Experimental Research Of Micro Groove Fabrication With A Force Control Method

Different from the conventional scratching method, the normal force is feed-backcontrolled to mechanically machine the micro grooves in the present study. During theprocess, the normal force is controlled to a constant value which is similar to themechanism of the commercial Atomic Force Microscope by which to measure the nanoscale sample topography through controlling the tip-sample interaction force. A simpleand low cost micro machining device which can control the normal force is established.This thesis aims to do some research on micro Al and PMMA structure scratching in abig range by the new system. The mainly contents are as follows:Firstly, the morphology, the depth and width of grooves could be generated byscratching with the triangular pyramid tip surface and edges by which the conclusionthat the surface or edges of the triangular pyramid tip is better could be obtained. Therelationship between the depth and width of the groove and the normal force could beobtained preliminary. The morphology of micro groove can be studied by scratching thesurface of Al under force closed loop and open loop control respectively.Secondly, the changes of force signal and the depth of grooves influence ondifferent factors, including different proportional coefficient, integral coefficient andfeed speed to use PID module of UMAC controller under the force closed-loop control.Eventually, the optimized feed speed, parameters of proportional coefficient Kpandintegral coefficient Kiare decided for scratching Al alloy.Finally，the morphology of PMMA and Al alloy grooves scratched by triangularpyramid tip in the air were compared. Then grooves of these two materials werescratched by triangular pyramid tip in liquid environment which includes water-basedlubricants and oil lubricant and the results were compared with those scratched in theair.