An environmental impact analysis of grinding

Abstract

This thesis was intended to investigate the environmental impact of grinding in the United States manufacturing industry. Grinding is an ideal method for producing parts with a fine surface finish and high dimensional accuracy and for shaping hard or brittle workpieces. There are a wide variety of different types of grinding machines, each with different applications and slightly different energy requirements. Workpieces are generally flooded with a stream of coolant while being ground or placed in a spray of coolant mist. Coolant recycling systems are used to filter ground off chips out of coolant and to remove foreign oils and bacteria which pose health hazards. Oil mist collectors both clean mist coolant and prevent the toxic coolant from being inhaled by machinists. In total, 63 *10¹⁵ joules of energy are consumed per year by grinding in manufacturing, 57% of which is directly used in material removal. A total of 1.5*10¹⁰ pounds of scrap chips, spent grinding wheels, and used filters are produced each year as a result of grinding, over 99% of that being scrap chips. About 2.3 million gallons of fluids per year of grinding fluids are incinerated. Grinding creates a significant environmental footprint, creating a need for methods to reduce energy use in grinding and for ways to recycle solid waste that would otherwise be sent to landfills or incinerated.