SAND as Granular Damper Material to Increase Stability Limits during Turning of Steel Pipe

Abstract

The occurrence of chatter during machining processes is a serious problem because of an excessive vibration that consequently dropped the quality of the machined surface. Especially on the turning process of tube shaped workpieces e.g. steel pipe that has relatively low stability limit represented by low critical depth of cut due to the naturally low dynamic stiffness of steel pipe. A cheap and simple method to increase the stability limits during the turning process of steel pipe has been developed in this research by using “Sand” as granular damper material to dissipate the elevated vibration energy. An experimental research is performed to investigate the performance of the sand damper by doing the cutting process of two different diameter the steel pipe that is filled up by sand. The result of the experiment shows that the 3 inch nominal diameter with fully filled of Sand can increase the stability limits from the critical depth of cut 0.68 mm (empty or without sand) up to 3.27 mm (full) or elevate by 4.8 times (almost fivefold). On the other hand, the 2.5 inch nominal diameter by filling with full of sand can improve stability limits from the critical depth of cut 0.95 mm (without sand) up to 3.05 mm or increase by 3.2 times. In simple words, the result of this research can be concluded that the increasing of the stability limits means also the elevated of the quantitative performance or the production rate of the turning process of Steel pipe almost up to fivefold. Keywords: Stability limits, chatter, sand damper, turning, steel pipe, vibration.