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12 - GLASSWORKiNG


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Amorphous glass
NONCRYSTALLINE CERAMIC MATERIAL, different from other types of ceramics by a noncrystalline structure, yet it's possible bring it into a crystalline shape in order to increase it's properties. >>> AMORPHOUS STRUCTURE OF SILICA SAND.
Glass creation
PREPARATION, MELTING, SHAPING AND HEAT TREATING THE GLASS PRODUCT. Silica sand is classified by size - 0.6mm to 1mm is the best particle size, melted down in a furnace, made into shape - bottles, bulbs, chandaliers, and heat treated for additional strength. >>> PuM SHoT: PREPARATION, MELTING, SHAPING, HEAT TREATING.
Glass raw material preparation
ADD STUFF TO SILICA SAND, after sifting silica sand according to size: 0.6 to 1mm is the best size, add soda ash, limestone, alluminum oxide, potash, and some recycled glass, before stuffing the batch into furnace.
Glass melting
Melting a batch (charge) of glass in a furnace at temperatures around 1500[degC] to 1600[degC].
Pot furnace
Heated ceramic pot for melting glass.
Day tank
Melts glass for batch production in a large vessel by burning fuels above it.
Continuous tank furnace
LONG, HEATED TANK - at the start comes in cold glass; molten glass leaves at the end of the tank.
Electric furnace
Electric furnace for glass.
Glass shaping
INSTILLING A FORM UPON THE GLASSY CREATIONS, processes one can put into three categories: [1] Discrete processes - make individual items, such as bottles, light-bulbs, telescope lenses. [2] Continuous processes - creation of continuous glass plates and tubes: glass shit for windows, tubes for florescent lights. [3] Fiber-making processes - creation of long or short glass fibers for isolation, glass fiber composites, fiber-optics. >>> DuC Fuk: DISCRETE, CONTINUOUS, FIBER
Shaping of piece ware
CREATION OF DISCRETE GLASS ITEMS by the following by: Spinning, Pressing, Blowing, Casting >>> SuP BooC: SPINNING, PRESSING, BLOWING, CASTING.
Glass spinning
SIMILAR TO CENTRIFUGAL CASTING - the rotating metal mold spreads out a piece of red hot glass on its surface, creating a desired shape of a glass or a bulb.
Glass pressing
SQUEEZING A PIECE OF GLASS BETWEEN THE MOLD PARTS, a process used to produce flat glass pieces, such as glass plates.
Glass blowing
SHAPE GLASS BY BLOWING, either by pressing it first and then blowing: a press-and-blow process in order to create wide mouthed containers, or by just blowing - a blow-and-blow process that creates small mouthed bottles, both processes are used to make anything from bottles to light bulbs.
Press and blow
PRESSES AND BLOWS UP GLASS INTO A CONTAINER SHAPE, first by putting a molten gob into a mold, pressing it to a parison (partially melted mass of molten glass), transferring the parison into a blow mold by the neck ring, and finally blowing the glass up into it's final, wide mouth shaped form.
Parison
Partially shaped mass of molten glass.
Blow and mold
FORMING A NARROW MOUTHED CONTAINER BY BLOWING OPERATIONS, first putting the glob into a blow mold, blowing it up into an initial shape, then transferring the parison into a final mold, instilling upon it the final, narrow entrance shape
Glass casting
USED TO CREATE MASSIVE OBJECTS, such as telescope lenses and mirrors, cooling them gradually, since cracking can easily occure in glass due to temperature gradients, a process used only for special, massive jobs due to a viscous nature of liquid glass, a property preventing it from reaching into all the nooks and crannies of the mold. >>> THERMAL GRADIENTS BREAK STICKY GLASS.
Shaping of flat and tubular glass
PRODUCTION OF CONTINUOUS FLAT PANES AND ROUND TUBES using the following processes: [1] Rolling of flat plate, [2] Float process, [3] Drawing glass tubes. >>> SHAPING OF FLAT AND TUBULAR GLASS
Rolling of flat plate
FORMING ROLLS SQUEEZE OUT MOLTEN GLASS onto the support rolls, determining the pane width by the degree of their separation, and the supporting rolls direct the glass into the annealing furnace after which the glass pane would be ground and polished for parallelism and smoothness.
