2-1

Chapter 2 IntroductionChapter 2 Introduction

Why would a product designer choose a die Why would a product designer choose a die casting over a component manufactured by casting over a component manufactured by another competing process? another competing process?

What are the capabilities of a product made What are the capabilities of a product made with a die casting? with a die casting?

2-2

Chapter 2 ObjectivesChapter 2 Objectives

List the advantages of using die castingsList the advantages of using die castings Identify die casting applicationsIdentify die casting applications List the characteristics of the optimum die List the characteristics of the optimum die

casting configurationcasting configuration Identify the components of the die casting Identify the components of the die casting

shotshot

2-3

New TermsNew Terms

Die casting “shot”Die casting “shot” EMIEMI OverflowsOverflows RunnerRunner Sprue Sprue

2-4

Die Casting AdvantageDie Casting Advantage

Produces components at high speedProduces components at high speed Uses a range of durable metal alloysUses a range of durable metal alloys Faithfully captures the most intricate design Faithfully captures the most intricate design

detailsdetails So, it’s the choice for:So, it’s the choice for:

• High volume High volume production components production components

• Lower-volume Lower-volume production as wellproduction as well

2-5

Die Casting ApplicationsDie Casting Applications

Agricultural machineryAgricultural machinery Automotive vehiclesAutomotive vehicles Building hardwareBuilding hardware Electrical and Electrical and

electronic equipmentelectronic equipment Hand toolsHand tools Home appliancesHome appliances Industrial productsIndustrial products

InstrumentationInstrumentation Lawn and garden Lawn and garden

equipmentequipment Office furnitureOffice furniture Office machinesOffice machines Portable power toolsPortable power tools Recreational Recreational

equipmentequipment

2-6

Optimum ConfigurationOptimum Configuration

Fill completely with metalFill completely with metal Solidify quickly without defectsSolidify quickly without defects Eject readily from the dieEject readily from the die

2-7

Principle 1Principle 1

Wall thickness should be as consistent as Wall thickness should be as consistent as possiblepossible• No hard and fast rulesNo hard and fast rules• Wall section possesses a dense fine-grained skinWall section possesses a dense fine-grained skin• Defects likely in material in between wallsDefects likely in material in between walls• Wall sections should be as uniform as possible. Wall sections should be as uniform as possible. • Thinner walls contribute a lesser heat load than Thinner walls contribute a lesser heat load than

heavier walls and will have a longer die lifeheavier walls and will have a longer die life

2-8

Principle 2Principle 2

Intersections of walls, ribs and gussets Intersections of walls, ribs and gussets should blend with transitions and generous should blend with transitions and generous radiiradii• Generous radii and transitions promote metal Generous radii and transitions promote metal

flow and flow and internal integrityinternal integrity

• Radii and fillets enhance structural integrity Radii and fillets enhance structural integrity • Fillets reduce heat concentration in both the die Fillets reduce heat concentration in both the die

and castingsand castings

2-9

Principle 3Principle 3

Specify standard draftSpecify standard draft• Draft is highly desirable on surfaces parallel to Draft is highly desirable on surfaces parallel to

the direction of die drawthe direction of die draw• Recommended draft is determined by:Recommended draft is determined by:

– The alloyThe alloy– The length of the dimension parallel to the die draw The length of the dimension parallel to the die draw – If the dimension is an inside or outside wallIf the dimension is an inside or outside wall

2-10

Principles 4 and 5Principles 4 and 5

Eliminate or minimize sharp cornersEliminate or minimize sharp corners• Accommodate them at parting lines and at the Accommodate them at parting lines and at the

junctions of die components junctions of die components • Break them with radii or chamfersBreak them with radii or chamfers

Avoid undercutsAvoid undercuts• May require machining operations or additional May require machining operations or additional

die components, such as retractable core slidesdie components, such as retractable core slides

2-11

Principle 6Principle 6

Dimensions with critical tolerances should Dimensions with critical tolerances should relate to only one die memberrelate to only one die member• Precision is greatest when related features are in Precision is greatest when related features are in

same piece of cavity steelsame piece of cavity steel• Precision is reduced for relationships across the Precision is reduced for relationships across the

parting line or to moving componentsparting line or to moving components• Judicious use of ribbing can aid die filling and Judicious use of ribbing can aid die filling and

strengthen the componentstrengthen the component

2-12

The ShotThe Shot

The result of injecting metal into the die, The result of injecting metal into the die, i.e., making a shot (verb), is also called i.e., making a shot (verb), is also called a shot (noun) a shot (noun)

Shot elements:Shot elements:• RunnerRunner• BiscuitBiscuit• Overflows (not pictured)Overflows (not pictured)• CastingCasting

2-13

Overflow Overflow

A reservoir for the first metal to flow through A reservoir for the first metal to flow through the cavitythe cavity

Vents inside provide a path for air to get out Vents inside provide a path for air to get out of the dieof the die• A strategically placed overflow can be used to A strategically placed overflow can be used to

add heat in a cold area of the die add heat in a cold area of the die May help eject the casting from the dieMay help eject the casting from the die

2-14

SummarySummary

Many reasons to choose die casting over a Many reasons to choose die casting over a competing processcompeting process

Many product lines made from die castingsMany product lines made from die castings 6 principles must be followed to ensure 6 principles must be followed to ensure

optimum designoptimum design