Page T 7

AQUEOUS CLEANING

Water is an excellent solvent for removing ionic
contaminants and water soluble fluxes. Water, in
combination with a saponifier, can remove non-
polar substances such as oil and rosin fluxes.
Aqueous cleaning systems generally consist of a
wash, rinse, and a dry stage (See Figure 3).

the wash stage, contaminants such as oils, grease,
and rosin react with the alkaline saponifiers (most
commonly alkanolamines) to form a water soluble
soap via a saponification process. Following
exposure to saponifier, the boards are rinsed. The
rinse step is important to remove saponified
contaminants, residual saponifier solution, and
other water soluble residues remaining. The rinse
step is generally carried out with deionized water
to maintain a high degree of purity. Aqueous
cleaning is most effective when combined with
high pressure and/or high volume sprays.

: ‘Aqueous ‘cleaning Offers several
potential advantages:

«aqueous ‘cleaning’ can. be: used to
remove’ water. soluble fluxes, and ‘in
conjunction: with: saponifiers, Tosin:
fluxes}; :

suitable ‘for cleaning through hole
‘and. surface. mount ‘assemblies;

nO: distillation equipment is required
to:recycle the: solvent;

no ‘costs’ of disposing spent solvents;

“a reduced. pretreatment costs. can be
-stealized “if water-treatment © 8-5
distillation, ‘reverse osmosis, heating,
tC.) is: not required.

Prior t to the use of aqueous dledning:
the following items:should be’.
‘considered:

~ difficult. Aqueous cleaning of

“rinse stages, a8: opposed: to..a

_ fora list of vendors).

: ‘Systems for other types of fluxes

-being discharged. This reduces the =
_ amountof wastewater: being: used.
_-and therefore, reduces the’ énergy.

-the discharge of process water (See:

Because ‘surface mounted
‘components :are placed closer. tothe:
board than traditional through-hole
components, adequate Cleaning in the
small. gaps ‘underneath: surface

mounted components is more:

Surface mounted assemblies (SMAs)
‘depends on a number of physical
properties including (1) surface’.
tension, (2) viscosity, (3) mechanical
energy, and (4) temperature. ‘You

parameters in mind when designing
aqueous cleaning processes for
SMAs. oe Be

Most newly designed aqueoi
Cleaning systems are: based «
closed loop recirculating wash and

continuous’ discharge system: The” :
‘wash and: rinse water is continuously
used: for :-weéks: Or, months. without

and disposal cost (See Perens 1

"Zero- discharge” ‘aqueous. ‘clean
systems are available that use closed
loop recycling systems to. minimize

Figure.4).. Such systems reduce:

‘water, energy; and. disposal: COSTS!
significantly. Currently these systems
are available for aqueous cleaning
Systems that use. water soluble fluxes.

(ie., rosin and Organic acid fluxes)
are being developed.



Page 7

Appendix 1 - Vendors (continued)

Fine Organics Corporation 9. Water Recycling Equipment
205 Main Street
Lodi, NJ 07644 Separation Technologists
(201) 472-6800 32 Granger Ave.
Reading, MA 01867

Orange-Sol (617) 942-0023
P.O. Box 306
Chandler, AZ 85244
(602) 961-0975

~ Petroferm

5400 First Coast Highway
Fernadina Beach, FL 32034
(904) 261-8286

3D Ine.

2053 Plaza Drive

Benton, Harbor, MI 49022
(616) 925-5644

8. Hydrocarbon/Surfactant Equipment

Accel

1825 E. Plano Parkway
Plano, Texas 75074-8129
(214) 424-3525

Detrex Corporation
P.O. Box 501
Detroit, MI 48232
(313) 358-5800

ECD

13626 South Freeman Road
Mulino, Oregon 97042
(503) 829-9108

Electrovert

4330 Beltway Place
Arlington, TX 76018
(817) 468-5171

Ultronix

RD2 Box 100D
Coopersburg, PA 18036
(215) 965-8009

U.S. GOVERNMENT PRINTING OFFICE: 1990 0944-602
a


Page 32

FIGURE 8

COMPARISON OF DIFFICULTY INDEX VS PRESENT VALUE

2
Option 7
oO
1.807
Option 6
3 qo
z 1.6 :
> Option 2
3 Option 5
2 oO
£146
a
Option 1
oO
1.2 Option 4
CFC-113
1 1 !
=

100 200 300 400 500 600 700
Net Present Value ($)



Page TI

some methanol in the waste water streams
and local legislation should be considered
in specifying equipment.

Systems can be sized to suit large and
small applications, and one adsorption
system can service more than one cleaner.
In the example developed in this manual,
four cleaners are handled by one
adsorption system.

It should be noted that in this example
the bulk storage tank, the stills, and the
adsorption system are all located in an
enclosed room. The room air itself also
Passes through the adsorption system
which captures and recycles any fugitive
CFC-113 losses.

Figure 2: CFC-113 VAPOR RECOVERY SYSTEM

‘SOLVENT LOADED ROOM AIR

VAPOR TANK 3

VAPOR TANK 2 STILLS

VAPOR TANK 1

ADDITIVES

| ‘STILL

‘SOLVENT FILL LINE

sTLL2
MIXING PUMP

CFC-113 STORAGE,
TANK

BLOWER

CLEAN AIR

CFC-113 CONDENSATE TANK

EXHAUST SOLVENT ROOM
ENCLOSURE
SOLVENT LOADED PROCESS AIR
al ——
i WASH 4 WASH3 WASH 2 WASH 1

STAND ALONE



Page ai

Conventional fluxes are more tolerant of minor
variations in the process parameters because of
their high solids content. The choice of solder
mask is a prime concern, as a poor choice results
in unacceptable levels of solder ball formation.

You should not expect the conversion of a
soldering line from a conventional to a low solids
flux to be easy. Some adaptation of the process
parameters and possibly the soldering machine
itself will be needed. Some users have
experienced initial difficulties when starting up
with these fluxes, but a little perseverance
generally resolves problems such as maintaining an
adequate foam head, measuring and adjusting the
flux solids, preventing water from entering the
flux, regulating the quantity of applied flux, and
adjusting the preheaters to a more critical degree.

Fluxes are now available in foam, wave, and spray
application. Wave application of low solids flux
presents minimal cost and retrofit difficulties. As
these processes all utilize low solids fluxes diluted
with isopropanol, you must consider adequate
ventilation and fire suppression. Optimization of
the process parameters using low solids flux can
be assisted by using applied statistical
quality/process control techniques (e.g. the
Taguchi method).


Te
STRUCTURE OF MANUAL

This manual is divided into the following sections:

: : _ Process Characterization; In this section, it is stressed that you :
to understand how you manufacture your product (design, assembly,
soldering, and cleaning), and where and how CFC-113 is used in this

process;

= Conservation practices ¢ & Strategies: ‘In this section, discrete
conservation projects are ranked so that you can choose the project(s
that will give you the biggest reduction of CFC-113 for the least”
amount of time and money;

» _ Non-CFC Processes: This section eae the choices of alternate :
non-CFC processes and technologies; and :

= Methodology to Select Non-CFC Processes: This section outlines a
methodology for the decision making criteria that can be used to: se

a non-CFC process.



Page 2

The costs associated with the CFC-113 and the
non-CFC processes have to include: (1) capital
costs of equipment (including costs of waste
treatment if needed), and (2) operating costs that
includes material costs, labor costs, maintenance
costs, and utilities costs. These cost estimates for
the non-CFC process can be developed through a
preliminary process design that estimates the
design parameters of the process. This in turn
will lead to preliminary cost estimates for the
process and waste treatment equipment, if needed.
Operating costs can also be determined from this
initial conceptual design.

