Analysis For The Plate Bending Process Of The Four-roll Plate Bending Machine

Four-roll plate bending machine is the necessary non-standard heavy machineryequipment in machinery and equipment industries, especially in container manufacturingenterprises. It belongs to the plastic molding equipment which is mainly used for differenttypes of steel (material) to be made into barrel type mechanical parts in accordance with thedesign and manufacture requirements.On the basis of structure parameters of W12LSZG-280×3000, plate bending process ofthe four-roll bending machine was analyzed aimed at determining the process parameters inthis paper. In order to achieve the purpose of precise control of each axis roll working position,rolling cylinder automatic production of four-roller bending machine, and so that get a betterprecision of steel plate and higher production efficiency, determination methods for theprecise location of each shaft roller were studied in the process of the whole process, areasonable mathematic model was established and precise working positions of lower roller,left roller and right roller in the center, bending and rolling process were derived and theirmathematical formula of feed displacement relative to the initial position was calculated.Based on the analysis of plastic bending deformation theory and combined with theexisting volume plate theory research, theoretical analysis of the plate bending processparameters were carried out. The existing theoretical research establishes mathematical modelbased on the premise that sheet material is pressed by upper and lower shaft roller, i.e. thedistance between the upper and lower shaft roller surface is equal to the thickness, on thisbasis, combined with the geometric relationship between the axial roller and sheet material offour-roller bending machine in plate bending process, the relatively complete theoretical ofplate bending process parameters’ calculation formula was derived. According to thecalculation method of the traditional craft parameter, each shaft roll feeding displacementwere calculated under the condition that rolling thickness is200mm, width is3000mm andthe minimum rolling radius is2000mm, and finally to the calculation resultsas the theoretical reference of finite element modeling when plate bending process is simulated and analyzed in four-roller bending machine.Using the finite element software ANSYS/LS-DYNA to analyze the plate bendingprocess in four-roll bending machine, respectively to simulate the four roll plate bendingprocess and roll bending simulation at a time, then measured the simulation roll bendingradius and compared the emulational radius value with the theoretical radius. The analysisresults showed as follows:①One time roll bending simulation gets a smaller radius thanmultiple times roll bending simulation, this is because material is after multiple sclerosis inthe process of repeatedly roll bending and one time roll bending only produce one sclerosis.②On the basis of the data got by a traditional craft parameter calculation method, finiteelement analysis model is established to simulate the process of rolled plate and a smaller drum radius value than theoretical calculation is derived, there are two main reasons for this:One is that the traditional craft parameter calculation method ignored the influence of sheetmetal meshes into the straight edge when established mathematical model; The other is thatthe mathematical model established in the traditional craft parameter calculation method (inother words the distance between the upper and lower roller surface equals to thickness ofplating and in the whole process of rolling the distance always remains the same) is ofinconsistent with the basic assumptions of the theoretical analysis (that is to say platethickness remains constant) and the two cannot be established at the same time.Aimed at two reasons of the smaller simulation roll bending radius through thesimulation, put forward the corresponding improvement plan on the basis of studying theexisting roll plate theory: considering the influence of the meshes into end straight edge, at thesame time, on the premise of guarantee sheet thickness constant considering the gap betweenupper and lower roller C values, to establish mathematical model, calculation formula of platebending process parameters is derived.Through this research, the problems existing in the traditional calculation method of theplate bending process parameters were discussed, the possible reasons were analyzed and thecorresponding improvement scheme was put forward, provides an effective thinking for thecontinuous improvement of follow-up rolled plate method to determine the processparameters.