1. a permanent mold casting process using pressure other than gravity
Die Casting
a permanent mold casting process using pressure other than gravity

2. Parameters shot pressures 1000 to 100,000 psi highly mechanized
cycle times
up to 18,000 shots per hour
small components like zipper teeth

3. Parameters (Cont.) 1/2 the die fastened to stationary platen
1/2 the die fastened to movable platen actuated by piston
casting pushed out by ejector pins

4. Two types of machines
hot chamber
cold chamber

5. Hot chamber machine chamber is submerged in molten metal
forced into cavity by plunger
use low melting metals like
lead, tin, zinc
metals that don’t attack and erode the metal pot, cylinder, and plunger

6. Cold chamber machine
molten metal ladled into shot chamber (chamber not heated)
metals cast
higher melting point
al, magnesium, copper, ferrous metals

7. Flash metal has flowed between die halves at parting line
reduced by adequate pressure clamping both die halves together
removed by shearing, blanking, grinding

8. Machine selection rated according to clamping pressures die size
25 to 3000 tons
die size
piston stroke
shot pressure
cost

9. Dies water or oil cooled use of release agents
wear increases with temp of molten metal
heat checking - surface cracking from repeated heating and cooling is a problem
can last up to 500,000 shots before significant wear occurs

10. Die Design
draft
removal of sprues and runners

11. Types of die cavities single multiple - several identical cavities
combination - several different cavities
unit - simple small dies that can be combined in two or more units in a master die

12. Application carburetors small motors
business machines and appliance components
hand tools
toys

13. Advantages can be automated minimum expenditure of metal
thin wall sections (.020”)
components cast internally
pins, shafts, fasteners

14. Advantages (Cont.) close tolerances
little or no finishing after removal of gate and flash
because molten metal chills rapidly, achieve fine grain structure with hard skin and higher strength

15. Disadvantages
equipment costs high