1996 Pollution Prevention Internship
Final Project Report
Intern:
Jeff LeBlanc
P.O. Box 216
Oxford, MA 01540
Home: 508-987-5036
Work: 603-898-8010 Ext 2343
Fax: 603-898-0526
E-Mail: jjlb@hopper.unh.edu
Facility:
HADCO Corporation
Tech Center One
7 Manor Parkway
Salem, NH. 03079
Contact Person:
Lee Wilmot
Corporate Safety, Health & Environmental Manager
Phone: 603-896-2424
E-mail: lwilmot @hadco.com
Marc Duquette
Senior Safety & Environmental Engineer
Phone: 603-896-2699
E-mail: mduquette@hadco.com
1
Table Of Contents
I.
Introduction.................................................................................................. 3
II. Executive Summary..................................................................................... 4
a. Water Recycling.................................................................................... 4
b. Mecer Filtration...................................................................................... 4
c. Mister......................................................................................................5
d. Diffusion Dialysis................................................................................... 5
III. Objective...................................................................................................... 6
IV. Water Recycling........................................................................................... 7
V. Mecer Filtration............................................................................................ 20
VI. Mister........................................................................................................... 26
VII. Diffusion Dialysis......................................................................................... 29
VIII. Appendix..................................................................................................... 31
I. Introduction
2
Hadco Corporation has a long history in pollution prevention techniques
and environmental concern. Over the past thirty years, Hadco has strived to
increase production while maintaining a perspective on environmental
awareness. As a producer of printed circuit boards, the demand for chemical
and water usage is high. Through pollution prevention techniques, Hadco has
taken steps to limit these demands.
This summer the goal was to further help Hadco in their effort to reduce
waste. Specifically I concentrated on reducing water usage to limit the amount of
waste water generated. By reducing Hadco’s water usage while maintaining
their high record of quality, great savings as a result of reduced waster
consumption could be achieved.
A second area for waste reduction that was explored over the course of this
internship was the recycling of spent nitric acid. Nitric acid is used in the solder
stripper to strip any excess tin/lead solder left on the board. At the present time
Hadco ships any spent solder strip off-site for disposal. By looking to reduce this
waste, Hadco is now considering the implementation of new technology that
would recycle this waste, thus reducing the amount of off-site shipments.
By implementing new technology, and evaluating existing technology, Hadco
has been able to reduce waste over the past few years. From water reduction
to chemical reduction, Hadco has set unprecedented records in waste reduction.
II. Executive Summary
IIa. Water Recycling:
3
As a PCB Corporation, the requirement for water consumption is relatively
demanding. Water is required for both industrial process as well as domestic
usage. Hadco Corporation has preset limits for water consumption, mandated
by Greater Lawrence Sanitary District (GLSD). With an increase in production,
Hadco Corp. must now evaluate new technology and present process
consumption to maintain operation within these set parameters. Process
equipment was evaluated based on flow rates, and general cleanliness of the
water. This value was determined from water analysis. Once flow rates and
water data was known, suggestions could be made for water reduction
techniques.
In conjunction with in house water reduction techniques, vendors were
contacted to make recommendations for the equipment that would be required
by Hadco, to recycle current waste water. The final objective for this project was
to perform cost analysis on all recommendations submitted by vendors. This
allowed for a cost comparison.
IIb. Mecer Filtration System.
The Mecer filtration system is an on site etchant recycling system. The Mecer
is designed specifically to handle ammoniacal etchant. Hadco Corp.
Implemented this system in February of 1995 in their Salem Tech Center One
facility. Due to the many problems experienced with the system over a period of
6 months, Hadco has since removed the Mecer system. However due to the
tremendous cost of purchasing and disposing of ammoniacal etchant, Hadco
now desires to evaluate the feasibility of re-implementation of a Mecer system.
In order to perform this evaluation, original problems with the system had to
be reviewed. Engineers and operators that worked on the original system had to
be contacted and alarm logs had to be reviewed.
In addition to evaluating past performance at TCI, other companies that have
installed this system were contacted. These companies could then be compared
to Hadco based upon process performance.
IIc. Mister
The ammonia etcher at Hadco is used to strip copper off the inner and outter
layers of the printed circuit boards. Fumes exiting the front of the etcher pose a
4
hazard to both the operator and other plant personnel working in the area of the
etcher. To minimize this exposure factor, a water spray mister has been utilized
to diminish the ammonia fumes. A second purpose for this mister is to remove
any residual etch that may accumulate on the rollers. However the water effluent
contains high concentration of chelated copper. This concentration poses
problems with waste water treatment. Such high concentrations are difficult to
treat. It was the goal of this project to find a new manner in which the ammonia
fumes could be treated so as to minimize the risk to workers and minimize
concentration levels at waste treatment.
