foundry technology
Post on 20-Jul-2016
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Foundry Technology
Introduction” Foundry or casting is the process of
producing metal/alloy components of desired shapes by pouring the molten metal into a prepared mold and then allowing the metal to cool and solidify. The solidified piece of metal is known as a CASTING”
Different Sections in Foundry Pattern making Sand mixing & preparation Mould and core making Mould assembly & handling Melting Pouring Knockout & Shot blasting Fettling & finishing Heat treatment Inspection & testing
Metals and alloys commonly used in Foundries:
1. Ferrous2. Non-Ferrous
FERROUS:a. Cast ironsb. Steels
NON-FERROUS:c. Copper alloysd. Aluminium alloyse. Nickel alloys
Pattern Making• A Pattern is a model or the replica of the
object to be cast.• Except for the various allowances a pattern
exactly resembles the casting to be made.• A Pattern may contain projections known as
core prints if the casting requires a core and need to be made hollow.
Materials for making patterns:a. Woodb. Metalc. Plasticd. Plastere. Wax.
Types of Patterns:1. Single piece
pattern.2. Split piece
pattern.3. Match plate
pattern.4. Cope and Drag
pattern.
Molding materialsIt also known as foundry sands, it defined by eight characteristics:• Refractoriness • Chemical inertness• Permeability• Surface finish • Cohesiveness • Flowbility• Collapsibility• Availability/cost
Sand Mixing &PreparationThe main ingredients of any molding sand are:• Base sand Base sand is the type used to make the mold or core without any binder• Binder Binders are added to a base sand to bond the sand particles together• AdditivesThese are added to the molding components to improve dry strength Refractoriness surface finish cushioning properties
A Typical Composition of Molding Sand:
Molding Sand Constituent Weight Percent
Silica sand 92
Clay (Sodium Bentonite) 8
Water 4
SAND-CASTING
MOLDING:Sand placed
into bottom mold form & compacted
MOLDING: Pattern placed into mold
sand casting process. . .
First of all, mix the sand.
21THEN
SAND-CASTINGMOLDING: Add the top mold form
3
4 MOLDING: Fill top form with compacted sand.
A tube or pipe provides a path to pour the metal in
Pattern is still inside!
SAND-CASTINGMOLDING: Take the top mold off and remove pattern & pipe or post
5
6 MOLDING: Replace the top mold and fasten securely!
Pouring hole
In the middle of the sand is a cavity shaped like the pattern!
SAND-CASTING
7 CASTING: Pour the metal (container is filled from furnace immediately before you are ready to pour)
8 Wait for the metal to cool(minutes to days, depending on the size of the casting)
SAND-CASTING
8 SHAKE OUT: Break apart the two halves of the mold & take out the part—usually requires vibrating or striking the mold to break apart the sand
CLEANING. Sand is cleaned off the part, the “tab” where metal flowed in must be removed.
9
A copy of the pattern has now been made in metal
10 Mold forms are reused
11Sand is broken up, screened to remove debris and clumps, and sent for remixing
Sand Casting: Parts of a Sand Mold
Sand mold - opened
Sand mold - closed
Mixing moulding sand with binders & adhesives
Filling sand in moulding flasks
Melting furnace
Pouring molten liquid
Knock out
Heat treatment
Machining
final products of casting
Thank you
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