Single
piece pattern:
This is the simplest type of pattern, exactly like the desired casting. For
making a mould, the pattern is accommodated either in cope or drag.
Used for producing a few large castings, for example, stuffing box of
steam engine.
Split
pattern:
These patterns are split along the parting plane (which may be flat or
irregular surface) to facilitate the extraction of the patternout of the
mould before the pouring operation. For a more complex casting, the
pattern may be split in more than two parts.
Loose
piece pattern:
When a one piece solid pattern has projections or back drafts which lie above
or below the parting plane, it is impossible to with drawit from the
mould. With such patterns, the projections are made with the help of loose
pieces. One drawback of loose feces is that their shifting is possible
during ramming.
Figure: Loose
piece pattern
Gated
pattern:
A gated pattern is simply one or more loose patterns having
attached gates and runners.
Because of their higher cost, these patterns are used for producing
small castings in mass production systems and on molding machines.
Figure: Gated
pattern
Match
plate pattern:
A match plate pattern is a split pattern having the cope and drags
portions mounted on opposite sides of a plate (usually metallic), called
the "match plate" that conforms to the contour of the parting
surface.
The gates and runners are also mounted on the match plate, so that very little hand
work is required. This results in higher productivity. This type of pattern is
used for a large number of castings.
Piston rings of I.C. engines are produced by this process.
Sweep
pattern:
A sweep is a section or board (wooden) of proper contour that is rotated
about one edge to shape mould cavities having shapes of rotational
symmetry. This type of pattern is used when a casting of large size is to
be produced in a short time. Large kettles of C.I. are made by sweep
patterns.
Figure: Sweep
pattern
Cope
and drag pattern:
A cope and drag pattern is a split pattern having thecope and drag
portions each mounted on separate match plates. These patterns are
used when in the production of large castings; the complete moulds are
too heavy and unwieldy to be handled by a single worker.
Skeleton
pattern:
For large castings having simple geometrical shapes, skeleton patterns are
used. Just like sweep patterns, these are simple wooden frames that
outline the shape of the part to be cast and are also used as guides by
the molder in the hand shaping of the mould.
This type of pattern is also used in pit or floor molding process.
Figure: Skeleton
pattern
Shell
pattern:
Figure: Shell
pattern
Follow
board pattern:
A follow board is not a pattern but is a device (wooden board) used for
various purposes.
Other Topics
IC engine,
Air
Standard Cycles,
Method
of Ignition,
Gear Types,
External
Gear Pump,
mechanical
Engineering,
Gears,
spur gears,
Helical
gears,
herringbone
gear,
Worm
gears,
English
books,
Photoshop
tutorials,
Physics files,
Thamizh,
Manufacturing,
Gears pdf,
Computer
science,
Harry
potter,
Best
100 english books,
Rack
and pinion,
Face Gears,
Involute
Splines,
Straight
sided Spline,
Bush
Roller Chains,
IC
engine,
Metal
Casting,
Metal
Casting Terms,
Categories
of metal casting processes,
Sand
casting,
SAND
Casting Quiz,
Casting
patterns quiz,
Sand
Casting Process
