metal processes Flashcards
what type of process is press forming
forming
what is a die
used to force a shape onto hard substances
what is a press blank
sheet of metal that is ready to be drawn, pressed, machined into a finished product
press forming process
- press blank placed between the female and male die
- hydraulic press punches the male die to the press blank
- formed press blank removed
press forming stock form
sheet
press forming products
car body parts
containers and boxes
metal seats
press forming key features
suitable for mass/large scale batch production
spinning process
- mandrel (former) is put onto the headstock
- press blank is placed between headstock and tailstock
- spindle is rotated
- press blank is pushed onto mandrel using roller tool to apply even pressure
- press blank forms over mandrel then when done is removed and trimmed
spinning stock form
sheet
spinning products
stainless steel kettles
light shades
saucepans
spinning key features
may show lines where sheet has been forced onto the mandrel
suitable for batch production, labour intensive
what type of process is spinning
forming
difference between deep drawing and cupping
deep drawing= depth exceeds the diameter
deep drawing and cupping process
- press blank placed between female and male die
- drawing punch pushes the press blank down into the female die to crate a basic cup shape
- cup is then pressed down further to create a tube shape
deep drawing and cupping stock form
sheet (round)
deep drawing and cupping products
fire extinguishers
aerosol cans
drinks cans
deep drawing and cupping key features
mass/ batch production
what type of process is deep drawing and cupping
forming
drop forging process
- upper die secured to ram, lower die secured to anvil
- metal is heated and placed onto lower die
- ram is bough down onto metal then ram is lifted
drop forging stock form
billet (metal bar)
drop forging products
spanners,
screwdriver shafts
pliers
products that need to be tough and hard as it maintains the internal grain structure retaining the strength
drop forging key features
mass production
wrought iron process
made by hand OR similar to drop forging (metal is HOT)
wrought iron stock form
bar
wrought iron products
decorative fencing
gate scrolls
wrought iron key features
one off / small scale batch production
what type of process is drop forging
forming
what type of process is wrought iron forging
forming
bending process
- press blank clamped between the punch and the die
- pressure applied to punch, punch lowered down and metal is bent
bending stock form
sheet
plate
bending products
seams on metal edges
product casings or housings
bending key features
cheap to set up
used in all scales of production
what type of process is bending
forming
hot/cold rolling process
- heated/cold metal passed through a series of rollers reducing the thickness of the material
hot vs cold rolling differences
cold rolling usually produces thinner products, better surface finish
hot rolling = uniform, mechanical properties, no deformation or stresses
hot rolling products
railway tracks
I Beams, angle, bar, plate
cold rolling products
filing cabinets, chairs, steel drums
rolling stock form
billet (bar like shape)
what type of process is rolling
forming
what type of process is sand casting
redistribution
sand casting process
- mould placed in bottom of box called a drag. Sand is packed into drag to cover mould.
- drag is turned over and a 2nd box (cope) is clamped on top. sprue pins added which will work as runners for molten metal
- sand is packed down onto other side of mould
mould and sprue pins are carefully removed from drag and cope leaving shape of mould in sand and sprue holes - small spikes are poked into sand to make vents.
- molten metal is tipped into sprue holes which flows into runner then into the cavity before finally flowing up through the riser
what is a sprue
Channel through which metal or plastic is poured into a mould
what is a riser
A riser, also known as a feeder, is a reservoir built into a metal casting mould to allow molten metal to flow out of mould.
