A unified computational model for surface texturing process of strip casting rollers

A new unified computational method is proposed for modeling the relationship between the parameters of the high-speed particle-impact texturing process and the final surface morphology of the casting roller. The whole surface-texturing process is divided into three parts. The first part is the acceleration process of particles inside and outside the nozzle,which can be analyzed using the computational fluid dynamics method to obtain the particle impact velocities. The second part is a simulation of the bombardment process of particles onto the roller surface using the LS-DYNA software as the analysis tool and the results obtained in the first part as input parameters. The last part is the continuously random impact process of particles on the casting roller surface to form a functional surface,which is characterized by a simplified roughness model. Finally,the above three parts are combined to establish a unified computational model,the performance of which is successfully verified in a series of experiments.

Research on Roll Expanding Technology with Double Rollers

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Structural Optimization of Metal and Polymer Ore Conveyor Belt Rollers

Ore conveyor belt rollers operate in harsh environments,making them prone to premature failure.Their service lives are highly dependent on the stress field and bearing misalignment angle,for which limit values are defined in a standard.In this work,an optimization methodology using metamodels based on radial basis functions is implemented to reduce themass of twomodels of rollers.From a structural point of view,one of the rollers ismade completely of metal,while the other also has some components made of polymeric material.The objective of this study is to develop and apply a parametric structural optimization methodology to minimize the mass of the two models of rollers.To represent the mechanical behavior of the rollers,simulations were performed using the finite element method.During the numerical optimization process,the variable parameters were the dimensions of the shaft and external tube.The geometric configuration that corresponded at the same time to the lowest mass and acceptable ranges for the stress and bearingmisalignment angle was determined.With the proposed methodology,a 32.3% reduction in mass was obtained for a metal roller design and an 18.9% reduction for a polymer roller.In both cases,the constraints were not violated.For the all-metal roller,the safety factors for the maximum stress and bearingmisalignment angle were 1.44 and 1.75,respectively,while for the polymer roller the corresponding figures were 1.50 and 2.23.This work describes a low-computational-cost optimization methodology for roller designs that have been little studied in the literature.Furthermore,the methodology could be adapted for use with other types of rollers and rollers made of different materials.

Optimization experiment on eccentric lapping of cylindrical rollers

Cylindrical rollers are important elements of bearings,and their machining accuracy and consistency affect the bearing quality.Using a GCr15 cylindrical roller ofФ11×12 as the processing object in this study,the effects of loading pressure,abrasive concentration,and speed combination on cylindrical roller machining precision were investigated using the orthogonal experimental design method on a double-side eccentric pendulum lapping and polishing machine.The machining parameters of the lapping stage were optimized,and the lapping optimal process parameters were determined by S/N response analysis and analysis of variance(ANOVA).The results show that when the experiment was optimized using loading pressure of 10 N/roller,abrasive concentrationof 20.0 wt%,and rotational speed combination,the material removal rate(MRR)of cylindrical roller reached 0.0896μm/min;the average roughness of the batch decreased from 0.056μm to 0.027μm,51.8%lower than the original batch average roughness,and the deviation decreased from the initial 0.022μm to 0.014μm;the batch average roundness error decreased from 0.47μm to 0.28μm,40.4%lower than the original batch average roundness error,and the deviation decreased from the initial 0.19μm to 0.038μm;and the batch average diameter variation decreased from 4.5μm to about 3.6μm,20%lower than the original batch average diameter variation.The double-side eccentric lapping of cylinder rollers does not only lead to improvement in the surface quality and shape accuracy of rollers,but also improvement in the batch consistency.

Design of Hard Compaction Rollers for Automated Fiber Placement on Complex Mandrel Geometries

This paper presents a methodology for designing hard compaction rollers for an AFP(automated fiber placement)head with a hot gas torch heating system for laying thermoplastic CFRP(carbon fiber reinforced plastic)tapes.Some manufacturing defects and alternative designs are reviewed to highlight the importance of AFP compaction roller conformity and surface adhesion.The formulation of a general parametric description of the design challenge is derived and adequately addresses the problem on a tow-to-tow basis.

