and ''bre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deburring Tool
A burr is a raised edge or small piece of material that remains attached to a workpiece after a modification process. It is usually an unwanted piece of material and is removed with a deburring tool in a process called 'deburring'. Burrs are most commonly created by machining operations, such as Grinding (abrasive cutting), grinding, drilling, Milling machine, milling, engraving or turning. It may be present in the form of a fine wire on the edge of a freshly sharpened tool or as a raised portion of a surface; this type of burr is commonly formed when a hammer strikes a surface. Deburring accounts for a significant portion of manufacturing costs. In the printmaking technique of drypoint, burr, which gives a rich fuzzy quality to the engraved line, is highly desirable—the great problem with the drypoint medium is that the burr rapidly diminishes after as few as ten impressions are printed. Types There are three types of burrs that can be formed from machining operations: ''Poi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electropolishing
Electropolishing, also known as electrochemical polishing, anodic polishing, or electrolytic polishing (especially in the metallography field), is an electrochemical process that removes material from a metallic workpiece, reducing the surface roughness by levelling micro-peaks and valleys, improving the surface finish. Electropolishing is often compared to, but distinctly different from, electrochemical machining. It is used to polish, passivate, and deburr metal parts. It is often described as the reverse of electroplating. It may be used in lieu of abrasive fine polishing in microstructural preparation. Mechanism Typically, the work-piece is immersed in a temperature-controlled bath of electrolyte and serves as the anode; it is connected to the positive terminal of a DC power supply, the negative terminal being attached to the cathode. A current passes from the anode, where metal on the surface is oxidised and dissolved in the electrolyte, to the cathode. At the cathode, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Abrasive Flow Machining
Abrasive flow machining (AFM), also known as abrasive flow deburring or extrude honing, is an interior surface finishing process characterized by flowing an abrasive-laden fluid through a workpiece. This fluid is typically very viscous, having the consistency of putty, or dough. AFM smooths and finishes rough surfaces, and is specifically used to remove burrs, polish surfaces, form radii, and even remove material. The nature of AFM makes it ideal for interior surfaces, slots, holes, cavities, and other areas that may be difficult to reach with other polishing or grinding processes. Due to its low material removal rate, AFM is not typically used for large stock-removal operations, although it can be. Abrasive flow machining was first patented by the Extrude Hone Corporation in 1970. Process In abrasive flow machining, the abrasive fluid flows through the workpiece, effectively performing erosion. Abrasive particles in the fluid contact raised features on the surface of the workp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Embrittlement
Embrittlement is a significant decrease of ductility of a material, which makes the material brittle. Embrittlement is used to describe any phenomena where the environment compromises a stressed material's mechanical performance, such as temperature or environmental composition. This is oftentimes undesirable as brittle fracture occurs quicker and can much more easily propagate than ductile fracture, leading to complete failure of the equipment. Various materials have different mechanisms of embrittlement, therefore it can manifest in a variety of ways, from slow crack growth to a reduction of tensile ductility and toughness. Mechanisms Embrittlement is a series complex mechanism that is not completely understood. The mechanisms can be driven by temperature, stresses, grain boundaries, or material composition. However, by studying the embrittlement process, preventative measures can be put in place to mitigate the effects. There are several ways to study the mechanisms. During me ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mass-finishing
Mass finishing is a group of manufacturing processes that allow large quantities of parts to be simultaneously finished. The goal of this type of finishing is to burnish, deburr, clean, radius, de-flash, descale, remove rust, polish, brighten, surface harden, prepare parts for further finishing, or break off die cast runners. The two main types of mass finishing are tumble finishing, also known as barrel finishing, and vibratory finishing.Degarmo, pp. 781–784. Both involve the use of a cyclical action to create grinding contact between surfaces. Sometimes the workpieces are finished against each other; however, usually a finishing medium is used. Mass finishing can be performed dry or wet; wet processes have liquid lubricants, cleaners, or abrasives, while dry processes do not. Cycle times can be as short as 10 minutes for nonferrous workpieces or as long as 2 hours for hardened steel. Mass finishing processes can be configured as either batch systems, in which batches o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glycol
