Metal Processes Flashcards
what 6 processes don’t involve heat?
press forming
spinning
cupping
deep drawing
bending
rolling
what are the 4 types of casting?
sand casting
die casting
investment casting
low temperature casting
what is press forming?
sheet of metal is held in place. former then pressed into the middle of the sheet causing it to deform. metal retains that new shape forever
what is spinning?
metal disk is placed over a mould. mould and metal spun at high speed as pressure is applied to the disk. as pressure is applied the disk flows over the mould and deforms into a new shape. this new shape will be the same as the mould
what is cupping?
sheet is pressed into a die. as long as the depth of the pressing does not exceed the diameter it is still considered cupping instead of deep drawing. cupping and deep drawing is used in the production of fire extinguishers and high pressure aerosol cans
what is deep drawing?
a sheet of metal is pressed through a die. it is considered deep drawing when the depth of the pressing has exceeded the diameter of the sheet.
what is forging?
there are three types, being cold, warm and hot depending on the amount of heat used. a hammer, often a power hammer or a die is used in order to deform the metal into a new shape singing controlled compressive forces in localised areas. warm and hot forging is done in a forge
what is drop forging?
this is when a hammer is dropped onto a heated piece of metal which will cause it to deform into the shape of the die or tool. the metal is heated in order to soften it and then cooled after the process in order to harden it again into its new shape
what is bending?
a fairly simple process of which a punch presses metal sheets into a v or u shaped change. as pressure is applied it causes a bend in the metal at it goes into its new shape. sometimes more bending is used than desired so that if the metal bends back slightly to its original position it only goes into the right one. this is decided by the type of metal
What is rolling?
rolling is a process of which involves two or more rollers. similar to calendaring with polymers however in this case in is metal being pressed between to rollers. this process is used to get metal that may be two thick into a thinner, more desirable shape
what is sand casting?
heavily packed sand is used to create the mould. once the sand is in place, strickling off is used to remove the excess. pouring basins are made along with pouring and rising holes from sprue pins. vents are also in place for air to escape. metal in poured in through the pouring hole and when it reaches the riser pouring stops. it is left to call and the hardened metal is removed
what is die casting?
molten metal is poured into a pressure chamber via a funnel. the plunger then forces the metal through the sprue and into the cavity of the mould. once the cavity is full the sprue stops the flow, after the metal has hardened the ejector pins release the metal from the two piece mould
what is investment casting?
a wax pattern is coated in a slurry to form a shell in the in the shape of what is to be casted. this is heated and the wax is melted out leaving an empty shell. the molten metal is poured into the mould and hardens inside. after it has cooled the metal is removed by disposing of the shell and being left with the metal shape inside
what is low temperature casting?
this process (used on pewter or other low temp alloys) involves a thermostatically controlled casting system is kept at a relatively low heat to keep the metal at a molten state. it can then be easily used to cast into a mould. The system typically takes 15 mins to be functional after turning it on
what 3 metal forming processes involve heat?
forging
drop forging
casting