Float process
MOLTEN GLASS MOVES ACROSS MOLTEN TIN, spreading evenly upon it's surface, achieving uniform thickness and smoothness, thus eliminating the need for further processing, except for the annealing furnace, the next destination of the glass pane, a furnace to which the flat, even, precise pane moves upon the careful, caring concerned love of the support rollers.
Drawing of glass tubes
THE DANNER PROCESS - a rotating and hollow mandrel blows air into the molten glass drawn over its surface, thus creating long hollow tube, a tube supported by the support rollers to a length of about 30 meters. >>> ROTATING MANDREL BLOWS INTO HOLLOW TUBE
Punty
Iron rod used in glassmaking for handling the hot glass.
Blowpipe
Pipe glass makers blow glass with
Crown glass
GLASS WITH A PUNTY MARK ON IT - at ancient times windows were made from thin sections of a blown up and shaped into a flat form glass, the thick, opaque central section with the punty mark was used for cheap windows, and the lenses made from glass made in this manner were also labeled as crown glass.
Forming of glass fibers
Two types of glass fibers are usually produces - long and short: short fibers that are used for insulation and composites, and long, continuous fibers used for composites and fiber optics, the short fibers are made by [1] Centrifugal spraying, and the long ones by [2] Drawing of continuous filaments.
Centrifugal spraying
MAKES GLASS WOOL BY FORCING THE GLASS THROUGH SMALL HOLES IN A ROTATING BOWL, thus shaping it into a multitude of short glass, just like sugar cotton, the fibers are ready for use in thermal and acoustic insulation.
Drawing continuous filaments
DRAWING A MULTITUDE OF SMALL FIBERS THROUGH A PLATE WITH A LOT OF SMALL HOLES, around 25 microns in diameters, spraying them with lubricating and protecting agents before reeling all the fibers on the collection spool.
Glass heat treatment
THERMAL TREATMENT FOR GLASS after forming by [1] Annealing to remove internal stress and [2] Tempering to make a stronger glass.
Glass annealing
RELIEVING INTERNAL STRESSES BY HEATING AND SLOWLY COOLING THE GLASS, since internal stresses that can make a glass crack at a slightest bump, a process of heating the glass to its annealing temperature, the temperature at which the glass is hard enough to resist deformation but soft enough for internal stresses to dissipate, heat soaking the glass until it's temperature is uniform, and cooling the glass at a predetermined rate below it's strain point, afterwards it can be cooled regularly. >>> HEATING AND SLOW COOLING REMOVE RESIDUAL STRESSES.
Lehr
GLASS ANNEALING FURNACE, regularly a long, tunnel like furnace, heated at the start, cold at the end, instilling the required cooling cycle upon the glass by the means of its movement speed through it.
Glass tempering
QUENCHING ANNEALED GLASS TO INCREASE ITS STRENGTH, heating it up above the annealing point and quickly cooling, thus creating a tough outer layer that works in compression, thus making a very tough glass that has to be worked before the tempering, since it will shatter to a lot of pieces if drilled or broken, its edges being particularly vulnerable due to stress concentrations.
Finishing
GRINDING, POLISHING, CUTTING, >>> Grinding and polishing the glass to remove impurities, and cutting the glass to size after annealing.
Glass product design considerations
[1] Glass is much stronger in compression than in tension - make it work in compression; [2] Glass is brittle - avoid shock and and impact; [3] Some glasses have low expansion and thus less suseptible to thermal shock - use such materials in temperature gradients. [4] Edges and corners concentrate stress - fillet or chamfer edges and corners. [5] Glass bottles can have course threads - make course threads on glass bottles. >>> CaB To CET: COMRESSION, BRITTLE,,, THERMAL EXPANSION,,, CORNERS, EDGES, THREADS