metal casting, CLA

1. Presented by
Jabin Mathew Benjamin
13MY04
Dept. of Metallurgical Engineering

2.  Permeable Mould
 Vacuum Valve
 Sprue Pipe
 Crucible

3. In CLA casting, the casting process consists of four major steps.
A. The permeable mould is positioned in a closed chamber with a
vacuum valve. An open, impermeable sprue pipe at the base of the
mold extends down out of the chamber.
B. The sprue pipe of the mold is lowered into the molten metal in the
crucible. An applied vacuum draws the molten metal up into the mold
cavity in a controlled flow.
C. The molten metal fills the mold cavity and the castings solidify, while
the central sprue stays molten.
D. When the vacuum is released, the still molten metal in the central
sprue returns to the crucible for reuse. The chamber is raised, and
the separate, solid castings remain in the mold.
 After cooling, the mold with the castings is removed from the chamber.
The individual, free-standing castings are removed from the mold.

5.  Yields parts that are substantially better in quality
 Only a short gating stub remains on the casting to be
removed by a mass production gate grinding machine.
 With CLA 60 - 94 percent of the metal is used to
produce product, compared with 15 - 50 percent in
gravity poured parts, where much of the cast weight is in
the sprue and gating.
 No need for the cut-off blade in CLA casting cluster.

6.  CLA process provides the ability to cast sections as thin as 0.015 of an
inch
 Allows the control of grain size
 Since the sprue is filled in a non-turbulent fashion from clean metal
beneath the surface of the melt, castings with far less slag and non-
metallic inclusions are produced

7. •The metal will contain less amount of slag and inclusions and
hence will be cleaner
•Increases the number of casting from a single sprue to 2 or 3
times that of conventional gravity type

10. THANK YOU