Research On New Roll Forming Process Of Integrated Plate And Shell With Difference Thickness Characteristics

The integrated plate and shell parts with difference thickness feature have great potential in realizing miniaturization,integration and light weight of products and short process manufacturing,but how to realize the forming of such parts is a difficulty.Roll rolling is a new process proposed to overcome the shortcomings of the existing forming methods,which can obtain various complex integrated plate and shell parts with different thickness characteristics under small loads.Based on physical experiments and numerical simulation,a series of researches have been carried out on the rolling process of integrated plate and shell parts with different thickness characteristics.The main work and conclusions are as follows:(1)In roll forming,the plate blank is compressed in the thickness direction,the compressed metal flows along the length direction,and a small amount of metal flows along the width direction.The latter has two situations: 1)When the projected length of the compression plane is greater than or equal to the width of the slab,a small amount of metal extends along the width direction;2)When the projected length of the compression plane is less than the width of the slab,the uncompressed metal on the same section extends along the length direction and shrinks in the width direction.(2)Aiming at the deformation characteristics of the rolling process,a new method for drawing the cross-section of the parting surface is proposed,which can be used to guide the design of the rolling die.Among them,for symmetrical parts with single-sided grooves and double-sided grooves,a cross-sectional view showing the overall cross-sectional change of the parts is adopted.For asymmetric parts with double-sided grooves,take parting surface as the boundary to draw the sectional views of the upper and lower parts respectively.(3)The basic geometric elements of the integrated plate and shell with different thickness characteristics are analyzed,and a variety of typical shell parts and their roller dies are designed.Physical experiments were carried out with plastic mud as blank on a 3D printing roller die,and numerical simulation was carried out with Al6061 as blank.The results show that the rolling process can meet the forming requirements of various complicated integrated plate and shell parts with different thickness characteristics.(4)Warpage,uneven height,uneven spread and incomplete filling are typical defects that may occur in the roll forming process of plate and shell parts,which can be controlled by adjusting process parameters.Among them,adjusting roller diameter d,adopting asynchronous roller diameter,asynchronous roller speed,etc.have obvious effects on improving the warpage,while friction has little effect.Increasing the plate thickness H can compensate for the insufficient forming height of parts.d,H and slab width B play an important role in improving the spread unevenness.multicollinearity analysis shows that the influence of various factors on the spread unevenness is d > B > H;The factors that affect the filling property include d,friction factor m,radius of round corner r,B.multicollinearity analysis shows that the influence of single factor on the filling property is d > m > r > B.(5)Combined with roll-forming and cold-bending technologies,a new forming process(bending-rolling process)of "cold-bending-roll-rolling" combination is proposed.Through one or more groups of counter-rotating roller dies,local volume forming occurs while bending the slab,thus obtaining integrated plate and shell parts with overall bending and local thickness difference characteristics.