1996 NH Pollution Prevention Internship Program
Internship Project Final Report
September 8, 1997
Project Title:Examining the Usage of Lead-Free Solder, No-Clean/VOC-Free Flux and No-Clean Solder Paste in the Manufacturing of PCB’s; Along with several side projects
Intern:David A. TeixeiraPhone: 603-868-9764
Facility:Cirtronics Corporation
PO Box 130, Elm Street
Milford, NH 03055
Contact Person:Jon BatesPhone: 603-654-6125
Production Coordinator
Table of Contents
Executive Summary3
Introduction3
Objectives3
Methodology4
Chemical Usage/Equipment Needs5
Releases/Waste Generated6
Results6
Pollution Prevention Benefits9
Future Efforts10
References10
Appendices11
Executive Summary
Cirtronics Corporation is an assembly house for printed circuit boards (PCB’s). In an effort to reduce waste and become a more environmentally “friendly” facility several pollution prevention (P2) projects were undertaken this past summer. These projects included a search into the use of lead-free solder, no-clean/VOC-free solder and no-clean solder paste, evaluating the efficiency of the current lighting system, locating a vendor for the reuse and recycling of toner cartridges, determining a means of recycling integrated circuit (IC) tubes and researching the options for implementing a conformal coating process. Samples were obtained for lead-free wire solder, no-clean/VOC-free flux and no-clean solder paste. Only the no-clean solder paste was able to be tested. The paste was tested on fourteen boards for a customer and met with the customer’s approval. Evaluation of the lighting system revealed a possible reduction of 51457 kWh/yr. This energy reduction could lead to a reduction of 5% in the amount of greenhouse gases, produced by Public Service of New Hampshire (PSNH), that can be related to Cirtronics. Quality Re-Inking was established as the vendor for the reuse and recycling of toner cartridges. The ground-work was started for the establishment of a consortium for the collection of IC tubes within the state of New Hampshire. Finally, the recommended means for conformal coating was concluded to be the use of a 100% solids coating applied via an automated spraying system.
Introduction
Cirtronics Corporation is a contract manufacturer of printed circuit boards (PCB’s). Manufacturing is divided between turn-key and consignment, with roughly sixty percent (60%) turn-key and forty percent (40%) consignment. The majority of Cirtronics products employ mixed technology. Mixed technology describes the process of producing PCB’s with both surface mount technology (SMT) and through-hole technology. Cirtronics is located in Milford, New Hampshire and is composed of approximately one hundred employees.
Objectives
The project initially consisted of four goals. The goals included researching, evaluating and possibly experimenting with lead-free solder, no-clean and VOC-free flux and no-clean solder paste, and examining the current artificial lighting system. As time progressed additional goals were incorporated into the project. The additional goals included locating a vendor for the reusing and recycling of printer ribbons and toner cartridges, establishing alternative methods for the removal of integrated circuit (IC) tubes and researching the requirements, feasibility and most environmentally “friendly” means of adding a conformal coating process.
Note: Without the use of no-clean products the manufacturing of PCB’s require a washing step to remove residue and active chemicals. At Cirtronics this washing step is provided by an aqueous cleaner.
Methodology
Researching, evaluating and the possible experimentation of lead-free solder, no-clean/VOC-free flux and no-clean solder paste were the primary goals of the project. A literature review and internet search of lead-free solder, no-clean/VOC-free flux and no-clean solder paste was performed in order to become familiar with the availability, variety, positive and negative aspects of each product and any possible additional equipment that may be required. Once the literature review and internet search were completed the appropriate vendors were contacted and asked for information on and samples of their desired product(s).
Included in the researching of lead-free solder and no-clean/VOC-free flux was one week spent training on the wave machine. The training allowed for a greater appreciation and understanding about how the effects that different fluxes and solder alloys have on the production of PCB’s.
The idea for examining the efficiency of the artificial lighting system at Cirtronics was initiated through a meeting with representatives from Public Service of New Hampshire (PSNH). The meeting was set-up due to PSNH supplying a portion of the funds required for the inclusion of a Pollution Prevention Intern at Cirtronics. During the meeting it was learned that PSNH supplied a free evaluation of artificial lighting systems. A time and date was established for an EnergyCHECK Engineer to visit the facility. The visit consisted of dividing the facility into specific areas and determining the type of artificial lighting and the amount of time the artificial lighting was in usage within those areas. This information was then entered, on site, into a computer program. The program produced three energy saving options for each specific area, providing alternative lighting fixtures and bulbs and an estimated return time on the cost of the change ( the return time included an estimated cost of labor). Option consisting of the shortest return time of the three was then selected. PSNH supplied a final report, which included a summary of the optimal options.
