Casting Concepts Engineering Workshop MECHANICAL THEORY

Casting Process:Importance, Advantages, Limitations,Moulding Materials, Mould, Methods

Casting Process: It is a process in which the liquid molten metal is poured into the casting cavity whose shape is same as that of the shape of the casting to be produced, allowing to solidify and after solidification, the casting will be taken out by breaking the mould called as Casting Process.Casting-Importance,Advantages,Limitations,Mould,Moulding Materials,MethodsCasting Process-Importance, Advantages, Mould, Moulding Materials, Methods

Importance of Casting Process:

  • This process is widely used to manufacture complex parts.
  • All major parts like milling machine bed, the bed of lathe machine, IC engine components, etc. are made by this casting process.
  • It produces the best quality sand casting products at the lowest possible cost compared to machining Process.
  • High Production rate.

Advantages of the Casting Process:

  • High complexity shapes: Casting Process can create any complex structures economically.
  • Short lead time: Short lead time compared to others and hence, ideal for short production runs.
  • Low-cost tooling: Tooling and equipment costs are low compared to some other metal manufacturing processes.
  • Design flexibility: The size of an object doesn’t matter for casting.
  • Wider material choice: all types of engineering alloys can be cast.

Limitations of the Casting Process:

  • Dimensional accuracy: Because of shrinkage in the casting, the dimensional accuracy might be at risk. So, the designers must take care of providing the allowance to the product(Pattern) before pouring the molten metal.
  • Low strength: Due to high porosity compared to a machined part.
  • Post processing: It requires Secondary machining operations in order to improve the surface finish.
  • Lower Melting Point: Generally limited to metals of the lower melting point.
  • Not suitable for low-volume production.

Mould:

  • It is described as a void or cavity created in a compact sand mass with the help of pattern which (mould), when filled with molten metal produce a casting.
  • The mould is made by using the moulding sand consists of basic elements such as
  1. Silica Sand Particles: They are used for producing the required strength of the moulding sand. (75-80%) of sand is filled with Silica sand Particles.
  2. Clay: It is used for producing the bond between the sand particles. (15-20%) of clay is filled in moulding sand.
  3. Water or Sodium Silicate: It is used for initiating the bond formation between the sand particles(6-8%).
Silica Sand + Clay + Water = Green Sand.

Silica Sand + Clay + Sodium Silicate = Dry Sand.

Green Sand or Dry Sand with 50% Clay is called as Loam Sand.

Moulding:

  • The process of making a cavity or mould in the compact sand is called as Moulding.

Moulding  Materials:

  • A  material which possesses high refractoriness can be used for mould making. Thus, the mould making material can be metallic or non-metallic(sand).
  • For Metallic Moulds, the common materials are Cast iron, mild steel, and alloy steels.
  • For Non-Metallic Moulds: Materials used are moulding sand, Plaster of Paris, silicon carbide, graphite, and ceramics.
  • Note: Out of all materials, the moulding sand is the most commonly utilized non-metallic moulding material because of its certain inherent properties namely refractoriness, high permeability, and workability along with good strength. Moreover, it is also highly cheap and it is easily available.

Methods of Moulding Process:[Not in Syllabus]

Read: Top 4 Machine Moulding Operations Used in Casting Process

  1. Machine moulding
  2. Loam moulding
  3. Skin-dried moulding
  4. .Green sand moulding
  5. Bench moulding
  6. .Pit moulding
  7. Dry sand moulding
  8. Floor moulding
  9. Cement bonded moulding
  10. Shell moulding

This is the complete explanation of the casting process with Importance, Advantages, Limitations etc. If you have any doubts, you can ask from the comments section.

Also Read:[For Continuation of the Unit]

  1. Pattern-Properties, Types, Pattern Materials, Disadvantages, and Applications
  2. Sand Casting Process – Definition, Steps, Diagram, Aspiration Effect, Elements of Sprue etc.
  3. Die Casting Process-Principle, Types, Gravity&Pressure Die casting, Applications, Advantages

 

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