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|Document Type: ||Thesis or dissertation|
|Title: ||Measurement and reduction of the environmental impact of industrial photochemical machining|
|Authors: ||Ler, Leong Tat|
|Supervisors: ||Allen, David|
|Issue Date: ||Oct-1998|
|Abstract: ||This thesis concerns research into the environmental aspects of the
photochemical machining (PCM) industry, involving measurement, analysis,
benchmarking, and reducing adverse environmental impacts.
The environmental audit of a PCM company found that the likely significant
environmental impacts are the use of ferric chloride etchant, solvents and
water. A comparison of the environmental performance of two UK PCM
companies showed that there were big contrasts in etchant utilisation and
solvent and water consumption, indicating that steps could be taken to reduce
A study to assess the feasibility of using laser direct imaging (LDI), a cleaner
technology in photoresist imaging, found that LDI could meet the technical
requirements of the PCM industry. For LDI to be economically feasible, the
reliability has to be high and maintenance cost has to be low.
Audit surveys of PCM companies world-wide regarding etchant utilisation and
solvent consumption indicated that:
(1) There is a vast difference between the performance of companies and
companies that regenerate etchants were more efficient in their FeCl3
utilisation. The industrial best practice for FeCl3 utilisation is 837%.
(2) Chlorination was the most popular regeneration method but most
companies would use a more environment-friendly system at a higher
overall cost. Regarding waste disposal, most companies sent liquid waste
etchant for reclaim or recycle.
(3) Half of the PCM companies no longer use solvents, and with the
development of liquid aqueous-based resists, it is envisaged that PCM
practitioners could eliminate the use of solvents in the near future.
Lastly, an investigation into the feasibility of using oxygen gas in regenerating
FeCI3 showed that the regenerated etchant could produce good quality
etchings. This syst'm is also the second cheapest. Therefore, it is a good
option for the PCM companies as the cost of regeneration is not too expensive
and it is environment-friendly.|
|Appears in Collections:||PhD, EngD and MSc by research theses (School of Applied Sciences)|
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