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Roller burnishing is a surface finishing technique where hardened rollers cold work surface imperfections to reduce surface roughness. Roller burnishing differs from abrasive surface finishing techniques in that material is displaced rather than removed. The tooling typically consists of a hardened sphere or cylindrical roller. [1] The tooling is pressed into the surface of the part while it is rotated (in some applications, the tools are rotated instead of the part). The burnishing tool rolls against the surface of the part at a constant speed, producing a very consistent finish across the part. A surface finish of less than Ra 0.1 μm is achievable with roller burnishing. [1] A side effect is that the outer surface of the part is work hardened.
Roller burnishing is used in the production of some crankshafts. A dual roller (cylindrical) tool is moved into the thrust bearing journal of a crankshaft, while the crankshaft is spinning the tool is indexed (so each roller is perpendicular to the thrust surface while backing each other up) deforming the surfaces. So the diameters of each roller added together (compensated for elastic deformation) equals the finish dimension of the thrust bearing.
In deep hole machining, a roller burnishing tool is often combined with skiving knives on the same tool. The skiving knives pass first, scraping the inside layer of metal, followed by the burnishing rollers, which cold work the tube to create a mirror surface finish. Skive-burnishing is often used in hydraulic cylinder applications. This process can happen on a deep hole drilling machine or a dedicated skiving machine.
Engraving is the practice of incising a design on a hard, usually flat surface by cutting grooves into it with a burin. The result may be a decorated object in itself, as when silver, gold, steel, or glass are engraved, or may provide an intaglio printing plate, of copper or another metal, for printing images on paper as prints or illustrations; these images are also called "engravings". Engraving is one of the oldest and most important techniques in printmaking. Wood engraving is a form of relief printing and is not covered in this article, same with rock engravings like petroglyphs.
Metalworking is the process of shaping and reshaping metals in order to create useful objects, parts, assemblies, and large scale structures. As a term, it covers a wide and diverse range of processes, skills, and tools for producing objects on every scale: from huge ships, buildings, and bridges, down to precise engine parts and delicate jewelry.
Machining is a manufacturing process where a desired shape or part is created using the controlled removal of material, most often metal, from a larger piece of raw material by cutting. Machining is a form of subtractive manufacturing, which utilizes machine tools, in contrast to additive manufacturing, which uses controlled addition of material.
A plain bearing, or more commonly sliding contact bearing and slide bearing, is the simplest type of bearing, comprising just a bearing surface and no rolling elements. Therefore, the part of the shaft in contact with the bearing slides over the bearing surface. The simplest example of a plain bearing is a shaft rotating in a hole. A simple linear bearing can be a pair of flat surfaces designed to allow motion; e.g., a drawer and the slides it rests on or the ways on the bed of a lathe.
In mechanical engineering, a rolling-element bearing, also known as a rolling bearing, is a bearing which carries a load by placing rolling elements between two concentric, grooved rings called races. The relative motion of the races causes the rolling elements to roll with very little rolling resistance and with little sliding.
Drilling is a cutting process where a drill bit is spun to cut a hole of circular cross-section in solid materials. The drill bit is usually a rotary cutting tool, often multi-point. The bit is pressed against the work-piece and rotated at rates from hundreds to thousands of revolutions per minute. This forces the cutting edge against the work-piece, cutting off chips (swarf) from the hole as it is drilled.
A grinding machine, often shortened to grinder, is any of various power tools or machine tools used for grinding. It is a type of material removal using an abrasive wheel as the cutting tool. Each grain of abrasive on the wheel's surface cuts a small chip from the workpiece via shear deformation.
Swaging is a forging process in which the dimensions of an item are altered using dies into which the item is forced. Swaging is usually a cold working process, but also may be hot worked.
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.
In machining, boring is the process of enlarging a hole that has already been drilled by means of a single-point cutting tool, such as in boring a gun barrel or an engine cylinder. Boring is used to achieve greater accuracy of the diameter of a hole, and can be used to cut a tapered hole. Boring can be viewed as the internal-diameter counterpart to turning, which cuts external diameters.