IId. Diffusion Dialysis
Diffusion dialysis is the process used to recover spent acid for reuse. This
technology can be used in a PCB manufacturing environment to reclaim acid
from spent baths. With a predicted reclaim of 85-90% of spent acid, this
technology could pose a large savings to Hadco. At the present time Hadco
Corp. is considering the use of this technology on their solder stripper to reclaim
spent nitric acid. Hadco presently uses 2090 gallons of solder strip a year. This
corresponds to a $27207 annual cost for purchase and disposal. By
implementing diffusion dialysis technology, there is the potential for a $24486/yr
savings.
III Objective
The main objectives presented at Hadco TCI this summer were:
5
1. Evaluate present process parameters and make suggestions for water
reduction.
2. Contact vendors and evaluate their suggestions for technology required for
water reduction.
3. Evaluate the Mecer system and evaluate the feasibility of re-implementation
of the system to the TCI facility.
4. Develop a way in which the ammonia fumes from the mister can be treated
while at the same time limiting copper sent to waste treatment.
IV. Water Recycling
Due to increases in production, Hadco Corp. now finds that it must evaluate
present process parameters to maintain operation within GLSD set parameters
for water usage. This project started by recording all flow rates for each process
6
within the TCI facility. Since some of the process machinery was not equipped
with flow meters, in many cases this required entering the trench, following pipes,
and measuring flow rates with a bucket. Also noted for each process were
counter flow measures, flow restrictors, board sensors, conductivity controllers
(where applicable) and the type of water (i.e. DI or city water). This information
was added to a database created for water consumption. Samples were taken
from each rinse tank every week and tested for conductivity (s), pH, totally
dissolved solids (mg/l), copper(mg/l), and lead (mg/l). These tests were repeated
over a seven week duration. The reason for seven weeks of testing was to
develop a spectrum of data that would allow for true maximum and minimum
values to be seen. During the seven weeks of testing, all disposition streams
were verified by entering the trench and following the piping. Upon completion of
the sampling and testing, averages were calculated for each rinse tank. Two
databases were then developed from this information. One database contained
the average values, while the second database contained the maximum
observed values. A copy of these two databases can be seen in the appendix
section IA. of this report. By observing the recorded data, changes to the
process could then be suggested. Suggestion were based upon cleanliness of
the water, determined by conductivity and TDS.
After reviewing the collected data, it was found that much water could be
conserved at the TCI facility. The following graph shows the processes and the
amount of water that could be conserved.
7
Potential For Water Savings
6000
5000
Gallons / Day
4000
3000
2000
1000
0
Final
Clean
Dep/Des
O/L
Strip
Oxide
8
Ni/Gold
Solder
Strip
I/L Strip
One area in which water consumption was able to be reduced was the black
oxide line. From the collected data, it was found that the effluent from the DI
rinse was cleaner than the feed to the city water rinse. Therefore the suggestion
was made to counter-flow of the DI effluent to the city water rinse tank. Below
you can see the original setup followed by the changes made as a result of the
data testing.
These changes yielded a savings of 3.25 gpm with a cost savings of
$ 8640.64/yr. The additional 0.75 gpm was added to rinse #18 to improve rinse
quality after the entek bath. After evaluating the collected data, it was
determined that the flow rate could be lowered from 3 to 1.5 gpm. Water quality
was monitored daily for a two week duration following these changes to insure
quality. The rinse water in stations 15 and 14 were found to improve due to DI
water addition.
9
A second area in which water reduction was targeted pertained to the
Nickel/Gold line. By reviewing the collected data, once again counter flow
options were suggested. Below you can see the previous and new setup.
Caution had to be taken so as not to contaminate any of the baths on this
line. By working with the process engineer an estimated 2.5 gpm of rinse water
was saved. This resulted in an annual savings of $1767.33. Again, the rinse
water quality will be analyzed daily for a two week duration to insure the quality
of the water.
Another area in which it was found possible to conserve water was the solder
stripper. After the board goes through the nitric acid bath, it then moves through
two rinse stages. The first rinse stage is a feed and bleed recirculating rinse tank
with a flow rate of 3 gpm. The second rinse consists of two spray rinses. The
water enters the stripper via a direct line and is used for the second spray rinse.
It is then collected in a basin at the bottom of the stripper. From there it is
pumped back to the top of the machine and used in the first spray rinse.