Exhibit 6 presents a comparison of the NPV
calculation for a CFC-113 process and an alcohol
process. It is assumed that the CFC-113 process
has zero capital investment because the process
is already installed and operational. However, this
might not. be the case if additional engineering
controls need to be installed as part of
conservation measures to reduce the use of CFC-
113. Based on Exhibit 6, the NPV of the CFC-
113 process is $329K and that of the alcohol
process is $754K.

EXHIBIT 6. NET PRESENT VALUE CALCULATIONS -
CFC-113 VS ALCOHOL PROCESS .

CFC-113 : :
(Thousands of U.S. $) (Thousands of U.S. $)

‘Alcohol

Capital Costs
Equipment
Waste Treatment
‘Total Capital
Operating Costs

Solvent Costs:
Labor Costs

Utilities Costs
‘Total Operating

NPV

Maintenance Costs

- 250
: 100

: 350

35 25

30 30

15 : 50

30 30
110 B35
329 S 784

‘situations.

Source: Northern Telecom

Note: These costs are indicative. ‘They may not accurately reflect costs in specific



— Page Te

Figure 3: TYPICAL AQUEOUS CLEANING CONFIGURATION

Wave
Soldering
Ast 2nd
Cleaned
Wash Rinse Rinse Dryer ment PWA
Stage Stage Stage
Recirculation
y
. Public/Municipal
| Periodic Dumping | Waste Treatment |—e1 waste Treatment

Facility



Page 7A

ALTERNATIVE SOLVENTS

There are a wide variety of alternative solvents
that are considered as possible replacements for

CFC-113.
(1,1,1-trichloroethane),

These include chlorinated solvents
alcohols and

hydrochlorofluorocarbons (HCFCs). These
solvents are briefly discussed in the next section.

q@

@)

1,1,1,-Trichloroethane:

1,1,1-Trichloroethane is an effective
substitute for CFC-113 in electronics
industry operations. Although a volatile
organic compound, the U.S. EPA has
exempted 1,1,1-trichloroethane from legal
classification as a volatile organic
compound (VOC). Furthermore, it is
nonflammable. It is possible, therefore,
that some substitution of  1,1,1-
trichloroethane will occur as CFC-113
becomes less available and users face
rising _ prices. However, —1,1,1-
trichloroethane has been identified as an
ozone depleting substance and may be
added to the Montreal Protocol in 1990.

Chlorinated Solvents:

Trichloroethylene, perchloroethylene,and
methylene chloride also are effective
cleaners. They are also volatile organic
compounds. However, each of these
solvents is considered a possible or
probable carcinogen. The U.S. EPA has
classified trichloroethylene in Category B2
as a "probable human carcinogen," while
the International Agency for Research on
Cancer (IARC) has classified this solvent
in Group 3, a substance not classifiable as
to its carcinogenicity in humans. The
IARC has classified perchloroethylene in
Group 2B as a substance considered
"possibly carcinogenic to humans.”
Finally, the U.S. EPA has classified
methylene chloride in Category B2 as a
“probable human carcinogen," while the
IARC has classified methylene chloride in
Group 2B as a substance considered

(3)

“possibly carcinogenic to humans".
Chlorinated solvents will be selected
substitutes for CFC-113 in some cases.
For example, in the United States,
trichloroethylene continues to be used
even with new regulations that reduce the
allowable worker exposure to the
chemical.

Organic Solvents and HCFCs:

Organic solvents such as alcohols and
HCFCs are possible replacements for
CFC-113. Five organic solvents and
HCFCs have been proposed as possible
CFC-113 substitutes: pentafluoropropanol
(5 FP), isopropanol, HCFC-225ca, HCFC-
225cb, and HCFC-141b/HCFC
123/Methanol blend (see Appendix 1 for
list of chemical suppliers). Exhibit 3
summarizes their physical properties which
are compared to CFC-113. Preliminary
research suggests these solvents have good
cleaning performance. However, long-
term toxicity testing is still being
conducted on several HCFCs.

Generally, the use of organic solvents in
the past has been small primarily due to
the flammability concern associated with
the use of these solvents. For example, the
use of isopropanol has been limited due
to its flammability. A large European
electronics manufacturer is operating a
modified, conveyorized, in-line isopropanol
cleaner. The machine, depicted in Figure
6, Cleans both through-hole and surface
mounted assemblies. The system has an
on-line still for recycling, and the system
is designed to be explosion resistant.


: Page 20

LOW SOLIDS FLUXES/'NO-CLEAN" ASSEMBLY

By carefully evaluating and selecting components
and assembly processes, benign low solids fluxes
can be used to eliminate cleaning in some
instances. Traditionally, the electronics industry
has used, and is still using, rosin fluxes containing
between 15 to 35 percent solids content for wave
soldering electronics assemblies (through-hole,
single-sided, and double-sided printed circuit
boards). Numerous low solids fluxes containing
1 to 10 percent rosin (or resin, or both) have
been formulated and tested.

Low solids fluxes*have the following
advantages:

«© "bed of. nails" testing on: printed
circuit’ board ‘assemblies can be.
carried: out immediately ‘after wave
soldering, without the problems
created by the’ presence of rosin
residues; ‘and

= the need for. defluxing: can ‘be
‘eliminated.

Depending on the solder mask or resist and the
low solids flux used, little or no visible residue
remains on the boards after soldering. The
remaining residues, if any, dry and rapidly harden.
Automatic testing can be done without cleaning
the boards. Because low solids fluxes are
generally considered non-corrosive and have high
insulation resistance, in most cases it is
unnecessary to remove them, even for cosmetic
reasons.

Prior. to using this process, yous should
note that: a

= These fluxes may have to be removed’
to meet military specifications and
are relatively. difficult to remove by:
traditional CFC-113: methods."

The use of incompatible cleaners can.
result in the formation of white :
residues or cosmetic imperfections ‘on.
the’ fluxed: surface. It is important

that you consider the: compatibility-of
these fluxes with cleaning media and |:
cleaning equipment. :

One ‘company:has: performed...
additional tests on: low. solids: fluxés.
‘The:test results: demonstrated: an
inverse relationship ‘between: surface
insulation. resistance (SIR) and:the =”
quantity of low solids flux ‘applied * ~~
and revealed: the: importance: of
process selection and process: control
in the application ofa number. of.

low: solids’ fluxes.

‘Aging studies’ showed’ that large
quantities of some, ‘but: not all, post-
solder low. flux residues can be,
detrimental.

To minimize excessive flux build-up a new fluxing
system has been designed that uses an
ultrasonically-controlled spray to disperse the flux
(U.S. Patent #4,821,948, April 18, 1989). This
system is commercially available. Other
commercial spray fluxes are also available (see
Appendix 1 for list of vendors). Other advantages
of this system include minimal deposition of flux
on the topside of circuit boards which can be
detrimental, and a closed flux reservoir system that
prevents alcohol evaporation (specific gravity
changes) and water absorption.


Page EK]

SELECTION OF NON-CFC PROCESSES

The selection of the non-CFC process can be made by:

. Listing all feasible non-CFC processes;

. Performing a preliminary analysis for each process to determine the difficulty index and the
NPV;

. Comparing the difficulty index and the NPV for the non-CFC process with the CFC-113
process;

. Once these have been determined for all the non-CFC processes being considered, plotting them

on a graph that represents difficulty index versus NPV (See Figure 8).

