A Cooperative Project
between the
U.S. Environmental
Protection Agency
and PWB
  May 1999
 EPA 744-F-99-004
                                                                       PRINTED WIRING BOARD CASE STUDY 9
             PRINTED WIRING
             BOARD PROJECT
      Flexible Simulation

  Modeling  of PWB Costs

  Kgnifjrou-Saye carefully researched how certain changes
 tryoilr prodjLCtioi^process may affect your costs, it can still
be difficultly anticipate the, effects of all possible changes.
The-envkonmejHal^ostST^uch as generation of waste,
treatmentspf waste, ^water, arid electricity use, can be
 articularly hard t6Tanticipat^, Wouldn't it be nice to have
       'ball ^predict the-effects of changes on your
       s*Sd production|^flie*Flexible Simulation Model,
      ed by the'fhdustria'l-Enlaneering Simulation
    HUtllUll Mi Ik  P  dta , =*     'imtmfmpr^
    iratonK(IESL) at the OSiverstty of Tennessee in
  Plteajifc*^ AtlrwiJJgi -»""  ^ %    '•fesBSMrtpC3
  ffunctton withrfie^PAVDfKttogram, can show you
  ' modifications in your 'fffOducJion process will affect
     >osts         i    Mr~~~~~—~~

          rings by Finding All Costs
PWB faciliti
                    ily at the dkect costs of
 changelp a pr|SeJf75:h?roduct. Direct: costs
apital expenditOTesYlatfbr, and materials. Some
     allocate-qpjLts associated with ak emissions,
         fand solid/haz^ous wastes to "indirect costs''
                 Nno4Sflier! When you are estimating
  !sts for new equipfmeilt, new products, or any other
process change, it is'fmpbrtant to fully consider both dkect
               , including handling of the wastes you will
By allocating waste handling and other environmental costs
to the specific processes from which they originate, you can
identify more precisely how much it will cost to run the
Knowing this information before you embark on a change in
your operations will help you configure the optimal process
design to keep your expenses as low as possible while reducing
your facility's impact on the environment.

Alternative Accounting Methods

Alternative accounting methods attempt to improve upon
traditional costing by including indirect costs as well as direct
costs, and by allocating indirect costs to the products or
processes that actually drive those costs. However, these
methods may require extensive data input, which can be so
time-consuming that it is not always practical.
Simulation modeling makes the process of assessing costs
much simpler. Simulation duplicates production processes on a
computer, allowing users to experiment with different scenarios
without disrupting production or incurring any of the costs of
actual implementation.  Since simulation models duplicate
production processes, they allow tracking of specific activities
that otherwise would be aggregated into overhead costs. These
models can be designed to allow the user to try out any number
of variables, such as the number and type of operations, the
sequence of operations, production volumes, and process times.
Some simulation models have been criticized for lack of
flexibility and applicability to the real world — in this case, to
printed wiring board (PWB) manufacturing.  In order to design
a generic "model" process that represents a typical or standard
process, software developers must make numerous assumptions
— about the sequence and timing of process  steps, the
chemistries used, the facility's operating hours, even the
physical size of tanks and equipment. PWB manufacturers
contend that an "average" facility is rarely representative of any
real operation, because there is such diversity in processes from
one facility to the next.

The Flexible Simulation Model

The Flexible Simulation Model, which was developed for PWB
manufacturers, allows facility staff to input the parameters of
their own particular production process. These inputs will
convert a standard process into one that is unique to the facility
being evaluated.

The Flexible Simulation Model has a number of benefits
for PWB manufacturers:
•   The model is a powerful tool to help you estimate
    the impact of process changes on a facility's costs
    and production metrics, such as throughput time,
    inventory, and scrap.
•   It provides a better understanding of total costs,
    which can help you identify areas where you can
    reduce wastes and inefficiencies to save money.
•   It allocates all costs directly to the specific
    processes from which they originate, so you can
    see exactly how any change you might make would
    affect other aspects of your operation.
•   It enables you to evaluate the costs and savings of
    switching to a new process in your facility — before
    you purchase equipment or disrupt production.
•   Even if you have no knowledge of computer
    modeling, the model allows you to experiment
    easily with different processes that are specific to
    your facility and its particular needs.
To use the Flexible Simulation Model, a user first enters
production data and parameters (e.g., cycle time, volume
of chemicals used, frequency of bath  additions). It is
important to realize that although this model can
produce powerful facility-specific results, good inputs
from production management and process engineering
are essential to producing accurate, reliable results.
Once the facility-specific information is  entered and a
specific number of boards are requested to be "run," the
simulation program "produces" the boards.  The model
then creates profiles for cost, production, and
environmental aspects of the PWB operation. To date,
the model has been run for the plating through-holes
process. It can be easily adapted to model any wet
chemistry process.

