Lesson 05 - What are the Types of Pattern ?

 Single-piece or Solid Pattern

• Solid pattern is made of single piece without joints, partings lines or loose pieces.
• It is the simplest form of the pattern.
• Simplest type, inexpensive used for limited production.
• Typical single piece pattern is shown in Fig.

Two-piece or Split Pattern

• When solid pattern is difficult for withdrawal from the mold cavity, then solid pattern is splitted in two parts.
• Split pattern is made in two pieces which are joined at the parting line by means of dowel pins.
• The splitting at the parting line is done to facilitate the withdrawal of the pattern.
• A typical example is shown in Fig.

Cope and Drag Pattern

• In this case, cope and drag part of the mould are prepared separately. This is done when the complete mould is too heavy to be handled by one operator.
• The pattern is made up of two halves, which are mounted on different plates. A typical example of match plate pattern is shown in Fig.

Loose-piece Pattern

• Used when pattern is difficult for withdrawal from the mould.
• Loose pieces are provided on the pattern and they are the part of pattern.
• The main pattern is removed first leaving the loose piece portion of the pattern in the mould.
• Finally the loose piece is withdrawal separately leaving the intricate mould.

Match plate Pattern

• This pattern is made in two halves and is on mounted on the opposite sides of a wooden or metallic plate, known as match plate.
• The gates and runners are also attached to the plate.
• This pattern is used in machine molding. A typical example of match plate pattern is shown in Fig.

Follow board Pattern

• When the use of solid or split patterns becomes difficult, a contour corresponding to the exact shape of one half of the pattern is made in a wooden board, which is called a follow board and it acts as a molding board for the first molding operation as shown in Fig.

Gated Pattern

• In the mass production of casings, multi cavity moulds are used. Such moulds are formed by joining a number of patterns and gates and providing a common runner for the molten metal, as shown in Fig.
• These patterns are made of metals, and metallic pieces to form gates and runners are attached to the pattern.

Sweep Pattern

• Sweep patterns are used for forming large circular moulds of symmetric kind by revolving a sweep attached to a spindle as shown in Fig.
• Sweep is a template of wood or metal and is attached to the spindle at one edge and the other edge has a contour depending upon the desired shape of the mould.
• The pivot end is attached to a stake of metal in the center of the mould.

Segmental Pattern

• Patterns of this type are generally used for circular castings, for example wheel rim, gear blank etc.
• Such patterns are sections of a pattern so arranged as to form a complete
• mould by being moved to form each section of the mould.
• The movement of segmental pattern is guided by the use of a central pivot. A segment pattern for a wheel rim is shown in Fig.

Shell Pattern

• Shell patterns are used mostly for piping work or for producing drainage fittings. This pattern consists of a thin cylindrical or curved metal piece parted along the center line.
• The two halves of the pattern are held in alignment by dowels.
• The outside surface of the pattern is used to make the mould for the fitting required while the inside can serve as a core box.

Location: United States

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