Shaping processes Flashcards
(8 cards)
What is hot chamber die casting?
Hot chamber die casting is a shaping process in which high pressure molten metal is forced into two-piece reusable hardened steel dies to make complex three-dimensional components
What is sand casting?
Sand casting is a process where molten metal is poured into a green (resin bonded) expendable sand mould
What are some differences between sand and die casting?
Sand casting moulds can only be used once, as opposed to hardened steel dies.
Sand casting moulds produce components with a rougher finish
Sand casting is much cheaper.
What is injection moulding?
Injection moulding is a shaping process in which high pressure molten thermoplastic is forced into two - piece hardened steel moulds to make complex three - dimensional components
What is powder metallurgy?
Powder metallurgy is a metal forming process that heats a compacted mix of fine metallic powders to just below their melting points. This fuses or sinters the particles of powder together into solid metallic components.
What does the DIPS acronym stand for?
Die casting
Injection moulding
Powder metallurgy
Sand casting.
Process for die casting
The two piece metal die containing the mould cavity is held closed
Molten casting metal fills the pressure chamber
The plunger forces a pre measured amount of molten metal into the die cavity
Metal cools and solidifies
Die is separated and ejector pins push the casing out of the die
Any remaining sprue or flash formed along the parting line is ground off the casing
Cycle repeats
Process for sand casting
Half pattern of cast component is placed into the bottom of the drag and covered with compacted green sand
Drag is inverted and cope bolted in place
Second half of pattern and pins for sprue and riser are added
Cope is filled with compacted green sand
A pouring basin is formed around the sprue pin
Drag and cope are split, sand is removed to form channels
Drag and cope are bolted together once the sand is fully dry.
Molten metal is poured into the pouring basin and into the sprue, and is stopped when molten metal emerges from the riser.
Mould can be broken off once cooled
