THE 3-D CHARACTERIZATION OF THE SURFACE-TOPOGRAPHY OF THE BALLIZING PROCESS

Engineering surfaces are produced by a large number of manufacturing p rocesses and once the processing is complete they are left with a surf ace texture which reflects the machining operation. Boring, turning, m illing, grinding, lapping and honing are typical machining process, wh ilst roller burnishing and ballizing are typical of processes where im proved surface finish as well as modified surface properties are requi red. These latter two processes, which have been in common usage for m any years, have advantages which have not yet been fully explored. Thi s includes the ability to deliberately impart negative residual stress es into the surface which are advantageous in improving the functional life of often stressed components as well as improved surface texture . The main purpose of this paper is to investigate the trends of rough ness and residual stress related to the parameters of the ballizing pr ocess. This paper uses the 3-D surface evaluation techniques to charac terise the ballized (engineered) surface and uses the ring cut-off met hod to calculate the residual stress on its circumference. This experi mental methodology and analysis are used to show that: 1)The wall thic kness of the ballized component and the interference amount are signif icant causes of roughness and residual stress. 2) The speed of the bal l (velocity) going through the holes has a little effect on the roughn ess and residual stress. (C) 1998 Elsevier Science Ltd.