This graph can be used to determine the range of
difficulty index - NPV combinations that can be
considered feasible. This range is represented by
the oval shape region defined in Figure 8. This
oval shape region has been defined using the
rational that a non-CFC process that has a high
difficulty index and low NPV, and a low difficulty
index and a high NPV is not feasible.

Based on such an evaluation you can perform a
preliminary screening of a wide variety of non-
CFC processes. Once such a_ preliminary
screening is completed, a more detailed evaluation
of the promising processes can be performed.
Such an evaluation will allow you to pin point
more promising alternatives and thus direct more
resources to evaluate them.


EE—— Page 1
RECAP ON PROGRAM TO THIS POINT

Following the recommendations presented above, your program at this point will have
consisted of the following sequerge of activities:

. management’s commitment to a successful reduction of CFC-113;

. designation of an individual with a mandate to proceed with the project;

. a survey of your CFC-113 purchases and uses;

. establishment of your CFC-113 use per area of board manufactured (kg/m?) and

procedures to calculate and monitor this ratio on a regular basis; and

. execution of conservation projects in the most appropriate order.

You are urged to follow these steps in this sequence before pursuing new replacement
technologies and processes. The benefits of doing so include:

. employees learn about the issues;

. a cultural change takes place in the location and elsewhere in the company which
is essential for the program’s success;

. employees develop a deep understanding of the manufacturing process and
equipment; and

. significant reductions in CFC-113 use are achievable in a short period of time.


Page 7

EXHIBIT :2. “PRINTED: CIRCUIT BOARD CLEANING EQUIPMENT PROFILE ce

A. ~ Identification”.

Equipmént Name:
Model Number:
Manufacturer:

‘Year: Purchased:

© Trade Name ‘of
Chemicals Used:

Annual Quantity of CFC b : : : ee ce
Purchased ‘for Use"in: this cS =
Equipment. (specify.-units):

Annual’ Quantity of CFC: Waste
Requiring: Disposal: or: Off-site
Recycling:

B.. Equipment Usage Pattern

‘Annual ‘Board Production
(please: specify units):

Average. Board: Area:
(please. specify. units):

Check: appropriate blanks:
Single: sided
*. Double: sided:

Multilayered
Number of: layers,

‘Average Number of Solder
Connections per Board:

C. “Emission: Controls’

Alternate Testing: Methods:
Onsite Recovery/Recycling: ©
Improved Loss Control Procedures:
Operator Awareness/Guidelines:



Page 70

Next, a weight is assigned for each of the above
criteria based on its importance (10 for the most
important and 1 for the least important). Exhibit
4 summarizes the weights assigned to each
criterion by Northern Telecom.

_ EXHIBIT 4. DIFFICULTY
CRITERION WEIGHTS

"Difficulty Criterion Weight

~ Compliance to. Specification
Defect Rate
Customer Return Issues
Industry Direction:
Cosmétics of the PCBs.
Flexibility of Process
“Ability to ‘Clean: SMT:
Fallback Position
"Process Control
Throughput
Environment, Health, and
‘Safety Concerns:
Future Costs
Availability of the Process
Ease. of Process: Installation
Process ‘Compatibility
Floor:Space ‘Requirements.

DAW 0 Oi0 0

Rea Ao

Source:. ‘Northern Telecom

Next, each of the above criteria is ranked for the
CFC-113 process and other non-CFC processes
being evaluated. The ranking system is based on
a scale of 1 to 10. One being the highest and 10
being the lowest ranking. Exhibit 5 presents the
ranking for CFC-113 and an alcohol based
process. Once the alternative has been ranked,
the weighted difficulty criterion is calculated by
multiplying the weight for each criterion by its
rank and by adding up the weighted ranks for
each factor. For example, for CFC-113 this is
equivalent to:

CFC113. = niga)

+ t Ceteet rate)(9* )

Aue + eer spacey(t*l)

Similarly, for the ‘Alcohol Process, the
value equals 236. :

The difficulty index is calculated by taking the
ratio of the weighted rank factor for the alcohol
and the CFC-113 process which, in this case, is
approximately one.

ECONOMIC FEASIBILITY

The economic feasibility is an important factor in
determining which alternative non-CFC process is
a viable substitute. This can be accomplished by
calculating the net present value (NPV) of the
CFC-113 process and the non-CFC alternative
being considered. To calculate the net present
value the costs associated with the process have
to be determined over a period of time. One
simple approach is to calculate NPV based on a
five year period assuming that the capital
investment for the process takes place in year zero
and the return on investment is 20 percent.
Based on this the NPV is calculated as follows:

“NPV = Costy + Cost, /.(1+i) +

Cost, / ati? +

+ Costs / (148



Page 7
HYDROCARBON/SURFACTANTS

A number of hydrocarbon/surfactant cleaning :
solutions are being developed to clean PCBs (See Prior to the use of this process the

Figure 7). One such solution, terpenes, is a _ following items. should be noted:
naturally-derived solvent, which is considered a
viable alternative for cleaning some electronics = Equipment specifically designed fo!
assemblies. Terpenes generally are isoprene terpene cleaning is necessary beca
oligmers, but may include derivatives such as of material compatibility,
alcohols, aldehydes, and esters. combustibility, and odor concerns
__associated with terpenes (See
Appendix 1 for list of equipment and
: | Teron display the following chemical. suppliers). :
| characteristics: :
: : « Cleaning machines using terpene.
«= work effectively i in close spacing Solvents must be "inerted" (purged
~ (clean SMDs); with inert gas such as nitrogen) foi
: safe operation because of low cl
* work at low (room or:slightly higher) cup flash point (47°C) and potent
temperatures; room temperature flammability:

: associated with spray mist.
# are noncorrosive (pass the copper oe oo
= Tetpenes are considered VOCs, and.

mirrof test); +
: 2 : therefore, adequate containment of
= have low viscosity. and.are:low terpene mist and vapors should be
foaming;'and 2 provided to control odor and

: minimize material losses,
«remove both polar, and non-polar a.
contaminants. ‘Only limited: testing of these
chemicals has been completed to
date. More information on health
and safety issues will become
available as development of this
onbon continues. =



Page 2

PROCESS CHARACTERIZATION

To develop an effective program to reduce and
eliminate CFC-113 use, it is vital that you develop
a good knowledge of your plant operations.

Under tanaing Plant Operations:
. Who purchases CFC-113?

: Who takes detivery?

» How it is handled from arrival to
: ultimate use? :

« How it is CFC-113 used? and

Where do losses take place?

Have the manager of your CFC-113 elimination
program start with a survey. A copy of a
questionnaire that can be used is shown in
Exhibits 1 and 2. This survey form should be sent
to individuals in different plant locations who are
responsible for, and who understand, Material
Safety Data Sheets (MSDS). All MSDS should be
checked for 1,1,2-trichloro-1,2,2-trifluoroethane
(CFC-113) to help identify the trade name.
Identify the quantities bought in the previous
calendar year and start reporting on a regular
basis (monthly or quarterly).

The following steps should then be followed:

(L) For a given time period (year, quarter,
month) determine total production of
boards in square meters of surface area.
Only measure the area of one side of the
board regardless of whether it is single
sided, two sided, or multiple layer in
configuration.

(2) Now you can, for a given period of time,
divide total quantity of CFC-113
purchased by total manufactured board
area for the same period to determine the

ratio of kilograms of CFC-113 used per
squaremeter of board produced, expressed
as kp/m?.