A hydraulic cylinder is a mechanical actuator that is used to give a unidirectional force through a unidirectional stroke. It has many applications, notably in construction equipment, manufacturing machinery, elevators, and civil engineering. A hydraulic cylinder is a hydraulic actuator that provides linear motion when hydraulic energy is converted into mechanical movement. It can be likened to a muscle in that, when the hydraulic system of a machine is activated, the cylinder is responsible for providing the motion.
Deep rolling is a method of cold work deformation and burnishing of internal combustion engine crankshaft journal fillets to increase durability and design safety factors. Compressive residual stresses can be measured below the surface of a deep-rolled fillet. Other types of fillets on shafts or tubes can also benefit from this method. Cast iron crankshafts will experience the most improvement potentially doubling their fatigue life. Typically the crankshaft is machined with under-cut fillets as opposed to tangential radiused for ease of manufacture, although all types can be deep-rolled. Most automakers are currently utilizing this crankshaft technology including: General Motors LLC, Ford Motor Company, and Fiat Chrysler Automobiles (FCA) The North American-based Hegenscheidt-MFD Corporation in Sterling Heights, MI, was established in 1966. Ingersoll CM Systems of Midland, Michigan with Global HQ located in Dalian, China and European based SPMS in Évry, France, are the only major machine/tooling manufacturers of this application in Europe and North America, supplying a highly specialised product throughout the global manufacturing sectors.
The cylindrical grinder is a type of grinding machine used to shape the outside of an object. The cylindrical grinder can work on a variety of shapes, however the object must have a central axis of rotation. This includes but is not limited to such shapes as a cylinder, an ellipse, a cam, or a crankshaft.
Skiving or scarfing is the process of cutting material off in slices, usually metal, but also leather or laminates. Skiving can be used instead of rolling the material to shape when the material must not be work hardened, or must not shed minute slivers of metal later which is common in cold rolling processes. It can also be used to create fins on a block of metal, not shaving the part entirely off.
Grinding is a type of abrasive machining process which uses a grinding wheel as cutting tool.
Burnishing is the plastic deformation of a surface due to sliding contact with another object. It smooths the surface and makes it shinier. Burnishing may occur on any sliding surface if the contact stress locally exceeds the yield strength of the material. The phenomenon can occur both unintentionally as a failure mode, and intentionally as part of a metalworking or manufacturing process. It is a squeezing operation under cold working.
Brinelling is the permanent indentation of a hard surface. It is named after the Brinell scale of hardness, in which a small ball is pushed against a hard surface at a preset level of force, and the depth and diameter of the mark indicates the Brinell hardness of the surface. Brinelling is permanent plastic deformation of a surface, and usually occurs while two surfaces in contact are stationary and the material yield strength has been exceeded.
Low plasticity burnishing (LPB) cold compresses metal to provide deep, stable surface residual stresses to improve damage tolerance and extend metal fatigue life; mitigating surface damage, including fretting, corrosion pitting, stress corrosion cracking (SCC), and foreign object damage (FOD). Improved fretting fatigue and stress corrosion performance has been documented, even at elevated temperatures where the compression from other metal improvement processes: low stress grinding (LSG) etc. relax. The resulting deep layer of compressive residual stress has also been shown to improve high cycle fatigue (HCF), low cycle fatigue (LCF), and stress corrosion cracking (SCC) performance.
A cam follower, also known as a track follower, is a specialized type of roller or needle bearing designed to follow cam lobe profiles. Cam followers come in a vast array of different configurations, however the most defining characteristic is how the cam follower mounts to its mating part; stud style cam followers use a stud while the yoke style has a hole through the middle.
Metal spinning, also known as spin forming or spinning or metal turning most commonly, is a metalworking process by which a disc or tube of metal is rotated at high speed and formed into an axially symmetric part. Spinning can be performed by hand or by a CNC lathe.