Investigation of One-way Abrasive Flow Machining and In-process Measurement of Axial Forces

Abrasive flow machining (AFM) is an abrasive machining process used to machine internal geometries like bores in terms of deburring and finishing the surface with high performance. A silicate-based medium is forced through the internal geometries of a work piece by a hydraulic cylinder. The medium contains a certain amount of abrasive particles like carbide or diamond which influence the removal rate and surface quality. E.g. components of fuel injection systems are treated with the process in order to withstand higher internal pressures. One goal is the improvement of the surface quality whereas the other one is the reduction of stress concentrations at bore intersections due to the abrasive deburring and defined rounding. This paper presents results of a parameter study that was used to identify the influence of medium pressure and lead time on the surface quality and form tolerance. A commonly used automotive steel AISI 4140 was used for the investigation. Additionally, an in-process measurement setup was developed in order to measure the influence of the applied medium pressure on the machined part of the work piece with the help of an axial force sensor.