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Metal Casting I—Casting Fundamentals
Published in Zainul Huda, Manufacturing, 2018
Manufacturing a defect-free casting is a challenging job since it requires strict process control and resource availability. There are six basic requirements for metal casting: (1) a mold must be produced with a mold cavity, having the desired geometrical design of the casting (solidified metal/product); (2) a melting furnace must be capable of providing molten metal at the right temperature in the desired quantity and quality; (3) a pouring facility must be available to admit the molten metal into the mold to fill the cavity; (4) the solidification process should be properly designed to ensure the desired cooling rate; (5) a proper mold removal technique must be devised; and (6) tools should be available for cleaning, finishing, and inspecting the cast product. There are a variety of different types of metal casting processes. Depending on the type of mold used, all casting processes may be classified into two groups: (1) expendable mold casting and (2) permanent mold casting. Expendable mold casting processes involve the use of temporary, nonreusable molds. Permanent mold casting processes involve a permanent mold that is reusable again and again.
Motor Frame Design
Published in Wei Tong, Mechanical Design and Manufacturing of Electric Motors, 2022
Permanent-mold casting refers to the casting process that employs reusable metal molds to produce casting products repeatedly. This casting process usually requires the preheat of mold. Therefore, when the molten metal is poured into the mold under the gravitational force, the expansion of the mold is smaller than that in sand casting without preheating. The molds are usually made of high-strength steel or iron alloys. To achieve the desired lifetime of the mold, this casting process is mainly used for lower-melting-temperature materials such as aluminum alloys. When the process is used to cast steel or iron alloys that have much higher melting temperatures, the mold life is extremely short [5.9].
Aluminum-Manufacturing Methods
Published in Raghu Echempati, Primer on Automotive Lightweighting Technologies, 2021
The second casting process is permanent mold casting, also commonly known as gravity die casting (Figure 4.8). Permanent mold casting involves molds and cores of steel, bronze, refractory metals, and graphite. Molten aluminum is usually poured into the mold and, on occasion, a vacuum is applied. To improve the life of the mold, the surface of the mold can be coated with a refractory slurry and the mold is heated to reduce thermal fatigue. Permanent mold castings can be made stronger than sand or die castings. Some common parts that are manufactured using permanent mold casting include gears, gear housings, pipe fittings, pistons, impellers, and wheels [10].
A study on the construction of die-casting production prediction model by machine learning with Taguchi methods
Published in Journal of the Chinese Institute of Engineers, 2023
Yung-Tsan Jou, Riana Magdalena Silitonga, Ronald Sukwadi
Die casting is a permanent mold casting process since the process utilizes reusable metallic dies. After the metal raw material melts, it will enter the mold cavity under high pressure. The die casting is more valuable in any intricate shape, such as narrow and complex ones, with minimizing the defective casting. Therefore, this process is better than conventional casting, which involves more defects and consumes more time (Sodhi 2018). We call the finished product a casting. Because the mold used in the casting operation is a steel mold (die), this operation is called die casting. Unlike other permanent molds, die-casting uses high pressure to force the liquid metal into the mold cavity (Adke and Karanjkar 2014).
Non-carcinogenic occupational exposure risk related to foundry emissions: focus on the workers involved in olfactometric assessments
Published in Journal of Environmental Science and Health, Part A, 2021
Elisa Polvara, Laura Maria Teresa Capelli, Selena Sironi
In the foundry process, a variety of techniques, with specific technical, economic and environmental properties, advantages and disadvantages, can be employed depending on the type of furnace, the molding and core-making system, the casting system or finishing techniques applied.[39] Despite the complexity of the process, the different single operations can be resumed into two distinct main phases: the melting phase, in which a metal alloy is prepared, and a molding phase, in which the molds are filled to obtain the final product. Typically, it is possible to classify foundry activities according to the metal alloys processed (ferrous or non-ferrous) or to the molding types employed in the production.[39] Indeed, the mold realization differentiates significantly the phases of the production cycle. In general, two different molding systems exist and can be applied in foundry process: the permanent mold casting, that employs reusable molds, and lost mold casting, in which the mold material is constituted by sand. In both the typologies, molten metal is poured into a mold that remains until the material cools and solidifies into the desired part shape. The difference is related to the final part of process. Indeed, the lost mold casting uses a single use mold (generally sand), destroyed after each cycle. In this casting, the mold is realized with silicon sand mixed with ligands or additives useful to obtain the necessary molding proprieties. Instead, permanent mold casting uses a metal mold that can be reused for several thousands of cycles. While several combinations can be possible, in general, lost molds are mostly used into ferrous foundries and permanent molds are employed in non-ferrous foundries.[39]