Evaluation and optimisation of micro flexible rolling process parameters by orthogonal trial design

Finite Element Analysis of Forward Slip in Micro Flexible Rolling of Thin Aluminium Strips

“…In general, the optimised model setting includes the simplification of the roll as a rigid cylindrical surface and the determination of mesh sizes for both roll and strip, in order to reduce the The strip was meshed with 10-node modified quadratic tetrahedron elements (C3D10M) with a fine mesh size of 0.04 mm to ensure a good convergence, as well as improving the mesh quality near grain boundaries, whilst the roll was coarsely meshed with 4-node 3D bilinear rigid quadrilateral elements (R3D4) by utilising mesh size of 0.16 mm in such a way as to prevent the nodes on the roll surface from penetrating into the workpiece [35,38].…”

“…Figure 4 presents the micro flexible rolled strip with a reduction of 20% to 50%, wherein red dots indicate the locations of the marks transferred from the roll within the thickness transition area. Furthermore, the strip was rolled at a speed of 20 cm/min and under dry friction (with an equivalent friction coefficient of 0.13 [38]), and both initial strip thickness and average grain size were set as 250 µm, which gives the T/D ratio of 1 for this case. In the current study grain size of 250 µm has been used, due to two main reasons, whereof one is that three types of T/D ratio can be considered, which means the scattering effect resulted from the difference between properties of single grains can be evaluated and compared when approximately one (T/D ratio is less than or equal to 1) or two layers of grains (T/D ratio is equal to 2) constitute the strip; and the other is that a bigger grain size is helpful to lessen the computation time for creating the Voronoi tessellation and performing the simulation tasks, while the grained inhomogeneity which is a key factor leading to scattering effect can still be reflected in spite of a large grain size.…”

“…To examine how lubrication condition affects the forward slip in micro flexible rolling four types of estimated friction coefficients have been selected to represent dry friction (with estimated friction coefficients of 0.13, 0.18, and 0.23, respectively) and rolling with lubrication (with estimated friction coefficient of 0.08) in accordance with previous investigations conducted by Qu et al [36,38]. In this section, all cases were performed with rolling speed of 20 cm/min and T/D ratio of 1.…”

“…(17) In addition, the root mean square error was calculated to be 1.7383, which indicates that the developed regression model has reasonable capability and accuracy in predicting the forward slip during micro flexible rolling of aluminium alloy 5052 strips with regard to a range of reduction combinations, rolling speeds, friction coefficients and T/D ratios. Finally, in order to investigate the magnitudes of each process parameter affecting forward slip, variance analysis has been carried out in accordance with [38], and the results are listed in Table 2. S, df and V in Table 2 denote the sum of squared deviation, degree of freedom and variance, respectively, and F value is the ratio of variance of each variable to that of the error (e) between the simulated and predicted forward slip which is 3.296 in the present study.…”

Analysis of Springback Behaviour in Micro Flexible Rolling of Crystalline Materials

“…e halfsymmetric 3D micro exible rolling nite element model has been established using the commercial FEA software package, ABAQUS/CAE. As exhibited in Figure 3, in order to achieve higher computational e ciency with less computational resource, the inner portion of the roll body has been removed as only its outer surface will be in contact with the material during the real forming process [54]. e basic geometric parameters of the FE model are as follows: outer diameter of the roll D 25 mm, length of the roll B 35 mm, length of the strip L 40 mm, width of the strip b 10 mm, and initial thickness of the strip H 250 µm.…”