Key Engineering Materials Vol. 496

Abstract: This paper applied the Taguchi approach to investigate the effects of polishing parameters to obtain the optimal processing conditions for CoCr alloy polishing using a multiaxis CNC controlled corrective polishing machine. The polishing medium used was 1m diamond paste with a Microcloth(polishing cloth). Surface finish parameter Sa was chosen as the criterion for process optimization. The experimental results indicate that the optimal polishing conditions for CoCr alloy polishing is 50 precess angle, 800 rpm head speed, 0.2mm tool offset and 1.5 bar tool pressure. With this optimal condition, a confirmatory experiment was conducted. The surface roughness Sa reduced from an initial 24nm to 7nm and reduction ratio was 70.8% which was very close to the estimated ratio of 64%.

Abstract: The multi-pass nanometric machining of copper with diamond tool was carried out using the Molecular Dynamics (MD) simulation. The copper-copper interactions were modelled by the EAM potential and the copper-diamond interactions were modelled by the Morse potential. The diamond tool was modelled as a deformable body and the Tersoff potential was applied for the carbon-carbon interactions. It was observed that the average tangential and the normal components of the cutting forces reduced in the consecutive cutting passes. Also, the lateral force components are affected by atomic vibrations and the cross sectional area during the cutting process.

Abstract: Abstract. This paper analyses the technological capabilities of a novel rotary (EDM) electrical discharge machining process for the manufacturing of high aspect ratio cylindrical micro-components. The process is called Inverse Electrical Discharge Grinding (ISEDM). An experimental analysis has been carried out on high speed steel (tool steel Vanadis 23), using a conventional EDM machine and graphite electrode. The effect of pulse off-time, work piece final diameter and machining length on material removal rate, electrode wear ratio, radial accuracy and surface roughness has been quantified. From the study, optimum strategies that involve the use of different EDM regimes for achieving the optimum requirements can be defined. Micro-pins of 0.3 mm diameter with aspect ratio as high as 100:1 have been successfully manufactured.

Abstract: In the submitted work the analysis of influence of a setting angle of chip grooves on the strength and durability of fine-sized spiral drills and the basing of utilization effectiveness of spiral drills with variable angle in comparison with standard drills are shown. The resistance to wear tests results and plan of subsequent studies are discussed.

Abstract: This work is focused on the investigation of the influence of the materials of PCB, feed rate, spindle speed and tool wear on thrust force when drilling PCB using 0.3 mm diameter cemented tungsten carbide drills. The results indicate that thrust force increases with feed rate and drill wear, but decreases with spindle speed firstly and then increases with it within the cutting range tested. Thrust force caused by the copper foil is much larger than that caused by the epoxy glass fiber cloth when feed rate is low. However, the difference between them decreases as feed rate increases. The thickness of nail head increases with thrust force. The accuracy of hole location increases with thrust force firstly but decreases afterward. The influence of thrust force on hole wall roughness is not obvious.