Polishing the surface of aerospace material Removing the white layer Surface finishing Figure A. Surface roughness value of Abrasive Flow Machined Ti-6Al-4V by180 mesh abrasive (a) before AFM process (b) After AFM prosess (c)Purpose: Traditional finishing techniques do not provide the desired surface quality, especially in industries such as aerospace and medical. Parts have to be kept in an extra finishing method to have the desired surface quality. Abrasive flow machining (AFM) technique is one of the non-traditional finishing process used to improve surface quality of parts. The aim of the study is to increase the surface quality of aerospace alloy (Ti-6Al-4V) by AFM process.
Theory and Methods:Abrasive flow machining (AFM) is a nontraditional machining process that was developed in the USA in the 1960s. AFM can be described as pressurized media passing through the surfaces to reach the desired surface quality. The experiments were performed on the Ti-6Al-4V alloy with three mesh size abrasive and three abrasive concentration. The pressurized abrasive media flowed through the WEDMed surfaces with an opening of 10×20 mm, the experiments were carried out for 1, 3, 5, 10, 20 and 50 cycles.
Results:The experimental study showed that the undesired white layer was removed by AFM process. The highest material removal rate was obtained by 180 grit size and 60% abrasive concentration of 14 mg / min. Workpiece surface quality was reduced from 3.5 µm to 0.25 µm by AFM process.
Conclusion:It is concluded that the surface quality of the titanium alloy (Ti-6Al-4V) produced by WEDM process, which is widely used in aviation industry, is improved after AFM process. The white layer formed during WEDM is successfully removed by AFM in a few cycles. The removal of this layer eliminates surface cracks and thus the fatigue strength may increase.