In locating a vendor for the reusing and recycling of toner cartridges and printer ribbons several were contacted. The vendors were then evaluated base on their ability to refill toner cartridges, re-ink printer ribbons and the cost of the service.
The first step taken in establishing alternative methods for the removal of IC tubes was determining the type of plastic the tubes were constructed from. Melissa Waleryszak, Pollution Prevention Specialist from the NH Department of Environmental Services, provided this information. In was concluded that the majority of the IC tubes were of type “3” plastic, or polyvinyl chloride (PVC). Melissa also provided information on producers of PVC products. “WasteNotes” was also searched for possible consumers of PVC. Finally an employee of Cirtronics was able to locate a recycling company in North Carolina.
The initial step taken in locating information on conformal coating was a literature review and internet search for information on the process. The next step was contacting the previous company contracted by Cirtronics to provide the conformal coating process and a customer currently using a conformal coating process. Vendors were contacted as well.
Chemical Usage, Equipment Needs
Table 1
Product / Chemicals / Cas Number / wt % / Equipment NeedsLonco 373 Additive / Isopropyl Alcohol / 67-63-0 / 99+ / Wave Machine **
Lonco Neutral Flux 373 / Isopropyl Alcohol,
Glycerine / 67-63-0
56-81-5 / 83
3 / Wave Machine **
Alphametals SMT-Core Plus Solder Wire / Hydrogenated Rosin (Flux) / 65997-06-0 / 1-3 / Soldering Iron
Alphametals Pure Core Wire Solder / Rosin Amine (Flux) / 51344-62-8 / < 2 / Soldering Iron
Kester “331” Flux Cored Solder / Carboxylic Acids,
Polyglycol Vehicle / 68937-68-8
25322-68-3 / < 1
< 3 / Soldering Iron
Alphametals Aqualine WS-609 Solder Cream / Beta Terpineol,
nonionic Surfactant / 8000-41-7
68439-49-6 / < 5
< 5 / Stencils, Squeegee and Reflow Oven*
* = Heller 1500 Reflow Oven
** = Dover-Soltec Wave Soldering Machine Model 6521CC
Releases/Wastes Generated
Table 2
Waste Generated / Source(s) / RateSolid Hazardous Waste
-Lead Clippings
-Soldering Sponges
-Solder Contaminated Clean Wipes / -Universal VCD, Amistar A1-800 Axial Inserter and Work Stations
-Work Stations
-Print-Perfect-System (Solder Paste Application) / 1 drum/yr
Hazardous Liquid Waste
-Outdated Flux and Thinner / -Work Stations, SMT area and Wave Machine / 1 drum/yr
VOC Emissions (2-Propanol) / Wave Machine Fluxing Unit / 10 lbs/yr
Drum = 55 gallons
Project Results
Lead-Free Solder: The literature review and internet search revealed no lead-free substitute alloy equivalent to lead-based solder. Alternatives for lead include silver, bismuth and indium. If the electronics industry were to consume silver and bismuth on a major level, the world supply would come into question (Litton Industries). Additionally bismuth is a lead-ore by product and contributes to brittleness (Litton Industries). Indium forms a weaker alloy with poorer corrosion resistance when used in significant concentrations (Litton Industries). Finally, most alternative alloys are not compatible with the standard 60/40 tin-lead alloys, which would lead to difficulties in repair work (Cross Talk).
Despite the numerous drawbacks a sample of lead-free/no-clean wire solder from Alphametals was ordered. The alloy composition is 96.5 tin and 3.5 silver.
No-Clean/VOC-free Flux: The literature review and internet search of no-clean/VOC-free fluxes revealed a 15 lbs/day of VOC emissions allowed by the EPA for manufactures of PCB’s (Scheiner). It was calculated that in a worst case situation Cirtronics generated approximately 10 lbs/day of VOC emissions. Despite falling under the legal limits for VOC emission the effort to locate a no-clean/VOC-free flux continued. During a site visit to one of Cirtronics customers it was learned that the customer currently used a no-clean/VOC-free flux in their wave soldering operations and had very little difficulty in switching over to the no-clean/VOC-free flux. Based on the recommendation of this customer two samples of no-clean/VOC-free flux were ordered from Alphametals.
No-Clean Solder Paste: After concluding the literature review and internet search samples of no-clean solder paste were ordered from three different vendors. The vendors consisted of Kester, Alphametals and ESP. It was decided to seek the permission of one particular customer to test the pastes on their product. This customer was determined because they have a particular PCB model that does not require the use of wave soldering due to a lack of through-hole parts. Therefore, this would lead to these particular boards from being rinsed in the aqueous cleaner.