ANALYSIS AND DESIGN OF LOAD-UNIFORMING MANGLE ROLLERS WITH AXIALLY-STAGGERED CONTACT

It is desirable to get a uniform load distribution for the pressure rollers of the mangle.In thispaper,the load uniforming principle of the axially-staggered pressure rollers and the rules for theroller design have been analysed by the theory of bending of beams.The ratio of maximum tominimum value of the distributed load in the nip being taken as a useful index to describe the uni-formity of the load distribution,the performance of the so-called load-uniforming pressure rollerswith rubber covering,under various operation conditions,has been evaluated.As a result,it isproved that the load-uniforming pressure rollers with axially-staggered contact is a pratically use-ful means of uniformizing the load distribution,which ensures that the mangle will squeeze the ma-terial to be processed uniformly over its whole width under any technological load,and needs onlysome simple regulations.The conclusions obtained in this paper can easily be extended to the pressure rollers with anysupport conditions.

Surface morphology and mechanical properties of the nanocrystalline tensile-straightening rollers treated by the ultrasonic particulate peening

Tensile-straightening rollers of a pickling line at Baosteel are surface nanocrystallined by the ultrasonic particulate peening(USPP)method.Surface morphology and mechanical properties of the rollers were characterized by scanning electronic microscope(SEM),a roughness meter and a microhardness tester.Results have indicated that there are a lot of randomly distributed impact pits on the surface after the USPP and that surface roughness can be adjusted within a range of Ra 1.5-2.5.The grain size in the surface layer is refined significantly.The microhardness of the surface layer can reach 920 HV after the nanocrystalline treatment.The dependency of the two main influencing factors,i.e.the working gas temperature and pressure,on the surface roughness and microhardness is presented.

Research on Yarn Tension under Positive Guiding by Feed Rollers

In the carpet tufting machine,feed rollers are used to guide the yarns positively.After deducing the general Euler formula of yarn tension under positive guide of rollers,a conclusion is got that the tension of yarns at the output side of each roller tends to decrease one by one.Afterwards,a computing formula of wrap angle of yarn passing through the feed roller is deduced by application of triangle geometry method.By analyzing the effect of each parameter on the yarn tension,values of the space between rollers and the roller diameter are proposed for design reference,and relations between the yarn tension and the two key parameters,the friction coefficient of roller surface and the speed of rollers,are illustrated in detail.Consequently,a policy is drawn out to control the yarn tension.The results of this paper provide not only theory foundation for empirical settings of the operational parameters of tufting machine,but also theory support for further research on yarn tension-control methods.

ROLLING CONDITION FOR ROLLERS ALONG CAMS IN COLD DOUBLE-SET MULTI-ROLLER TUBE ROLLING

The necessary condition of pure rolling for the rollers moving along its individual cams are obtained by the analysis of the loading status of the rollers and it provides a theoretical basis for adjustment of rolling stand.

A combined experimental and analytical method to determine the EHL friction force distribution between rollers and outer raceway in a cylindrical roller bearing

Friction force is a crucial factor causing power loss and fatigue spalling of rolling element bearings.A combined experimental and analytical method is proposed to quantitatively determine the elastohydrodynamic lubrication(EHL)friction force distribution between rollers and outer raceway in a cylindrical roller bearing(CRB).An experimental system with the instrumented bearing and housing was developed for measuring radial load distribution and friction torque of bearings.A simplified model of friction force expressed by dimensionless speed,load,and material parameters was given.An inequality constrained optimization problem was established and solved by using an experimental data-driven learning algorithm for determining the uncertain parameters in the model.The effect of speed,load,and lubricant property on friction force and friction coefficient was discussed.

