Taking care

A key requirement of any web conversion operation is to ensure that the substrate is maintained in optimum condition both before and during the various processes it must undergo to achieve a finished product of the best possible quality. Cleaning, static control and web treatment all play their part.

Eddie Schleising, managing director of the Schleising Consultancy, says static elimination is becoming increasingly important to meet today's requirements for safety and comfort of production line operators, as well as for quality and speed of production. "In the interests of saving costs it should be realised that static does not need to be removed from every point that it occurs, only where it creates problems," he stresses. "No matter what the line speed, level of static, width of line, simple questions and logical reasoning can deal with all problems."

The Schleising Consultancy has treatment equipment that can be hired and adapted to fit into lines for trial purposes. Having established the performance of equipment in-house, it can extrapolate results and specify what is required for permanent installation.

Eurograv provides UK converters with static control solutions developed by ACE di Barbui Davide & Figli, including anti shock, anti static bars, air blow ionizing devices and ESA electrostatic assist systems used in gravure printing of flexible packaging. The company's Rotostatic system is said to increase print quality and production speeds on low grade or recycled paper and on strongly insulated plastics film. Missing dots are a common quality problem associated with static and gravure printing. According to ACE, the Rotostatic ensures complete and accurate transfer of ink to paper or film without excessive roll pressure. Configured to suit specific applications, a basic system includes a control panel connected to an electrostatic bar located above the pressure roll. ACE also produces non contact web/sheet cleaners that will remove particles smaller than one micron.

Following an investment of over £3M in cast and blown stretch film technology, UK producer of palletwrap film Eurofilms Extrusion needed a static control solution for the film casting process, to control the film as it is applied to the casting roller. UK/Eire agent for Eltex Elektrostatik Arrowquint used the German manufacturer's KNH18 static inducement generator and R23ATR pinpoint charging electrodes, to provide Eurofilms with "product consistency on a 24/7 basis". By inducing a static charge on the two edges of the film ('edge pinning'), the stability of the material is enhanced, which in turn, offers greater product consistency and a reduction in film shrinkage.

The latest version of the Process Control Co's X-STAT high performance ionizing bar used on converting, and reeling operations, and plastics bag manufacturing machines is lighter and stronger than the one it replaces, making it easier to mount on the machine. The new bar is also said to ionize more efficiently and is effective at web speeds of 600m/min.

The bar can be supplied with an integral air manifold, allowing it to be effective at greater distances from the static charge, using clean, dry compressed air. In the Bi-phase version, it is effective on web speeds of 1,200m/min.

To monitor residual static charge levels on a web, Meech International's new Model 987 charge sensor is said to be effective and inexpensive. Suited to a wide range of applications including slitters and rewinders, it can also be used to monitor static charge levels within classified hazardous zones. This is particularly important for processes such as coating, laminating and gravure printing. Alarm features warn operators if the residual static charge reaches an unacceptable level. An output terminal for data logging is also incorporated to allow connection to a Factory Management System for real-time, continuous monitoring. The company's 988 sensor bar can be used within a classified hazardous zone by connection through a Zener barrier to the 987 controller mounted in a safe area. This alerts the operator when the static charge level presents an explosion or fire hazard.

Two other new Meech solutions for static control in classified hazardous environments are the Model 915Ex AC system and the 976Ex pulsed DC bar for long range ionization up to 600mm. Both products are certified by BASEEFA to comply with Article 9 of the Council Directive 94/9/EC (ATEX) and are particularly suited to coating, laminating, finishing and gravure printing applications, where the highest safety standards are mandatory. Both bars are said to offer enhanced ionization, longer effective life and reduced contamination.

Film and sheet handling is set to be "revolutionized" by a new Simco static control system, according to exclusive UK distributor Advanced Dynamics, formerly WLT. The PerforMAX 3 is said to be the most advanced system available for monitoring static neutralizing performance. "It provides outstanding extended range performance to eliminate static charges even when installed up to 250mm from webs and up to 500mm on winders," it is claimed. The system is also said to be capable of neutralizing charged materials travelling up to 2,500ft/min.

