A review of methods and effects for improving production robustness in industrial micro-deep drawing

Deep-drawing is a method in which flat sheets of metal are formed into complex 3-dimensional geometries. Three main types of challenges arise when transitioning from the macro-scale to micro-deep drawing. These can be summarised as: (1) tribological effects, which mainly stem from the relative difference in surface characteristics between the two size scales, (2) material behaviour effects which arise from the increasing heterogeneity of materials that have a decreasing number of grains that are deformed in forming, and (3) dimensional effects which relate to difficulties in handling and inspection of small components at high rates and challenges in manufacturing and monitoring of tool components for use in micro-deep drawing. Various methods or effects can be applied to micro-deep drawing processes to tackle these challenges. This paper reviews research on methods and effects that can be used to improve the robustness in micro-deep drawing processes. Small changes, such as the choice of lubricant and slight changes to the punch geometry are considered, but so are larger changes such as the use of ultrasonic vibration to improve formability and adjustable tooling. The influence of process monitoring and simulation on process robustness is also considered. A summary of methods and effects is drawn at the end to highlight potential space for innovation.