RoHS compliance versus other conventional
product certifications such as CE and UL - the
genuine problem arising
from the definition of homogeneous materials
18 April 2006
Professor Y.C. Chan
Director, EPA Centre and RoHS & WEEE Research Programme
Chair Professor of Electronic Engineering,
City University of Hong Kong
Ms. Brenda Lam MSc (Eng), BSc
Engineer, RCW Centre, City University of Hong Kong
1
Product Certification
UL : Underwriters Laboratories Inc.
o
Product and component level - Safety testing
o
Evidence of product’s and component’s compliance per US &
Canadian safety requirements
o
As of 2005, 1291 UL standards and 376 ULC standards
e.g. UL 94 flammability testing for plastic materials
o
UL also adopts another international standards such as IEC, CSA, etc.
e.g. UL60950 for information and technology equipment product
( Source: UL web-site )
2
Product Certification
CE Mark
o
Conformance to European Economic Area (EEA)
- 25 EU member states and 3 EEA EFTA states (European Free Trade
Association); Iceland, Liechtenstein, and Norway
o
Product level testing
- certifies products for meeting
o
¾
EU health, safety and environmental requirements
¾
Consumer and workplace safety
Over 20 CE directives
e.g. EMC, Toy Safety, Low voltage directive (LVD) etc.
( Source: Europa web-site)
3
RoHS ?
o
Restriction of the use of certain hazardous substances in
electrical and electronic equipment
o
EU Directive 2002/95/EC dated on 27 January 2003
o
Effective from 1 July 2006
o
Hazardous or banned substances :
>
Lead (Pb), Mercury (Hg), Cadmium (Cd), hexavalent chromium (Cr6+),
flame retardants ( PBB & PBDE)
4
CE, UL, RoHS ?
Conventional product certifications
CE, UL
o Product level testing
o Safety and environment requirement
o
RoHS Directive
Down to material level
o Protection of human health and environment
o
5
RoHS Directive – Restriction of
banned / hazardous substances
down to material level ?
6
What is the meaning of “banned /
hazardous substance” in RoHS
Directive ?
Substance
Max. conc. value by weight in a homogeneous
material
Lead (Pb)
Mercury (Hg)
Hexavalent chromium (Cr6+)
Cadmium (Cd)
PBB
PBDE
0.1%
0.1%
0.1%
0.01%
0.1%
0.1%
7
Why define “homogeneous
material” ?
e.g. Electronic Product – 1kg = 1000g
Max. weight of banned substances
Pb
Hg
Cr6+
Cd
PBB
PBDE
1 product
1g
1g
1g
0.1g
1g
1g
↓
8
1 million products
1000kg
1000kg
1000kg
100kg
1000kg
1000kg
Why define “homogeneous
material” ?
Product (1kg = 1000g)
……………..
100 homogeneous materials
Each such material ~ 10g cannot exceed the max. allowed concentration
Pb,
Hg,
Cr 6+
0.01g
0.001g
Cd
PBB
PBDE
9
Why define “homogeneous
material” ?
Chance of 100 such homogeneous materials simultaneously
having maximum concentration is practically ZERO
Hence substantially minimizing the banned
substances effectively
Also greatly increasing the number of
chemical tests
10
What is the meaning of a
“homogenous material” ?
Not defined in the directive and related amendments ?
¾
DTI ( Department of Trade and Industry – UK)
….. RoHS regulations : Government Guidance Notes dated
Nov. 2005
o
‘Homogeneous’
Homogeneous -> uniform composition throughout
o
‘Homogeneous material’
material means a material that cannot be mechanically
disjointed into different materials
o
e.g. plastics, ceramics, alloy, glass, etc.
11
What is the meaning of
“mechanically disjointed” ?
‘Mechanically Disjointed’
Disjointed
o
A part / component can, in principle, be separated by mechanical
actions such as unscrewing, cutting, crushing, grinding and
abrasive processes.
12
Challenge to industry ?
Assembled Product
Parts
Homogeneous
Materials
Homogeneous
Materials
Parts
Parts
……………
……………………………..
Homogeneous
Materials
One product may contain over hundreds of homogeneous materials
Cost consideration !
13
?
Parts
Homogeneous
Materials
How to define homogeneous material
in the actual cases ?