Validating the Flexible Simulation Model

Before the new model could be considered reliable by
PWB manufacturers, it had to be validated.  The
validation process confirms that the model generates
results that reflect the actual world of PWB
manufacturers. To collect the data needed to validate
the model, a team from the D3SL made a two-day site
visit to ITO Industries in Bristol, Wisconsin. ITO
Industries manufactures PWBs for the medical,
telecommunications, and building safety device
industries. ITO operates three shifts per day, with over
60 production employees.
The validation compared the cost, production, and
environmental profiles generated by the model to the
known costs tracked by ITO Industries. To simplify the
validation, the team focused on one process line, the direct
metallization of through-holes. The validation involved
three phases:
•   Simulation validation: The model estimated the
    amount of labor, time, water, chemicals, and other
    inputs required to produce 350,000 surface square feet
    (ssf) of boards. ITO verified that these numbers were
    accurate, thereby validating the process simulation.
•   Cost validation: The model estimated the resulting
    cost/ssf for the direct metallization line to be $0.26/ssf.
    This cost was compared to ITO's in-house estimate,
    which was calculated manually as $0.20-0.30/ssf.
•   Comparison to a static model: The University of
    Tennessee team also compared the cost generated by
    the model to their own manual estimate, which also was
The consistency of these results validates the model for the
process of making holes conductive.

To Model or Not to Model?

The Flexible Simulation Model uses ARENA 3.0
simulation software. Running the model yourself in your
facility requires having both the model and the software to
run it.  This option can be especially useful if you have  a
large facility with many choices to make. If your company
is interested  in using the Flexible Simulation Model, you
may purchase the ARENA simulation software, obtain the
model at no cost from the University of Tennessee, and
run as many  scenarios as you  choose. (The ARENA
software retails for approximately $16,000.)  Alternatively,
you may have the IESL at the University of Tennessee
analyze your data for you, for a nominal fee.  Depending
on the process, fees are expected to range from $250 to

The Real Costs  of Doing Business

Whether or not you decide to  use a modeling simulation
program, the concepts behind the model are always
important to  consider when you estimate costs for your
PWB operations. The chart on the facing page lists the
major categories of costs that you should think about
when thinking about making a change to your
operation. Within each category, you may want to
include other items that are specific to your business.
                                                                      (Text continues on the backpage of this document.)

   Cost Categories to Consider Before Making Changes to PWB Operations
r   These are general categories, and not every item will be relevant to your business. However, every cost in your
i   facility should be allocated to one or more specific operational areas, rather than being tucked away in a separate
;"   category such as "overhead."  An item is sometimes listed in more than one location, because it may apply to several
5   categories (e.g., purchasing water treatment equipment would be relevant to both Capital Costs and Wastewater Costs).
I   Capital Costs
|        * Equipment purchase and installation
J        * Purchase of buildings and/or property
"        * Project engineering, site preparation
i        * Labor for planning, preparation, :installation
    Material Costs
I:        * Chemicals
;        * Personal protective equipment
»        * Other supplies
*'   Maintenance Costs
if        * Bath setup
|        * Sampling and analysis of bath chemicals
I        * Filter/membrane replacement
*        * Tank cleanup
I        * Labor for maintaining equipment and bath
1          chemistry
    Other Production Costs
    These costs will depend on the specifics of your
    operation. Categories to consider may include the
         * Transportation of material within facility
         * Labor for line operation
         * Time needed to produce desired output of boards
           (including ssf/hr)
         * Down time (for breakage, equipment
           malfunctioning, bath replacement time, etc.)
         * Quality cost (scrap)

