Theoretical Research On Fixed Mixed Contact Abrasive Processing

Compared with the traditional free abrasive machining, fixed abrasive processingcan get higher efficient use of the abrasive materials and easier control method.However, in order to meet the surface precision requirements of work piece, fixedabrasive polishing pad needs to be replaced several times during the processing due tothe limit of grain size of abrasives. It would destabilize the machining process andreduce the efficiency. Thus mixed contact fixed abrasive processing was proposed inthis paper for controlling the grinding depth of a definitive tool and decreasing thetool switches frequency. The influence of the polishing agent liquid membranebetween tool and workpiece was studied.The main research in this paper includes four aspects: Firstly, the polishingpressure is shouldered by the polishing agent liquid membrane and the abrasives thatcontact with the work piece. So the equations of liquid membrane thickness andgrinding depth were deduced by using the established model of polishing pad surfacetopography; Secondly, the liquid membrane fluid lubrication behavior was describedby equations which were combined by liquid membrane distribution andhydromechanics fundamental equations. Then explicit difference algorithm wasadopted; Thirdly, the polishing pressure and the contact force between pad and workpiece were calculated based on the brittle material removal mechanism; Finally, therelationship of liquid membrane’s hydrodynamic pressure, contact force and grindingdepth were studied from the perspective of machining control. The influence ofprocess parameters and the proportion of liquid membrane’s hydrodynamic pressurewere discussed.The effect of the polishing agent liquid membrane between tool and workpiecewas introduced to fixed abrasive processing in this paper. The numerical simulationwas conducted to analyze the machining system. It has guidance to the practicalapplication.