Search Results (2)

The selection of the right tool path trajectory and the corresponding machining parameters for end milling is a challenge in mold and die industries. Subsequently, the selection of appropriate tool path parameters can reduce overall machining time, improve the surface finish of the workpiece, extend tool life, reduce overall cost, and improve productivity. This work aims to establish the performance of end milling process parameters and the impact of trochoidal toolpath parameters on the surface finish of AISI D3 steel. It especially focuses on the effect of the tool tip nose radius deviation on the surface quality using precision measurement techniques. The experimental design was carried out in a systematic manner using a face-centered central composite design (FCCD) within the framework of response surface methodology (RSM). Twenty different experiment trials were conducted by changing the independent variables, such as cutting speed, feed rate, and trochoidal pitch distance. The main effects and the interactions of these parameters were determined using analysis of variance (ANOVA). The optimal conditions were identified using a multiple objective optimization method based on desirability function analysis (DFA). The developed empirical models showed statistical significance with the best process parameters, which include a feed rate of 0.05 m/tooth, a trochoidal pitch distance of 1.8 mm, and a cutting speed of 78 m/min. Further, as the trochoidal pitch distance increased, variations in the tool tip cutting edge were observed on the machined surface due to peeling off of the coating layer. The flaws on the tool tip, which alter the edge micro-geometry after machining, resulted in up to 33.83% variation in the initial nose radius. Deviations of 4.25% and 5.31% were noted between actual and predicted values of surface roughness and the nose radius, respectively. Full article

The inner roller exerts a supportive and thinning effect on the inner side of the tube during counter-roller spinning. In this paper, the Finite Element Analysis (FEA) model of counter-roller spinning for a 6061 aluminum alloy tube was established based on the ABAQUS/Explicit module. The deformation characteristics and the influence of inner roller geometrical parameters on the tube spinning were analyzed. The results showed that the stress–strain on the outer of the tube was greater than that of the inner, and flaring was more prone to occur in the initial stage of counter-roller spinning compared to traditional mandrel spinning. The order of the effects of geometrical parameters of the inner roller on the roundness error and wall thickness deviation was as follows: nose radius > diameter > front angle. The order of factors influencing the inner and outer spinning force was as follows: diameter > nose radius > front angle. Increasing the diameter of the inner roller can improve the spinning stability and forming accuracy of counter-roller spinning. It was beneficial to improve the forming accuracy when the nose radius of the inner roller was slightly larger than that of the outer roller. The front angle of the inner roller has little influence on the spinning forming accuracy. Full article