Three-dimensional quantification of the manufacturing defects for tolerances analysis

Purpose - The purpose of this paper is to present an experimental approach to measure and quantify the three-dimensional geometrical manufacturing errors on a mass production of parts. Design/methodology/approach - A methodology is developed to model and analyse the combined effect of these errors on a machined feature. Deviation of a machined feature due to the combined errors is expressed in terms of the small displacement torsor (SDT) parameters. Given a tolerance on the machined feature, constraints are specified for that feature to establish a relationship between the tolerance zone of the feature and the torsor parameters. These constraints provide boundaries within which the machined feature must lie. This is used for tolerance analysis of the machined feature. An experimental approach is proposed to measure and quantify the three-dimensional manufacturing variations as torsors. The results are used to verify the analytical model. Findings - Results show that it is possible to quantify manufacturing dispersions. The paper proposes a measuring method which can be done during the production. In the context of process planning, these experimental data allow us to perform realistic geometrical simulation of manufacturing. The results of this method are torsor components dispersions. Analysis and synthesis of the geometrical simulation of manufacturing are viable with reliable numerical data in order to predict the defects. Originality/value - To perform realistic geometrical simulation of manufacturing, an experimental approach to measure and quantify the three-dimensional geometrical manufacturing errors is proposed which is based on the SDT concept.