Casting Process

Consider the casting process at 645 B.C, the first traces of the Sand Molding was found. Now consider the state-of-the-art Electromagnetic casting process. Truly, the Casting process has traversed a long path and impacted human civilization for nearly five millennia. With technological advances, metal casting is playing a greater role in our everyday lives and is more essential than it has ever been.

Selecting the Right Metal Casting Process
  • For any Metal Casting Process, selection of right alloy, size, shape, thickness, tolerance, texture, and weight, is very vital.
  • Special requirements such as, magnetism, corrosion, stress distribution also influence the choice of the Metal Casting Process.
  • Views of the Tooling Designer; Foundry / Machine House needs, customer's exact product requirements, and secondary operations like painting, must be taken care of before selecting the appropriate Metal Casting Process.
  • Tool cost.
  • Economics of machining versus process costs.
  • Adequate protection / packaging, shipping constraints, regulations of the final components, weights and shelf life of protective coatings also play their part in the Metal Casting process.

The Metal Casting or just Casting process may be divided into two groups: Hot Forming Process
Examples are Centrifugal casting, Extrusion, Forging, Full mold casting, Investment casting, Permanent or Gravity Die casting, Plaster mold casting, Sand Casting, Shell Mold casting. The method to be used depends upon the nature of the products to be cast.

Cold Forming Process
Examples are Squeeze casting, Pressure die casting, Gravity die casting, Burnishing, Coining, Cold forging, Hubbing, Impact Extrusion, Peening, Sizing, Thread rolling.

Comparative Advantages, Disadvantages and Applications for Various Casting Methods :

Sand Casting
Advantages Disadvantages   Recommended Application
Least Expensive in small quantities (less than 100)

Ferrous and non - ferrous metals may be cast

Possible to cast very large parts.

• Least expensive tooling
Dimensional accuracy inferior to other processes, requires larger tolerances

Castings usually exceed calculated weight

Surface finish of ferrous castings usually exceeds 125 RMS
Use when strength/weight ratio permits

Tolerances, surface finish and low machining cost does not warrant a more expensive process
Permanent and Semi-permanent Mold Casting
Less expensive than Investment or Die Castings

Dimensional Tolerances closer than Sand Castings

Castings are dense and pressure tight
Only non-ferrous metals may be cast by this process

Less competitive with Sand Cast process when three or more sand cores are required

Higher tooling cost than Sand Cast
Use when process recommended for parts subjected to hydrostatic pressure

Ideal for parts having low profile, no cores and quantities in excess of 300
Plaster Cast
Smooth "As Cast" finish (25 RMS)

Closer dimensional tolerance than Sand Cast

• Intricate shapes and fine details including thinner "As Cast" walls are possible

• Large parts cost less to cast than by Investment process
More costly than Sand or Permanent Mold-Casting

Limited number of sources

Requires minimum of 1 deg. draft
Use when parts require smooth "As Cast" surface finish and closer tolerances than possible with Sand or Permanent Mold Processes
Investment Cast
Close dimensional tolerance

Complex shape, fine detail, intricate core sections and thin walls are possible

Ferrous and non-ferrous metals may be cast

As-Cast" finish (64 - 125 RMS)
Costs are higher than Sand, Permanent Mold or Plaster process Castings
Use when Complexity precludes use of Sand or Permanent Mold Castings

The process cost is justified through savings in machining or brazing

Weight savings justifies increased cost
Die Casting
Good dimensional tolerances are possible

Excellent part-part dimensional consistency

Parts require a minimal post machining
Economical only in very large quantities due to high tool cost

Not recommended for hydrostatic pressure applications

For Castings where penetrant (die) or radiographic inspection are not required.

Difficult to guarantee minimum mechanical properties
Use when quantity of parts justifies the high tooling cost

Parts are not structural and are subjected to hydrostatic pressure
More Info Hub

Enviornmental Issues

In depth analysis of industry process, recycling, and environmental issues of the cast metals industry.Know More

Major Casting Components

Major casting components including Automobile Casting Equipments, Pumps and Valves Components.Know More

New Technology Research

Latest manufacturing technology research in production, manufacturing engineering and management.Know More

Casting Applications

All about industrial applications of metal casting technologies in Automobile, Industrial Machinery.Know More