A taper tension profile maker in a converting machine

Chang Woo Lee,Jang Won Lee,Kee Hyun Shin,Soon Oh Kwon 대한기계학회 2008 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.22 No.1

Winding is an integral operation in almost every web handling process, and a center-wound roll is one of the suitable and general schemes in a winding system. However, improper internal stresses within a center-wound roll can cause damage such as buckling, spoking, cinching, etc. Wound roll quality and performance are known to be related to the distribution of in-roll stresses. It is therefore necessary to analyze the relationship between taper tension in the winding section and internal stress distribution within the center-wound roll to prevent winding failure. But it is hard to compensate for an undesirable winding roll shape such as starring, buckling, and telescoping. This is because the winding section is the final process in a roll to roll system and has no feedback control system to correct winding roll shape directly. A time varying tension profile and accurate control of it in a winding section is one way to shape the fail-safe in-roll stress distribution of a winding roll. In this study, a new taper tension profile making method is aimed for designing high quality wound rolls. A new method to determine the proper taper tension profile was designed by analyzing the winding mechanism which includes the stress model in center-wound rolls, nip induced tension model, relationship between taper tension profile and telescoping, relationship between taper tension type and internal stress distribution. An auto taper tension profile making method was proposed not only to optimize radial stress distribution but also to minimize lateral error (telescoping). Simulation results show that the proposed method is very useful for determining the desirable taper tension profile during the winding process and preventing defects of winding roll shape such as telescoping, starting, and dishing and so on.

Design of Roll Profile for LM-Guide Block in Horizontal- Vertical Shape Rolling by 3D-EFA

이상진,이경훈,김병민 한국정밀공학회 2015 International Journal of Precision Engineering and Vol.16 No.4

In this paper, the design method for intermediate rolls has been developed to manufacture a linear motion (LM) guide block inhorizontal-vertical (H-V) shape rolling, based on the three-dimensional electric field analysis (3D-EFA). This design method canpredict appropriate cross-sections of roll profile at each pass based on the initial and final shapes. 3D-EFA simulations are performedseparately for the horizontal and vertical rolling passes to obtain roll profiles from equipotential lines. The roll profiles obtained basedon 3D-EFA are simulated by the commercial program Deform 3D, and are the reselected by compensating for the area of the errorfrom the equipotential lines. For convenience of field work and reducing strain concentration of the products, the roll profiles for thefirst and second passes are modified to be flat rolls because the roll profiles are almost rectangular. The effectiveness of the proposeddesign method is verified experimentally using AISI4120 steel for H-V shape rolling. From the experimental results, some over- andunder-filling ate the roll gap are observed for the final pass. However the dimensional errors are within ±0.3 mm, and no crackingor shearing is observed. The proposed design method will improve the efficiency of the design process by reducing time and costs.

Development of L-Sectioned Ring for Construction Machines by Profile Ring Rolling Process

박민철,이찬주,이정민,이인규,전만수,김병민,이경훈 한국정밀공학회 2016 International Journal of Precision Engineering and Vol.17 No.2

Recently, there is an increasing commercial interest in manufacturing rings with a complicated cross-sectional shape directly by a metal forming process instead of by machining. Profile ring rolling is one of the advanced metal forming technologies to manufacture large or small seamless profile rings. Compared with plain ring rolling, profile ring rolling can yield considerable savings in material cost and a shorter cycle time for additional machining. In this study, a profile ring rolling process for producing large-scale profile rings with an L-section for construction machine parts is developed. The manufacturing process of large-scale profile rings with Lsection consists of a forging stage and a profile ring rolling stage. In the forging stage, the raw material is formed to initial blanks for profile ring rolling. The forged initial blanks are then formed to the final product shape in the profile ring rolling process, which is designed to occur in a single pass to minimize the cycle time. The design of the blank shape is very important, to enable the design of a profile ring rolling process without forming defects, such as fishtails, underfilling, and distortion of the ring. A finite-element (FE) analysis was performed to optimize the blank ring shape, with the objective of minimizing forming defects. After determination of the initial blank shape, the effects of process variables such as feed conditions of mandrel and axial rolls on the final product shape was investigated to improve the dimensional accuracy. Also, forming experiments were conducted based on the results of the FE analysis. The experimental results were in good agreement with the results of the FE analysis.

