FKM – ASTM– FKM is the ASTM designation for a class of fluorinated, carbon-based synthetic rubber, commonly known as fluoroelastomer. FKM has impressive heat resistance, allowing FKM seals to withstand temperatures greater than 200°C.
FKM is the American standard ASTM short form name for Fluro-Elastomer. It is the designation for around 80% of Fluoro-Elastomers defined by ASTM D1418. VITONâ„¢ is a registered trademark of Du Pont performance elastomers, the original developers of the rubber.
FADE-O-METER – fadeometer (plural fadeometers) A device that measures the degree that an ink sample will fade when exposed to light.
A general term for a chamber used to expose materials to a Carbon arc lamp under controlled and monitored conditions.
FILLER– Fillers are particulate material, such as minerals, diatamaceous earths, and talc, which are added to polymers to reduce cost. Fibrous reinforcements, such as glass and carbon fibers, are added to polymers to increase stiffness and to some degree strength.
Fillers in composites can be made of glasses, ceramics, metals etc. Glass fillers are usually made of crystalline silica, silicone dioxide, lithium/barium-aluminium glass, and borosilicate glass containing zinc/strontium/lithium. Ceramic fillers are made of zirconia-silica, or zirconium oxide.
The top filler materials used are ground calcium carbonate (GCC), precipitated calcium carbonate (PCC), kaolin, talc, and carbon black. Filler materials can affect the tensile strength, toughness, heat resistance, color, clarity etc. A good example of this is the addition of talc to polypropylene.
FILLER, INERT– Support columns are easily filled with Inert Filler. The inert material is of a dense consistency, and the angular particles’ size and shape minimises the presence of voids, which in turn reduces resonances that can be created in a speaker stand’s support column.
Inert fillers reduce the organic content of the fuel, which tends to reduce not only the combustibility but also the yields of toxic products. FR properties are enhanced when the filler is active, such as by releasing water or by char formation.
Filler content refers to basically all kinds of posts that you write and publish just to fill in a gap, posts that don’t provide much practical information and that aren’t really worthy of people’s shares.
FLASH – 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.
Flash is a molding defect that occurs when some molten plastic escapes from the mold cavity. Typical routes for escape are through the parting line or ejector pin locations. This extrusion cools and remains attached to the finished product.
The raw material is heated in the mould until pliable while the mould is closed for a specified period. Upon removal it is quite common that the moulded product to contain excess materials, normally called flashing, which has extruded while being heated and compressed in the mould.
FLEX CRACKING – A flex crack refers to a crack formed by excess bending of an MLCC once it has been soldered onto a PCB (Print Circuit Board). These cracks differ in appearance to cracks created by other means, such as impact or electrical overstress.
The main cause of cracking is mechanical stress, such as the mechanical/thermal stress when mounting on a substrate and deflection of the substrate after mounting.
FLOW MARKS, LINES OR CRACKS– Flow marks, also known as flow lines, are molding defects that can occur in the manufacturing process of injection molding. … They commonly occur when there is a large variation between cooling speeds of sections of the material as it flows through the mold.
FOAM RUBBER– Foam rubber is found in a wide range of applications, from cushioning in automobile seats and furniture to insulation in walls and appliances to soles and heels in footwear. Foams are made by forming gas bubbles in a plastic mixture, with the use of a blowing agent.
Foam is a substance with so many tiny air bubbles that it becomes frothy or thick. … When something froths up this way, you can say that it foams, like turbulent ocean water or a bubble bath that grows as you add water to the tub. The Old English root word is fam, which means “foam,” but also “saliva froth” and “sea.”
Foam rubbers are durable materials made of varying blends of polymers and elastomers that produce some of the most versatile and unique materials in the world of foam. … This material is durable, but not to the degree of some of the blended forms which have undergone formulaic additions to enhance performance attributes.
Silicone foam/sponge are great thermal insulators for a few reasons: They are blown materials, so the cells hold off transfer of heat well. They have high heat resistance. Many silicone foam rubbers are capable of going above 350°F.
FORMULATION – A formulation can be described as a mixture of chemicals that do not chemically react. … Formulation chemistry is a broad field responsible for producing many products used in every day life. Some examples are paints, medicine, sun screen, fuels, cleaning agents, fertilizers, and processed foods.
Product formulation is the understanding of how materials behave and interact to provide enhanced properties, improved processing and delivery of an active ingredient in a convenient and useable form. … Ingredients in a formulation work together and changing one can have a knock-on effect to others.
FREE SULFUR– Sulfur is used in the vulcanisation of black rubber, as a fungicide and in black gunpowder. Most sulfur is, however, used in the production of sulfuric acid, which is perhaps the most important chemical manufactured by western civilisations.
Sulfur is low in toxicity to people. However, ingesting too much sulfur may cause a burning sensation or diarrhea. Breathing in sulfur dust can irritate the airways or cause coughing. … If animals eat too much sulfur, it may be toxic and can be fatal.
