Metal patterns are commonly used for machine molding due to their strength, accuracy, and resistance to warping, moisture, and abrasion compared to wood patterns. Common metals used include aluminum alloys, steel, cast iron, and brass. Plastic patterns are also used and provide benefits such as being lightweight, durable, and corrosion resistant, but can be more fragile. The appropriate type of pattern depends on factors like the production quantity, part complexity, molding method, and potential design/molding problems. Common pattern types include one-piece, split, match-plate, cope and drag, loose piece, sweep, and skeleton patterns.

1. Presented by Mukesh Karnik

7.  METAL
Metal pattern are cast from wooden pattern.
The different metals and alloys used for making pattern.
Metal patterns are mostly used for machine molding.
Advantage :-
1. They are more stronger and accurate as compare to
wooden patterns.
2. They do not wrap.
3. They do not absorb moisture.
4. They can withstand with rough handling.
5. They possess excellent wear resistance .
6. They have accurate dimensional tolerance.
7. They possess greatly resistance to abrasion.

8. Limitation :-
1. It is a expensive method.
2. Ferrous pattern get rusted.
3. They are heavy in weight.
4. They cannot be machined so easy as woods ones.
Application :-
Metal pattern are employed where large number of casting
have to be produced from the same pattern.
Different metal used for pattern making along with their
advantages limitation and application are given below:
a. Al & AL- alloys
b. Steel
c. Cast iron
d. Brass
e. White metal

9.  Plastics
Advantages :-
1) Durable
2) Provide a smooth surface.
3) Moisture resistance.
4) Light weight
5) Good strength
6) Wear and corrosion resistance.
7) provides good surface finish.
8) It possess low solid shrinkage.
Disadvantages :-
1. Plastic patterns are fragile and thus light section may need
metal reinforcements.
2. Plastic pattern may not work well when subject to condition
of serve shock as in machine molding.
3. It is used in only small and medium size pattern making.

13. For selection a particular kind of pattern for making a casting,
one may consider the following points.
1. Quantity of casting to be produced.
2. The size and complex of the shape of the be produced.
3. Type of moulding method to be used operation such as
withdrawing the pattern from the moulding etc.
4. Other difficulties resulting from poor casting design or
pattern design.
5. problem associated with the moulding.
The different types of patterns commonly used are:-

14.  It is a simplest type of pattern.
 The pattern is made of on piece and does not contain
loose piece or joints.
 It is inexpensive.
 One piece pattern made of up of wood or metal depending
upon the quality of casting , to be produced.
 One piece pattern is accommodate either in cope or in
the drag.
 One piece pattern moulding operations like cutter , runner ,
gates and providing riser ,
 Being large manual consume a lot of time and for this
reasons one piece is used for producing small number of
casting only.

15.  The upper and the lower part of the spilt pattern are
accommodated in the cope and drag portion of the mould
respectively
 Dowel pins are used for keeping the alignment between the
two part of the pattern.
Patterns for still more indicate castings are made in more than
two piece for facilitation their moulding and withdrawing.

16. A split pattern models the part as two separate pieces that
meet along the parting line of the mold.
 Using two separate pieces allows the mold cavities in the
cope and drag to be made separately and the parting line is
already determined.
Split patterns are typically used for parts that are
geometrically complex and are produced in moderate
quantities.

17. A match-plate pattern is similar to a split pattern, except
that each half of the pattern is attached to opposite sides of
a single plate.
The plate is usually made from wood or metal.
This pattern design ensures proper alignment of the mold
cavities in the cope and drag and the runner system can be
included on the match plate.
 Match-plate patterns are used for larger production
quantities and are often used when the process is
automated.

18. A cope and drag pattern is similar to a match plate pattern, except that
each half of the pattern is attached to a separate plate and the mold
halves are made independently.
Just as with a match plate pattern, the plates ensure proper alignment
of the mold cavities in the cope and drag and the runner system can be
included on the plates.
Cope and drag patterns are often desirable for larger castings, where a
match-plate pattern would be too heavy and cumbersome.
They are also used for larger production quantities and are often used
when the process is automated

19. Certain patterns cannot be with drawn once they are
embedded in the moulding sand. such patterns are usually
made with one or more loose piece for facilitating their
removal from the molding box are known as loose piece
pattern.
Loose piece pattern or piece remain attached with main
body of the pattern with the help of dowel pins.
The main body of the pattern is drawn first form the
molding box and there after as soon as the mould cavity.
Loose piece pattern involve more labour and consume
more time in the moulding operations.

20. Sweep pattern can be used for both green and dry sand
moulding.
A sweep pattern is just a form made on a wooden board
which sweep the casting into the sand all around the
circumference the sweep pattern rotates about the post
Once the mould is ready sweep pattern and the post can
be removed.
Sweep pattern avoids the necessity of making a full,
large circular and costly three dimensional pattern.
A sweep pattern is preferred for producing large casting
of circular section and symmetrical shapes.

21. A skeleton pattern is the skeleton of a desired shaped.
Which may be a chute or something else the skeleton frame
is mounted on a main base.
The skeleton is made from wooden strips and is thus a
wooden framework.
The skeleton pattern is filled with sand and is rammed.
A skeleton assists in giving the desired shape to the sand and
removes extra sand.
Then the two moulds can be assembled before pouring the
molten metal.
A skeleton patterns are employed for producing a few large
casting. It involves less material costs.
Casting for turbine casing, water pipes, chutes etc.

22. The accuracy of dimension and surface finish of the object than a
carpenter.
The following tool are used for different purpose by a pattern maker-
 measuring , marking an layout tools:-
-Steel rule
-Caliper t bevel
-Marking gauge Divider
-Try square Shrinkage rule
(B) Tools for clamping purpose:-
- hand vice pattern makers vice
- Bar clamp c - clamp
- hard screw pinch dog

23. (c) Drilling & boring Tools :-
- hand drill brace
-Auger bit counter sink bit
- Gimlet
(D) Wood planning tool:-
-Jack plane smooth plane
-Block plane scrub plane
- circular plane core box plane
(E) Other pattern making tools :-
- Gauges mallet
-Hammers screw drivers
- nail set fillet iron