10
Following this procedure the water is discarded to WWT. The flow rate for the
second rinse is 5 gpm. From testing the water, it was found that the exiting
water from the second rinse was clean to the point of acceptance for use as the
feed for the first rinse. The flow rate for the second rinse could not be turned
down to match the flow rate of the first rinse due to the fact that the high flow rate
was required to maintain spray pressure. So by counter-flowing the second rinse
to the first, 3 gpm will be saved resulting in a savings of $1595.19/yr. This
should also improve the quality of the water in the first rinse due to the fact that
water will be fed and bled off at a greater rate. A diagram of this change can be
seen below.
11
By reviewing water data for the inner layer stripper, it was found that effluent
water was not contaminated to the point of disuse. There were two options on
what to do with the water at this point. The first option was to run the water
through a filter and into a recirculation tank. This would close-loop the water for
the inner layer stripper for a time interval to be determined. The second option
was to simply decrease the flow rate to the stripper. By working with the process
engineer, it was determined that the best choice would be to lower the flow rate
to the system. By recirculating the rinses, chemistries within the solution would
have concentrated to unacceptable quality levels. Therefore, the decision was
made to turn down the flow rate from 3 gpm to 2 gpm. This produced a water
savings of 600 gpd resulting in a $1292.91 annual savings. Again, the water
quality was monitored daily over a two week interval to insure quality.
The final clean was found to have effluent as pure as the feed water. I
proposed adding a 20 micron filter and recirculating tank to this system to closeloop the water usage. The final clean presently runs at 4 gpm. However, due to
new technology being implemented at Hadco, the final clean machine will be
replaced in one month. For these reasons, this water reduction technique was
deemed unnecessary.
I am presently working with Technics, the vendor which implemented the
software on the deposition line to establish a way in which water usage can be
regulated on this line. At the present time, the deposition line is operated about
20 hours a day. During this time, the line is only utilized for work 12 out of the 20
hours. The remainder of the time, the line is left running to maintain the baths.
Many times, the operators will leave the water to the rinses running, while no
work is being processed for those 8 hours. Water regulation in this area will
have a significant impact on water control at Hadco TCI. To control water
consumption on this line, Technics is investigating the feasibility of implementing
two photoelectric switches on the front of the deposition line. These switches will
in turn send a beam through the racks in which the boards are placed. If the
rack is found not to contain boards, then the beam will not be reflected.
However, if there are boards in the rack and the beam is reflected, a signal will
be sent to a timer and a motorized ball valve that will activate the rinses for the
duration of the time it takes for the rack to pass through every stage. This
technology would allow for a 5520 gpd savings, corresponding to a annual
savings of $12229.83.
To sum up all conservation measures recommended to Hadco, the table
below shows the estimated water savings:
12
Process
Deposition
Etcher
I/L Strip
Nickel/Gold
Oxide
Solder Strip
Old Flow
(GPM)
11.50
220 GPD
3.00
5.50
10.75
8.00
New Flow
(GPM)
11.50
50 GPD
2.00
3.00
7.50
5.00
TOTALS
Savings
(GPM)
0.00
0.00
1.00
2.50
3.25
3.00
Savings
(GPD)
5520
150
600
600
3900
720
9.75
11490
This is a 17.6% savings in Hadco’s total daily water consumption.
The savings from these expected changes can be seen in the table below:
Amt. Water
GPD
10890 (Cw)
600 (DI)
TOTAL
Cost Per Kgal
$
6.07
8.07
Total Savings
$/Day
66.1023
4.842
70.9443
Total Savings
$/Year
24127.33
1767.33
25894.66
After all in-house water conservation techniques had been exhausted, outside
vendors were contacted to make suggestions to further help Hadco reduce water
usage. The implementation of the above in-house water conservation measures
will not guarantee that Hadco maintains water compliance during busy times. To
insure future compliance vendors were asked to speculate on a 20-30 gpm water
recycling system. Vendors that were contacted include:
Kinetico
Manchester Corp.
Remco Engineering
U.S. Filter
Memtek
Dynatec
Selection was based upon reference from Hadco personnel. All vendors
were supplied with the collected water data averages and maximums. Quotes
from the vendors were then obtained for evaluation.
Cost analysis was performed on all quotes received from the vendors. This
entailed acquiring a current water bill from the town of Salem, a current electric
13
bill from Granite State Electrical, and the schematic breakdown for sludge
pricing.
