document: Comparative statistical analysis of hole taper and circularity in laser percussion drilling Investigates the relationships and parameter interactions between six controllable variables on the hole taper and circularity in laser percussion drilling . Experiments have been conducted on stainless steel workpieces and a comparison was made between stainless steel and mild steel . The central composite design was employed to plan the experiments in order to achieve required information with reduced number of experiments . The process performance was evaluated . The ratio of minimum to maximum Feret 's diameter was considered as circularity characteristic of the hole . The models of these three process characteristics were developed by linear multiple regression technique . The significant coefficients were obtained by performing analysis of variance -LRB- ANOVA -RRB- at 1 , 5 and 7 % levels of significance . The final models were checked by complete residual analysis and finally were experimentally verified . It was found that the pulse frequency had a significant effect on the hole entrance diameter and hole circularity in drilling stainless steel unlike the drilling of mild steel where the pulse frequency had no significant effect on the hole characteristics
doc_bio_tags: B I I O B I O B O B I I O O O O O O O O O O O O B I O B O B I I O O O O O O B I I O O O O O O O O O B I O O B I I O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O B I I I O O O O O O O O B I I O B O O O O O O O O O O O O O O O O O O B I I O O O O O O O O O O O B I O O O O O O O O O O O B O O O O O O O O B I O O B I O O O O O O O O
extractive_keyphrases: comparative statistical analysis hole taper circularity laser percussion drilling stainless steel workpieces mild steel pulse frequency central composite design process performance linear multiple regression technique analysis of variance anova complete residual analysis
abstractive_keyphrases: laser peak power laser pulse width assist gas pressure focal plane position equivalent entrance diameter ferets diameter least squares procedure stepwise regression method