Design Guide For Mobile phone housing
Dynamic fatigue behavior
Why is the dynamic fatigue behavior so important for mobile phone? Dynamic fatigue behavior
16 12 8 4 0
HI-100Βιβλιοθήκη BN HR-1008BN PC/ABS
Many weld lines
Low weld line strength =>cause failure
Test condition - 2 gate Izod impact specimen (unnotched, 3.2mm)
2500
No. of cycles of failure
2000 1500 1000 500 0
HI-1001BN HR-1008BN PC/ABS
Under iterative loading condition
Sudden catastrophic failure in a brittle mode
The dew point at dryer:-29 ~ -40oC, hopper capacity depends on residence time
< 0.5 6 ~ 20 Good gas vent, strong structure, mold inter-locked 2
Last Updated OCT 07 1998
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Design Guide For Mobile phone housing
Material guide for Mobile Phone Housing Characteristics of PC, PC/ABS Property
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Design Guide For Mobile phone housing
Flow characteristics Spiral flow length of STAROY PC/ABS
Closed loop, micro process control
Compression ratio: 2:1 ~2.5:1, L/D = 20:1 ~ 24:1, flight NO at 3 zone: 5/10/5
>2 40 ~ 60
0.6 ~ 2.0 20 ~ 40 Good gas vent, strong structure, many eject pins
Housing Materials for Mobile Phone should
- have a high impact resistance - be easily processed for thin walls - be resistant to the daily life chemicals - be amenable to post-molding treatment
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Design Guide For Mobile phone housing
Material guide for Mobile Phone Housing STAROY HI-1001BN, HR-1008BN
Generally, STAROY PC/ABS alloy has
- high impact resistance - good melt flow - good chemical resistance - easy post-molding treatment
Furthermore,
STAROY HI-1001BN and HR-1008BN are superior to other PC/ABS grades, widely used for mobile phone housing, in the following properties that are critical for housing materials for mobile phone… Excellent dynamic fatigue behavior Higher weld strength Superior impact resistance
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Design Guide For Mobile phone housing
Impact resistance
Notched impact strength (3.2mm thick specimen) Falling dart impact on 3mm sheets
1.2 ~ 2.0
90:1 ~ 150:1 High performance 1100 ~ 1380 standard Closed loop, micro process control
Wall thickness(mm)
L:T Injection machine Injection pressure (kg/cu.cm) Hydraulic system Control system Screw design Molding condition Fill time(sec) Cycle time(sec) Drying condition Mold
Flowability
PC
PC/ABS
Impact/Stiffness Balance
Thermal resistance Post-molding treatment
Chemical resistance
Thin wall Grade STAREN PC HF-1023I STAROY PC/ABS HI-1001BN HR-1008BN
Molding
Mold:Gate(CAE), Vent, Eject, Polish, Heavy High speed injection(< 1sec) & Pressure(> 100MPa)
Design
Impact : curved part, fastened component Stiffness : small rib & gusset Interlock : low strain
Test condition - Constant amplitude of cyclic strain - 3.7% strain at tensile specimen
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Adequate design to small size Requires more tough mechanical properties Many problems due to the failure of flip
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Test condition - Injection machine: 10 oz - Wall thickness: 1mm - Injection speed: 80% - Injection pressure: 80% - Injection temperature (oC) : 240(nozzle)-230-220-210 - Mold temperature: 60 oC
Design Guide For Mobile phone housing
Weld line strength
Why is the weld impact strength so important for mobile phone? Weld impact strength
20
Weld impact strength (kgf cm/cm)
2.0 ~ 3.0
< 100:1
Advanced part < 1.2
90:1 ~ 150:1 Specific for part 1380 ~ 2410
Accumulator at injection & clamping unit, servo valve
standard
620 ~ 970 standard Standard
ABS, PC/ABS(Monitor)
PC, PC/ABS (Notebook PC) PC, PC/ABS (Mobile phone)
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Design Guide For Mobile phone housing
Triangle of Thin Injection Molding Material