Expendable mold casting is a broad category of casting processes where the mold used to form the metal part is destroyed or "expended" after each casting cycle. This is in contrast to permanent mold casting, where the mold can be used repeatedly. The fundamental principle of expendable mold casting is to create a mold cavity that matches the shape of the desired metal component, pour molten metal into the kavitet och låt metallen stelna . När metallen har stelnat bryts formen bort för att ta bort gjutningen .
Det finns flera vanliga typer av förbrukningsbara mögelgjutningsprocesser:
Sandgjutning:
This is one of the most widely used expendable mold casting methods. In sand casting, the mold is made from sand mixed with binders. A pattern, which is a replica of the part to be cast, is used to create the cavity in the sand mold. The molten metal is then poured into the cavity, and after solidification, the sand mold is broken to extract the casting. Sand casting is suitable for a wide range of part sizes and is cost - effective for low - to - medium production volumes. It can be used with various metals, including aluminum, iron, and steel. For example, large engine blocks for trucks and heavy - duty machinery are often produced using sand casting.
Investeringsgjutning:
Also known as lost - wax casting, investment casting involves creating a wax pattern of the desired part first. The wax pattern is then coated with a ceramic shell, and the wax is melted out, leaving a cavity in the ceramic shell. Molten metal is poured into this cavity, and after solidification, the ceramic shell is broken away. Investment casting is highly precise and can produce parts with complex geometries and fine details. It is commonly used in industries such as aerospace, where components like turbine blades need to be manufactured with tight tolerances, and in the medical field for producing surgical instruments and prosthetics. Compared to other expendable mold casting methods, investment casting can achieve higher surface finishes and dimensional accuracy but is typically more expensive and has longer lead times for complex Delar .
Skalformning:
Similar to sand casting, shell molding uses a sand - resin mixture. However, instead of creating a solid sand mold, a thin shell of the sand - resin mixture is formed around a heated pattern. This shell is then assembled to form the mold cavity. Shell molding offers better dimensional accuracy and surface finish compared to traditional sand casting and is often used for producing small - to - medium - Stora delar, såsom bilmotorkomponenter och ventilkroppar .
Plaster Mold Casting: In this process, the mold is made from a plaster - based material. The plaster mixture is poured around a pattern to create the mold cavity. Plaster mold casting is suitable for non - ferrous metals and can produce parts with good surface finishes. It is often used for producing decorative items, jewelry, and small mechanical components.
Expendable mögelgjutning erbjuder flera fördelar .
För det första ger det en hög grad av designflexibilitet, vilket möjliggör produktion av delar med komplexa former och interna funktioner .
För det andra, eftersom formen förstörs efter varje användning, finns det inget behov av att oroa sig för mögelslitage, vilket kan påverka kvaliteten på delar i permanent mögelgjutning .
Dessutom kan utgiftsgjutningsprocesser användas med en mängd olika metaller, från vanligt aluminium och stål till mer specialiserade legeringar . Men en av de viktigaste nackdelarna är att mögel måste skapas för varje gjutningscykel, vilket kan öka produktionstiden och kostnaden, särskilt för produktion med hög volym.}}}}}}
Sammanfattningsvis är utgiftsgjutning en mångsidig grupp av gjutningsprocesser som spelar en avgörande roll i modern tillverkning, vilket möjliggör produktion av ett stort utbud av metallkomponenter över många industrier .