News

Modular Rewinds and Unwinds Allow Easy Increased Production and Added Capabilities

Wind Gap, Pennsylvania: CAC's latest single station and multi station unwind and rewind systems are engineered as modular technology allowing them to be easily integrated into existing lines. Among the benefits offered by CAC unwinds and rewinds are that they allow processors to easily and economically add a station and increase production, expand capabilities and reduce changeovers by allowing larger rolls.

According to Jeff Damour, CAC Engineering Manager, CAC unwinds and rewinds can be custom configured using off the shelf components and may be as simple or as sophisticated as the customer's application requires. They are exceptionally competitively priced competitive, are usually delivered and installed very quickly and are compatible with all web production materials.

CAC offers an exceptionally broad range of sizes and capabilities, including manual and automatic controls. Rolls can be handled at up to 2000 fpm in diameters to 60 inches and web widths to 120 inches and weights to 3000 lbs. For wider web applications, stand alone systems are the preferred choice. Machine mounted systems are available for narrow web operations and are offered in a wide range of simple to sophisticated systems.

”The benefits of our unwinds and rewinds are extraordinary. With a simple installation we can allow a converter to develop an entirely new process, such as laminating, for example. The modular construction designs made possible by our decades of experience in virtually all types of web operations make these systems an unusually cost effective solution to a converter's desire to grow without investing in a major overhaul. It is precisely the kind of technology converters tell us they are looking for-effective, easy to install, easy to maintain,“ Damour said.

CAC unwind and rewind options include single and multi-station in dual support pedestal and cantilevered configurations. CAC unwind and rewind stands feature compact designs to minimize floor space requirements and are heavy-duty; constructed of structural steel for maximum strength and rigidity. All systems are engineered to be readily retrofitted to existing lines and to seamlessly incorporate the full range of CAC web handling technology including air shafts, and safety chucks.

A typical custom configured CAC unwind/rewind system may include a wide range of CAC supplied options, including closed or open loop automatic tension control, web guide systems, COR-LOK® air shaft featuring exceptional gripping power, Shaft-Lok safety chucks, and idler rolls featuring Winertia® engineered aluminum tubing.

Currently celebrating its 31st year of success, Converter Accessory Corporation designs, engineers and manufactures web handling equipment for converters of paper, film, foil, nonwovens and textiles. Engineered solutions include high quality, cost effective equipment from the simplest aluminum core cone to the most sophisticated unwind/rewind system. CAC is represented by knowledgeable sales engineers and provides extensive consultation and post sales support.

For more information contact Pam Damour, Converter Accessory Corporation, 201 Alpha Road, Wind Gap, PA 18091-1279, (800) 433 2413, fax (610) 863 7818. CAC@epix.net Web site: www.handleyourweb.com

New Dual Station Scrap Rewind System Offers Exceptional Efficiency

Converter Accessory Corporation (CAC®) is introducing a new dual station system (SW2) that allows on-the-fly cutover with minimal to zero stop time. The SW2 is engineered for web widths to 30 inches and capable of rewinding rolls up to 36 inches in diameter in weights to 600 pounds. A robust drive delivers speed ranging from fractional to 1000 feet per minute. The complete, belt driven system is supplied with a torque controlled motor with manual control, digital torque setting and emergency ”stop“function.

The SW2 will readily accommodate automatic tension control if desired.

According to Jeff Damour, CAC® Engineering Manager, the SW2 is ideal for rewinding edge trim and label matrix scrap and is much faster than single station systems. While aimed at scrap rewind, the SW2 may also used for any rewinding application that fits the SW2's capabilities.

”Like all CAC systems, the SW2 is engineered for easy operation, easy maintenance and easy installation. It can be installed on a machine frame, table top or floor mounted. The belt drive is designed for reliable, quiet operation,“ Damour said.

The SW2 features CAC's widely used COR-LOK air shafts for fast, easy core locking and rapid roll changes.

In addition to the SW2, CAC offers a wide range of unwind and rewind technology optimized by CAC's unique ”building block“ approach. This approach begins with two basic pedestals to which any or all of CAC's web handling accessories can be added; including core support systems, shaft support systems, pneumatic conveying systems and wrinkle removal systems.

Drawing on the experience of more than 30 years of success, Converter Accessory Corporation designs, engineers and manufactures web handling equipment for converters of paper, film, foil, nonwovens and textiles. Engineered solutions include high quality, cost effective equipment from the simplest aluminum core cone to the most sophisticated unwind/rewind system. CAC is represented by knowledgeable sales engineers and provides extensive consultation and post sales support.