In North American industry this ratio appears to
be in the order of 2.0 kg/m? for a production
facility operated with today’s technology and
minimal attention to chemical handling.
Determine your ratio first before you start your
conservation and elimination programs.

At this point you have. to ‘make ‘the.
tollowing decision:

« If you are already at 0.5 kg/m? then
"you likely have good conservation
_ practices in place and you will be
__Teady to focus more of your time |
and effort on exploring alternate
processes and sechnologies:

« If your ratio is higher. than 05 kom
you can benefit from & conservation

| programs.

Calculate this ratio and report it on a regular
basis - monthly is recommended. It is important
because you will be able to monitor success as
your conservation programs go into effect, and
your employees will take an interest and
participate in the drive towards reaching the
objectives of reducing CFC-113 use.

Next, do an assessment of where you are losing
CFC-113. Do this for the whole plant beginning
with the delivery of CFC-113. You may wish to
develop a simple flow schematic as is shown in
Figure 1. This will give your project manager and
your technical staff an understanding of the areas
to focus on first. If you have more than one
cleaning machine you should do an analysis of
each since CFC-113 losses may vary significantly
from machine to machine.


Page 3

REQUIREMENTS FOR PROGRAM SUCCESS

You can reduce the use of CFC-113 by up to 70-85 percent in your cleaning

processes through conservation, and you can eliminate the remainder by.
_Paopting technologies that are now. available. :

This Program will only be successful if you
__ make your staff aware of and get them involved in the program;

. identify individuals who will monitor the program and be responsible

gain management commitment at all evel, and all functions; >

understand how and wniere you use CEES

for its implementation ‘through to completion;
adopt conservation programs;
set realistic targets and achieve them; and

evaluate and adopt non-CFC processes.



Page To

NON-CFC PROCESSES

In addition to conservation procedures, you want
to evaluate non-CFC processes. There are a
number of alternatives to CFC-113 now available
for cleaning of PCBs and PWAs. It is important,
however, that your customer requirements be
closely examined before moving toward
implementing these alternatives. This is necessary
because traditionally cleanliness of PCBs and
PWAs is cited as a reliability requirement.
Studies have shown, however, that this may not be
so, and therefore, the application of any alternate
is now dependent on addressing cleanliness and
Teliability issues.

It is important that you determine and establish
on paper what tests and standards will be applied
for cleanliness and reliability. For example, while
cleaning may not be required for final product
Teliability, it may still be required to do tests on
the boards; therefore, testing methods would have
to be specified. You will need to take into
account your customers’ perception of what
constitutes an acceptable product in terms of
reliability and testing. This approach will be a
new way of thinking for many manufacturers.

= aqueous cleaning;

Once your criteria are established, consider one or more of the. following
Options which are available today: ‘

« low residue. fluxes/no-clean' assembly;
* _ controlled atmosphere soldering;

+ alternate solvents (chlorinated solvents, alcohols, and
hydrochlorofluorocarbons (HCFCs)); and

= hydrocarbon/surfactant cleaning.

Each of these offers advantages and disadvantages.



Page 4

EXHIBIT 1, CFC USAGE PROFILE

‘A. Identification
Name of Product:

‘Manufacturer:

Purchase Number:
CFC Components:

Chemical Name: Percent or Concentration
1
2.
3.

B. -Quantification:of Usage Patterns

Quantity Purchased: ° (please specify units)
1988: 1990:
1989: 1991;

C.... CFC. Disposal Practices
: 1988 1989 1990 1991

Annual quantity shipped out

‘as waste: for disposal:
(please specify units)

Annual’ disposal: costs:

‘Annual quantity shipped out for
Teclamation: (specify: units)

Annual. cost of reclamation:

Annual quantity lost to the
environment: . (specify units)
Through leakage:

Through spillage:
Through testing:

Through drag-out and
evaporation:

By. other: means (specify)

Unaccounted for:



Page oy]

CONTROLLED ATMOSPHERE SOLDERING

A new soldering process, inert gas wave soldering,

recently has been developed by a large West
German group who is licensing the manufacture
of machines (See Appendix 1 for list of vendors).
The process operates under a nitrogen atmosphere
and applies finely divided activators via ultrasonic
injection (See Figure 5). The carboxylic acid
activators include formic acid, acetic acid, citric
acid, and adipic acid. Other processes are also
being developed that function on the same
principle except that soldering is carried out in
vacuum instead of a nitrogen atmosphere.

Inert gas wave soldering has been tested by a large
West German electronics manufacturer with
numerous conventional wave soldering systems in
operation. Preliminary test results show no
significant differences in the quality of solder
joints. Boards tested by Northern Telecom after
inert gas wave soldering found better solderability.
These preliminary tests showed an order-of-
magnitude decrease in solder defects. In addition,
several European and North American companies
will soon be using the inert gas process to wave
solder both through-hole and surface mounted
assemblies. Results are preliminary and tests are
underway to further quantify the process.
Processes are currently being developed and
patented to allow blanketing of existing through
hole equipment. SMT technology is about to see
controlled atmosphere applications as well.

The particular features that make’ this
process preferable to the well

established and widely used: method : of ao
soldering under atmospheric conditions
(ie., in the presence of: oxygen) are:

soldering takes place: with
metallically pure solder: (i.¢., in an
oxide-free soldering module, oxygen
levels in and above the bath are
monitored by solid electrolytes at
less than two Pm);

oxide formation is greatly reduced: ‘on
the printed circuit: boards: both:
before and after soldering (dross: *
formation is ‘reported to be only 10
percent of that generated in-normal
soldering machines, i-e.; 0.5: f 0.

Kg/day),

the system operates without
conventional rosin or: resin: fluxes;
and

post-cleaning required for assemblies
‘wave soldered on equipment:

currently in use and utilizing:

conventional fluxes (rosin, inorganic
or synthetic fluxes) is eliminated:for
many applications. The residues
remaining on the printed circuit.
boards after soldering have been
reported to be less than 3.5.
micrograms/square centimeter NaCl
equivalent.



United States Air And . EPA 400/3-90-003
Environmental Protection Radiaiton March 1930
Agency (ANR-445)

SEPA Manual Of Practices

To Reduce And Eliminate
CFC-113 Use In The
Electronics Industry

|

Ts es
—— =
f f “NZ
fi ——
am Poel Pare -
inal rm
£

Printed on Recycled Paper


. . Page 3

(4%)

6)

In optimizing the machine, examine the
potential for reducing the conveyor belt
speed. This will keep the board in the
vapor zone longer for more complete
evaporation of solvent, thus reducing drag-
out to a minimum.

Check all temperature measuring devices
and controls. Correctly calibrated
instruments will optimize machine
performance and reduce solvent losses.

Board Cooling:

Solvent cleaners often are placed
immediately following wave solder
machines. This reduces the cooling time
before cleaning. If the boards are
entering the cleaner at a temperature
greater than the vapor temperature, the
heat will be transferred to the vapor and
liquid CFC-113. This creates a super
heated vapor and an elevated temperature
in the various chambers of the cleaner,
resulting in a less efficient operation
which may increase solvent losses.

A solution is to mount small fans above
and below the conveyor to cool the boards
before they enter the cleaning machine.
Fans should be directed away from the
opening(s) of the equipment to prevent
disturbing the vapor blanket within the
machine which could result in increased
solvent loss.