Before a final decision on pilot testing can be made, the decision must be
made whether to implement an IX or RO system at Hadco. Both systems offer
various advantages and limitations in daily operation. Below is a list for the
advantages and disadvantages for each system.
IX system Advantages:







Quality of recycled water would abolish need for DI resin columns
Recycled water could be used for bath make ups
High metal removal efficiency
Recycled water would have a TDS level of 1 ppm.
High reclaim ratio (in %)
Lead/Lag setup allowing for zero down time while cleaning/performing
maintenance.
Possibility for metal recovery through Electrowinning
IX system Disadvantages:





Limited feed streams
Potential for resin fouling
High initial cost
Lower TDS feed limit
Poor organic removal
RO system Advantages:




Lower cost
High metal and organics removal
Consistent water quality
Higher TDS feed streams
RO system Disadvantages:
14







Reclaim ratio (around 65-70% w/out more expensive membranes)
Potential for membrane fouling
More expensive in annual maintenance
Lower quality in recycled water (usually 10% of TDS fed)
Potential hazard when using water for bath make ups
Water must be treated with DI resin columns to produce DI water
Cleaning Time may incur unacceptable down time for permit levels.
A schematic for each system can be seen as follows:
15
It is recommended that vendors be sent a second copy of water data with the
updated technology. This will have to include the data on the PAL line, data on
the new developer, and data on the new chem clean system.
Based upon the initial proposals from the vendors, I would recommend that
Hadco consider a treatability study followed by the pilot testing of a Kinetico IX
system. This recommendation is based upon many researched findings. The
first thing to consider was the company background. As large manufactures in
water recycling, Kinetico has over twenty years of knowledge in water recycling
technology and how it relates to a PCB manufacturing environment. The
company has over 300 systems installed in this type of manufacturing
background. The most important point considered was the quality of the effluent
water proposed by Kinetico. Kinetico has proposed an Ion Exchange system
which will recycle water to DI quality. With the regenerated water being of DI
quality, there would no longer be a need for present resin columns used to
generate DI water. Recycled water could be used in all plating baths and rinses
without concern of chemical reaction and/or contamination. Secondly, by using
the ion exchange system, the possibility for metal recovery also exists. This
would produce a revenue stream to help offset the initial costs for the equipment.
The Kinetico design proposes a 90 to 95 percent reclaim ratio on the spent
water. This was the highest reclaim ratio proposed out of all the vendors.
Other vendors, while proposing quality systems were excluded based upon
the following reasons.
Dynatec:
Dynatec proposed the use of an RO system for the TCI facility. However
without Hadco putting up the initial cost for a treatability study, Dynatec was
reluctant to specify possible recycle streams, size of the required RO, and cost
for the system. It was also stated in the information packet received from
Dynatec that even after passing through the membrane columns, it is possible
that the recycled water would not be acceptable for all rinse applications. To
further treat the water the use of DI resin columns would be required. It is
possible that the recycled water from this system would cause chemical reaction
and therefore could not be used for concentrated bath make ups.
Remco Engineering:
Remco Engineering was found to be an “off the shelf” distributor of water
recycling technology. Based upon the proposal received from Remco, it was
determined that this company would not be able to provide the knowledge
required to service the unit.
US Filter:
16
While a quote has yet to be received from US Filter, it was the feeling of their
sales representative that US Filter would suggest the use of an RO system for
Hadco. Since there was no proposal available for review, I could only review the
experience of the company. It was discovered during review that while US filter
has much experience in water purification, their experience with how this relates
to a PCB manufacturing environment was limited. To further investigate this
factor, I visited Elexsys Corp. located in Nashua, NH. The company is using a
US Filter RO system to recycle spent waste water. What I found at Elexsys was
that while the system was working to acceptable levels, the company was only
able to achieve a reclaim ratio of 65%. Secondly, the effluent water was found to
have a TDS of typically 10% of the feed to the unit. This produced water that
while Elexsys claimed was pure, they were not using for concentrated bath make
ups.
Manchester Corp:
Manchester Corp. was the company that designed the existing conventional
waste treatment system (CWTS) in the TCI facility. Manchester proposed an RO
system for Hadco to consider for water recycling. Manchester’s design for this
system did have a few drawbacks. First, the maximum expected reclaim ratio
was 80%. With such a low reclaim ratio, the quality of the reclaimed was
expected to be of DI quality. However, this was not found to be true. The
system that Manchester designed would require the use of resin columns to
further treat the water to obtain DI quality. Another drawback to the Manchester
system was the cost. This system was priced roughly equal to the Kinetico
system while the water quality proved to be poorer. Also due to the nature of the
RO system, no metal recovery could be utilized to offset the initial cost. Finally
an RO cleaning solution would have to be purchased to clean the membrane.
