Die Casting

Presentation Pressure Die Casting Sam Mande Deepak Ch Veera Pratap Vamsi raj J (BUB0912011) (BUB0912016) (BUB0912013) (BUB0912010) M. Sc. (Engg. ) in Engineering Manufacturing and Management Module Leader : Dr N S Mahesh M. S. Ramaiah School of Advanced Studies 1 History Casting since about 4000 BC… Ancient Greece; bronze statue casting 450BC Iron works in early Europe, e. g. cast iron cannons from England 1543 2 M. S. Ramaiah School of Advanced Studies Introduction Die casting is a very commonly used type of permanent molding process in which surface finish and tolerance of die cast parts is good that post-processing can be eliminated in many cases. • Die casting molds are expensive and require much time to manufacture they are generally called dies. • Die casting is done for high volume with high details, and value added economically priced cast parts. M. S. Ramaiah School of Advanced Studies 3 Die Casting Process 1. Die is ready to start 2. Die is closed, molten metal is filled in the chamber . The ram pushes the molten metal in to the die 4. Die cavity is filled with molten metal in few micro seconds 4 M. S. Ramaiah School of Advanced Studies Die Casting Process 5. The metal than solidifies 6. The component casted is ejected from the die 7. The die is cleaned and sprayed with releasing agents 8. Die is ready for the next cycle 5 M. S. Ramaiah School of Advanced Studies Die casting process • In Die-Casting the metal is injected in to the mold under high pressure 10-210 Mpa (1,450-30500 psi) Casting can produce very complex geometry parts with internal cavities and hollow sections. • It is economical, with very little wastage, the extra metals in each casting is melted and reused • The clamping pressure exerted on the die is Rated in “Clamping tons” • The capacity varies from 400 tons to 4000 tons. M. S. Ramaiah School of Advanced Studies 6 Die Casting Process • Most of the die castings are made from non-ferrous metals, particularly zinc, copper, aluminum, magnesium, lead, and tin based alloys, although ferrous metal die castings are possible The die casting method is especially suited for applications where a large quantity of small to medium sized parts are needed with good detail , a fine surface quality and dimensional tolerance • There are two common types of die casting: hot- chamber process and cold-chamber process • Example: Pressure die casting M. S. Ramaiah School of Advanced Studies 7 Cold chamber process • The essential feature of this process is the independent holding and injection units • In the cold chamber process metal is transferred by ladle, manually or automatically, to the shot sleeve • Actuation of the injection piston forces the metal into the die.

This is a single-shot operation • This procedure minimizes the contact time between the hot metal and the injector components, this extend their operating life M. S. Ramaiah School of Advanced Studies 8 Cold chamber process • Hot melt is pressurised with high-speed injection is likely to enter air in the metal, which can cause porosity in the castings • The cold chamber process is used for the production of aluminium, copper base alloys and steel castings • Next to zinc, aluminium is the most widely used die-casting alloy The mould has sections, which include the “cover” or hot side and the “movable” or ejector side M. S. Ramaiah School of Advanced Studies 9 • The die may also have additional moveable segments called slides or pulls, which are used to create features such as undercuts or holes which are parallel to the parting line • Available machine capacity ranges 300 to 4000 T clamping pressure M. S. Ramaiah School of Advanced Studies 10 Cold-Chamber Die Casting Process Operating Sequence of the ColdChamber Die Casting Process

The die is closed and the molten metal is ladled into the cold-chamber shot sleeve. The plunger pushes the molten metal into the die cavity where it is held under pressure until solidification. Ejector pins push the casting out of the ejector die and the plunger returns to its original position The die opens and the plunger advances, to ensure that the casting remains in the ejector die. Cores, if any, retract. M. S. Ramaiah School of Advanced Studies 11 Applications • • • • Fuel Pumps Carburetor Parts Valve Covers Handles M. S. Ramaiah School of Advanced Studies 2 Hot Chamber Process • Hot chamber process is the process where the metal is maintained at an appropriate temperature in a holding furnace adjacent to the machine • The injection mechanism is located within the holding furnace and a part of it is therefore in constant contact with the molten metal • Pressure is transmitted to the metal by the injection piston through the gooseneck and into the die • On the return stroke metal is drawn into the gooseneck for the next shot M. S. Ramaiah School of Advanced Studies 13 Hot Chamber Process In this process there is minimum contact between air and the metal to be injected • Due to the contact between the metal and parts of the injection system hot chamber is restricted to zinc-base alloys • The Zinc alloys are mostly used in the die casting process • They have physical, mechanical and casting properties • Applications limited to low melting point metals that do not chemically attack nozzle and other mechanical components M. S. Ramaiah School of Advanced Studies 14 Hot Chamber Process • The main advantage of this process includes fast cycle times of approximately 15 cycles per minute Due to this process, hot chamber machines are used with Casting metals likes zinc, tin, lead, and magnesium M. S. Ramaiah School of Advanced Studies 15 Hot Chamber Die Casting Process M. S. Ramaiah School of Advanced Studies 16 Advantages • Economical for large production quantities • More accuracy • Surface finish is good • Thin sections are possible • Fast cooling leads small grain size and also good strength to casting • Dimensional control is achieved • Due to thin walls, weight is reduced M. S. Ramaiah School of Advanced Studies 17

Disadvantages • High tooling costs • Size restrictions of castings • Volume restrictions • Generally limited to metals with low metal points • Part geometry must allow removal from die M. S. Ramaiah School of Advanced Studies 18 Applicability • Excellent for large and complicated shapes, particularly with internal features • Can produce net shape or near net shape components • Used where mechanical properties are not important • Used where solid state processing is difficult or uneconomical M. S. Ramaiah School of Advanced Studies 19 Conclusion Depending on the field of application Die casting plays a crucial role in fulfilling the requirement accordingly &depending on the size and shape of component and material used the appropriate process should be selected •Mainly by controlling and maintaining the various parameters such as material, machine, cycle time and impression(mould)the effectiveness can be improved and its directly reflects in M. S. Ramaiah School of Advanced Studies 20 • Reducing maintenance cost • Quality of component is improved • Rejection rate is less • Wastage of material is less Life of machine and mould is improved • By following these parameters overall process will be effective & which leads to economic effectiveness M. S. Ramaiah School of Advanced Studies 21 Reference [1] Unknown. , pressure die casting process, www. wikipedia. com, [2] Unknown, Advantages of PDC, www. dynecast. com, [3] Unknown. , cold chamber die casting, www. diecastetechnology. blogspot. com , [4] Unknown. , Hot chamber die casting, www. duecasting. com [4] Module notes ENG:MATLS. Dr Ns mahesh MSRSAS Bangalore. , M. S. Ramaiah School of Advanced Studies 22 THANK YOU M. S. Ramaiah School of Advanced Studies 23

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