The earliest examples
of die casting by pressure injection - as opposed to casting by gravity
pressure - occurred in the mid-1800s. A patent was awarded to Sturges in 1849
for the first manually operated machine for casting printing type. The process
was limited to printer�s type for the next 20 years, but development of other
shapes began to increase toward the end of the century. By 1892, commercial
applications included parts for phonographs and cash registers, and mass
production of many types of parts began in the early 1900s.
The first die casting
alloys were various compositions of tin and lead, but their use declined with
the introduction of zinc and aluminum alloys in 1914. Magnesium and copper
alloys quickly followed, and by the 1930s, many of the modern alloys still in
use today became available.
The die casting
process has evolved from the original low-pressure injection method to
techniques including high-pressure casting � at forces exceeding 4500 pounds
per square inch � squeeze casting and semi-solid die casting. These modern
processes are capable of producing high integrity, near net-shape castings with
excellent surface finishes.
Refinements continue in both the alloys used in die casting and the
process itself, expanding die casting applications into almost every known
market. Once limited to simple lead type, today�s die casters can produce
castings in a variety of sizes, shapes and wall thicknesses that are strong,
durable and dimensionally precise.
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