Automation and Vision Systems
 

Web guides Web guides for improved quality and productivity

Made in Germany. Since 1919.
About Erhardt+Leimer

Systems for web guiding with state-of-the-art networking technology

Web guides ensure continuous alignment and accurate positioning of the web and precise winding results. Depending on the material, application and task, Erhardt+Leimer offers a range of different systems for web guiding with the latest networking technology for this – for clear quality improvements and productivity that pays off.

Function 

On an ELGUIDER pivoting frame system, the web changes direction four times, each time by 90°. This web guide is based on a pivoting frame with two path rollers. The imaginary pivot point is located on the infeed plane. Lateral web corrections can only be achieved by swiveling around this pivot point. The prerequisite here is that there must always be sufficient web tension to establish traction between the web and the positioning roller.

Area of use

Thanks to optimized exploitation of elasticity ranges, the pivoting frame can be used for web guiding even in really tight spaces. 

Application

The greater the web tension, the module of elasticity and the required correction, the longer the infeed, outfeed and transfer paths should be designed. Experience has shown that these paths should be the equivalent of 60 to 100 % of the web width. The sensor should be positioned behind the positioning roller, as near to it as possible.

Key

A = Web tension distribution at infeed | B = Web tension distribution at outfeed | K =  Web correction | a = Correction angle max. ± 5° | σ1 = Web basic tension | σ2 =  Tension distribution due to pivoting action of roller frame at the infeed | σ3 = Tension distribution due to pivoting action of roller frame at the outfeed | 1 =  Pivot point | 2 =  Infeed roller | 3 =  Roller frame | 4 =  Sensor | 5 = Locking roller | LÜ =  Transfer length | L1 =  Infeed path | L2 = Outfeed path | AB = Operating width |

Position control and command station

Support Beam VS 45
Support beam VS 46

Position control and command station

Command station DO 40
Function 

ELROLLER steering roller systems used for web guiding already correct the web position on the infeed plane. They consist of a fixed base frame and a movable guide frame. The latter accommodates one or two positioning rollers and swivels round an imaginary pivot point on the infeed plane. A steering roller is referred to as a proportional actuator, which means that it operates under friction and must not permit slipping between the web and positioning roller. 

Area of use

ELROLLER systems are always used for web guiding where there is a long entry path due to technical process reasons.

Application

Depending on the available space, steering rollers can be equipped for web guiding with one positioning roller (web is guided with a 90° wrap) or two positioning rollers (lower wrap angles possible). The following applies when mounting an ELROLLER for web guiding: The infeed path should be the equivalent of two to three times the web width, the outfeed path should be between 50 % and 100 % of the web width. The sensor should be positioned behind the positioning roller, as near to it as possible. This offers a short response time, creating improved actuating dynamics.

One positioning roller

Key

A = Web tension distribution at infeed | B = Web tension distribution at outfeed | K = Web correction | a = Correction angle | σ1 = Web basic tension | σ2 =  Tension distribution due to pivoting action of roller frame at the infeed | σ3 = Tension distribution due to pivoting action of roller frame at the outfeed | 1 = Pivot point | 2 =  Infeed roller | 3 =  Guide roller(s) | 4 =  Sensor | 5 =  Locking roller | L1 = Infeed path to the pivot | L2 = Infeed path from pivot to steering roller | L3 = Infeed path | L4 =  Outfeed path |

Two positioning rollers

Key 

A-A = Web tension distribution at infeed | B-B = Web tension distribution at outfeed | K = Web correction | a = Correction angle | s1 = Web basic tension | s2 = Tension distribution due to pivoting action of roller frame at the infeed | s3 = Tension distribution due to pivoting action of roller frame at the outfeed | 1 = Pivot point | 2 = Infeed roller | 3 = Guide roller(s) | 4 = Sensor | 5 = Locking roller | L1 = Infeed path to the pivot | L2 = Infeed path from pivot to steering roller | L3 = Infeed path | L4 = Outfeed path

Position control and command station

Command station DO 40
Function 

In production processes with moving webs, there is typically an unwinding station at the machine infeed and a rewinding station at the outfeed. During unwinding, the winding station is moved via a linear drive to feed the web in the desired position. On the other hand, during rewinding, the winding station follows the constantly changing web position via a linear drive to achieve an evenly wound reel. 

