Environmental Impact Reduction for a Turning Process: Comparative Analysis of Lubrication and Cutting Inserts Substitution Strategies

Machine tools are responsible for a relevant share of environmental impact related to production processes. This is due to their widespread use, the huge energy requirements during operations and the disposable materials involved in the process like scraps, cutting inserts and exhausted oil. This study presents a holistic analysis of the main contributions that are responsible for the environmental impact of the process and the use of the analysis's results to optimize the process setup for a specific case. The factors included in the analysis are: cutting parameters, lubrication strategy and cutting inserts substitution. Regarding the cutting parameters choice, the analysis of the tests carried out highlighted that the best solution is to use the most demanding process parameters in terms of material removal rate, using the tool strength as a constraint. The comparison of alternative lubrication strategies shows the advantage of using dry machining, to be replaced with MQL only when hard-to-cut materials must be machined. Finally, the approach developed to assess the environmental footprint associated to the cutting inserts allowed to define a new substitution rule. The obtained solution is consistent with the usual industrial practice to change the tool when the geometrical tolerances could not be meet anymore, this result is due mainly to the high environmental impact of the production phase of the insert.