This could prove, pending upon the annual cost of the solution, to make the cost
of this system greater than the Kinetico system.
Memtek:
While a proposal has yet to be obtained from this company, the objective of
Memtek has been made known to Hadco. Memtek, while considering water
recycling technology, is also evaluating concentrated baths for an ERU system.
It is their feeling that by recovering the metals from the concentrated baths, the
generated revenue will offset the cost for the water recycling technology.
However, this approach may be a more aggressive approach than Hadco is
looking to take. In the long run, the extra plating equipment and engineering
services required to determine what could/could not be plated may end up
costing Hadco more in an initial cost than previously listed vendors.
17
When performing a cost analysis on the vendor technology, many factors had
to be considered. Most of the streams that the vendors recommended for
recycle were low TDS and Cu streams. For this reason when performing the
cost analysis the present chemistry cost was not considered to decrease with the
implementation of a water recycling system. With the implementation of a
recycling system, the present flow rates to the conventional waste treatment
system (CWTS) would be reduced, allowing for a greater contact time. In this
case the pumps would require the same amount of energy to pump water at a
lower flow rate. Therefore, the electricity cost was considered to stay the same
for the CWTS. The addition of a water recycling system would actually increase
power consumption, imposing a larger cost for electricity. In the case of an Ion
exchange system, the cost for resin replacement had to be taken in to
consideration, whereas for a reverse osmosis, the cost for membrane
replacement must be considered. The final consideration was the amount saved
from water reduction. For each recommendation given from a vendor, all these
facts were summed up and an expected payback was calculated.
One consideration when performing the cost analysis was the chemical cost.
When I first started to perform the analysis, the WWT department had no log for
chemical usage. If a specific quantity had to be known, an operator would have
to pull all prior purchase requisition forms and sum the quantities. This could
prove to be a tedious task for tracking annual usage. For this reason, I
developed a WWT chemical usage log. This log can be seen in appendix
section IB of this report. The log allowed the operators to know how much they
use of a specific chemical on a daily basis. This will also easily allow them to
track chemical usage on an annual basis.
By working with Rich Slager, (WWT operator) I was able to establish the
chemical cost to treat the water on a daily basis. By knowing this amount, I was
then able to calculate chemical cost per Kgal of water. This value could then be
compared to the national average posted by the EPA. Since most streams being
considered for recycling purposes, consist of low copper concentration, and a
TDS level, chemical cost was considered to remain unchanged when
determining chemical cost.
A second value that had to be considered when performing the cost analysis
was the sludge cost per Kgal of water. If a recycling system was designed to
remove metals from the rinse water, a sludge reduction would be observed.
Again, prior to performing these calculation Hadco TCI did not know their sludge
cost per Kgal of water. By contacting Franklin Environmental, I was able to
obtain the pricing matrix for sludge removal and treatment. These values could
be used in the future to perform cost analysis if deemed necessary.
18
V. Mecer System
The Mecer system, designed in Sweden by Sigma Maeb Corp. is an on site
etchant recycling system. The system is specifically designed to treat
ammoniacal etchant. The theory behind the machinery is the copper in the
19
spent etch and rinse water would be plated out using an Electrowinning unit.
Various chemistries are required to remove the copper from the spent etch and
water. A schematic of this process can be seen below.
As you can see from the schematic, an organic solution is used to remove the
copper from the etchant. The copper depleted etchant is then returned to the
etcher for reuse. The organic is then combined with the rinse water, and the
copper is removed from the rinse water. The copper depleted rinse water can
then be recycled to the etcher for reuse. The organic solution containing the
copper from the etchant and water is then mixed with sulfuric acid to produce
copper sulfate. The copper sulfate is then sent off to the electrowinning process
for copper recovery. While this system is designed to replace the contemporary
feed and bleed system, fresh etch must still be added to the etcher by the use of
a density meter to maintain proper operation parameters. However, the amount
of fresh etch required would be reduced by 80-90%.