Area of use

The ELWINDER web guiding system with winding stations is always used if it is not possible to use a pivoting frame or steering rollers due to lack of space.

Application

During unwinding with ELWINDER web guiding systems, the sensor is mounted on the machine to define the target web position. The position detection system should be located as close to the final winding station guide roller as possible. During rewinding, the sensor is fastened to the winding station to set the target position of the winding station for the controller. Here, the position detection system should be located as close to the final machine guide roller as possible. The guiding path L1 depends on the elasticity of the web. The larger the transverse elasticity range, the shorter the path L1 can be. Experience has shown that the guiding path should be the equivalent of half a web width.  

Unwinder Station

Key

 A = Web tension distribution on the guiding path | K = Web correction | a = Correction angle | σ1 = Web basic tension |  AB = Operating width | 1 = Linear drive |  2 = Infeed rollers | 3 = Reel station | 4 = Sensor | 5 = Locking roller | L1 = Guiding path |

Rewinder station

Key

A = Web tension distribution on the guiding path | K = Web correction | a = Correction angle | σ1 = Web basic tension |  AB = Operating width | 1 = Linear drive | 2 = Infeed rollers | 3 = Reel station | 4 = Sensor | 5 = Locking roller | L1 = Guiding path |

Command station

Command Station DO 30
Function

Web guiding with ELTURNER turning bar systems is based on a simple principle: A bar is mounted at an angle of 45° to the longitudinal and transverse axes while the web runs over it with 180° wrapping. This has the immediate effect of changing the direction of web travel by 90°. To correct the web at the same time, the turning bar is moved parallel to the infeed plane according to the actuating signal, thus offsetting the web to the side as it runs off.

Area of use

Use of a turning bar control system for web guiding is recommended in cases where space restrictions prevent the use of an ELGUIDER or ELROLLER system after the 90° deflection.

Application

When the turning bar is used as a web guide, there must be points of traction between the bar and the web. To protect the web surface, the friction can be reduced by inserting an air cushion between the turning bar and the web. Guiding precision of up to ± 1 mm can be achieved. For improved dynamic adjustment, a guide roller should also be moved together with the turning bar. The distance between the guide roller and the locking roller should correspond to half the web width. The sensor should be mounted immediately after the outfeed roller as close as possible. 

A combination of pivoting frame and turning bar causes the web to turn and at the same time ensures precision positioning control in the range of ± 0.1 mm.

Key

Key

 A = Web tension distribution at infeed | B = Web tension distribution at outfeed | K = Web correction | a = Correction angle | s1 = Web basic tension | s2 = Tension distribution during actuating movement to left | s3 = Tension distribution during actuating movement to right | 1 = Pivoting frame | 2 = Infeed roller | 3 = Turning bar | 4 = Sensor | 5 = Locking roller | 6 = Pivot point | LÜ = Transfer length | L1 = Infeed path | L2 = Outfeed path | AB = Operating width |

Turning bar guiding systems

VWS Turning bar system

Position control and command station

Command station DO 40
Function

ELPLACER lateral displacement roller systems position running webs via axial adjustment of the positioning roller. Here, if the positioning roller reaches the end position, the material is lifted by a device, the positioning roller is centered and the web is set back down. As the lateral displacement roller is only used in production systems with cycled operation, the process of lifting the web must always take place during stop times. 

Area of use

The field of applications extends primarily to tire building machines, as the webs like the ply and the inner liner are fed in from the loop in cycled operation. 

Application

The infeed always takes place from the loop from the bottom upward. Here, the infeed length should be half to a full web width. By contrast, the outfeed path is to be kept as short as possible. The sensor should be positioned behind the positioning roller, as near to it as possible. Thanks to the short response time, improved control dynamics are achieved. 

Schiebewalzensystem ELPLACER

Key

A-A = Web tension distribution at the infeed | B-B = Web tension distribution at the exit end | K = Correction of web run | α = Correction angle | σ1 = Basic tension of web | 1 = Pivot point | 2 = Infeed roller | 3 = Lateral shifting roller | 4 = Sensor | 5 = Lock roller | L1 = Entry length | L2 = Exit length

Position control and command station

Command station DO 40
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