Design and experimental study of the fertilizer applicator with vertical spiral fluted rollers

To improve the uniformity and accuracy of fertilizing amount for fertilizer applicators with spiral fluted roller,this paper experimentally studied the influence of major structural parameters on the fertilizing performance.Through two sets of orthogonal tests,it is found that the helix angle and installation angle of spiral fluted rollers are the main factors,which affect the uniformity of fertilizer discharge and the linear relationship between fertilizing amount and opening,respectively.Based on these findings,the experiment and analysis were carried out to determine the optimal helix angle and installation angle for the spiral fluted roller The experimental results of fertilizing performance show that:when the helix angle is 45°,it able to achieve satisfactory uniformity of fertilizer discharge and linear relationship between fertilizing amount and rotational speed;when the installation angle is 40°,it enhances the accuracy of fertilizer discharge with good linear relationship between fertilizing amount and opening.Compared with the fertilizing performance of traditional fertilizer applicators with horizontally installed straight fluted roller,in the aspect of uniformity,the optimized fertilizer applicators reduce the variation coefficient of fertilizing amount within 0.2 s at low speed(10-30 r/min)from 5.1%-52.5%to 4.2%-14.7%;in the aspect of accuracy;and increase the correlation coefficient square R2 between fertilizing amount and opening from 0.93-0.97 to no less than 0.996,and the regression intercept in the fitting equation is reduced from larger than 10.0 to less than 1.0.

Young Chinese Baker Rocks “Bread Olympics”

A young Chinese baker became a world champion by pursuing his passion and working hard to overcome challenges.Adancing lion,giant panda,roller coaster,and a merry-go-round in eye-popping shapes-when these elements are grouped together,what kind of magic can happen?Winning magic if you are Gong Xin,a Gen Z baker from China who made a one-meter-high artistic creation using all of these elements.He won the ninth World Bread Competition(Mondial du Pain)as a result.Many Chinese found it hard to believe what he had done after seeing pictures.“This is virtually a work of art,”and“it is equivalent to a foreigner taking first place in a dumpling-making contest in China,”were some of the many online comments.As the host of the competition,France,famous for its bread-making techniques,was beaten into second place,leaving the French media shocked that a Chinese baker had won the famous world bread contest.

Monforts to debut the coaTTex at Techtextil 2024

At the Techtextil show for technical textiles which take place in Frankfurt from April 23-25,Monforts launched its new coaTTex coating unit exclusively dedicated to air knife and knife-over-roller coating.For single-sided application with paste or foam,the versatile coaTTex is suitable for both incorporation into existing finishing ranges as well as installation with new Monforts lines,notably the industry-leading Montex stenter systems.

Roller Screw and Threaded Chain Speed Reducer: An Experimental Evaluation

We are developing a speed reducer that can be considered a transformation of a worm gear reducer: the worm is replaced by an inverted roller screw, and the gear is replaced by a threaded chain drive. This configuration lessens wear, increases load capacity, and improves efficiency. The threaded chain consists of nut-shaped links. This paper presents the results of tests carried out on a prototype with a reduction ratio of 46.

Deviation Prevention Ability of Rollers in Continuous Annealing Furnace and Application

In order to reduce the strip deviation in the practical production procedure in the continuous annealing fur- nace, a dynamic simulation model was built through finite element method （FEM） to conduct the quantification cal- culation of the effect of regular roller contour types on strip deviation. The result reveals that comparing to the flat roller, forward roller contour can prevent the strip deviation to some degree. In terms of prevention ability, double- taper roller is the strongest, single-taper roller and crown roller are less stronger; and more roller contour values raise the prevention ability. Accordingly, optimization method was applied to continuous annealing furnace, and it largely reduced accidents such as strip break and limited speed that are caused by the deviation.

