Question

Comparisons of quality aspects of metal casting processes . 

Answer 1

There are lots of metal casting processes implemented in the manufacturing of parts . There is expendable casting and long-lasting mold/permanent casting.

Expendable molds are utilized for a single metal casting while long-lasting molds or permanent molds are utilized for several. When considering manufacturing procedures, there are pros and cons to both of the processes.

Expendable molds

1. can produce one metal casting only
2. made of sand plastic or other similar metal
3. binders used to help material hold its forms
4. mold that metal solidified in,must be destroyed to remove casting
5. more geometry are possible for casting

Permanent molds

1. can manufacture many metal casting
2. usually made of metal
3. mold has section that has open or close,permitting removal of casting
4. need to open molds limit part shapes

casting is a process in which liquefied material, such as molten metal, is poured into the cavity of a specially designed mold and allowed to harden. After solidification, the workpiece is removed from the die to undergo various finishing treatments or for use as a final product.

Casting is typically used to create intricate solid shapes, and cast products are found in a wide range of applications, including automotive components, aerospace parts, electronics, mechanical devices, and construction supplies.

Although casting is one of the oldest known manufacturing techniques, modern advances in casting technology have led to a broad array of specialized casting methods. Hot forming processes, such as die casting, investment casting, plaster casting, and sand casting, each provide their own unique fabrication benefits. Comparing both the advantages and disadvantages of the common types of casting processes can help in selecting the method best suited for a given production run.

Sand casting

mainly based on silica-based materials, such as synthetic or naturally bonded sand. Casting sand generally consists of finely ground, spherical grains that can be tightly packed together into a smooth molding surface. The casting is designed to reduce the potential for tearing, cracking, or other flaws by allowing a moderate degree of flexibility and shrinkage during the cooling phase of the process. The sand can also be strengthened with the addition of clay, which helps the particles bond more closely. Many automotive products, such as engine blocks and housings, are manufactured through sand casting.

Investment casting

it is used as a disposable wax pattern for each cast part. The wax is either injected directly into the mold or pre-coated with a liquid refractory material before injection. Molten forming material is then poured into the mold and allowed to harden and set into the shape of the wax pattern. The component is then ejected, while the wax pattern is melted out of the casting and made available for re use. Investment casting is often used to manufacture parts for the aerospace and automotive industries, as well as the military.

Plaster casting

it is similar to the sand casting process, using a mixture of gypsum, strengthening compound, and water in place of the sand. The plaster pattern is typically coated with an anti-adhesive compound to prevent it from becoming stuck against the mold, and the plaster is capable of filling in any gaps around the mold. Once the plaster material has been used to cast a part, it usually cracks or forms defects, requiring it to be replaced with fresh material.this process is more expensive as compare to other metal casting prcess.

Die casting

it is a method of molding materials under high pressure and usually involves non-ferrous metals and alloys, such as zinc, tin, copper, and aluminum. The mold is coated with lubricant to help regulate the die’s temperature and to assist with component ejection. Molten metal is then injected into the die under high pressure, which remains continuous until the workpiece solidifies. This pressurized insertion is rapid, preventing any segment of the material from hardening before being cast. After the process is completed, the component is taken out of the die and any scrap material is removed.

process	advantage	disadvantage
sand casting	Almost any metal can cast,small to large part, Low tooling cost. Relatively inexpensive production costs, especially in low-volume runs. The ability to fabricate large components. A capacity for casting both ferrous and non-ferrous materials. A low cost for post-casting tooling.	Low dimentional accuracy and surface quality
investment casting	Good dimentional accuracy and surface finish. complex shape ,fine detail. A high degree of accuracy and precise dimensional results. The ability to create thin-walled parts with complex geometries. The capacity for casting both ferrous and non-ferrous materials. Relatively high-quality surface finish and detail in final components	cost are higher than sand ,permanent mold or plaster process casting..
plaster casting	A very smooth surface finish. The ability to cast complex shapes with thin walls. The capacity for forming large parts with less expense than other processes, such as investment casting. A higher degree of dimensional accuracy than that of sand casting. good dimentional accuracy and surface finish.	more costly than sand or permanent molds casting,limited to non ferrous metal.
die casting	excellent dimentional and tolerance and surface finish high production rate Close size and shape tolerances. High component dimensional consistency and uniform design. A reduced need for post-casting machining	high die cost ,part size limited ,limited to non ferrous metal...