In the modern automotive industry, the maintenance of the vehicle during its life cycle is increasing in importance due to both economical and environmental considerations. A new frontier is the reparation of large parts, originally made by fusion, by the addition of material. The standard technique in the field is the use of TIG welding, but in the last few years Cold Dynamic Gas Spray (CDGS) has started to show many promises in supplanting TIG repairs. The main advantage of CDGS is the absence of thermal stresses in the repaired zone with the elimination of thermal distension treatment of the part. In this paper we study the use of CDGS to repair wear damage on a commercial aluminium engine block in comparison with the standard repair procedure with TIG. The result obtained shows that CDGS is an effective technology for industrial-level repair.

The influence of the dynamic behaviour of the machine tool/workpiece system on the surface accuracy plays an important role in finish machining. In particular, the machine tool/workpiece dynamics determines the topography of the machined surface, which is crucial in determining the quality and performance of a mechanical part. A model to predict the dynamic effects of the cutting process in turning, as part of a machining simulation framework, is presented in this paper. Thermally, kinematically and dynamically induced errors can be easily implemented into the proposed model. Finally, several examples of the use of this model under different turning conditions are presented and compared to typical machined surfaces. The proposed model can effectively compute the roughness, form and dimensional accuracy of a turned surface.