20
Hadco TCI experienced many problems as a result of the implementation of
the Mecer system. The first problem experienced was due to flow imbalances
upon start up of the system. This was followed by dendrite formation in the
electrowinning unit. The copper spike built up between the anodes and
cathodes would cause the system to short out. Another problem experienced
was resist lift from the boards. This problem was experienced due to Hadco
using this system for inner layer etching as well as outer layer etching. Chronic
alarms posed a serious problems with this unit. Alarms constantly called for
etch/water to be added or removed from the system. A copy of the Mecer alarm
log can be seen in the appendix section IIA of this report. As can be seen from
the alarm log, this unit required constant monitoring by Hadco personnel. The
system was also shipped with a defect in the electrowinning unit. The fiberglass
casing had a crack in it, causing the unit to leak and trigger alarms. However, it
should be noted that Hadco was not alone in experiencing these problems with
the Mecer system. Over the course of my evaluation, I contacted companies
both domestic and overseas (overseas companies were limited to European) to
obtain their perspective of the Mecer system in its daily operation. The
companies consisted of:






Circo Craft (Canada)
Ericcson (Kumla, Sweden)
H&L Electronics (Atlanta, Georgia)
Praegitzer (Washington)
Printed Circuit Corporation (Woburn, Mass.)
Spei-Orion (Italy)
Out of all the companies I contacted, 100% of the companies experienced
problems with dendrite formation in the electrowinning unit. Some companies
after a year of operation still experience this same problem. Out of all the
companies I contacted that use this system for both inner and outer layer
etching, 100% of the companies experienced problems with resist lift on the
inner layer boards. Most companies experienced flow imbalances upon startup
of the unit, and two companies that I contacted experienced similar chronic
alarms problems as Hadco experienced. One problem that Hadco did
experience solely was the problem with fine line etching by using the Mecer
system. Hadco was the only company that has installed the Mecer and etches
below 4-5 mm lines and spaces, that I was able to discover during the coarse of
my evaluation. Therefore, it remains unknown as to whether or not the Mecer
system can reproduce etch with the quality to handle fine lines and spaces.
However to better evaluate this matter, I arranged for boards to be sent to a
company by the name of H&L electronics located in Georgia. This company has
been using the Mecer system for two years, and has the capability to etch to 4
mm lines and spaces. Upon reviewing the etched boards from H&L electronics
many interesting conclusions were drawn. All the boards etched on H&l’s etcher
were over etched. From this we concluded that in order to control a copper
21
footing, H&L slowed down the speed of their etcher. This in turn would cause for
an over etch when dealing with smaller patterns. The second item that we found
interesting when reviewing the boards, was that in certain areas, the copper had
been etched from under the resist film. This shows the same problem that
Hadco experienced when using the Mecer system.
During the coarse of my evaluation, I had the opportunity to visit Printed
Circuit Corporation (PCC) in Woburn, Mass. PCC implemented the Mecer
system in their facility two years ago. Upon start up they experienced immediate
problems with flow imbalances and dendrite formation in the electrowinning unit.
PCC also experienced problems with resist lift and chronic alarms with the
system. While it was speculated that one of the problems with the Mecer at
Hadco was due to the extended distance the Mecer was located from the etcher,
I found this to be an insignificant cause through my visit at PCC. PCC has their
system set up such that the Mecer is located a distance of 300 ft. from the
etcher. No additional problems were experienced as result of this extended
distance.
One major contrast that was found about the Mecer system as a result of this
evaluation was the level of support and service that each company received. All
European companies that I talked to about the Mecer system had no complaints
about the level of service they encountered. These companies, however,
received their support from Sigma directly. In the United States, all companies I
talked with dealt with Cognis, the US licensed vendor for the Mecer system.
Opinions on service quality varied based upon level of difficulty experienced with
the Mecer system. Those companies that only experienced problems due to
dendrite formation as a result of start up replied that service was adequate, if not
better, from Cognis. Those companies that experienced more complex
problems as a result of start-up such as flow imbalances, resist lift and chronic
alarms reported that service from Cognis was poor and unacceptable. This was
due to the lengthy time span experienced from the moment a problem occurred
to the time Cognis would arrive to evaluate and assist in correcting the problem.
Cognis in the case of EPROM’s at Hadco actually made the problem worse with
their corrections. It was admitted by a Cognis representative that visited Hadco
that during the initial stages of Cognis being a vendor that the technology was
new to them. They may not have had the proper amount of knowledge initially
required to sell and service the Mecer to US companies. As a result, US
companies implementing this technology, were limited to the quality and quantity
of service they received.
Even with the lack of experience and support from Cognis Corporation, all the
companies I contacted in the US were able to get the Mecer system to work. It
should be noted that for most companies it took at least one year to debug the
machine and get the system to work in a proper manner. The companies I
talked to in the US set up their system in such a way that the Mecer system
could be shutdown and switched over to the conventional feed/bleed system by
22
the turn of a few valves. This saved in down time as a result of plumbing
requirements to convert from one system to the other. Out of all the US
companies I talked with, 100% of the companies stated that the first year of
debugging posed many frustrations as a result of having to learn how to react to
the system and handle the resulting problems.
