Drilling of Composite Materials

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CONTENTS

INTRODUCTION

COMPOSITE DRILLING

DRILLING PARAMETERS

DRILLING DEFECTS IN COMPOSITES SELECTION OF DRILL BIT MATERIAL

TOOL WEAR AND CHIP FORMATION

ANALYSIS

CONCLUSION REFERENCE

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INTRODUCTION

Drilling , secondary machining forjoiningstructures.

Drilling process is performed with rotating

cylindrical tool

Nowadays composites used in aircrafts to reducefuel consumption.

Major problem in composite drilling isdelamination damage

Drill point angle can influence the tool wear

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DRILLING PARAMETERS

Lower cutting speed

Lower Feedratein drilling

Machining time/Drilling time

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COMPOSITE DRILLING

Composites are

made oftwo or

more materials

Increasing

demand in drilling

composites

Process is hard

since strength-

weight ratiois high

for composites

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DRILLING DEFECTS IN

COMPOSITE MATERIALS

Drill wear limits tool life

Tearing away of material from wall of the hole

Delaminating damage andchipping in work

piece

Fiber pullout / matrix cracking

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DRILL TYPES IN COMPOSITE

MACHINING

Twist drill

Saw drill

Core drill

Step drill

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SELECTION OF DRILL BIT

MATERIAL

Tool characteristics

Performance capabilities

Should have good mechanical properties

Cost should beless

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TOOL WEAR AND CHIP

FORMATION

Due to friction between tool and work piece

Wear includes flank wear, crater wear andchisel wear

Chip shape determines smoothness of drilling

process

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TYPES OF CHIPS

Continuous chips

Discontinuous chips

Build up edge

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TOOL WEAR ANALYSIS

Decreasestool life

Flank wear increaseheat between tool & work

piece

Wear causes irregularity among tool edge

Excessive tool loadcauses chipping

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EFFECT OF POINT ANGLE ON

FLANK WEAR

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CHIP FORMATION ANALYSIS

Process issmooth if chips arewell broken

Ductile materials don't break during drilling

Chip formation influence ontool performance

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CONCLUSION

Flank wear and chisel wear will be large

for 118 degree point drill as compared with

130 degree point drill.

Tool fails if it form long ribbon like form

chip.

Overall performance of 130 degree point

drill is betterthan 118 degree point drill.

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REFERENCE

www.sciencedirect.com/science/article/pii/S1877705813016470

www.sciencedirect.com/science/article/pii/S0

020740307000021

www.iosrjournals.org/ccount/click.php?id=2615

en.wikipedia.org/wiki/Drilling

en.wikipedia.org/wiki/Composite_material

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THE END

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Drilling of Composite Materials