THE OPTIMUM CONDITION OF MANUFACTURING A SMOOTH ENGINEERED SURFACE USING THE INTERNAL-IRONING PROCESS

Internal-ironing is a newly developed process for making a smooth surf ace by replicating the tool roughness onto the workpiece. A simple but useful slab analysis is proposed to investigate the influences of ope rational conditions, such as reduction, die angle, and friction on the asperity flattening. A new sheet metal forming tribometer is designed to simulate the internal-ironing process. Different lubricants, reduc tions, and ironing speeds an used in the experiments. The experimental results confirm that the theoretical model is successful in analyzing the smoothing effect. The optimum replication (minimum roughness) tak es place at a moderate reduction of about 30 percent when the roughnes s lays (texture fines) of the workpiece are parallel to the ironing di rection, well lubricated on the ironing die and unlubricated on the re plication side.