Board Orientation:

Orientation of the board plays a key role
in the volume of CFC-113 dragged-out of
the cleaners. In many instances it has
been found that CFC-113 adheres to the
underside of components and connectors.
This could be minimized through
reorientation.

Reorientation can be as simple as
changing the method by which the boards
are processed. This may require an
intelligent controller interfaced with a

©

10)

(8)

turntable located after the wave solder
machine. The turntable may require a
faster cycle time to reduce the adverse
effects on production.

Solvent Recycling:

CFC-113 often is used to clean flux
residue from washers and stills when
preventative maintenance is carried out.
External reclamation and recycle facilities
are often available which will provide a
reclamation and reconstitution service for
this contaminated solvent. You may have
the choice between having the solvent
returned to you for re-use or receiving
credit with the solvent being made
available for resale to others.

Filter Improvements:

Original filters reach the limit of their
usefulness relatively quickly under normal
operating conditions. The use of more
effective filters results in fewer changes
over time and less solvent loss.

For example, the use of an engine oil
filter and a pump can filter out additional
impurities in the solvent distillation
process. This can be used to increase the
time between preventative maintenance
requirements, which in turn decreases
solvent losses.

Machine Rationalization:

Consider using one solvent cleaner to
handle the boards from two or more
solder machines. Large losses are seen
in cleaners that are under utilized and
have an extended idle mode or cycle
through frequent start-ups and shut-downs.

This will require reworking equipment
placement, conveyor lines, controllers, and
other features. If successful, benefits
include not only reduction of losses of
solvent but also removal of extra


Page 2

CONSERVATION PRACTICES AND STRATEGIES

Once you have characterized your current use of
CFC-113, you can begin to develop a conservation
Strategy. At first, you should choose conservation
options that are easy to put into place in the
short-term. These will give immediate results and
will provide encouragement to employees to
continue and accelerate their efforts.
Conservation practices are divided into two
categories: in-line cleaning and batch cleaning.

_- Operator Awareness of the CFC
Issue and Training in the
_ Handling of CFC-113;

In general, it has been found that
‘Operators are unaware of the
financial or the environmental costs
associated with the use of CFCs.
Increased. operator awareness and
respect for chemicals translates into.
-a reduction. in consumption, since.
Operating practices and methods can
"usually be improved.

Operators; once educated, are able to
change the methods and _ practices.
For instance: keeping lids and
windows closed, turning off the
cleaner when not in use, conducting
maintenance regularly, and exercising
care while: working with machines
__and equipment.

You may also wish to review
~ Chemical ‘handling procedures and
testrict access to CFC-113 to a few
_-employees. —

_ IN-LINE CLEANING PRACTICES

Choices for in-line cleaning are listed and ranked
Starting with the easiest to do. These options
include:

() Examine and Replace, Repair or
Upgrade the Seals and Gaskets on
Pumps, Valves, Pipe Joints,

. Covers, Lids, and Elsewhere:

Pump seals deteriorate when not in
contact with CFC-113. A “running dry"
condition erodes the seal surface and the
seal prematurely fails.

The design and maintenance of cleaners
and stills requires a focus on the seals and
gaskets on covers, lids, and panels. High
volume leaks often occur around corners
and joints where two seals meet.

Check for compatibility of new and
replacement materials.

(2) Reduction of Air Currents:

Excessive air currents outside in-line
solvent cleaners disturb the vapor blanket
within the equipment and losses increase.
When excessive air movement is a
problem, remove the source or consider
the installation of baffles or partitions on
the windward side to divert the draft away
from the cleaning unit.

(3) Cleaning Machine Optimization:

Take advantage of services often offered
by the machine manufacturers; they have
experience in fine tuning the cleaner to
minimize losses. You may wish to
complement this with services offered by
CFC-113 suppliers who often have
programs and information that also can
help operators better manage the process.



Page 3

METHODOLOGY TO SELECT NON-CFC

PROCESSES

The methodology used to select a non-CFC
process has to take into account a host of
important considerations that might include the
process compatibility, flexibility and performance,
the capital costs (i.¢., the costs of the cleaning
equipment and waste treatment equipment if
needed), operating costs, and safety and
environmental issues. For each alternative non-
CFC process these considerations have to be
compared to the CFC-113 alternative to evaluate
the technical and economic feasibility of
substitution,

To evaluate the technical and economic feasibility
of substitution, a methodology was developed at
Northern Telecom that standardized the procedure
used to compare alternatives. This methodology
can be used as the basis for preliminary screening
of various alternatives. The methodology is based
on the principle that the two most important
factors to be evaluated are the technical and
economic feasibility for substitution. The
technical feasibility criteria are evaluated by
establishing a difficulty index that compares the
difficulty of using a non-CFC process with a-‘CFC-
113 process. The economic feasibility is
evaluated by estimating the net present value of
the non-CFC process and comparing it with that
of the CFC-113 process. The next sections
describe this methodology in more detail.

TECHNICAL FEASIBILITY

The technical feasibility of a non-CFC process is
evaluated by establishing a difficulty index. This
is accomplished by first establishing a set of
criteria that need to be considered to evaluate the
merit of a substitute; second, each criterion is
weighted based on its importance; and third, each
criterion is assigned a value based on its
feasibility. This is performed for the CFC-113
process as well as for the non-CFC processes that
are being considered.

include:

cs omnis to specification (

« defect rate (ic, the rate at which

‘s process compatibility, and

The factors that you might evaluate to
determine the technical feasibility

military specifications);

parts do not meet inspection :
Standards),

customer return issues;

industry direction (e., |
widespread commercaliaden and
use);

cosmetics of the PCBs. Gleaned;

flexibility, of the process;

ability to clean surface mount
assemblies (SMT);

fallback position for the P

process control;

throughput of the dleaning process; :

health, safety, and: environmental
concerns;

future costs associated with the
"process;

availability ‘of the process;

® ease of process installability,

floor space requirements.



vo, Page 78

FIGURE 7

Configuration of Hydrocarbon/Surfactant Based Cleaning Process

Wave
Soldering
Wash Rinse Dryer:
Stage: Stage: ryer:
Concentrated Water Room Temp Air |——t Cleaned
Hydrocarbon! or Heated Air PWA.
Surfactant
sou) Ne)
Recirculation
y Y
Public/Municipal
| Periodic Dumping Waste Treatment |—® waste Treatment
. Facility



Page 5

With your knowledge of consumption and where
your losses are occurring you can now select the
appropriate conservation programs. These are
described in the next section.

Figure 1: CFC-1 13 LOSSES IN A TYPICAL PLANT

Evaporative Losses, DragOut Evaporative Losses,
Seals, etc. 12% 40% Seals, etc. 2%

Evaporative Losses

Process Still
1%

Transport 3%

18%
Spills, Leaks

Recycle

Solvent =>

Holding Hand
Tanks 1%
Leaks Cleaning

15% Evaporative Losses
Spills



Page 7

Figure 4. "ZERO DISCHARGE" WATER RECYCLING SYSTEM CONCEPT

Tap
Water
Evaporated
Water a
I |
1 Closed-Loop I
|
Contaminated ; P; |
Water Re ‘article Organic |
lemoval ————"|_—seRemoval
| (tittration) i]
|
Aqueous | |
PWA | \
Cleaner |
I |
Purified | |
Water fl lonic 1
|e.
1 Removat |
Il I
Il |
i |
Loe eee Se ees nen |
Al y

Soil Disposal



Page 72

APPENDIX 1 - VENDORS?