Experimental and Simulation Studies on Fabricating GCr15/40Cr Bimetallic Compound Rollers Using Electroslag Surfacing with Liquid Metal Method

Electroslag surfacing with liquid metal （ESSLM） is an excellent method for producing high quality bimetallic compound rollers. The quality of each compound roller is primarily determined by the metallurgical quality of the combined interface. A GCrl5/40Cr compound roller is produced using an ESSLM non-consumable electrode electro- slag heating method. The temperature and electric fields produced by the ESSLM system are calculated. As the roller core moves downward in the mold, it passes through five sections., the preheating section, the rapid heating section, the temperature homogenizing section, the bimetal fusing section and the cooling section which listed from the top to bottom of the mold, respectively. The temperature distribution and the degree of the surface temperature fluctuation in the roller core are different for each section. Near the combined interface, four layers are found from the roller core to the cladding layer= the remelting layer, the fusion layer, the interface solidification layer and the chilling layer, re spectively. Among these, the fusion and interface solidification layers are the key transition zones that greatly influ- ence the combination quality. The surface temperature of the roller core prior to cladding is mainly determined by the drawing velocity, and the thickness of the transition layer increases as the drawing velocity decreases. A transition layer that is too thick or too thin will reduce the mechanical properties at the combined interface. Therefore, the drawing velocity should be limited to a moderate range to produce a satisfactory bimetallic Compound roller.

Analysis of Dynamic Characteristics of Forced and Free Vibrations of Mill Roll System Based on Fractional Order Theory

In this paper,the main researches are focused on the horizontal nonlinear vibration characteristics of roll systems for rolling mill,mainly including the study of forced vibration and free vibration of the roller.Firstly,the nonlinear damping parameters and nonlinear stiffness parameters within interface of the rolling mill are both considered,and a fractional-order differential term is also introduced to model the horizontal nonlinear vibration.Secondly,the averaging method is introduced to solve the forced vibration system of the mill roll system,and the amplitude-frequency characteristic curves of the system are obtained for different orders,external excitation amplitudes,stiffness and fractional order coefficients.Thirdly,the amplitude-frequency and phasefrequency characteristics of the free vibration of the mill roll system are investigated at different fractional orders.Then,the accuracy of the averaging method for solving the dynamic characteristics of the system is verified by numerical analysis,and the effect of the fractional differential term coefficients and order on the dynamic characteristics of the roll system are investigated.Finally,the time-frequency characteristics and phase-frequency characteristics of free vibration systems at different fractional orders are studied.The validity of the theoretical study is also verified through experiments.

Optimal Design of Tapered Roller Bearings Based on Multi⁃Physics Objectives Using Evolutionary Algorithms

Rolling element bearing is the most common machine element in rotating machinery.An extended life is among the foremost imperative standards in the optimal design of rolling element bearings,which confide on the fatigue failure,wear,and thermal conditions of bearings.To fill the gap,in the current work,all three objectives of a tapered roller bearing have been innovatively considered respectively,which are the dynamic capacity,elasto-hydrodynamic lubrication(EHL)minimum film⁃thickness,and maximum bearing temperature.These objective function formulations are presented,associated design variables are identified,and constraints are discussed.To solve complex non⁃linear constrained optimization formulations,a best⁃practice design procedure was investigated using the Artificial Bee Colony(ABC)algorithms.A sensitivity analysis of several geometric design variables was conducted to observe the difference in all three objectives.An excellent enhancement was found in the bearing designs that have been optimized as compared with bearing standards and previously published works.The present study will definitely add to the present experience based design followed in bearing industries to save time and obtain assessment of bearing performance before manufacturing.To verify the improvement,an experimental investigation is worthwhile conducting.

Discussion on Lightning Protection Design of "Feilongzaitian" Roller Coaster of Fangte in Zigong

The lightning protection design of "Feilongzaitian" roller coaster of Fangte in Zigong was discussed, and the lightning protection measures of "Feilongzaitian" roller coaster were analyzed from the aspects of direct lightning protection, grounding and lightning electromagnetic impulse protection.

Analysis of Vibrations of Roller of the Polymer Composite Coating Equipment on Stitches of Tarpaulin Materials

The article presents a structural diagram and the principle of operation of the installation of a sewing machine for applying a polymer composition to the stitch lines of tarpaulin materials. The calculation schemes and the mathematical model of oscillations of the axis of the composite roller during the application of the polymer composition along the lines of tarpaulin materials are presented. Based on the numerical solution of the problem, the regularities of roller oscillations are presented. The main parameters of the system are substantiated.