    General Facility Costs
         * Utilities (water, sewer, electricity, natural gas, oil,
Air Emissions Costs
      * Control equipment
      * Labor (for tracking, monitoring, reporting,
       maintaining equipment, etc.)
      * Permits, fees

Wastewater Costs
      * Treatment chemicals
      * Treatment equipment
      * Labor costs (for on-site water treatment, etc.)
      * Permits, fees

Solid Waste Costs
      * Management of solid waste on-site
      * Transportation equipment
      * Transport of waste off-site
      * Permits, fees
      * Labor (for monitoring, completing waste manifest
       paperwork, handling solid waste, etc.)

Training, Supervision, and Management1
      * Salaries and benefits
      * Supplies and materials

Potential and Actual Liability Costs1
      * Penalties and fines for unallowed/excess
      * Personal injury and property damage
      * Costs of litigation or of mediation with
       community, other businesses, etc.
      * Corporate/business image to community,
       investors, lenders, regulatory groups, etc.

1 These categories are not included in the Flexible
 Simulation Model.

Similarly, some of the items listed may not apply to your
Careful consideration of all the costs that a change in
process could generate is just smart business. By
considering environmental costs and impacts in addition to
performance and other product costs, you will obtain a much
more complete and accurate picture of the full impact on
your operation of any potential change. This knowledge will
help you to reduce your expenses and remain more
competitive, while decreasing the environmental impact of
your work.  Once you begin taking environment costs into
account, you may be able to identify ways to  operate your
business more efficiently.


EPA's Design for the Environment Program would like to
thank ITO Industries and the University of Tennessee for
participating in this case study.
                                                           For More Information
                                                               To have the University of Tennessee run
                                                               the PWB model for a specific scenario, or
                                                             * to obtain the Flexible Simulation Model for
                                                               use in your own facility, please contact Dr.
                                                               Rupy Sawhney at the University of
                                                               Tennessee, Department of Industrial
                                                               Engineering, Industrial Engineering
                                                               Simulation Laboratory:
                                                                      Telephone: 423-974-3333
                                                                      Fax: 423-974-0588
                                                                      E-mail: sawhney@utk.edu
                                                               —.——™-™.	™™-—'
    Design for the Environment Printed Wiring Board Project

Through the Design for the Environment (DfE)
Printed Wiring Board (PWB) Project, representatives
of the PWB industry and other interested parties
formed a partnership with the U.S. Environmental
Protection Agency (EPA). This project is a
voluntary, cooperative, effort in which EPA and its
partners are working together to develop technical
jnformatipn on pollution prevention technologies and
practices specific to the PWB industry.

The DfE PWB Project has conducted two
comprehensive evaluations for the PWB industry,
which are called Cleaner Technologies Substitutes
Assessments, or CTSAs: The topics of the CTSAs
\.  Alternative Technologies for Making Holes
    Conductive (completed)
i;  Surface Finish Alternatives to the Hot Air Solder-
    leveling Process (in progress)
      evaluations enable PWB manufacturers to
     informed business decisions that consider
Iiuman health and environmental risks, as well as
performance and cost.
       Printed on paper that contains at least 30% recycled fiber.
The DfE PWB Project has also developed other case
studies that examine pollution prevention
opportunities for the PWB industry. All case studies
are based on the experiences of facilities in
implementing pollution prevention initiatives^  You
can read and download the case studies and the
Making Holes Conductive CTSA from the DfE
website, at:
You can also order documents from:
      Pollution Prevention Information
      Clearinghouse (PPIC)
      U.S. EPA
      401 M Street, S.W. (7409)
      Washington, DC 20460
      Phone: 202-260-1023
      Fax: 202-260-4659 	"  '"
      E-mail:  PPIC@epa.gov
                        „,;;,;	j,  	';,,,,     "hi \

The DfE Program welcomes your feedback.  If you
have implemented any of the ideas in this series of
PWB case studies, please tell us about it by calling
the DfE Program at 202-260-1678, or via E-mail at:
oppt.dfe @ epa.gov.
                                                                                                        T	S

                                                                                                        IT Mli