A diol is a chemical compound containing two hydroxyl groups ( groups). An aliphatic diol is also called a glycol. This pairing of functional groups is pervasive, and many subcategories have been identified. The most common industrial diol is ethylene glycol. Examples of diols in which the hydroxyl functional groups are more widely separated include 1,4-butanediol and propylene-1,3-diol, or beta propylene glycol, . Synthesis of classes of diols Geminal diols A geminal diol has two hydroxyl groups bonded to the same atom. These species arise by hydration of the carbonyl compounds. The hydration is usually unfavorable, but a notable exception is formaldehyde which, in water, exists in equilibrium with methanediol H2C(OH)2. Another example is (F3C)2C(OH)2, the hydrated form of hexafluoroacetone. Many gem-diols undergo further condensation to give dimeric and oligomeric derivatives. This reaction applies to glyoxal and related aldehydes. Vicinal diols In a vicinal diol, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cryogenic
In physics, cryogenics is the production and behaviour of materials at very low temperatures. The 13th IIR International Congress of Refrigeration (held in Washington DC in 1971) endorsed a universal definition of “cryogenics” and “cryogenic” by accepting a threshold of 120 K (or –153 °C) to distinguish these terms from the conventional refrigeration. This is a logical dividing line, since the normal boiling points of the so-called permanent gases (such as helium, hydrogen, neon, nitrogen, oxygen, and normal air) lie below 120K while the Freon refrigerants, hydrocarbons, and other common refrigerants have boiling points above 120K. The U.S. National Institute of Standards and Technology considers the field of cryogenics as that involving temperatures below -153 Celsius (120K; -243.4 Fahrenheit) Discovery of superconducting materials with critical temperatures significantly above the boiling point of nitrogen has provided new interest in reliable, low cost ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flash (manufacturing)
Flash, also known as flashing, is excess material attached to a molded, forged, or cast product, which must usually be removed. This is typically caused by leakage of the material between the two surfaces of a mold (beginning along the parting line) or between the base material and the mold in the case of overmolding. Details Molding flash is seen when the optimized parameter on cull height is not calibrated. Proper design of mold parting surfaces can reduce or eliminate flash. Molding flash can be caused from old or worn mold cavities that no longer fit tightly together. Other times, the complexity of the part requires so many mating pieces with such precise geometries that it is almost impossible to create a perfect fit on every impression. Most often, the type of material being molded, and its attendant viscosity in its liquid form, is the primary factor that leads to the creation of the unwanted mold flash.Bozzelli, Joh"An Expert Tells How to Stop Flash" ''Plastics Technolog ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Die Cast
Die casting is a metal casting process that is characterized by forcing molten metal under high pressure into a mold cavity. The mold cavity is created using two hardened tool steel dies which have been machined into shape and work similarly to an injection mold during the process. Most die castings are made from non-ferrous metals, specifically zinc, copper, aluminium, magnesium, lead, pewter, and tin-based alloys. Depending on the type of metal being cast, a hot- or cold-chamber machine is used. The casting equipment and the metal dies represent large capital costs and this tends to limit the process to high-volume production. Manufacture of parts using die casting is relatively simple, involving only four main steps, which keeps the incremental cost per item low. It is especially suited for a large quantity of small- to medium-sized castings, which is why die casting produces more castings than any other casting process. Die castings are characterized by a very good s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plastic
Plastics are a wide range of synthetic or semi-synthetic materials that use polymers as a main ingredient. Their plasticity makes it possible for plastics to be moulded, extruded or pressed into solid objects of various shapes. This adaptability, plus a wide range of other properties, such as being lightweight, durable, flexible, and inexpensive to produce, has led to its widespread use. Plastics typically are made through human industrial systems. Most modern plastics are derived from fossil fuel-based chemicals like natural gas or petroleum; however, recent industrial methods use variants made from renewable materials, such as corn or cotton derivatives. 9.2 billion tonnes of plastic are estimated to have been made between 1950 and 2017. More than half this plastic has been produced since 2004. In 2020, 400 million tonnes of plastic were produced. If global trends on plastic demand continue, it is estimated that by 2050 annual global plastic production will reach over 1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Liquid Nitrogen
Liquid nitrogen—LN2—is nitrogen in a liquid state at low temperature. Liquid nitrogen has a boiling point of about . It is produced industrially by fractional distillation of liquid air. It is a colorless, low viscosity liquid that is widely used as a coolant. Physical properties The diatomic character of the N2 molecule is retained after liquefaction. The weak van der Waals interaction between the N2 molecules results in little interatomic interaction, manifested in its very low boiling point. The temperature of liquid nitrogen can readily be reduced to its freezing point by placing it in a vacuum chamber pumped by a vacuum pump. Liquid nitrogen's efficiency as a coolant is limited by the fact that it boils immediately on contact with a warmer object, enveloping the object in an insulating layer of nitrogen gas bubbles. This effect, known as the Leidenfrost effect, occurs when any liquid comes in contact with a surface which is significantly hotter than its boil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