The customer was contacted and gave permission to run test with the sample from Kester only. Fourteen PCB’s were processed with the no-cleans solder paste from Kester. The PCB’s were then sent to the customer and met with their approval.
Lighting Efficiency: In the final report presented by PSNH it was concluded that if all the optimal options selected were installed at Cirtronics there would be an energy savings of 51457 kWh/yr. A reduction of this magnitude, as shown in table 3, would lead to a reduction of 5% in the amount of greenhouse gases produced by PSNH that are a result of supplying energy to Cirtronics.
Table 3
GreenHouse
Gases / Emissions Factor from Marginal Station [lbs/kWh] * / Energy Consumption [kWh/yr] / Emissions Generated
[lbs/yr] / kWh/yr saved / Reduction
[lbs/yr] / Percent Reduction ***
CO2 / 0.17 / 434988 / 73948 / 51457 / 8748 / 5%
SO2 / 0.0016 / 434988 / 696 / 51457 / 82 / 5%
NOx / 0.000367 / 434988 / 160 / 51457 / 19 / 5%
* Marginal Station is least efficient power station in use by PSNH
*** Assumed only 40% of power derived from green house producing plants
(60% of PSNH power derived from Nuclear) Power Plants)
Note: Emissions Factor data provided by Robert S. Leatherbee, P.E., C.E.M.; Senior Engineer for PSNH.
Toner Cartridge Reuse and Recycling: As stated before, several vendors were contacted. Only three responded, from these three Quality Re-Inking out of Clairmont, NH was chosen. The reason for this selection, as shown in table 4, was the fact that Quality Re-Inking was the only vendor, which supplied services for refilling toner cartridges and re-inking printer ribbons.
Table 4
Re-ink: add ink to existing ribbon fabricReload: add toner to cartridge
Current Cost for new ribbons and toner kits / Quality Re-inkingContact: Walt Gobin
Phone: 603-542-2811 / Reliable Technologies, Inc.
Contact: Mike Lambert
Phone: 800-346-7890 / Cartridge Warehouse
Contact: Norman Head
Phone: 603-679-8690
Epson 7753
(ribbon) / Re-ink: $2.00
Reload: $3.00 / New: $4.25 / New: $7.08
Okidata 590/591
(ribbon) / $12.28 / Reload & Recharge inking mech.: $3.00 / New: $9.99 / New: $9.45
Ahearn & Soper
(ribbon) / will investigate / Not Available / New: $11.58
HP LJ 5P
(toner) / $90.00 / Reman: $37.50 / New: $79.00 / Reman: $59.00
HP LJ 5L
(toner) / $90.00 / Reman: $37.50 / New: $79.00 / Reman: $59.00
Okidata 810e
(toner) / $19.95 / Reman: $15.00
Generic replacement: $18.50 / New: $22.00 (double check about new) / New: $25.00
Konica 3135/4145
(toner) / $80.00
5+ $70.00
10+ $59.00 / Not available / New: $53.00 / New: $60.70
Panafax UF-322
(toner) note: uses HP cartridge / $36.00 / Recharge: $9.00 / New: $25.00 / Reman: $14.50
Panafax UF-550
(toner) / $250.00 / Not available / New: $195.00 (double check) / New: $215.00
Panafax UF-733
(toner) / $61.00 (toner)
$380.00 (process kit: drum & developer) / Generic replacement: $29.50 / Reman: $30.35
IC Tubes: Polymer Reclaim and Exchange was the recycling company located out of North Carolina. Geoff Southworth was the contact person from Polymer Reclaim and Exchange. A meeting with Geoff Southworth, Barbara Bernstein from WasteCap and Dennis Amell of Revamp Inc. was established. At this meeting it was determined that a small company such as Cirtronics did not posses a large enough volume of IC tubes to represent a viable source of raw material for Polymer Reclaim and Exchange. Instead the first step were taken in establishing a consortium for the collection of IC tubes within the state of New Hampshire. The criterion for acceptable IC tubes was also established. IC tubes must be of type “3” plastic, contain no paper labels, stoppers or pins and must be clear or blue tinted in color.
Conformal Coating: Completion of the literature review and internet search revealed the most economical, worker “friendly” and environmentally “safe” means of implementing a conformal coating process was through the use of a100% solid conformal coating and applying the coating with a automated spraying system. The 100% solid coatings contain no solvents and therefore produce no VOC’s. An automated spraying system allows for the minimal amount of employee contact with the coating and applies the coating in the most efficient manner.
