Korporacja KGL S.A.kgl.pl/wp-content/uploads/2015/10/1-EMI-Shielding-webinar-18062014... · EMI Shielding is a function of 4 variables: ... –We can test unique compounds for relative

www.kgl.pl

Korporacja KGL S.A.

przy współpracy z / in co-operation with

RTP Company

przedstawia / presents

Wykorzystanie tworzyw sztucznych tłumiących fale

elektromagnetyczne (EMI) w celu zmniejszenia masy

i poprawy efektywności projektowania.

Utilizing EMI Shielding Plastics

to Reduce Weight and Improve Designs

YOUR GLOBAL COMPOUNDER OF CUSTOM ENGINEERED THERMOPLASTICS

What is EMI?

• ElectroMagnetic Interference = EMI

• Emitted from a source or Received by a device

• Frequency range of 1 kHz to 10 GHz

• Faraday Cage Principle:

– Barrier that reflects or conducts signals to ground

• Shielding provides “Immunity”


EMI in Action

EMI shields protect sensitive devices from high frequency sources in the area.


EMI in Action

EMI shields protect sensitive devices from high frequency sources in the area.


EMI in Action


Controlling EMI

EMI Shielding is a function of 4 variables:

– Conductivity of the material

– Thickness of the material

– Frequency of the interference

– Distance between the source of the

interference and the shield


EMI Shielding Fillers

Electrically Conductive modifiers:

• Carbon Powder

• Carbon fiber

• Carbon Nanotubes

• Stainless steel fiber

• Nickel-coated carbon fiber

• Other metallic additives


Stainless Steel Fiber – Minimal affect on neat

resin properties

– Neat resin shrinkage

– Good shielding

– Cost effective

– Colorable

Nickel Coated Carbon Fiber

– Properties similar to carbon fiber compounds

– High shielding performance

– Higher cost

– Less colorable

Key Additive Comparison


The Long Fiber Process


• This process results in very long, oriented fibers

relative to a conventional compounding process

• Our oriented, long fibers create much better

shielding coverage in molded housings than

random, short fibers

• We optimize other properties through base polymer

The Long Fiber Product


The Long Fiber Compound

Optimized via “Cube Blends”

“A” Pellet – LF Product provides EMI shielding

“B” Pellet – Optimizes all other properties

(including: Shrinkage, Color, FR, Impact Resistance)


EMI Shielding Compounds

Cube Blends:

• Pre-blended mix of 2 different pellet types

(shielding + physical properties)

• Blending ratio is maintained through shipping

• Retain long fiber length/aspect ratio

• Evenly dispersed during injection molding process

• SS loading up to 20% by weight


Shielding Effectiveness (SE)

• A reduction in energy level of an EMI wave

through reflection and absorption

• Varies with frequency

• Expressed in Decibels (dB)

• Attenuation – Analogous to shielding effectiveness

• Expressed as a % of original signal


SE vs. Attenuation

Shielding Effectiveness

Attenuation Comparative

Rating

20 dB 90% Minimal Shielding

40 dB 99% Average Shielding

60 dB 99.9% Good Shielding

80 dB 99.99% Excellent Shielding


• ASTM D4935

• Direct measurement method

• Relative ranking of materials

• Frequency range of 300MHz to 1.5 GHz

• Fast & Repeatable

• Flat test specimen – min. 6” diameter

• Units = Decibels of SE

Coaxial Transmission Line Test

Spectrum

Analyzer/Tracking

Generator

Test specimen


30

50

70

90

110

300 700 1100 1500

SE, d

B

MHz

SE of SSF Composites

D %

C %

B %

A %

ASTM D4935 Typical Results


Variables Affecting Performance

• Frequency of Interference

• Distance from the Source

– Near Field -- Distance < Wavelength/6

– Far Field -- Distance > Wavelength/6

• Characteristics of the Source

– High Current, Low Voltage -- High Magnetic Component (H)

– High Voltage, Low Current -- High Electric Component (E)


• Metallic paint/metal coatings

– Traditional TV Cabinets

• Metal foil/screen

– Microwave ovens operate at 2.45 GHz (122 mm)

• Actual metal housing

• Polymer compound

– Increases design freedom, part consolidation

– Eliminates secondary operations & reduces part cost

EMI Shielding Methods


Challenges In Automotive Sensors

• Weight reduction

• Consistent shielding and quality

• Low frequency shielding

• Thermal management

• Global manufacturing and tech. support


Eliminate Conductive Paint

• Review of Conductive Paint:

– Durability (flaking and scratching)

– Potential thin spots in coating

– Yield fallout from masking operation

– Environmental considerations

– Additional process

– Additional supplier

– Added cost


EMI Compounds Conductive Paint Metal Parts

Design Compatibility Injection molding provides

maximum design flexibility Line of sight process

requires simple designs Forming and fabrication

methods limit designs

Secondary Operations None Required Masking and coating by

outside supplier De-burring, screw bosses,

plating, etc.