By reviewing the amount of spent etch used three months before the Mecer
went on-line, during the Mecer usage, and for three months after the Mecer was
turned off a percentage savings from the Mecer could be determined. It was
calculated that an 87% savings in etchant usage was experienced while the
Mecer system was in operation. This can be seen from the following graphical
representation for etchant usage over this period.
Drum Off-site shipments 93/94
14
12
# of drums shipped
10
8
6
4
2
0
11-Jan
1-Mar
20-Apr
9-Jun
23
29-Jul
17-Sep
Other factors that had to be considered were scrap due to under and over
etching, and missed deliveries. However, due to non-documented scrap figures,
the overall estimate for scrap during this time could not be determined. Since
TCI is a “quick turn” board shop, any down time experienced with the etcher
would cause late or missed deliveries. By not installing the Mecer system such
that to convert to the conventional feed/bleed system only required the turn of a
few valves, much down time was experienced. In a shop such as TCI, this was
not an acceptable result.
On a final note, 100% of the shops I talked to were able to successfully get
the Mecer system to run after at least one year of frustration and debugging. All
US companies suggested not dealing through Cognis, but rather through Sigma
Corporation directly. With the sudden decline in Cognis, the future in US Mecer
sales will rely solely on Sigma Corp. in Sweden, or the development of a new US
licensed vendor.
It is my recommendation that Hadco Corp. take a slow approach to the Mecer
system. I recommend that Hadco waits to consider implementing a new Mecer
system until a new US distributor has been established. The reason for this
recommendation is based upon the required amount of service this unit will
require when installing and initially operating. Without a US vendor, I do not feel
that Hadco would receive the level of support needed to successfully start up the
Mecer system. Pending a new vendor is found, I would recommend that Hadco
try and implement a new Mecer system under the following conditions:

An individual is dedicated to the system as a sole project until installation
and continuous successful operation has been obtained.
 A contract be negotiated such that Technical Assistance be provided
when ever necessary, and on-site service provided without extenuous
delays.
 The system be given at least a year and a half to allow for all bugs to be
worked out and operational parameters to be established.

The system be installed in such a way that to convert from the Mecer to
the conventional feed/bleed requires nothing more than the turn of a few
valves. This set up would minimize down time experienced as a result of
the Mecer system.
24
VI. Mister
Hadco Corp. uses an ammoniacal etch to etch copper off the printed circuit
board. Conveyerized rollers are used to carry the board through the etcher. On
the front of the etcher, a spray is used for two purposes. The first purpose is to
knock down any ammonia fumes that may be escaping the front of the etcher
that would pose a health hazard to plant operators. The second purpose is to
clean any residual etch off the rollers that would damage the board. The
problem that Hadco is experiencing with the mister, is that spent etch is escaping
out of the chamber inside the etcher and mixing with spent mister water. The
mister produces, at the present time, 220 gallons per day to be sent to waste
treatment. If the spent mister water contained no etch, it could be treated in the
CWTS without further problems. However, since etch is mixing with the water,
the water now has a copper level of 1776 ppm. The mister is presently plumbed
to the non-chelated batch tank so that the spent mister water, containing etch
can be treated in the Romar reactor. While this system works to treat the water,
the large amount of water that needs to be treated on a daily basis does not
allow for other waste to be treated. The result was an excess amount of waste
that had to be shipped out at a large expense.
The approach to this project was to evaluate first-off why the etch was
entering the mister chamber. By meeting with the technician for the etcher, it
became clear that by the design of the machine, etch was going to spill into the
mister chamber. The next step was to see how other Hadcofacilities using the
same equipment were handling this matter. By talking with the Steve Raper
(environmental engineer) at Hadco Hudson, I was able to determine how they
handled spent mister water. After visiting the Hudson facility, I had a basis for
comparison between Hudson’s etcher and the etcher at TCI. I found that the
etcher at Hudson was only using 12 GPD of water and was vented slightly
different than etcher at TCI. After examining the mister on the TCI facility, it was
found that one of the atomizers(spray nozzles) was not functioning properly and
was releasing more water than expected. By reviewing this information with the
Dave Pratt, (process engineer at TCI) we were able come up with four affirmative
25
actions that could be taken to control the problems being experienced with the
present mister setup. These actions included:




Placing new, smaller if possible, atomizers on the mister
Placing a flow restrictor on the feed to the mister
Setting the mister to run on the board sensor located on the front of the
etcher
Possibly reusing some of the spent mister water to control chloride levels
in the etcher
A flow restrictor set for 1 gpm was next placed on the mister feed to control the
amount of water. This in turn reduced the quantity of water to 150 gpd. A
second flow restrictor was then installed set for 0.5 gpm. At the same time new
atomizers were installed to replace the defective ones. This then reduced the
flow rate to 73 gpd. The next step in this project will be to attach the mister to
the board sensor located on the front of the etcher. It is expected that the board
sensor will reduce the water consumption by 1/3, thus reducing the mister flow
rate to 50 gpd. This was the targeted goal at the beginning of this project. A
flow of 50 gpd, could be treated in house without further complication to WWT.