열간압연용 롤 정밀 측정시스템 개발

이성진,이영진 한국공작기계학회 2002 한국공작기계학회 춘계학술대회논문집 Vol.2002 No.-

In hot strip mills, Portable Roll Scanner (the portable roll surface temperature and profile measuring device) can be used to calibrate on-line process models for strip crown and flatness by measuring the thermal expansion and wear profile of the rolls. And the surface temperature measurement can be used to optimize the roll cooling system. Portable Roll Scanner consists of the measuring device, which has two contact inductive distance transducers for roll profile measurement and one infrared pyrometer for surface temperature measurement, and computer-based controller that is equipped with the measuring device. By the wireless data communication, the data is transferred to the memory of notebook for further analysis. After roll extraction from mills, Portable Roll Scanner measure the roll profile and surface temperature simultaneously along the work roll face and display the results in the TFT color monitor of notebook. Portable Roll Scanner is useful at mill-side and roll grinding shop.

Effect of taper tension profile on the telescoping in a winding process of high speed roll to roll printing systems

이창우,강현규,김호준,신기현 대한기계학회 2009 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.23 No.11

Winding is an integral operation in almost every roll to roll system. A center-wound roll is one of the suitable and general schemes in a winding mechanism. In general, the quality of wound roll is known to be related to the lateral displacement error and starring defect of a wound roll. Especially, a telescoping within a center-wound roll can cause damages such as misalignment between layers, folding, wrinkle, etc. Taper tension is known to be one of the major factors which affect the shape of a wound roll. It is therefore necessary to analyze the relationship between taper tension profile and telescoping within the center-wound roll to prevent winding failure and to sustain high quality of the printed materials. It is hard to compensate for undesirable winding roll shapes such as telescoping, because a winding is commonly a final process in roll to roll systems and has no feedback control mechanism to correct winding roll shape directly during winding operation. Therefore, an optimal taper tension profile and the accurate control of it in a winding section could be one way to shape the fail-safe of a wound roll. Through the correlation between taper tension profile and telescoping in a winding process, a mathematical model for the telescoping due to tension distribution in cross machine direction was developed, and verified by experimental study. A new logic to determine the proper taper tension profile was designed by combining and analyzing the winding mechanism which includes nip induced tension model, relationship between taper tension profile and telescoping, relationship between taper value and telescoping. Numerical simulations and experimental results show that the proposed method is very useful for determining the desirable taper tension profile during the winding process and preventing defects of winding roll shape such as telescoping.

냉간 압연에서 압하력 분포 예측 - Part I : 수식 모델 개발

남승연,황상무 한국소성∙가공학회 2019 소성가공 : 한국소성가공학회지 Vol.28 No.4

The capability of accurately predicting the roll force profile across a strip in the bite zone in cold rolling process is vital for the calculation of strip profile. This paper presents a derivation of a precision mathematical model for predicting variations in the roll force across a strip in cold rolling. While the derivation is based on an approximate 3-D theory of rolling, this mathematical model also considers plastic deformation in the pre-deformation region which is located close to the roll entrance before the strip enters the bite zone. Finally, the mathematical model is expressed as a boundary value problem, and it predicts the roll force profile and tension profile in addition to lateral plastic strain profile.

Study on the improved accuracy of strip profile using numerical formula model in continuous cold rolling with 6-high mill

Sang-Ho Lee,Gil-Ho Song,Sung-Jin Lee,김병민 대한기계학회 2011 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.25 No.8

The quality requirements for thickness accuracy in cold rolling continue to become more stringent. In cold rolling mill, it is very important that the rolling force calculation considers rolling conditions. The rolled strip thickness was predicted using calculated rolling force. However, the prediction of strip thickness in cold rolling is very difficult; in particular, for 6-high mill with shifted intermediate roll (IMR), the accuracy of thickness is not good. In this study, to improve the accuracy of rolled strip thickness, the roll gap flattening can be given based on Hertz contact theory, with contact between rolls and the smooth cylindrical rolls for the rolling elastic deformation. Also,the distribution of the roll gap flattening may be calculated using the contact force of unit transverse length. The strip profile at the continuous cold rolling is calculated by using the numerical analysis model considering the initial strip profile before cold rolling. Hence, we propose that the numerical model can predict the rolled strip profile more quickly and accurately and be applicable to the field. The results of the proposed numerical model were verified by FE-simulation and cold rolling experiments of 6-high mill with five stands.