1. Solvent Cleaning Equipment

Baron Blakeslee

2001 No. Janice Ave.
Melrose Park, IL 60160
(312) 450-3900

Detrex

P.O. Box 501
Detroit, MI 48232
(313) 358-5800

Ultronix

RD2 Box 100D
Coopersburg, PA 18036
(215) 965-8009

2. Alternate Solvents

Allied-Signal
2001 North Janice Ave
Melrose Park, Illinois 60160
(312) 450-3880

Dow Chemical
2020 Dow Center
Midland, MI 48674
(517) 636-8325

DuPont Electronics
Wilmington, DE 19898
(302) 999-2889

ICI Americas Inc.

Wilmington, DE 19897

(302) 575-8669 or

ICI Chemicals

Solvents Marketing Department
P.O. Box 19

Runcorn, Cheshire, WA7 4LW
(0928) 512245

Pennwalt Corporation
Three Parkway
Philadelphia, PA 19102

2Note: This is not an exhaustive list of vendors.

3. Aqueous Cleaners

Advanced Chemical Company
Ben Franklin Technology Court
South Mountain Drive
Bethlehem, PA 18015

(215) 861-6921

Baron Blakeslee

2001 No. Janice Ave.
Melrose Park, IL 60160
(312) 450-3900

DuBois Chemicals, Inc.
511 Walnut Street
Cincinnati, OH 45202
(513) 762-6839

Indusco Chemicals

1806 Southeast Holgate Blvd.
P.O, Box 42194

Portland, Oregon 97242 -
(503) 236-4167

Kester Solder

515 East Touhy Ave

Des Plaines, IL 60018-2675
(312) 297-1600

London Chemical Company (LONCO)
P.O. Box 806

Bensenville, IL 60106

(312) 287-9477

4. Aqueous Cleaning Equipment

ECD

13626 South Freeman Road
Mulino, Oregon 97042 ©
(503) 829-9108

Electrovert

4330 Beltway Place
Arlington, TX 76018
(817) 468-5171


Page 77

Appendix 1 - Vendors (continued)

Hollis Automation, Inc.
15 Charron Ave.
Nashua, NH 03063

Ultronix

RD2 Box 100D
Coopersburg, PA 18036
(215) 965-8009

Westek

400 Rolyn Place
Arcadia, CA 91006
(818) 446-4444

5. Low Solids/"No-Clean" Assembly

Alpha Metals

600 Route 440

Jersey City, New Jersey 07304
(201) 434-7508

Cramco Inc.

P.O. Box 88500
Atlanta, Georgia 30338
(404) 475-6100

Hi-Grade Alloy Corporation
17425 South Laflin Street

P.O. Box 155

East Hazel Crest, Illinois 60429

Kester

515 East Touhy Ave

Des Plaines, IL 60018-2675
(312) 297-1600

Kester Solder Company of Canada, Ltd.

One Prince Charles Road, Bos 474
Branford, Ont N3T 5N9
(519) 753-3425

London Chemical Company (LONCO)
P.O. Box 806.

Bensenville, IL 60106

(312) 287-9477

Multicore Canada Inc.

5730 Coopers Ave., Unit 21-22
Mississauga, Ont. LAZ 2E9
(416) 890-6955

6. Controlled Atmosphere Wave Soldering

OCS-SMT Automation Inc.

121 Montee De Liesse

St. Laurent, Quebec, Canada H4t 186
(514) 739-2076

Soltec

P.O. Box 143

4900 AC Oosterhout
Karolusstraat 20 The Netherlands
31-(0)1620-83000

7. Hydrocarbon/Surfactants

Alpha Metals

600 Route 440

Jersey City, NJ 07304
(201) 434-6778

Asahi Glass Co., Ltd.
1150, Hazawa-cho,
Kongawa-ku,221, Japan
045-381-1441

Brulin

2920 Dr. Andrew J. Brown Ave.
P.O. Box 270

Indianapolis, IN 46206

(317) 923-3211

Daikin Industries Ltd.
Chemical Division

1-1 Nishi Hitotsuya,
Settsu-shi

Osaka, 566, Japan
Osaka (06) 349-1778

DuPont Company

Electronics Department

Customer Service Center, B-15305
Wilmington, DE 19898
1-(800)-661-8450


Page Py

‘Spraying Operation 1

Figure 6. DIAGRAM OF A MODIFIED CONVEYORIZED IN-LINE CLEANING
: MACHINE USING ALCOHOL SOLVENT



Page 7

FOREWORD

The Montreal Protocol on Substances that
Deplete the Ozone Layer restricts the production
and consumption of some ozone-depleting
chemicals. Chlorofluorocarbon (CFC)  1,1,2-
trichloro-1,2,2-trifluoroethane, commonly referred
to as CFC-113, is one of these chemicals. Recent
scientific evidence suggests that the measures
outlined in the Montreal Protocol to reduce the
production of CFCs to SO percent of the 1986
levels by 1998 will not be sufficient to prevent
further depletion of the stratospheric ozone layer.
This has led some member nations to the
Montreal Protocol to call for a complete phase
out of CFCs by year 2000. There is a good
possibility of this happening.

The time has come to seriously consider
alternatives that could be used to replace the use
of CFC-113 in the electronics industry. The
situation provides us with a unique opportunity to
rethink and reevaluate the processes and
technologies that have been used for decades. It
is a time to innovate and commercialize new
technologies and processes. The inevitable price
increases in CFC-113 as production drops may
create a de facto situation in which CFC-113
becomes economically less desirable and a more
rapid phase out of CFC-113 may occur than is
currently foreseen. Thus, processes and
technologies that currently do not seem
economically viable might become cost competitive
or economically more attractive than current CFC-
113 processes.

You, as a manufacturer of printed circuit boards
(PCBs) and printed wiring assemblies (PWAs),
need to quickly find ways to reduce and eliminate
your use of CFC-113. You can meet these
challenges through conservation programs followed
by adoption of one or more choices of alternate
technologies.

In response to this important CFC issue and the
need to identify and develop alternative strategies
to reduce the use of CFC-113 in the electronics
industry, Northern Telecom and the U.S. EPA
have undertaken a joint program to provide users

of CFC-113 with help to reduce and/or eliminate
the use of CFC-113. This effort resulted in the
publication of this manual, which is intended to
provide company personnel involved with the CFC
issue with guidelines and strategies to
minimize/eliminate the use of CFC-113.
Information provided in this manual is based on
Practices that have been adopted at Northern
Telecom, and it is intended that the procedures
and practices adopted by Northern Telecom will
serve as an example for plant personnel in
companies worldwide.

This manual of guidelines takes you through a
simple structured program. It focusses first on
conservation programs where reductions of up to
70-85 percent of your current use can be attained.
Then it outlines for you the alternate technology
and process options that are available to eliminate
the remainder of your CFC-113 use. North
American use of CFC-113 in PCB and PWA
manufacturing appears to be in the order of 2.0
kg/m? of boards produced. Simple and
inexpensive conservation techniques will reduce
this use by 40-50 percent, and the addition of
solvent vapor carbon adsorption will net an
overall reduction of up to 80-85 percent.
Alternate technologies such as aqueous cleaning,
low solids fluxes/"no clean" assembly, controlled
atmosphere soldering, alcohols and
hydrochlorofluorocarbons (HCFCs), and
hydrocarbon/surfactants will be needed to
eliminate the remaining 15-20 percent.

Although this manual will primarily benefit
manufacturers of PCBs and PWAs, others who
process small electronic parts, for example, will
also find this manual helpful.