For a cost analysis on this project, I first calculated what it would cost to run
the mister 24 hrs/day, 7 days a week at the 200 gpd flow rate. The cost break
down for the mister breaks down into two categories. The first is the chemical
cost to treat 700 gpw of spent water, while the second category consists of the
shipping cost to ship out the remaining spent water. The two tables below show
the breakdown for these costs.
Chemical Costs
Chemical
Quant.
(lb/day)
377.6
TOTALS
Chemical
(Cost/lb)
Total
Cost/Day
209.1415
Total
Cost/Yr
74245.23
Shipping Costs
# of drums/wk
13
Cost to ship drum
250
Cost/wk
3250
TOTAL EXPENSE : 243,245.20 / Yr.
26
Cost/yr.
169,000
This large expense and damage to WWT is the present reason for the mister
not being used. With the planned modified changes to the mister, a new cost
was then calculated. This can be seen in the below table.
Future Expected Costs
Amount Mister Water
(GPD)
50
Chemicals
Cost/day
52.58
Total
Cost/yr.
18,559.40
TOTAL EXPENSE : 18,559.40
These changes produce a tremendous cost avoidance of $224,685.80/yr as
can be seen from the above tables. The changes will allow Hadco to operate the
mister in a cost effective manor while at the same time not placing a tremendous
burden on WWT.
27
VII. Diffusion Dialysis
Diffusion dialysis is a process used to reclaim spent acid from concentrated
baths. The process was reviewed for implementation on Hadco’s solder stripper.
Hadco purchases solder strip from MacDermid Corp. under the trade name of
Eliminator III. The solder stripper uses a 25% by weight nitric acid to remove a
Sn/Pb solder from the circuit boards. The remainder of the Eliminator III consists
of a proprietary mixture. A schematic of the diffusion dialysis setup can be seen
in the below diagram.
The theory behind diffusion dialysis is that spent acid will be placed in contact
with one side of an anionic ion exchange membrane. Simultaneously water is
placed into contact with the recovery side of the membrane. The majority of the
acid migrates through the membrane into the water, leaving contaminants and
28
heavy metals behind. The purified acid would then be returned to the process
tank for reuse, while the concentrated contaminant and metal stream would be
sent for metal recovery or to WWT.
At the present time MacDermid Corp. is testing this technology on Hadco’s
spent solder strip. MacDermid is developing a replenisher solution that would
have to be added to the recovered nitric acid to account for the rest of the
proprietary mixture that was lost as a result of passing through the membrane.
By talking with a MacDermid representative, I was able to evaluate the
present status of this project. I was able to learn that MacDermid has been able
to successfully recover 80% of the spent nitric acid out of the solder strip. They
are now designing the replenisher that would be required for the recovered acid.
Pending completion of this, MacDermid will test the recycled Eliminator III on
Hadco’s solder strip to insure that Hadco can maintain a high quality level of
operation.
At the present time it was calculated that Hadco will purchase 38 drums of
Eliminator III for the entire year of 1996. This would produce an annual cost of
$19878 to purchase the mixture, and $7,332 to dispose of the spent solder strip.
This yields a combined cost of $27,210/yr. With the recovery of 80% of this
spent solder strip Hadco would save $21,768 before including the cost of the
replenisher solution. A cost analysis can be performed when the cost for the
replenisher solution becomes known to Hadco.
By contacting Pure Cycle, a vendor for diffusion dialysis, it was determined
that Hadco would require a 5 gpd system to recover the spent solder strip. The
cost for a system of this size is $8,800. Cost effectiveness for this machine will
be decided upon completion of successful testing of MacDermid recycled solder
strip on Hadco’s solder stripper.
29
VIII. Appendix
30