Slip Casting(old)
Forming a hollow ceramic part by introducing a pourable slurry into a mold. The water in the slurry is extracted into the porous mold, leaving behind a drier surface. Excess slurry can then be decanted.
(Askeland, D.R.,The Science and Engineering of Materials,3rd Edition,PWS Publisihing Company, pg.464)
edit:
Green compacts for tungsten, molybdenum, and other powders are sometimes made by slip casting. The powder, converted to slurry mixture, is first poured into a plaster of Paris mold. Because the mold is porous, the liquid gradually drains off into the plaster leaving a solid layer of material deposited on the surface of the mold. For hallow objects, after sufficient time has been allowed for a desired thickness to accumulate, the remaining slurry is poured out. Upon drying the green components are sintered in the usual manner. This procedure is simple and permits considerable variation in size and shape.
Increasing emphasis is being directed to this process because parts can be made that are too large or too complex to pres. An expensive pres is not required, and improved physical properties are additional advantages. The principal disadvantage is time lag in producing parts.
(Amstead, B.H., Ostwald P.F., Begeman, M.L., Manufacturing Processes, 8th Edition, John Wiley & SOns, Inc, pg.202)
Slip Casting(new) [manufacturing method]
Preparation of Slip:Suspension of clay in water.
Preparation of Casting: Forming pottery by pouring slip into porous moulds. On emptying, an even layer of slip coats the interior of the mould.
(Slipcasting Author: Sasha Wardell p.7)
-new definition is more understandable and better
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Filament winding:(12:44 5.4.2011)(old)
Filament winding is a relatively simple process in which a band of continuous reinforcements (fibres) or mono-filaments is wrapped around a rotating mandrel and cured to produce closed-form hollow parts. The winding operation is achieved by the use of specially designed machines. These machines, which can have up to 6 - axes (even 7-axes with robotic enhancements), allow the operator to control various parameters, includig the winding speed, winding angles, fibre placement, resin temperature and fibre tension. THe filaments (or reinforcement bands) are wrapped around the mandrel as adjacent bands of repeating patterns. These cover the mandrel surface to produce one complete layer. The winding is continued with successive layers, which can be in different winding angles until the number of layers required by the designer is reached. The winding angle may vary with respect to mandrel axis. Winding angles are very close to 90 degree are termed hoop winding, whereas winding using other angles is termed helical winding.
(Guneri Akovali, Handbook of Composite Fabrication, pg:103)
Filament Winding(new) [manufacturing process]
FW is the process of impregnating glass fiber reinforcement with resin, then applying the wetted fibers onto a mandrel in a prescribed pattern. Fillers, if used, are added during the winding process. Chopped glass rovings may be used as supplemental reinforcement. Repeated application of wetted fibers, with or without filler, results in a multilayered structural wall construction of the required thickness. After curing, the pipe may undergo one or more auxiliary operations such as joint preparation. The inside diameter of the finished pipe is fixed by the mandrel outside diameter. The outside diameter of the finished pipe is variable and determined by the wall thickness.
The FW process is illustrated in the figure. Within the broad definition of FM there are several methods used including reciprocal, continuous, multiple mandrel and ring and oscillating mandrel.
(Fiberglass Pipe Design Author: American Water Works Association p.19)
-new definition is more clear and better
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Pressure Casting: (13:40 5.4.2011)(old)
Molten metal is injected under pressure into a hardened steel die, usually watercooled. Metal cores are used to produce cavities and undercuts. AFter solidification, one half of the die is moved and the casting is pushed out by ejector pins. This process is suitable for non-ferrous castings of small to medium size, varying complexity and thin walls.
(B. Ravi, Metal Casting: Computer-Aided Design and Analysis, pg:8)
Pressure Casting(new)[manufacturing method]
Pressure casting is a prpcess where a molten metal is introduced to the mold by the application of pressure to a hermetically-sealed metal bath forcing the molten metal up through a narrow diameter fill stalk tube from a furnace usually residing below the casting machine; although there is a version using electromagnetic forces to lift the material into the mold and then the furnace might be an open hearth located beside the casting machine. The process can be considered for low to high volumes of castings from 5 to 100g and usually incorporates the use of iron or steel permanent molds.
(Casting Design and Performance Author: ASM International p.18)
-new definition is more dense and better
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Squeeze Casting: (13:46 5.4.2011)(old)
In these processes, solid metal is forced nder pressure in to a metal mould, giving a fine microstructure free from dendrites(tree like structures) otherwise obtained in conventional casting processes. The mechanical properties of the castings approach those of forging. These are useful for non-ferrous metals and composites and are applied for aerospace and automotive parts.
(B. Ravi, Metal Casting: Computer-Aided Design and Analysis, pg:8)
Squeeze Casting(new)[manufacturing method]
Squeeze casting is an advanced metal processing technology where solidification is promoted under a high pressure to produce castings with compact interior and excellent mechanical properties. It is important to apptopriately control the process to avoid the formation of porosity in the casting as the existance of porosity significantly reduces the tensile strenght, elongarion, fatigue strenght and toughness of the castings, which fails the attempts to improving casting quality through the squeeze process. Posoity is resulted from volume shrinkage caused by cooling and phase change as well as the precipitation of dissolved gas in the liquid metals. In the squeeze casting, the pressure transferred into the casting decreases with the increasing of the thickness of solidified shell, and when the pressure inside the casting drops to a certain extent, porosity may form due to insufficient feeding and gas precipitation.
(Shape Casting: Fourth International Symposium 2011 (in Honor of Prof. John T. Berry) Author:The Minerals Metals & Materials Society (Tms) p.61)
-new definition is more understandable and better
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Lanxide process:(old)
The lanxide process involves the formation of a ceramic matrix by the reaction between a molten metal and a gas, e.g., molten aluminium reacting with oxygen to form aluminia. Growth of the ceramic occurs outwards from the original metal surface and through a perform as shown in Figure 4.11. In fact a preform is not a prerequisite and particulate reinforced composites may also be produced by simply placing the particles above the liquid metal. In both cases the only requirtements are that the fibers/particles do not react with the gas and are wetted by the ceramic.
(Composite materials: engineering and science, F.L. Matthews, p.131)
Lanxide Process (new) [manufacturing]
The Lanxide process depends on the simultaneous oxidation of a molten metal such as aluminum and the simultaneous wicking of the molten metal through channels in the oxide. Thus the buildup of the oxide occurs at or on the continually replenished melt/gas interface. Alloying additions may be added to enhance the kinetics or modify the structure. In some cases other gases may be used to produce nitrides or other reaction products. By confining the space and providing fibers or other phases in the space into which the wicking will occur, various fibers can be incorporated into the structure.
The consolidation of the matrix pccurs by oxidative crystal growth, which generally requires lower temperatures than conventional sintering. Accordingly, some fibers can be used that otherwise might be degraded during processing. However, the composition of the matrix is restricted to those metals that exhibit this kind of growth phenomenon. since capillarity is needed to maintain the supply of reactant to the surface, the resultant structures will either contain residual metal in the channels or porosity if the metal is drained out.
(Fiber Reinforced Ceramic Composites: Materials, Processing, and Technology Author: K. S. Mazdiyasni p.262)
-new definition contains more information and it is better.
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