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Cope And Drag
In foundry work, the terms cope and drag refer respectively to the top and bottom parts of a two-part casting flask, used in sand casting. The flask is a wood or metal frame, which contains the molding sand, providing support to the sand as the metal is poured into the mold. In flaskless molding, the same terms are used, cope for the top or upper piece and drag for the bottom or lower piece. In the simplest sand casting procedure, the drag is placed upside down on a board, around a pattern of the part to be cast. The pattern is a model of the desired casting. Talcum powder is often dusted over the pattern to aid in the removal of the pattern. Sand is sifted over the pattern until the model is covered by a few inches of sand. More sand is then dumped into the drag, and rammed with a wooden wedge, or mechanically vibrated to pack the sand down. The sand is then struck level with the top edge of the drag, using a wooden or metal strake. A board is then placed on top of the drag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Foundry
A foundry is a factory that produces metal castings. Metals are cast into shapes by melting them into a liquid, pouring the metal into a mold, and removing the mold material after the metal has solidified as it cools. The most common metals processed are aluminum and cast iron. However, other metals, such as bronze, brass, steel, magnesium, and zinc, are also used to produce castings in foundries. In this process, parts of desired shapes and sizes can be formed. Foundries are one of the largest contributors to the manufacturing recycling movement, melting and recasting millions of tons of scrap metal every year to create new durable goods. Moreover, many foundries use sand in their molding process. These foundries often use, recondition, and reuse sand, which is another form of recycling. Process In metalworking, casting involves pouring liquid metal into a mold, which contains a hollow cavity of the desired shape, and then allowing it to cool and solidify. The solidified pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Casting Flask
A flask is a type of tooling used to contain a mold in metal casting. A flask has only sides, and no top or bottom, and forms a frame around the mold, which is typically made of molding sand. The shape of a flask may be square, rectangular, round or any convenient shape. A flask can have any size so long as it is larger than the pattern being used to make the sand mold. Flasks are commonly made of steel, aluminum or even wood. A simple flask has two parts: the cope and the drag. More elaborate flasks may have three or even four parts. Flask design Flasks are often designed with bars that extend to span two opposite sides. The bars act as reinforcement to the molding sand, which is relatively weak in tensile strength. The bars help support the sand through the molding and pouring operation. Flasks are designed with an alignment or registration feature, so that the two flasks can be aligned to one another to ensure a casting can be more dimensionally accurate and also in smal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sand Casting
Sand casting, also known as sand molded casting, is a metal casting process characterized by using sand as the mold material. The term "sand casting" can also refer to an object produced via the sand casting process. Sand castings are produced in specialized factories called foundries. Over 60% of all metal castings are produced via sand casting process. Molds made of sand are relatively cheap, and sufficiently refractory even for steel foundry use. In addition to the sand, a suitable bonding agent (usually clay) is mixed or occurs with the sand. The mixture is moistened, typically with water, but sometimes with other substances, to develop the strength and plasticity of the clay and to make the aggregate suitable for molding. The sand is typically contained in a system of frames or mold boxes known as a flask. The mold cavities and gate system are created by compacting the sand around models called patterns, by carving directly into the sand, or by 3D printing. Basic pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pattern (casting)
In casting, a pattern is a replica of the object to be cast, used to prepare the cavity into which molten material will be poured during the casting process. Patterns used in sand casting may be made of wood, metal, plastics or other materials. Patterns are made to exacting standards of construction, so that they can last for a reasonable length of time, according to the quality grade of the pattern being built, and so that they will repeatably provide a dimensionally acceptable casting. Patternmaking The making of patterns, called patternmaking (sometimes styled pattern-making or pattern making), is a skilled trade that is related to the trades of tool and die making and moldmaking, but also often incorporates elements of fine woodworking. Patternmakers (sometimes styled pattern-makers or pattern makers) learn their skills through apprenticeships and trade schools over many years of experience. Although an engineer may help to design the pattern, it is usually a patternmaker w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Screed
Screed has three meanings in building construction: # A flat board (screed board, floating screed) or a purpose-made aluminium tool used to smooth and to "true" materials like concrete, stucco and plaster after they have been placed on a surface or to assist in flattening; # A strip of plaster or wood applied to a surface to act as a guide for a screed tool (screed rail, screed strip, screed batten); # The material itself which has been flattened with a screed (screed coat). In the UK, ''screed'' has also come to describe a thin, top layer of material (sand and cement, magnesite or calcium sulphate), poured in situ on top of the structural concrete or insulation, on top of which other finishing materials can be applied, or the structural material can be left bare to achieve a raw effect. Screed board In the United States, screeding is the process a person called a concrete finisher performs by cutting off excess wet concrete to bring the top surface of a slab to the proper ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sprue (casting)
A sprue is the vertical passage through which liquid material is introduced into a mold and it is a large diameter channel through which the material enters the mold. It connects the pouring basin to the runner. In many cases it controls the flow of material into the mold. During casting or molding, the material in the sprue will solidify and need to be removed from the finished part. It is usually tapered downwards to minimize turbulence and formation of air bubbles. Casting In casting, a sprue is the passage through which a molten material is introduced into a mold, and the term also refers to the excess material which solidifies in the sprue passage. Function Sprues can serve as filters, as heat sinks, and as feeders. Bronze, in particular, has a high shrinkage rate as it is cooling. A sprue is tapered with its bigger end at the top to receive the liquid metal, the smaller end is connected to the runner. Sprue design The design of the sprue gating and runner is also essen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Riser (casting)
A riser, also known as a feeder, is a reservoir built into a metal casting mold to prevent cavities due to shrinkage. Most metals are less dense as a liquid than as a solid so castings shrink upon cooling, which can leave a void at the last point to solidify. Risers prevent this by providing molten metal to the casting as it solidifies, so that the cavity forms in the riser and not the casting.. Risers are not effective on materials that have a large freezing range, because directional solidification is not possible. They are also not needed for casting processes that utilized pressure to fill the mold cavity. Theory Risers are only effective if three conditions are met: the riser cools after the casting, the riser has enough material to compensate for the casting shrinkage, and the casting directionally solidifies towards the riser. For the riser to cool after the casting the riser must cool more slowly than the casting. Chvorinov's rule briefly states that the slowest cooling ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cheek (casting)
A core is a device used in casting and moulding processes to produce internal cavities and reentrant angles (an interior angle that is greater than 180°). The core is normally a disposable item that is destroyed to get it out of the piece.. They are most commonly used in sand casting, but are also used in die casting and injection moulding. For example, cores define multiple passages inside cast engine blocks. One model of GM V-8 engine requires 5 dry-sand cores for every casting. Materials required to make cores *Core sand *Bentonite clay *Pulverized coal *Resin oil Advantages and disadvantages Cores are useful for features that cannot tolerate draft or to provide detail that cannot otherwise be integrated into a core-less casting or mold. The main disadvantage is the additional cost to incorporate cores. Requirements There are seven requirements for cores: #Green strength: In the green condition, there must be adequate strength for handling #In the hardened state, it must b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
