The Indiana Clean Manufacturing Technology and Safe Materials Institute
2655 Yeager Road, Suite 103, West Lafayette, Indiana 47906-1337
ELECTROCHEMICAL COATINGS INCORPORATED
POLLUTION PREVENTION TECHNICAL ASSISTANCE
Electrochemical Coatings Incorporated (ECC) initiated a project with the Indiana Clean Manufacturing Technology and Safe Materials Institute (CMTI) to identify possible causes of rework in ECC’s automatic lead plating process. Eliminating the cause of the rework will save time and money as well as reduce the use of chemicals used in processing.
ECC is a nationally-known manufac-turer of high quality, lead-plated conductors and connectors for the battery industry. ECC is regarded as the premier lead-plating facility in the nation. The company is one of twelve Indiana electroplaters that are participating in the United States EPA Common Sense Initiative Strategic Goals Program for Metal Finishing. The company is located in Lebanon, Indiana, and employs approximately forty-eight people.
ECC's automatic lead plating process is a rack plating process. Copper parts awaiting lead plating are hung on racks designed for that particular part’s size and shape. The rack’s design allows the parts to become cathodes in an electrochemical lead-plating bath. The cathodic state of the copper part allows it to attract lead ions (which are in the bath solution). The attracted lead ions form a lead plate over the copper part. Prior to entering the lead-plating bath, the copper parts go through several cleaning and pickling baths to properly prepare the parts for the lead plate. Upon exiting the lead-plating bath, the parts are rinsed and hot-air dried. Then the parts are inspected and removed from the rack and transferred to the next processing station.
ECC also employs manual lead-plating rack and barrel processes at the Lebanon facility.
The parts requiring rework from the automatic lead plating process increase hazardous waste production by an estimated fifteen percent. These parts must be plated again in order to be acceptable for shipping. Replating is accomplished during the manual plating process, which has a higher lead exposure risk factor than the automatic plating process. Eliminating the factor (or factors), that result in rework, from the automatic lead plating process, will greatly reduce or eliminate the additional hazardous waste generation and reduce exposure risk potential.
Identifying the factor or factors responsible for the rework was the first challenge. Determining how to eliminate or minimize these factors, was the second challenge. The third challenge: the implementation of procedures that would eliminate the rework factors.
The CMTI/ECC team tackled the first challenge by observing the automatic process in operation and asking personnel appropriate questions regarding the controlling factors that resulted in parts requiring rework. Two rework factors were identified: (1) faster part drying time and (2) rinse water criteria (which focussed on cleanliness and dwell time).
The team utilized ECC's laboratory and set up miniature rinse tanks containing water from the plating process rinse tanks, water directly from the tap, and D. I. (deionized) water. Parts were removed from the plating racks immediately after undergoing the lead plating process and were rinsed in the various rinses set up in the plating laboratory. Parts were also allowed to air‑dry.
The rinsing technique test in the laboratory indicated that rinse cleanliness was the most important factor. All rinses after the lead plating bath should be maintained in an optimally clean condition; however, the rinse immediately following the lead plating bath was found to be the most critical. Based upon these results, the ECC/CMTI team recommended that the company continuously monitor and maintain the rinse tanks following the lead plating bath in an optimally clean condition. The team also recommended counterflowing the rinse water in order to save water and reduce wastewater volume. The first rinse immediately following the lead plating bath should receive the fresh water, and the overflow from it should go to the subsequent rinse tanks. This countercurrent discharge should lead to the last unheated rinse, which should discharge directly to waste water treatment. It is also strongly urged that the rinse water from the final heated rinse tank be emptied, cleaned, and recharged on a weekly basis.
POTENTIAL ENVIRONMENTAL AND COST BENEFITS
It is conservatively estimated that by changing rinsing criteria, rework could be reduced by ninety percent. As previously stated, rework increases labor and hazardous waste production by an estimated fifteen percent. Therefore, it is estimated that F006 hazardous waste will be reduced by 13.5 % (90% x 15% = 13.5%). Furthermore, labor costs, hazardous waste disposal costs, and raw chemical costs will be reduced by 13.5%. Rinse criteria changes are estimated to accomplish the following:
Estimated F006 hazardous waste
reduction (yearly): ........... 2000 pounds
Estimated savings (yearly):
Labor cost reduction ............... $18,900
Waste cost reduction ................. 2,000
Chemical cost reduction ........... 16,875
Total ........................................ $37,775
Estimated costs (one time):
Counterflow rinses .................... $1,500
Total .......................................... $1,500
Estimated payback period ....... less than 1 mo.
ECC’s automatic lead plating process creates rework due to inadequate rinsing and drying. By implementing the improved rinsing/drying techniques, ECC will eliminate the need for replating unacceptable parts. These improved techniques will reduce ECC's chemical usage and hazardous waste production by making the automatic lead plating process more efficient—thereby, accomplishing cost and waste reduction through pollution prevention.