The ability to manufacture accurate parts in single point incremental forming is dependent on the capability to properly predict accuracy response surfaces of individual features and feature interaction combinations formed using uncompensated tool paths. Recent studies show that the accuracy profiles obtained are dependent on the choice of material used for forming, in terms of magnitude, geometric shape and nature of errors (under forming and over forming). In this paper, an attempt is made to capture the effect of material properties on the accuracy response surfaces. The response surfaces are modeled using Multivariate Adaptive Regression Splines (MARS), which is a non-parametric multivariate regression technique that helps generating continuous response surfaces. The MARS functions are based on process and feature specific geometric parameters. A set of features and feature interactions for which the response surface dependence on material properties is well predicted is used to illustrate the applicability of the MARS method for predicting the accuracy. An in-process stereo camera system is used to measure the displacement fields for different materials using digital image correlation (DIC) and understand the material dislocation mechanism. Improvements in accuracy for different sheet metal materials based on the predicted response surfaces are then discussed.

In this work, a numerical model simulating friction hysteresis for lubricated rough and textured surfaces in contact is presented. Friction hysteresis occurs in sliding contacts that are subjected to a non-constant (e.g., sinusoidal) motion. It refers to the phenomenon where the observed friction force during acceleration differs from that during deceleration. Besides the dynamics of the sliding system, a classic mixed friction model is adopted, in which the transient Reynolds equation for the description of the thin lubricant film is combined with a statistical Greenwood–Williamson model for the description of rough surface asperity contacts. The model enables the prediction of the friction hysteresis for predefined contact descriptions (i.e., surface profile and roughness, lubricant, etc.) and allows the study of the physics and parametric influences of dynamically sliding contacts. In this paper, it is shown that (i) friction hysteresis is captured by classic transient models for mixed lubrication; (ii) system parameters, such as roughness, applied load, viscosity and velocity, including the offset, amplitude and motion reversal, influence the shape and area of friction hysteresis; and (iii) the selection of the aforementioned parameters may minimize friction hysteresis.

Many parts require high strength materials, exhibiting high temperatures or where formability should be reduced, requiring new processing technologies. The application of hybrid manufacturing processes can answer the needs. This paper gives first a classification of hybrid manufacturing processes, followed by a description of various productivity improvements. The latter is also demonstrated by various examples in cutting, grinding, forming and chemical & physical processes like EDM, ECM and laser.