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| History of the
Investment / Lost Wax Casting Process
Investment Casting using the lost wax technique is not new,
on the contrary , it is one of the oldest casting methods
known and examples of its use to produce statuary and jewelry
can be traced back to antiquity. In the early part of this
century the method was applied to the manufacture of gold
fillings and dental inlays for false teeth, while in 1932
the lost wax ceramic block mould process was developed, using
cobalt-chromium alloys for dental applications, and orthopedic
components. The demands of the second world war changed the
limited application of the technique and in the wake of the
introduction of the aircraft gas turbine and intensified development
of turbo chargers for high flying bombers and fighters, designers
were drawn to investment casting to produce the necessary
high quality components.
The 1950's saw the expansion of the industry, mainly allied
to aircraft and military applications but with a significantly
increasing involvement in the general commercial field. With
the introduction, in the mid of 50's of the ceramic shell
mould process, the range of materials cast increased dramatically
and to the original alloy steel and super alloys were added
carbon steels, tool steels, aluminum alloys, copper alloys,
magnesium alloys, and more recently, titanium alloys, typifying
the versatility of the process. |
Why Investment Casting?
With it's numerous advantages, Investment Casting finds it's
application in various industries as:
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a.
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Design Flexibility
Investment casting produces near-net-shape configurations,
offering designers and engineers freedom to design the
part of maximum function The process is capable of producing
precise details like complex undercuts, slots, holes,
lettering and dimensional accuracy in parts weighing many
pounds or just few ounces |
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b.
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Reduce production cost
Investment casting offers a combination of features which
can translate to cost saving benefits for you. The piece
price for investment casting is not always the lowest,
but the saving is reduced machining, material costs, and
tooling start-up costs make the lost wax process very
competitive when you consider overall cost. |
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c.
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Wide choice of alloys
Even alloys that cannot be cast by other methods or which
are difficult to machine can be investment cast, more
than 100 ferrous & non ferrous metals are routinely cast. |
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d.
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Close tolerance
Investment casting promises tight linear tolerances of
an average +_ 0.15mm/ inch, with even more exact tolerances
depending on the part size & complexity. |
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f.
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Tooling Economy
Our tooling is usually much less expensive than tooling
for other "hot" methods, since dies are built to withstand
wax injection rather than metal injection. |
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g.
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Weight Reduction
Investment casting process can eliminate unnecessary metal
and weight from non functional areas of the part. |
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| General Tolerances |
| Flatness |
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Length(mm)
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Tolerance TIR
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Upto 25.0
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0.2
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Over 25.0 to 50.0
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0.4
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Over 50.0 to 75.0
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0.6
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Over 75.0 to 100.0
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0.8
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Over 100.0 to 125.0
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1.0
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| Ovality Tolerances |
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Diameter (mm)
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Tolerance TIR
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Upto 25.0
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0.24
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Over 25.0 to 75.0
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0.48
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Over 50.0 to 75.0
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0.72
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Over 75.0 to 100.0
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0.96
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Over 100.0 to 125.0
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1.20
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| Linear Tolerances |
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Linear (mm)
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Tolerance TIR
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Upto 25.0
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0.12
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Over 25.0 to 50.0
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0.24
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Over 50.0 to 75.0
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0.36
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Over 75.0 to 100.0
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0.48
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