14
Case 1 : Watch Assembly
Metal spring
Metal shaft
Panel
Plastic case
Metal cases
Metal screw
Metal nuts
Metal ring
PCBA
Plastic plate
Rubber band
Plastic part
15
Metal case
Case 1 : Watch Assembly – cont’l
epoxy
PCB
SMD
Components
16
Watch Assembly – cont’l
Item 1
Item 3
Item 2
1a
strap
1b
2a
2b
1c
17
Case 2 :Printed Circuit Board
PCB contains 3 homogeneous materials :o
Coating (green, White, lacquer) on epoxy
resin board.
o
Copper metal in epoxy resin board
o
Epoxy resin board excluding coatings and
copper metal
18
Case 3 :SMD component
Terminal
Plating
Homogeneous materials :o Terminal plating
o Ceramic body and internal
electrode
How to mechanically disjoin?
Crushing ? Grinding ? Cutting?
19
Ceramic Body
Case 4 : A semiconductor
package
Homogeneous materials :o Plastic molding material
o Tin electroplating coatings on the
lead frame
o Lead frame alloy
o Bonding wires
How to mechanically disjoin?
Crushing ? Grinding ? Cutting?
¾
20
Genuine problem – mechanically
disjoint ?
o
There is no clear definition on
o
o
o
o
Requirement of the machine
o
o
How to mechanically disjoin the sample ?
Manual ?
Using machine ?
Any pressure, temperature , power specified ?
Consideration on sample preparation methods
o
Cross-contamination ?
21
Other problems in testing
XRF ( X-ray fluorescence )
o
Detector diameter ~ 10mm
o
Sample size smaller than 10mm ?
→ “average effect”
XRF result :
7% lead and 0.2% Cd
e.g.
Location ??
SEM / EDX result :
37% lead in solder
and 1.3% Cd in silver
contacts
XRF – for screening purpose but
not for certified RoHS compliance !
Information from ERA document “Evaluation of ED-XRF as a RoHS Analysis and Enforcement Technique”
22
Test Standards – banned/hazardous
substance in electrical equipment
material
Substance
Standard
Comments
Lead
BS 6534:2003
Suitable or accurate analysis of termination coating but
requires caution if coating is a tin alloy such as SnCu
as the copper content will slightly affect the result
Method for quantitative
determination of lead in tin
Coating
BS 6721-9:1989, ISO 47491984
Suitable for checking the lead content of copper alloys
Sampling and analysis of
copper and copper alloys.
Method for determination of
lead in copper alloys by
flame atomic absorption
Spectrophotometry
(Source: ERA Guide to RoHS compliance 3rd ed.)
23
Test Standards – banned/hazardous
substance in electrical equipment
material
Cadmium
For cadmium in plastics
EN 1122:2001
Plastics. Determination of cadmium. Wet
decomposition method
For cadmium in paint coatings
BS3900-B9:1986, ISO 3856-4:1984
Methods of test for paints. Tests involving
chemical examination of liquid paints and dried
paint films. Determination of "soluble" cadmium
content
(Source: ERA Guide to RoHS compliance 3rd ed.)
24
Test Standards – banned/hazardous
substance in electrical equipment
material
Cr VI
BS 3900-B10:1986, ISO 3856-5:1984
Method of test for paints, tests involving chemical
examination of liquid paints and dried paint films.
Determination of hexavalent chromium content of
solid matter
BS EN ISO 3613:2001
Chromate conversion coatings on zinc, cadmium,
aluminium-zinc alloys and zinc-aluminium alloys.
Test methods
Suitable only for certain types of paints as
pigment needs to be extracted without altering
its composition. Accuracy reported to be low
Need to know coating mass (ISO3892:2000)
Procedure has limitations. Note that CrVI
content of conversion coatings decreases
with age.
(Source: ERA Guide to RoHS compliance 3rd ed.)
25
Test Standards – banned/hazardous
substance in electrical equipment
material
o
No analysis standard specifically for mercury or flame
retardants ?
26
Other Testing Methods
o
US EPA 3050B or 3052: Microwave assisted acid digestion for Pb, Cd, Hg
o
US EPA 3060A: Alkaline digestion for Hexavalent chromium.
o
US EPA 7196A: Colorimetric method for Hexavalent Chromium.
o
US EPA 3550: Ultrasonic Extraction for organic compound
Those methods are basically for environmental purpose
e.g. soils. Not originally intended for EEE!
27
Summary
The importance arising from the definition of homogeneous
material
o
- Minimizing the banned / hazardous substances effectively
The definition of mechanically disjoint is not absolutely
clear from the fundamental scientific standpoint
o
- No solid guideline or requirement.
o
Cost considerations and exemptions
o No unified international testing standards for electrical and
electronics equipment
Standards only cover part of the products
- No standards for mercury and flame retardants
- Different testing labs. may use different testing method.
- IEC TC 111 and ASTM F40 have the draft document but the formal
document not yet issued.
_
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Thank You!
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