Study Of Abrasive Flow Machining Technology For Additively Manufactured Grille Parts

Metal grille parts are widely used in the aerospace field.Additive manufacturing(AM)technology which is obviously advantageous in producing parts with complex structures provides a new method to manufacture the metal grille parts.However,it's difficult for the as-built surfaces of AM parts to meet the required surface quality,as the as-built surfaces are deteriorated by inherent characteristics of powder adhesion and balling effect for metal AM technology,e.g.selective laser melting(SLM).In this paper,the three kinds of additively manufactured grille parts used in aerospace field were put forward AFM technical solutions which is suitable for them.And related simulation and processing experimental studies were carried out,main job description is shown as follows.The abrasive flow machining(AFM)is used to polish the outer and inner surfaces of additively manufactured aluminum alloy grille parts with straight holes.The mechanism of material removal of "powder adhesion" and "Balling effect" on the surface of the parts processed by AFM was explored.The removal process can be divided into loose layer removal stage,spheroidal layer removal stage and metal layer removal stage.The outer and inner surfaces of the parts are effectively polished with suitable process parameters and flow channel.And the surface roughness was reduced to Sa 1.8 ?m.The residual stress on the surface of the additively manufactured material is changed from tensile stress to compressive stress after being polished by AFM process.And parts fatigue strength is improved.The AFM experiments and related simulation was carried out to polish the outer and inner surfaces of additively manufactured aluminum alloy grille parts with oblique holes.The effect of AFM process parameters on the machining results such as the size of grains,placement angle of the part and working pressure of the equipment were analyzed.The optimum process parameters such as negative placement angle and mixed particle size abrasive media were obtained.The outer and inner surfaces of the parts are effectively polished and the surface roughness was reduced to Ra 0.97 ?m.Two process routes proposed for additively manufactured titanium alloy grille parts with oblique holes are AFM after sandblasting and AFM combined with CNC grinding.Related simulation and experiments were carried out.Both of the processes have achieved significant processing results and high processing efficiency.And surface roughness was reduced to Ra 1.6 ?m.For the follow-up industrial production has laid a solid technical foundation.