FRICTIONING– Friction is the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other. There are several types of friction: … Fluid friction describes the friction between layers of a viscous fluid that are moving relative to each other.
Friction is the resistance to motion of one object moving relative to another. It is not a fundamental force, like gravity or electromagnetism. Instead, scientists believe it is the result of the electromagnetic attraction between charged particles in two touching surfaces.
Friction can be a useful force because it prevents our shoes slipping on the pavement when we walk and stops car tyres skidding on the road. When you walk, friction is caused between the tread on shoes and the ground. This friction acts to grip the ground and prevent sliding. Sometimes we want to reduce friction.
An object that is partly, or completely, submerged experiences a greater pressure on its bottom surface than on its top surface. An object in a fluid is displacing some of the fluid. … The upthrust force is equal in size to the weight of the fluid displaced by the object.
Face – The exposed area of a coal bed from which coal is being extracted.
Face cleat – The principal cleavage plane or joint at right angles to the stratification of the coal seam.
Face conveyor – Any conveyor used parallel to a working face which delivers coal into another conveyor or into a car.
Factor of safety – The ratio of the ultimate breaking strength of the material to the force exerted against it. If a rope will break under a load of 6000 lbs., and it is carrying a load of 2000 lbs., its factor of safety is 6000 divided by 2000 which equals 3.
Fall – A mass of roof rock or coal which has fallen in any part of a mine.
Fan, auxiliary – A small, portable fan used to supplement the ventilation of an individual working place.
Fan, booster – A large fan installed in the main air current, and thus in tandem with the main fan.
Fan signal – Automation device designed to give alarm if the main fan slows down or stops.
Fault – A slip-surface between two portions of the earth’s surface that have moved relative to each other. A fault is a failure surface and is evidence of severe earth stresses.
Fault zone – A fault, instead of being a single clean fracture, may be a zone hundreds or thousands of feet wide. The fault zone consists of numerous interlacing small faults or a confused zone of gouge, breccia, or mylonite.
Feeder – A machine that feeds coal onto a conveyor belt evenly.
Fill – Any material that is put back in place of the extracted ore to provide ground support.
Fire Clay – A geological formation, when found is usually immediately beneath a coal bed. Its heat resistant and easily processable qualities make it invaluable for use as a fire brick.
Fire damp – The combustible gas, methane, CH4. Also, the explosive methane-air mixtures with between 5% and 15% methane. A combustible gas formed in mines by decomposition of coal or other carbonaceous matter, and that consists chiefly of methane.
Fissure – An extensive crack, break, or fracture in the rocks.
Fixed carbon – The part of the carbon that remains behind when coal is heated in a closed vessel until all of the volatile matter is driven off.
Flat-lying – Said of deposits and coal seams with a dip up to 5 degrees.
Flight – The metal strap or crossbar attached to the drag chain-and-flight conveyor.
Float dust – Fine coal-dust particles carried in suspension by air currents and eventually deposited in return entries. Dust consisting of particles of coal that can pass through a No. 200 sieve.
Floor – That part of any underground working upon which a person walks or upon which haulage equipment travels; simply the bottom or underlying surface of an underground excavation.
Flue Gas Desulfurization – Any of several forms of chemical/physical processes that remove sulphur compounds formed during coal combustion. The devices, commonly called “scrubbers,” combine the sulphur in gaseous emissions with another chemical medium to form inert “sludge” which must then be removed for disposal.
Fluidized Bed Combustion – A process with a high degree of ability to remove sulphur from coal during combustion. Crushed coal and limestone are suspended in the bottom of a boiler by an upward stream of hot air. The coal is burned in this bubbling, liquid-like (or “fluidized”) mixture. Rather than released as emissions, sulphur from combustion gases combines with the limestone to form a solid compound recovered with the ash.
Fly ash – The finely divided particles of ash suspended in gases resulting from the combustion of fuel. Electrostatic precipitators are used to remove fly ash from the gases prior to the release from a power plant’s smokestack.
Formation – Any assemblage of rocks which have some character in common, whether of origin, age, or composition. Often, the word is loosely used to indicate anything that has been formed or brought into its present shape.
Fossil fuel – Any naturally occurring fuel of an organic nature, such as coal, crude oil and natural gas.
Fracture – A general term to include any kind of discontinuity in a body of rock if produced by mechanical failure, whether by shear stress or tensile stress. Fractures include faults, shears, joints, and planes of fracture cleavage.
Friable – Easy to break or crumbling naturally. Descriptive of certain rocks and minerals.
Fuse – A cord-like substance used in the ignition of explosives. Black powder is entrained in the cord and, when lit, burns along the cord at a set rate. A fuse can be safely used to ignite a cap, which is the primer for an explosive.