sand casting stock form
molten metal from billet
sand casting products
railway carriage wheels
vices
bollards
post boxes
drain covers
sand casting key features
not a high quality surface finish
suitable for one off/ small batch production
what process is gravity die casting
redistribution
gravity die casting process
- molten metal is poured down a sprue hole into a chamber and is run out of a riser
- once metal is cooled the product is removed
gravity die casting stock form
molten metal from a billet
gravity die casting products
engine components
door knobs and handles
alloy wheels
gravity die casting key features
mass/ large scale batch prod
uses low melting point metals ie aluminium and aluminium based alloys, zinc based alloys
what type of process is hot chamber and cold chamber pressure die casting
redistribution
hot chamber pressure die casting process
- molten metal placed in chamber
- hydraulic plunger forces the molten metal into the cavity within the die
- ejector pins are removed, cooled product is removed
cold chamber pressure die casting process
- molten metal poured into shot chamber
- ram forces the molten metal through the shot chamber into the cavity in the die
- ejector pins are removed, cooled product is removed
cold/hot chamber pressure die casting stock form
molten metal from a billet
cold/hot chamber pressure die casting products
toy cars
collectable figures
door knobs and handles
cold/hot chamber pressure die casting key features
mass/ large scale batch prod
uses low melting point metals ie aluminium and aluminium based alloys, zinc based alloys
investment casting process
(lost wax casting)
- Replica is made from wax.
- Wax replica is dipped into clay before being fired in a kiln which removes the wax.
- Molten metal is poured into hot clay mould.
- Metal is allowed to cool.
- clay mould is broken.
- Runners and vents are machined off.
investment casting stock form
molten metal from a billet
investment casting products
hip replacement joints
jewellery
collectable figures
investment casting key features
intricate/ awkward shapes that are otherwise difficult to mould
high quality and excellent finish
repeatable process
low temp pewter casting process
- Mould is made out of simple materials such as MDF or Plywood using laser cutter. Mould will include sprue or runner.
- Mould is sandwiched between 2 pieces of MDF.
- Pewter is melted in ladle and poured into sprue.
- Once pewter has cooled mould is removed.
low temp pewter casting stock form
molten metal from billet
low temp pewter casting products
jewellery
key fobs
low temp pewter casting key features
suitable for one off production/ small batch prod
MIG welding process
- consumable electrode wire is fed through the welding gun at a continuous rate
- the electrode produces an arc at the metal work piece
- the arc melts the base metals allowing them to join together with the consumable electrode also being melted and added to the arc as well reinforcing the arc.
MIG welding products
tubular products like
climbing frames
bike frames
vehicle exhaust
MIG welding key features
used with metals like mild steel, aluminium, copper
suitable for one off or on an assembly line
faster than TIG
brazing process
- gas or oxygen acetylene turned on, then put into flame
- compressed air turned on to turn flame blue
- pieces to be worked heated up until they are same temperature below 1000 degrees
- powder flux added to filler rod
- brass filler rod is placed onto work piece and powder flux melts and act as glue
- flame is removed yippee!!!!!
brazing products
joining thinner gauge mild steel tube or bar
radiators
brazing key features
- one off small batch production
- used to join dissimilar metals like mild steel to aluminium, copper and nickel
solder process
- solder iron is cleaned using a solder sponge
- solder iron is placed on the work piece to heat it up a bit
- solder (filler rod) is added to where the solder iron is to join the two metals
solder products
electrical circuit boards
joining precious metals like gold, silver
joining copper in pipework
solder key features
solders tend to be copper or tin
solder is at a lower melting point than metal being joined
spot welding process
- transformer transfers electricity into high current, low voltage into upper electrode
- work piece placed between the upper and bottom electrode
- arm adjustment pulled and the electrodes meet at the work pieces to be joined
spot welding products
mild steel sheets that need to be welded at length
spot welding key features
can be mass, batch or one off
oxy acetylene process
- oxygen is switched and flame is put on
- acetylene put on accordingly deepening on metal thickness
- work piece metal is heated, steel filler rod then melts in between two metals and acts as a joiner.
- ya
tungsten inert gas process
- non consumable tungesten electrode fed through the nozzle
- flame creates arc where consumable filler rod is melted into
- ya
TIG welding products
stainless steel ladders for swimming pools/boats
car exhausts
MIG vs Tig
MIG
faster
thicker metals
not nice finish
automatically fed though welder so easier to control
TIG
better finish
pop riveting process
- The two pieces of metal are drilled to a size slightly larger than the rivet
- The pop rivet is passed
through both holes in the metal. - The rivet pliers are pushed on to the pin of the rivet and the handles are pulled together.
As this happens the pin head is pulled into the rivet and the end of the rivet is expanded. - the pin will break off leaving the rivet permanently fixed in position holding the two pieces metal together.