For more information contact Pam Damour, Converter Accessory Corporation, 201 Alpha Road, Wind Gap, PA 18091-1279, (800) 433 2413, fax (610) 863 7818. CAC@epix.net Web site: www.handleyourweb.com

Grooved Rollers for Wrinkle Removal

escription: A grooved spreader roller can be manufactured from a variety of materials, such as steel, aluminum, stainless steel, plated aluminum or steel and hard rubber. A rigid grooved spreader roller has grooves machined into the roller face surface. These grooves (resembling screw threads) are machined – starting from the center of the roller and leading out to each edge of the roller face. The grooves can be supplied in almost any fashion; from as simple as wrapping masking tape across the face of a standard idler roller to a machined groove that has very intricate machining details. Groove design is completely application dependent, however it can be generally stated that the greater the number of groove starts there are the greater the spreading will be realized. Theory of operation: Quite simply the theory is that the grooves will push wrinkles out of the web, from the center out to each edge, which, unfortunately is not always the case (see advantages and disadvantages, below). Recommended wrap angle for this type of spreader roller normally ranges between 90° - 180°. Advantages when applied as an idler roller:   This type of spreader roller will remove air when air entrainment is a problem (this in itself will help to remove or prevent wrinkles). Depending on the groove design, these rollers can often be manufactured by most machine shops, rubber roller manufacturer or idler roller supplier. Making this type of spreader one of the least expensive, most readily available types of spreader roller. Simplicity of design, with no special parts, makes this spreader roller extremely easy to maintain. Because this roller is linear across its face, it will not stretch, distort or tear any portion of the web. This type of spreader roller is best suited for use with textiles and non-wovens. It has limited application with papers, foils and films. Disadvantages when applied as an idler roller:   When this spreader is applied as an idler roller (driven at the surface speed of the web), the grooves do not push wrinkles out from the center of the roller face (even though this is most often believed to be the case). When the surface of the grooved roller is driven at the same speed as the surface of the web (such is the case when used as an idler roller) the tangent point, at any given point across the web or roller face, where the web first touches the roller remains in a constant position through the roller rotation. Because the tangent point of the web lying on top of the groove does not vary, the groove has no cross machine direction movement effect on the web. The belief that the grooves have some effect on the web is mostly an optical illusion (like the illusion caused by a rotating barber shop pole). An engineer once told me an excellent analogy of the non-effect of the grooves on the web in this application (I can’t take credit for the analogy); if you place a plow in a field, does the field plow itself by the rotation of the earth? Of course not, and the reason is because the tangent point of the plow in the field remains constant with the earth in its rotation. This type of roller does not have a smooth surface so it has the potential to mark the web surface. Some materials may deform across the web face and the groove will actually form in the profile of the web causing wrinkles. Advantages when used as a “dead bar” or driven slower or faster than the web:   All the advantages as an idler roller plus one more. When the surface speed of this type of roller is not synchronized with the web speed (standing completely still is included here) then we get a different level of performance with this type of roller. When this is the case, the grooves will push the web outward toward each edge of the roller face. This effect occurs because the tangent point where the web touches the roller face is ever-changing as the web travels around the circumference of the roller. The changing position of this tangent point ensures that the web, at that point, will travel in the direction the groove is facing. Disadvantages when used as a “dead bar” or driven slower or faster than the web:   Web marking and scratching will occur much more frequently than with spreader rollers that rotate, at the same rate, with the web. When there is speed differential between the roller face and the web, the web is not in traction with the roller. For this reason the web position can vary across the roller face causing edge guiding and possibly wrinkling problems down-line of this spreader roller. Grooved Roller – Soft Flexible Rubber Description: A soft flexible grooved roller can be manufactured from different types of rubber compounds, but what is most important is that the rubber is soft enough to flex under the pressure of the web tension. The flexible grooved roller has grooves machined under its’ surface. The grooves must be precisely spaced. The groove depth is varied across the roller face, as the grooves move out from the center of the roller, they get deeper. This depth variance is even across the face of the roller and must be accurately controlled. Theory of operation: As this roller rotates with the same surface speed as the web, it has flexible lands (created by grooves machined into the surface of the soft rubber face), which deflect under the webs tension. The lands deflect in the direction they are angled, from the center out to each edge of the roller face. The depth of the grooves increases from the center out to each edge of the roller face. The reason for the depth adjustment out to each edge of the roller face is so each land will flex more than the land next to it, ever increasing from the center of the roller. The difference in flex amount between each land is important because it provides for web spreading between each land. In other words if all the lands flexed exactly the same amount, spreading would be achieved only in the center of the web, there would be no spreading from land to land. Recommended wrap angle for this type of spreader roller is strictly application dependent and can vary between 30° to 180° Advantages:   This type of spreader will remove air when air entrainment is a problem. This will help keep the web in traction with this roller improving its’ operation. Because this roller is linear across its face, it will not stretch distort or tear any portion of the web. Because of its soft surface, this roller will not mark or scratch the web. This type of spreader is used with all types of webs. Disadvantages:   While the lands do flex under the pressure of the tension on the web, they will return to their natural position as the pressure is being relieved. The pressure is relieved as the web exits the roller. As the lands flex back to their natural position, some of the wrinkles the roller removed may return. This roller does not have a smooth surface, so some webs may deform inside the groove, taking on the profile of the groove.