Consistency Uniform performance Difficult to measure

thickness uniformity Uniform performance

Grounding Ground from any surface Ground from coated surface

only Ground from any surface

Durability/ Reliability Integrated into compound Subject to scratching,

flaking, or delamination Inherent to material

Production Volume Easily Increased Problematic to increase Capital Intensive

Production Speed 1-Step Process Additional processing step

by secondary supplier Time and labor intensive

Special Handling None Required due to poor

damage tolerance None

Weight Light-weight Light-weight Heavy parts

Review of Shielding Options


Evaluating EMI Shielding Options

• Volume resistance is key

specification parameter

• Part surface molds resin

rich so surface resistance

is misleading

• Shielding effectiveness

depends on filler loading

and thickness of housing

• Grounding from anywhere

on part minimizes system

EMI

• Surface resistance of inside is

key specification parameter

• Outside surface has no

conductivity

• Since conductive coating is

thin, volume resistance will be

dominated by insulative layer


depends on conductivity of

coating and coating thickness

• Grounding only from inside

surface

• Conductivity is consistent

on inside or outside of

housing

• Volume resistance can be

measured


depends on thickness of

metal

• Grounding from anywhere

on part


• EMI 300 Series (PC)

– UL Listed: V-0 @ 1/16”

(1.5 mm)

– Stainless steel fiber

– Glass fiber

reinforcement

– Pre-colored

Combination of Properties


Applications for EMI Plastics

• Housings

• Connectors

• Sensors

• Gaskets

• Wire and Cable


Position Sensor Housings

• RTP 200 Series (PA66)

• Laser welding grade

• Natural cover is laser transparent

• Black body is laser absorbing

• Eliminated need for adhesive

• Increased quality

• Reduced system cost

Sensor Application Successes

Picture Courtesy of Rofin


RTP Conductive Resin:

Stainless Steel and Carbon Powder Filled PBT

(Shielding through Reflection and Absorption)

Results: • Uniform SE, even in sharp corners

• Better grounding

- All surfaces are now conductive

• Eliminates process steps

• Eliminates added supplier

• Improves yield

• Reduces total cost

Sensor Application Successes


• EMI 300 Series (PC)

• UL Listed V-0 @ 1/16”

• SE 40-60 dB

• Economical alternative to

metal or coated plastics

– Complex Design

Metal Replacement


RTP Product Base

Polymer Shielding Effectiveness

(3 mm @ 1.5 GHz)

EMI 261 PA 6/6 40 dB

EMI 262 PA 6/6 53 dB

EMI 263 PA 6/6 74 dB

EMI 1061 PBT 39 dB

EMI 1062 PBT 55 dB

EMI 2161 PEI 40 dB

EMI 2162 PEI 55 dB

EMI 2561 PC/ABS 38 dB

EMI 2562 PC/ABS 54 dB

Sample EMI Compounds from RTP


Conclusions

• RTP’s EMI Shielding Compounds are:

– Capable of providing required levels of EMI shielding

– Allow for increased design freedom

– Provide precise combination of properties to meet

application requirements

– Cost effective alternative to other shielding methods

– Permanent and durable solutions

– We can test unique compounds for relative SE


Advantages of RTP TCCs

• Customized performance to meet specific application

requirements (Conductivity, FR, Color, etc.)

• Independent polymer and filler selection

• Global manufacturing capability to minimize lead times

• Dedicated technical service to help optimize mold

design and processing for maximum TCC performance

in your specific application


Combining EMI + TC

• SSF is a poor thermal conductor

• Thermal fillers can provide some EMI shielding

• Custom formulations can balance design requirements

RTP

Formulation

Shielding

Effectiveness (300 MHz – 1.5 GHz)

Thermal

Conductivity (Through-plane)

Thermal

Conductivity (In-plane)

RTP EMI 2562 60 – 85 dB 0.3 W/mK N/A

299X124222C 30 – 55 dB 3.4 W/mK 25 W/mK

299X124222D 32 – 38 dB 3.1 W/mK 19 W/mK

299X124222E 40 – 60 dB 5.3 W/mK 32 W/mK

299X124223B 45 – 55 dB 1.4 W/mK 4.1 W/mK

Tworzywa nie z tej Ziemi … ABS (35 kolorów, transparent, galwanizacja, samogasnący), ASA, SAN, PC, PMMA, PA, PBT, POM, PPS, PS, EPS, PVDF PPH, PPC, PPR, PP metalocenowe, LDPE, HDPE, MDPE, PE metalocenowe, TPE: SBS, SEBS, TPV (EPDM/PP), wypełniacze kredowe, PP wypełniany…

Dziękujemy !

Thank you !

Informacje / Information

Korporacja KGL S.A.

http://www.kgl.pl

Email: [email protected]

M: +48 604 136 236

T: +48 22 321 30 00 ext. 221

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Korporacja KGL S.A.kgl.pl/wp-content/uploads/2015/10/1-EMI-Shielding-webinar-18062014... · EMI Shielding is a function of 4 variables: ... –We can test unique compounds for relative