Pattern

Pattern is duplicate of the component manufactured by casting material.

Pattern Materials• Wood• Metals• Plasters• Plastics and Rubbers• Waxes

Types of Patterns

Types of Patterns Used in Sand Casting: (a)solid pattern(b)split pattern(c)match plate pattern‑(d)cope and drag pattern (e)gated pattern(f)loose piece pattern(g)sweep pattern(h)shell pattern

Solid Pattern (Single Piece)

Split Pattern

Cope and Drag Pattern

Match Plate Pattern

Pattern Allowances

Pattern Allowances1.Shrinkage allowance2.Draft allowance3.Finish allowance4.Shake allowance5.Distortion allowance

Core and Core MakingCore is part used in casting processes to produce internal cavities.

Requirements of Core• There must be adequate strength for handling.• In the hardened state it must be strong enough to handle

forces of casting.• Permeability must be very high to allow for the escape of

gases• Good refractoriness is required as the core is usually

surrounded by hot metal.• A smooth surface finish• A minimum generation of gases during metal pouring.

Core Making ProcessPurpose of CoreFor hollow castingUsed to strengthen the moulds Core Making process• Core Sand Preparation• Core Making• Core Baking• Core Finishing

Types of coresi)According to the shape and position of the CoreHorizontal, Vertical ,Hanging ,Balancedii)According to the state or condition of coreGreen Sand , Dry Sandiii)According to the type of core hardening process

employedHot box , Cold set, Cast able Sand, Oil-No-Bake Process

Core Boxes• Core box is basically a pattern for making cores• Core boxes are employed for ramming core in them • Core boxes impart the desired shape to the core

sand Types of core boxes• Half core box• Slab or Dumb Core box• Gang Core Box• Loose Piece Core Box