This type of spreader roller has no wrap angle. Because the web is not supported across its full width, the material must be fed straight in and out of this spreader roller assembly.

Advantages:

• This type of spreader roller is the most aggressive.
• Simplicity of design makes this type of spreader roller easy to maintain.
• The amount of spreading is easily adjustable, by changing the angle of each nip set independently of each other.
• Works well with woven and non-woven webs.

  

Disadvantages:

• Because this spreader roller will not support the web across its full width, it will mark, distort and possibly tear most foils.
• This type of spreader roller is specifically designed for woven and non-woven materials. Any other type of materials may have difficulty with this type of spreader roller, because of web distortion.

Considering a New Roll Stand?

If you are a converter of paper, film, foil, textile or nonwoven webs, you are, most likely, familiar with unwind and rewind stands used in the converting process. There may come a time when you are considering replacing the existing unwind or rewind section of your converting process. This may be because you are looking to increase capacity, improve quality and performance or possibly to accommodate changes to your web. Whatever your motivation, the task of acquiring an unwind or rewind stand to accommodate your requirements may seem overwhelming. You may be asking yourself, where to start.

Budget: Understanding your budget and conveying that information to a potential supplier can save a lot of time. This information is important when considering the type of roll stand and many of the available options, like web guide, core holding, shaft support, tension control and anti-wrinkle requirement.

Double E Group Simple, Cantilevered Unwind Station

Lead time requirement: Most roll stands are custom engineered, designed and manufactured around customer operating specifications. This process may take considerable time, so understanding your requirement for delivery window will, often times, assist with equipment specification. Which leads me to the next bit of information any machinery manufacturer will require.

Double E Group Shafted Unwind Stand

Your operating specifications: This roll stand will most likely be manufactured to unwind or rewind specific size rolls at specific rates into a converting process requiring specific values. The information an equipment manufacturer will require includes these operating specifications:

• Machine - type of converting process
• Material(s) - type of webs to unwound or rewound
• Material thickness range - thinnest to thickest
• Core size
• Maximum roll diameter
• Web width range - narrowest to widest
• Web tension range in pounds per linear inch (PLI) - minimum to maximum
• Running speed range (usually in feet per minute, in the US) - minimum to maximum
• Maximum roll weight

A word about operating specifications: DO NOT over specify range. Price, design and operation will all be dictated by accommodating your operating specifications. Over specifying can lead to overpriced, over complicated and difficult to attain design parameters. Also, keep in mind 0 FPM or 0 PLI are not valid low-end speed and tension specifications.

Does your roll stand require web guide?

Most unwind stands require web a web guide system. There are a couple of ways to web guide unwind stands.

• Move the roll of material as it is being unwound. This type of web guide is more compact and potentially simpler than an intermediate guide system. However, it will induce more stress on your web when moving the roll laterally, during the web guiding operation than an intermediate guide.

Simple Unwind Stand with Roll Shifting Web Guide System
 

• Intermediate guide will move one layer of the web as it is unwound (instead of moving the whole roll of material). This type of web guide system induces the least amount of stress on the web.

Dual Station Unwind Stand with Intermediate Web Guide System

Some rewind applications will benefit with the use of an automatic web guide system.

• Moving the rewind stand laterally is actually considered a chasing operation. Instead of positioning the web where it needs to be - you will chase the rewind to where the web is going, as it is being rewound.
• Intermediate guiding onto the rewind is true web guiding, not chasing.

What type of tension control?

• Manual (really no tension control): This is manual control of a torque output device; brake, clutch or drive. Keep in mind unwind and rewind zone tension is directly affected by roll radius. Tension will change, proportionally to roll radius change as unwind rolls get smaller and rewind rolls build. Torque adjustments will, most likely, need to be completed as the unwind or rewind is running.
• Open loop tension control is an excellent upgrade to manual control. Open loop tension controls will sense roll radius change to adjust a torque output device.
• Closed loop dancer or load-cell control will measure web tension in the unwind or rewind tension zone and will adjust torque output of a brake, clutch or drive, automatically.
• These are the BASICS. Please understand there are whole classes and many documents dedicated to web tension and tension control. This is a white paper discussing the mechanical basics: https://www.converteraccessory.com/whitepages/tcpaper1.pdf

Shaftless roll stands support the core and roll with struts that supply torque to the core and roll from the ends.

Double E Group Shaftless Unwind Technology

Shafted roll stands include a center shaft, usually an air shaft that supports the full core and roll width.

Example of Core Shafts

Double E Group Multi-Station, Shafted Unwind Stand

Double E Group Heavy Duty Shafted Unwind Stand

These are just some starting points when considering a new, custom engineered and manufactured roll stand for your application. As you discuss your needs with an equipment manufacturer, more information will come to light as available designs and technology are discussed and pondered.

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Web Handling & Converting Industry Specialists | Double E Group