The success of your CFC-113 elimination program
will depend upon how effectively you coordinate
your program. Management commitment is
needed at all levels.


. Page 7

BATCH CLEANING OPERATING
PRACTICES!

Operating practices that can reduce losses from
batch cleaning process are described below.

qa

(2)

Location of Cleaning System (Air Current
Reduction):

As with the case for in-line equipment,
batch cleaners should be placed in an area
that is as draft-free as possible.
Turbulence caused by drafts from adjacent
windows, doors, fans, unit heaters,
ventilators or spray booths will greatly
increase the rate of evaporation of solvent

vapor.

To avoid excessive air movement, consider
installing baffles or partitions on the
windward side to divert drafts away from
the cleaning unit.

For open-top equipment, problems with
drafts can be avoided or corrected by
using hooded enclosures with automated
work-handling facilities.

Size of Workload:

Decrease the loss of solvent vapor by
avoiding the processing of workloads that
exceed the cleaning system’s design
capabilities.

A workload that is too large in physical
size can displace vapor from the cleaning
unit by the "piston effect.". Losses caused
this way can be minimized by making sure
that the area of the workload is not
greater than SO percent of the horizontal
cross-sectional area of the sump into
which it is being introduced.

‘This section was prepared using information from
the DuPont Company

(3)

Also, the introduction of a workpiece that
is too large in mass will cause
condensation of too much of the vapor
blanket. This will cause air to infiltrate
the cleaner.

During reestablishment of the vapor
blanket, the infiltrated air saturated with
solvent vapors will be expelled from the
cleaning unit. If this occurs on a regular
basis, contact the equipment manufacturer
to determine if additional heating and
condensing facilities can be incorporated
into the cleaning unit.

Start-Up/Shutdown Procedures:

Solvent emissions during start-up can be
minimized through the following steps in
the order shown:

. Start-up the condenser cooling
system and make sure that it is
operating properly.

. Start-up any auxiliary emission
control equipment.

. Check and adjust solvent levels in
all compartments.

. Turn-on heaters.

. Start-up the spray pumps once a
stable vapor blanket is established.

. Process work pieces only after the

vapor blanket has been stabilized.

Use the following steps, in the sequence
shown, when shutting down the system:

. Stop work processing and clear
the machine of all work.

. Turn-off the heaters.

. Activate sump cooling coils where
provided. ©

. Allow the vapor blanket to
collapse completely.

. Turn-off the condenser cooling
system.

. Close the cover on open-top units.


Page Te

(uy)

downnward descent, the lid closes.
Subsequeent losses due to the "piston
effect” or sprayers disturbing the vapor
blankket are minimized. After vapor
condensation ceases or spraying is
terminated, the workload can be raised
into the cooling coil zone of the
degreaser with the lid still closed. Again
disturbed vapor zone and potential
workload drag-out losses are minimized.
When the solvent has vaporized and the
product is free of liquid solvent (dry), the
hoist begins raising the product out of the
degreaser, the lid opens and then closes
after exiting.

Such designs can be purchased as an
integral part of many new degreaser
designs. Retrofit kits consisting of a lid,
hoist or a combination of the two are also
available to convert existing degreasers.

Handling of Solvent:

Add solvent to the cleaner carefully to
minimize disturbing the vapor/air
interface. Solvent should be pumped into
the cleaner through a liquid-submerged fill
connection. Makeup solvent should be
added to a rinse compartment, or better
yet, to the cleaner’s condensate collection
tank. Cold solvent definitely should not
be added to a boiling sump; it may stop
the boiling and cause the vapor blanket
to collapse.

Avoid overhead pouring of solvent via
buckets and drums to an open-top cleaner.
This produces turbulence at the vapor/air
interface and increases the possibility of
the vapor blanket to collapse. Solvent
handling in open-top containers should be
avoided because it offers the opportunity
for solvent evaporation and spillage.

Keep drums containing solvent tightly sealed
between transfer operations to prevent unnecessary
evaporation losses. And store drums with the
bung end up to eliminate the possibility spillage
of solvent through a leaky bung. Consider a bulk
storage system for solvent and delivery of the
solvent through a piping system to the batch
cleaners.


Disclaimer

Northern Telecom and the U.S. Environmental Protection Agency do not endorse the cleaning
performance, worker safety, or environmental acceptability of any of the technical options discussed.
Every cleaning operation requires consideration of worker safety, proper disposal of contaminants, and
waste products generated from cleaning processes. Moreover, as work continues, more information on
the health and safety of the alternatives will become available for use in selecting among alternatives
discussed in this document.


Page 3
IN CLOSING .......... essnsaes

Northern Telecom has successfully implemented conservation practices at its divisions. It has designed, built
and operated a state-of-the-art vapor adsorption system, and has used the methods described here to select
non-CFC alternatives. These are the principal actions that will allow the company to eliminate the use of
CFC-113 in its manufacturing operations worldwide by the end of 1991.

‘You may want to contact Northern Telecom for more information as you move forward with your CFC-
113 reduction and-elimination programs. The key contacts are: -

A. D. FitzGerald M. Brox

Director, Environmental Affairs Project Manager, CFC Elimination
Telephone: 416-566-3048 :-: . . |. Telephone 416-566-3232.

Fax: 416-275-1143 Fax: 416-275-1143

Northern Telecom’s address for both individuals is:

Northern Telecom Ltd
3 Robert Speck Parkway
Mississauga, Ontario
Canada LAZ 3C8

The addresses for the other authors are:

Dr. Stephen O. Andersen

Chief, Technology & Economics Branch
Division of Global Change.

Office of Air & Radiation

Mail Code ANR-445

Room 745 WT; 401 M Street, SW
Washington, D.C. 20460

Telephone: 202-475-9403

Fax: 202-382-6344

Sudhakar Kesavan Farzan Riza
Vice President . ‘Associate
ICF Incorporated ICF Incorporated

ICF’s address for both individuals is:

409 12th Street, SW
Suite 700

Washington, D.C 20024"
Telephone: 703-934-3000
Fax: 703-934-3590

The authors welcome comments on this manual.


Page 7

[ | a aa
ne | Oo aaa! of\ pea Ao
[Oo | Li---- 4 ad
smo
untrasonic Solder Additive
Fuxer Bath
Z\ Airtight System
Gas
Oxygen Residues
Fiux Prehester Soldering Belt Conveyor
Module Module Module

Figure 5. DIAGRAM OF A CONTROLLED ATMOSPHERE WAVE SOLDERING MACHINE



MANUAL OF PRACTICES
TO REDUCE AND ELIMINATE

CFC-113 USE IN THE ELECTRONICS INDUSTRY

by:

Arthur D. FitzGerald, P.Eng.”
Murray D. Brox, P.Eng.”

Stephen O. Andersen, Ph.D.
U.S. Environmental Protection Agency

January 1990

“arthur FitzGerald and Murray Brox are employed in the Mississauga, Ontario, Canada office of
Northern Telecom. Contributing authors were Sudhakar Kesavan and Farzan Riza of ICF Incorporated,
Washington, D.C. We would like to thank the many individuals who provided insights and information
that helped to produce this manual, particularly Joe Felty of Texas Instruments. This handbook was

funded by U.S. EPA and Northern Telecom.


