C.U.SHAH COLLEGE OF

ENGINEERING AND TECHNOLOGY. Wadhwan city.

ManufacturingProcesses-II

Code:151901year:2K14-2K15

Created by:

MEMAN M.RAFIK J. Enrolment No: 120440119032

Topic:DIE CASTING.

B.E. 5th Mechanical

Introduction. History of casting. Types of Die casting.Types of Dies are used in Die casting.Possible Defects in Die casting.Minimum recommended wall thickness.Design Rules in Die casting.Advantages & Disadvantages of die

casting.

Overview:

What is Die casting? Die casting is the art of rapidly and

accurately dimensioned parts producing by the forcing molten metal under pressure into split metal dies which resemble a common type of permanent mould.

This process is particularly suitable for lead , magnesium ,tin , zinc alloy , copper and aluminium metals.

Introduction

Casting technology , according to biblical records , reaches back almost 5000 years B.C., 3200 B.C. a copper frog , the oldest known casting in existence , was cast in mesopotamia.

460 B.C. Bronze statue of zeus (the supreme god of ancient Greek mythology) was cast in Greece.

233 B.C. cast iron plowshares were poured in China. 1455 A.D Dillenburg castle in germany was the first

person to use cast iron pipe to transport water. 1480 A.D. Birth of vannoccio Biringaccio ( 1480-1539)

, “the father of foundry industry” in Italy , He was the firstman to document the foundry process in writing.

HISTORY OF CASTING

Hot chamber die casting. Cold chamber die casting.

Types of Die Casting

In hot chamber die casting the plunger operates in one end of gooseneck which is submerged in molten metal.

Therefore molten metal flow by gravity into the cylinder by help of intake port, after applying force on plunger , the molten metal is forced into the die through the gooseneck channel and in gate.

The force on plunger may be manually , mechanically or hydraulically.

And at bottom one burner is provided for continuous heating throughout the operation to keep the metal in liquid form.

Here the air pressure is below 150 kg/ cm2 .

Hot chamber Die casting.

In cold chamber die casting the horizontal plunger is driven by air or hydraulic pressure to force the molten metal into the die.

After pouring molten metal by ladle into the cylinder , the plunger will move inside and forces the molten metal into the cavity.

After the metal solidified, the core is removed and then the die is opened.

Ejectors are provided to remove the casting automatically from the die.

Pressure loosely in cold chamber machine range from 300 to 1600 kg/ cm2 .

Cold chamber Die casting.

1.Single cavity Die: The single cavity die

mainly used to produceone component at timeof casting.

2.Multiple cavity Die: It is used to produce a number of identical parts at one time.

Types of Dies used in Die casting.

3. Unit Die: Unit die is used toproduce different partsat one time.

4. Combination Die: It is used to produce several different partsfor an assembly.

Flash- Due to injection pressure too high & clamp force too low.

Hot tearing-Due to non-uniform cooling rate.

Bubbles-Due to very high injection temperature & non-uniform cooling rate.

Unfilled sections-Due to slow injection & low pouring temperature.

Ejector marks-Due to very short cooling time & high ejection force.

Possible Defects

Die casting Wall thickness.

1.Wall thickness: 2.Corner: Incorrect Incorrect

Non-uniform wall thickness. Sharp corner.

Correct Correct

Uniform wall thickness. Rounded corner.

Design Rules

3.Draft: 4.Undercuts:

Incorrect Incorrect

No draft angle. Die cannot separet.

Correct Correct

With draft angle. Die easily separet.

Very high rate of production is achieved.Close dimensional tolerances of + 0.025

mm is possible.Surface finish of o.8 microns can be

obtained.Very thin sections of 0.50 mm can be

cast.Longer die-life is obtained.Less floor space is required.Unit cost is minimum.

Advantages of Die casting:

Only economical for nonferrous alloys.

Not economical for small runs.Heavy castings cannot be cast.Cost of die and die casting equipment

is high.Die casting usually contain some

porosity due to the entrapped air.

Disadvantages of Die casting:

Thank You