REDUCING WASTE WITHIN THE HIGH PRECISION MANUFACTURING INDUSTRY TO ACHIEVE UK NET ZERO AND SUSTAINABILITY TARGETS. A CASE STUDY: ELE ADVANCED TECHNOLOGIES.

Abstract

High precision manufacturing (HPM) generates large amounts of waste material due to relying on subtractive manufacturing (SM) processes, such as grinding and electrical discharge machining (EDM). Finding ways to optimise resource use and waste management for these processes is essential to improving the sustainability of the HPM sector. This research used the HPM company ELE Advanced Technologies as a case study. Grinding wheel use was monitored over a three-month period by measuring the remaining diameter of spent wheels. During this time, all grinding operators (n = 32) received a questionnaire designed to identify barriers to efficient resource use. Additionally, contaminants within waste dielectric fluid from the EDM process were removed using filtration and centrifugation. Fluid samples were classified as ‘untreated’, ‘filtered’, ‘centrifuged’, ‘filtered and centrifuged’ or ‘clean’. Sample absorption values and microparticle sizes were analysed using UV-Vis and DLS, while the elemental composition of the contaminants was determined using SEM-EDS. GC-MS identified the hydrocarbon structures that composed each sample. During wheel monitoring, very few wheels achieved their minimum diameter (11.11%), lack of appropriate training for grinding operators and insufficient provisions for wheel re-use were the main reasons for this. If grinding operators adopted sustainable behaviours, between 1.8 - 6.0 tCO2eq emissions could be saved annually. For EDM, the pollutants chromium VI and nickel II were identified at concentrations of 7.33 mg L-1 and 9.40 mg L-1 respectively. Centrifugation was the most effective contaminant removal method. ‘Centrifuged’ samples displayed a significantly lower absorption value at the wavelength maxima than ‘filtered’ (p<0.001). Hydrocarbon structures remained consistent between samples. Overall, the culture at HPM companies affects their carbon footprint and sustainability. Implementing appropriate training and providing opportunity for employees to display sustainable behaviour results in less material waste. For unavoidable waste, removing contaminants can lower the polluting risk and increase opportunity to re-use the waste. These steps improve HPM company’s sustainability and reduce their carbon footprint.