rib boom drilling a380
DESCRIPTION
Rib Boom Drilling - a380TRANSCRIPT
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DRILLING
The Experience of drilling through composite is quite different than drilling through metal.
Composite can be very easily damaged so it is extremely important to follow carefully the
procedures during drilling operations
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DRILLING
SRM 51-44-21
General
Hole sizes
Hole data
Drill data and drilling requirements
General requirements
Drill data
Drilling CFRP and GFRP, drilling AFRP
Drilling Composite / Metal combination
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SRM 51-44-21HOLE SIZES 2/4
Hole dimension and tolerances according to the fastener and hole fit depending on the repair design
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SRM 51-44-21
Fastener HL1011VF 6
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HOLE SIZES 4/4
Fastener ABS0257-6
Hole Tolerance
0.08 mm(0.00315 in)
0.017 mm(0.00067 in)
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Always clearance fit or close tolerance fit
Never interference fit (unlike for metal structure)
Fastener bending or turning in the hole is prevented by clamping force
FASTENER INSTALLATION
Interferences:
Even if interference are widely used in metallic structures, they should be avoided in composite structure due to possible local damage (delamination) during fastener installation. Holes are so generally drilled with a clearance fit.
In some cases ,where assembly is done between aluminium and composite parts (i.e.wing root area) moderate interference is used to minimize the aluminium part fatigue.
GENERAL REQUIREMENTS
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HOLE AND DRILL DATA
Attach material to prevent any movement and use a sacrificial composite back-up material when drilling.
Drill guide tools must be used to drill at right angles with a twist-drill.
For large holes, it is recommended to drill pilot holes.
Screw pin or skin pin
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GENERAL REQUIREMENTS
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According to the material to be drilled, the drill material and drill type
DRILLING DATASRM 51-44-21
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Cutting speed Aluminium (m/min)
Cutting speed Carbone (m/min)
Cutting speed Carbone (m/min)
Cutting speed Carbone (m/min)
Drill with sickle-shaped grinding angle,MBBN 569
Twist drill ground on 4 faces, MBBN 570
Tapered drill-reamer
Mini Maxi Mini Maxi Mini Maxi Mini MaxiDrill
Diameter 61 91 50 100 20 25 35 45
2.7 7200 10000 6000 12000 2300 2900 4150 5300
Cutting speed (RPM)
4.2 5000 6500 3500 7500 1500 2000 2700 34005.1 4000 5600 3200 6200 1300 1560 2200 2800
Cutting speed choice (RPM)
6000 and 8000 6000 1500 and 2500 2600 and 5000
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SRM 51-44-00
Cutting speed Ca / Alu (m/min)
Cutting speed Ca / Ti (m/min)
Cutting speed Stainless steel
Mini Maxi Mini Maxi Mini MaxiDrill
Diameter 25 50 9 12 9 12
2.7 3000 6000 1000 1400 1000 1400
Cutting speed (RPM)
4.2 1900 3800 680 900 680 900
5.1 1600 3100 600 700 600 700
Cutting speed choice (RPM)
3000 700 and 1200 700 and 1200
DRILLING DATA COMPARISON
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SRM 51-44-21
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DRILLING TOOLS
Twist-drills applicable to Composite Structures
To produce holes in composite structures, it is recommended that twist-drills with special ground tips should be used. These twist-drills should be solid carbide or carbide-tipped.
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MBBN 570
TWIST-DRILL GROUND ON 4 FACESSOLID CARBIDE OR CARBIDE TIPPED
SRM 51-44-21 DRILLING TOOLS
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MBBN 569
DRILL WITH SICKLE-SHAPED GRINDING ANGLESOLID CARBIDE
SRM 51-44-21 DRILLING TOOLS
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DRILL WITH SICKLE-SHAPED GRINDING ANGLE AND LEADSOLID CARBIDE
SRM 51-44-21 DRILLING TOOLS
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SRM 51-44-21
Hole diameter range
Composilok
Tolerance
0.08 mm(0.00315 in)
0.017 mm(0.00067 in)
Hi lok
Tolerance
DRILLING SEQUENCES
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Hi lok Composilok
Pilot hole
Ream under size
Ream to size
Pilot hole
Drill to size
Drill under size
SRM 51-44-21
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Countersink defined by:- depth- angle
Depth in relation with:- fastener nominal diameter - head form (Tension / Shear)
Angle is usually 100° but may be 130° for some applications
COUNTERSINKINGREQUIREMENTS
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COUNTERSINKING TOOLS AND SETTINGS
Depen
ding o
n the
counte
rsunk
angle
Pilot pin
Fast. hole
Pilot pin Countersunk bit
The pilot pin diametermust fit with the
fastener hole diameter.
Carbide inserts
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As defined in the SRM for fastener installation, corner must be ‘radiused’ or chamfered
CORNERREPAIR IMPLEMENTATION
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Countersunk recess
Countersunk fastener
Smooth surface
Countersunk fastener
Countersunk recess
Smooth surface
COUNTERSINKING DATA
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