Pollution Prevention Benefits
Lead-free Solder: Reduces lead waste stream and reduces intimate contact between employees and lead-based products
No-Clean/VOC-Free Flux: Virtual Elimination of VOC emissions and reduced workload on the aqueous cleaner. The aqueous cleaner is closed-loop system, therefore there is no water waste stream. However, a carbon column and two anion/cation columns are employed for the aqueous cleaner and are properly cleaned by a vendor. A reduction in the workload of the aqueous cleaner will reduce the amount of waste generated by this particular vendor.
No-Clean Solder Paste: Reduction in workload of aqueous cleaner.
Lighting Efficiency: Reduction in pollutants generated by local power stations.
Toner Cartridge Reusing and Recycling: Reduction in toner cartridge and printer ribbon waste stream.
IC Tube Recycling: Transformation of IC tube waste stream into valuable raw material.
Conformal Coating Process: If and when the process is incorporated, the use of 100% solids coating and an automated spraying system will generate the least amount of waste.
Future Efforts
The complete conversion to a no-clean process would greatly enhance performance at Cirtronics. No-clean wire solder is already used, therefore a conversion to no-clean solder paste and no-clean flux will removed the need of the aqueous cleaner. Eliminating the aqueous cleaner removes an entire process step, reduces energy and water consumption, frees up vital floor space and eliminates waste generated from the carbon and anion/cation columns.
To assist in the efforts to switch over to a complete no-clean process the implementation of a nitrogen inerting process for the wave machine is recommended. This involves applying a nitrogen blanket over the solder wave in the wave machine. The nitrogen atmosphere removes the worry of oxidation during soldering, which enhances the performance of a no-clean flux. Along with assisting the no-clean flux, the nitrogen atmosphere eliminates dross.
The final future recommendation is the retrofitting of the wave machine with a force convection pre-heat, assuming the use of a VOC-free flux. A VOC-free flux uses DI water as thinner, without force convection a layer of super-saturated air can form above the PCB. This layer of super-saturated air prevents the complete burn-off of the DI water. If the DI water remains on the PCB when it comes into contact with the solder wave the DI water will volatilize and cause solder balls, which can lead to shorts. The force convection pre-heat will remove this layer of super-saturated air.
References
Litton Industries, Inc., Kester Solder Division, “Lead Free Alloy Position Paper”,
Cross Talk, “Lead-Free Solder? – Not Yet!”,
Scheiner, Assistant Manager, Market Technology Kester Solder Division, Litton Industries, “Manufacturing Considerations When Implementing VOC-Free Flux Technology”,
Appendices
Contact Person / Company & Title / Address / Phone & FaxAmell, Dennis / Revamp, Inc., General Manager / 8 McGuire St. Concord, NH 03301 / Tel:(603) 228-5211
Fax:(603) 228-5333
Bernstein, Barbara D. / WasteCap, Director / 122 No. Main St. Concord, NH 03301 / Tel:(603) 224-5388
Fax:(603) 224-2872
Fedock, Joe / Hi-Teck Automation Inc., Sales and Engineering Support / 4 John Tyler St. Unit F Merrimack, NH 03054 / Tel:(603) 880-9050
Fax:(603) 880-9505
Gobin, Walt / Quality Re-Inking / Clairmont, NH / Tel:(603) 542-2811
Head, Norman / Cartridge Warehouse / Tel:(603) 679-8690
Lambert, Mike / Reliable Technologies, Inc. / 55 So. Commercial St. Manchester, NH 03101 / Tel:(603) 644-2528
Leatherbee, Robert S. / PSNH, Senior Engineer / 1000 Elm St. P.O. Box 330 Manchester, NH 03105-0330 / Tel:(603) 634-2458
Fax:(603) 634-2449
Matson, Amanda / EnergyCHECK Engineer, PSNH / PO Box 330 Manchester, NH 03105-0330 / Tel:(603) 634-2894
Fax:(603) 634-2449
McCallum, Daniel R. / PSNH, Account Executive / 370 Amherst St. Nashua, NH 03063 / Tel:(603) 886-1387 Ext. 5280
Fax:(603) 886-4655
Odoardi, Jim / Jaro Corp., President / 15 Spring St. Unit 1 Peabody, Ma 01960 / Tel:(508) 532-2717
Fax:(508) 532-3533
Southworth, Geoff / Polymer Reclaim & Exchange, / 674 Gilmer St. Burlington, NC 27217 / Tel:(212) 769-4081
Fax:(212) 769-0784
Waleryszak, Melissa / NH DES, Pollution Prevention Specialist / 6 Hazen Drive Concord, NH 03301-6509 / Tel:(603) 271-6460