Design of Roll Profile in Shape Rolling by 3D-EFA

이상진,이경훈,고대철,이상곤,김병민 한국정밀공학회 2015 International Journal of Precision Engineering and Vol.16 No.4

The design of roll profile in shape rolling is important as a key role in improving product quality, such as dimensional accuracy,ensuring defect-free property and good mechanical properties. In this study, the design method using three dimensional electric fieldanalysis (3D-EFA) is proposed to design intermediate roll profiles for the shape rolling. The shape of equi-potential lines asintermediate roll profiles could be generated between the initial shape and final shape by 3D-EFA. The intermediate roll profile foreach pass is selected among a numerous equi-potential lines, and the effectiveness of the selected roll profiles is verified by FEsimulation. The over- or under-filling area is calculated from the result of FE-simulation, another equi-potential line is selected tocompensate for the area of the error. The proposed method is applied to a shape like rear door hinge that is generally designed bythe trial and error method to show the applicability of this method for various shapes. The lab-scale experiment is carried out withplasticine, and the results are within the allowable tolerance of ±0.5 mm. Therefore, the proposed method can be widely used to designroll profiles for complex shapes thereby reducing the design time.

Design of Roll Profile for Complex Shape in Shape Rolling by Combined 3D-EFA and BWT

이상진,이경훈,김병민 한국정밀공학회 2015 International Journal of Precision Engineering and Vol.16 No.2

A design method using three-dimensional electric field analysis (3D-EFA) and a backward tracing scheme (BWT) is proposed toimprove the dimensional accuracy for a complex shaped product in shape rolling. A complex door hinge used in the door hinge ofautomobile is taken as a case study. A shape rolling process for this hinge is designed using the proposed method, and a backwardtracing scheme is then applied to find a more suitable roll profile. 3D-EFA is carried out for this purpose, and the roll profiles ateach pass are selected based on the 3D-EFA results using the reduction ratio in the area per pass. In addition, a BWT is applied tothe selected roll profile in order to achieve the dimensions of the required product. The effectiveness of the proposed design methodis verified via FE-simulation and experimentation using plasticine. The results of FE-simulation and experiment show that theproposed design method can be used to effectively design the roll profile for the complex door hinge, leading to an accurate shapeand correct dimensions of the final within an allowable tolerance of ±0.5 mm. Therefore, it can be concluded that the proposed designmethod can be widely used to design roll profiles for producing a precise product.

Experimental and Semi-analytical Study of Wear Contour of Roll Groove and Its Applications to Rod Mill

Byon, Sang-Min,Lee, Youngseog The Iron and Steel Institute of Japan 2007 ISIJ international Vol.47 No.7

<P>In this study, we propose a semi-analytical model which predicts the wear contour of grooved roll in the oval–round (or round–oval) pass rolling process. In the proposed model, the wear contour is assumed to be of a second order polynomial function and computed by using the linear interpolation of the radius of curvature of an incoming workpiece, that of roll groove and a weighting function which takes into account roll force, longitudinal contact length of work roll that undergoes during rolling, property of work roll and roll tonnage. The validity of the proposed model has been examined by applying it to the roughing train in the POSCO No. 2 Rod Mill.A wear measurement system of roll groove has also been developed. Roll wear contour was measured using ‘resin plastics’ which can flow, under small external load, without restraint into any region worn out. The deformed resin plastics, <I>i.e.</I>, roll wear contour, was measured.Results show the proposed model in this study, in overall, has a reasonable accuracy in predicting the roll wear contour but the model underestimates slightly the measurements as the roll speed increases. Roll wear has been found to be linearly dependent on the longitudinal contact length of work roll, roll tonnage, but non-linearly on the roll force and inverse proportional to hardness of work roll.</P>