Research On Incremental Forming Of 1060 Aluminum Sheet Square Box Parts With Punch Support

Incremental forming process is an advanced intelligent manufacturing technology that realizes the integration of CAD/CAM/CAE.Taking typical square box parts as the research object,and using a combination of numerical simulation and experiment to study the forming rules of incremental forming with punch support for square box parts,which provides a reference basis for forming other complex straight-walled parts.Based on the ANSYS/LS-DYNA,a finite element model of the incremental forming of square box parts with punch support was established.The response surface method was used to study the optimal process parameters of the incremental forming with punch support for square frustum under different sheet thickness conditions,namely the diameter of the tool head,the axial feed rate and the forming speed;when the height-to-width ratio H/B of the square frustum part is 0.5 and 1.0respectively,the critical forming angle of the single-pass forming square frustum part corresponding to different side length B and different sheet thickness t was studied,and the calculation formulas of the critical forming angle of the square frustum part with H/B=0.5 and H/B=1.0 was obtained.For the single-pass incremental forming of square box parts with punch support,firstly,the forming depth of the square box parts under the different width-to-diameter ratio B/r was studied.The results showed that when B is different and r is the same,the results showed that when B is different and r is the same,the height-to-width ratio of the square box formed by single-pass decreases with the increase of the side length B;and when B is the same and r is different,the height-to-width ratio of the square box formed by single-pass increases as the fillet radius r increases.Secondly,the rules of forming depth of the square box parts under the same width-to-diameter ratio B/r(B/r=4)were studied,and the results showed that when B/r=4 does not change,the height-to-width ratio of the square box formed by single-pass decreases with the increase of the side length B.At the same time,the fitting equation f(B,at)of the height-to-width ratio of the square box parts formed by single-pass under different sheet thickness and different sheet thickness coefficient values was obtained.Finally,the ultimate forming depth of square box parts formed by single-pass with punch support was studied.The results showed that when forming the same size square box parts,the value of the limit height-to-width ratio H_limit/B increases significantly with the increase of the sheet thickness.In the case of the same original sheet thickness,the value of the limit height-to-width ratio H_limit/B is significantly reduced with the increase of the side length,and the reliability of the simulation results were verified through physical experiments,and the calculation formula of the ultimate height-to-width ratio of the square box parts formed by single-pass under different sheet thicknesses and different side lengths was obtained.For the multi-pass incremental forming of square box parts with punch support,taking the square box part with B/r=4 as the research object,three multi-pass forming paths were firstly proposed,which are the constant-height and the contour-parallel straight-line forming path,the variable-angle straight-line forming path and the constant-height and variable-angle forming path.Secondly,the optimal path plan for forming shallow square box parts(H/B=0.5)and deep square box parts(H/B=1.0)was discussed.The simulation and experimental results showed that the best path for forming square box parts with H/B=0.5 is a linear forming path with variable angles,and the best path for forming square boxes with H/B=1.0 is a linear forming path with constant height and variable angles.Finally,the optimal number of forming passes for forming three different side lengths(B=40mm,60mm,and 80mm)of shallow square box parts(H/B=0.5)and deep square box parts(H/B=1.0),and the original sheet thickness and corresponding wall thickness distribution of square box parts(H/B=0.5 and H/B=1.0)with different side lengths which can be formed were studied.According to the simulation results,the minimum original sheet thickness t_minthat can be formed is determined,That is,the t_minof forming B=40mm,60mm,and 80mm shallow square box parts are 0.84mm,1.10mm and 1.30mm,respectively,and the t_minof forming B=40mm,60mm and80mm deep square box parts are 1.30mm,1.50mm,and 2.00mm,and the same conditions of experiments were designed to verify the reliability and accuracy of the simulation results.According to the above research results,the rapid incremental forming of square box parts of other sizes can be realized.