_ Difficulty. Criteria -CFC-113. Alcohol Comments
: - Rank
: Compliance 10 Specification 1 os Alcohols Not Yet ‘Approve
e : By Military Specification:

Defect Rate 1 a oo
Customer. Return: Issues : 1 1

Industry Direction id. 3 Industry Moving Towards

: = Alcohols ee

Cosmetics of the PCBs A 1

Flexibility of Process 1 1

Ability to Clean SMT 1 i :
Fallback Position 10 10

Process Control L 4

‘Throughput 1 1

Environment, Health and ce
Safety. Concerns 1 6 Alcohols Combustible:
Future Costs 3 1 Future CFC-113 Price
Increases a oe
Availability of the Process 1 1

Ease of Process 1 6 Major Equipment
Installability Installation

Process Compatibility 1 1

Floor Space Requirements 1 4

Alcohol Process has Bigger
Equipment

Source: Northern Telecom



Page 70

These machines are currently commercially
available and the equipment range covers:

» cold solvent cleaners with brush
option;

» hot solvent cleaners with ultrasonic
option;

= vapor phase batch cleaners with
ultrasonic option; and

« in-line continuous cleaners with spray
and ultrasonic option.

Ancillary equipment for solvent recycling is also

available.
EXHIBIT 3. _PHYSICAL:PROPERTIES - HCFCS & OTHER SOLVENT BLENDS: 88"
HCFC=141b/.
: E Pentafluoro HCFC? 1237.
: CFC: 113 HCFC-225ca'’ HCFC-225CB -- Propanol Isopropanol’. © Methanol: <-* |
Chemical Formula CCLDFCCLFS: CF3CFOCHCL>  CCLFCFQCHCLF CF3CF2CH2OH CHCHOHCH3 CHCLOF/
CHCLOCE3/.
CH30H
Ozone Depleting 0.8 $0.5: <0.5. e 0.0 0 (0.07-0708;.
Potential oe «
Boiling Point: (:C). 47.6 51.1 56.1 81 82. = 30-32
Viscosity: (cps) 0.68 0.59 0.61 ae oe
25°C : :
Surface Tension’. -: 17.3 es 16.3." 17.7. 19.0 22.6 0242
(dyne/em) aS
Keuri-Butenol Value 31 % 30 36 N/A .
Flash Point °c None None None None 12
Toxicity Low Being Being Being "| Moderate Being he
‘ ‘Conducted Conducted Conducted i Conducted:



Page To

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equipment with a reduction in operating
and maintenance costs.

System Enhancements:

There are a number of enhancements that
can be made to the solvent cleaner which
you may wish to consider. These are
hardware add-ons or modifications that
require capital expenditures and are not
the machine optimization . aspects
previously described. System enhancements
include:

» increased freeboard height;

« increased cooling system compressor
capacity; and

« additional cooling coils on inlets and
outlets.

Cleaner manufacturers and experts in
chilling/refrigeration should be consulted
for their expertise. Consider reviewing
the condensing effectiveness of your
chiller/refrigeration system with the
assistance of a knowledgeable contractor.
Improved condensing efficiency through
additional cooling coils at the entrance
and exit of the wash and perhaps through
compressor resizing will reduce
evaporative and drag-out solvent losses.

Use gas detectors to give accurate
information on where leaks are and how
effective your efforts are.

Bulk Solvent Handling:

A bulk CFC-113 handling system, shown
in Figure 2, reduces CFC-113 losses in
drum handling, in transferring to small
containers, and in filling the cleaners.
With appropriate real time alarms,
personnel are alerted to possible leak
conditions by monitoring consumption or
loss in each cleaner as CFC-113 is
supplied.

Solvent is delivered by bulk tanker and is
then pumped into a bulk storage tank

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where it is held until needed. The tank
is non pressurized and, in the example, is
within the plant. Distribution to the
cleaners is provided through a series of
pumps and PVC pipes. Therefore, the
system eliminates all manual handling of
CFC-113 and minimizes losses. Control
is provided by float switches within
individual washer units.

A microprocessor can be used to monitor
the consumption of CFC-113. This allows
for daily collection of consumption data
for each cleaner. The computer also can
adjust for excessive consumption. In
addition, if an alarm condition occurs, the
cleaning system is checked for leaks.

Solvent Vapor Recovery:

Drag-out losses are a major contributor
to the overall loss of solvent in the system
and vapor capture systems should be
considered. These systems adsorb the
non-polar CFC-113 molecule on an
activated carbon bed, which is then
extracted by steam for blending with
additives and re-use in the system.

The intake and exhaust ports of the
cleaner are vented to hoods where vapors
are drawn under negative pressure through
the activated carbon bed. It is vital to
properly design the collection hood at
the cleaner discharge since this is where
drag-out and drying losses are most
significant.

Adsorption continues until the carbon bed
is saturated at which time the bed is
steam injected to strip off the CFC-113
for condensing and water separation.

Three streams are produced: pure CFC-
113, clean air, and wastewater. Waste
water is treated and released to the sewer
system; the air is returned to the plant or
exhausted into the atmosphere; CFC-113
is reblended/reconstituted with additives
and reused in the process. There will be


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Consolidation and/or Work Scheduling:

Start-up always results in some solvent
vapor loss as air is purged from the
system. When the cleaner is used on an
intermittent basis, emissions caused by
frequent start-ups and shut-downs can be
minimized by deferring cleaning until a
full day’s cleaning work is accumulated
for processing. Thus, there will only be
one start-up of the cleaning equipment.

As well, you can reduce vapor emissions
by consolidating operations of several
open-top units into a single, enclosed unit
designed for continuous operation.

Positioning Work To Reduce Drag-Out
Loss:

You can reduce drag-out losses if the
work being cleaned, whether contained in
baskets, suspended from hooks or racks,
or conveyed on a belt, is always positioned
so that it permits maximum liquid
drainage. Solvent trapped in pockets and
recesses results in excessive drag-out
losses.

Cover Design:

Hinged covers, if opened too quickly, tend
to drag some of the solvent vapor with
them. Consider an alternate design such
as a cover which slides open.

Vapor Dwell Time:

If possible, hold the workload in the
vapor zone after the final cleaning step
until its temperature equals that of the
vapor zone and vapor stops condensing on
the part. Work taken out earlier will
emerge wet with solvent condensate.

Dwell times that are too short are most
often seen in open-top units where the
work is manually moved into and out of
the unit. Automatic hoists can help

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reduce excessive drag-out due to
insufficient dwell time.

Movement of Workload:

Arecommended maximum speed for work
entering and leaving the cleaner is three
meters/min. Higher throughput rates can
cause vapor/air interfacial disturbances
that result in high vapor losses.

Again, the use of automatic hoists and
programmed work transporters is
recommended. The speed of the piece
entering and leaving should be optimized.

Spraying:

Spraying of work pieces by spray-lance or
spray headers should be performed deep
within the vapor zone. This avoids excess
disturbance of the vapor/air interface.

Take care to avoid having the liquid
solvent ricochet into the free-board zone
or out of the machine when lance

spraying.

Avoid spraying cold solvent vapor because
this results in the loss of heat from the
vapor blanket, which increases the
potential risk of collapsing the vapor
blanket. Use warm solvent (100° F to
112° F) for spray washing. This minimizes
the potential for vapor blanket collapse,
and the loss of solvent that takes place
when the vapor blanket is reestablished.

Integrated Cover/Hoist Designs:

The inclusion of an integrated degreaser
cover and hoist design is effective in
reducing working solvent loses. The
presence of a motorized, horizontal
sliding, two-piece lid can be integrated
with an automated programmable hoist.
As the hoist lowers the workload to the
degreaser, the lid slides open to allow
entry of the product into the vapor zone.
When the workload clears the lid on its