Suitable for a wide range of applications including film rolls, plastics sheets, paper, printing plates, and web systems, PerforMAX 3 features include rugged bar construction with precise emitter spacing for maximum performance, a bar-to-bar connection capability, and a graphic display that indicates when the bar requires cleaning or if there is a fault. It is also suitable for use in hazardous conditions.

Advanced Dynamics director Mike Essler says: "PerforMAX 3 is a technology breakthrough and should provide significant cost savings for those involved in film and sheet handling."

Ion Industrial's Virtual AC static neutralizer is now offered as standard on Kampf slitter rewinders, to neutralize static charges on webs running at speeds up to 1,200m/min. According to Kampf, with the Virtual model, half the number of ionizers are needed to achieve the same performance as with conventional static control equipment.

Just three standard Ion 8001KD-W neutralizing bars can be combined for any of the numerous slitter sizes from 3,750-9,000mm, simplifying replacement and reducing the spare bar inventory. System wiring is simplified with the use of short high voltage cables (max 0.5m) connecting the bars to an IP54-rated high voltage power supply.

Also offered on Dusenbery Worldwide slitters, the Ion Industrial neutralizers can now be quickly and easily integrated into a process control system over industrial networks to improve productivity and operator safety.

For corona treatment applications on blown extruders, Ferrarini & Benelli offers the Poliplast Bikappa bilateral treatment station. Made of anodized aluminium and stainless steel, the unit has a vacuum electrode holder hood system, directly connected to an extraction fan. This allows the use of high power coefficients, needed for the high speed treatment even of extremely slippery materials, without creating deformation of the electrode and thus modification of the air gap.

For corona treatment applications on cast extrusion and extrusion coating lines, F&B offers the new Kappa Plus high performance mono-lateral treatment station. Said to be extremely versatile, it can be equipped with aluminium electrodes for treatment of films and paper, and ceramic electrodes for treating conductive films in general. Key new feature is that the electrode groups are interchangeable, so that all types of materials can be processed with the best results.

The electrode can be equipped with a special air gap adjustment system that may be used even when the machine is running. Adjustment by a graded knob simplifies setting. Both systems feature a special up-down electrode permitting simple selection of the zones to be treated, as required. An external adjustment system is said to ensure easy setting of the electrode-roller gap when electrodes are replaced and/or to process materials of different thickness. A fast take-off system facilitates maintenance.

Aerogen's flame pre-treatment systems have undergone a number of developments recently, including automated burner position control and automatic deckling of the flame width. Also, heightened capacity of the flame systems now allows for operation at speeds up to 650m/min. Flame pre-treatment of cartonboard is applied to the web prior to lamination to enhance adhesion to the polar LDPE laminate. The flame also removes loose surface fibres and warms the substrate slightly to make it more compatible with the molten laminate. This gives the board-to-laminate bond greater strength, preventing delamination throughout the life of the carton. This technology is widely used in the laminating of liquid packaging such as juice and milk cartons.

Aerogen has also broadened its range of treatment stations with equipment available for post treatment of film and laminate webs. Advances in automation of the combustion systems required to control the process are said to have led to greater process control and improved gas savings.

Kelva and Vetaphone combined their respective expertise in the CC-Plus Corona Cleaner, claiming it "the best narrow web combination on the market" for web cleaning, corona surface treatment and static neutralization. This novel unit is said to "reduce space requirements drastically and increase functionality to ensure higher overall print performance through efficient web cleaning and high surface adhesion". Suitable for stand-alone operation or complete machine integration, it can be mounted cantilevered and has all connections at the back. Profi-Bus/Can-Bus/TCP-IP/MOD-Bus or PLC interface is possible, and three models are available, for web widths up to 300, 450, and 600mm.

Airknife systems are ideal for cleaning and even de-ionization of web materials, as well as drying, cooling and curing, says Air Control Systems. Providing a continuous and even curtain of air across full web widths through linear plenums, they ensure the full surface area is treated. The company claims its blower driven airknife systems "provide a cleaner, quieter and more cost efficient option than conventional compressed air alternatives". A de-ionization bar can be added to combat static problems.