What's new in film processing technology
Die locks out leaks
A flat die originally designed by Extrusion Dies to prevent melt leakage at the deckled portions of the die gap in extrusion coating is said to provide the same benefits for cast film.
The new system combines an internal deckle (which blocks flow with blades between the die lips) and an external deckle (which seals off the die gap from outside). “Because the external deckle is linked to the drive of the internal deckle, the units function as one system, providing precisely co-ordinated movement and a truly leak-proof barrier”, explains Sam Iuliano, manager of technical sales.
While the external deckle in the coating version covers both die lips, for the film version, EDI has developed one that mounts only on the flexible lip side of the slit. This leaves the fixed lip side unobstructed to ensure that the air gap necessary between lips and casting roll is not compromised.
“The streamlining achievable with an internal deckle is even more important for cast film than for coatings, which are more ‘forgiving’ of hang-ups or dead spots in melt flow,” says Sam Iuliano. “In cast film, the polymer degradation caused by such flow disruptions can cause serious optical defects and degrade physical properties.
“Even though the melt pressure behind a deckle can be very high, a well designed deckle should be leak-proof if the operator fully tightens the lip adjusting bolts at each product change-over. In the real world, however, operators often do not tighten the bolts fully, opting instead for a torque level that allows blade movement without need for loosening and retightening the bolts.”
The new dual deckle system is available with a motorized drive or a manual one operated by a handwheel.
Breathable film costs cut
‘Direct extrusion’ – the compounding and processing of highly filled polymers in a single production step, has enormous cost advantages that have led to its use in an increasing number of applications.
Reifenhäuser offers the Reitruder, an extruder with co-rotating twin screws, for this type of work. According to the company, production of breathable film can derive substantial benefits from direct extrusion. A considerable amount of money can be saved, it states, as the complete compounding process can be omitted. Compared with ready compounds, the required raw materials are much cheaper; and costs can be reduced further by combination with Reifenhäuser’s non woven coating technology, which enables the processor to produce film of lower weight.
Ready compounds can also be processed. In this case, pre-drying is not required, as the Reitruder is provided with a venting system.
A second Reitruder line for production of breathable film is about to be shipped. It has a capacity of 500kg/h and is capable of producing film of up to 1,600mm trimmed width.
Fast, accurate analysis of the oxygen permeation performance of packaging film up to 1.27mm thick can be performed with Systech’s Series 8000 analyzers.
Two versions are available: the Model 8000 has a wide measurement range of 0.008-432,000cc/m2/day; and the Model 8500 is suited for less demanding applications, covering 50-99,999cc/m2/day. Both are said to achieve analysis without complex extrapolations, combining speed with precision. The control software runs on any Windows platform, automatically guiding the operator through the test procedure.
Winding whatever you want
Independent Machine Co has developed a system for slitting and traverse winding a wide range of PSA coated film and foam materials. The 15in wide system features nine computerized Smartwinder-2000 modular spool winding cubes capable of different winding patterns.
The auto edge guided cantilevered unwind has programmable tension controlled by non contact ultrasonic diameter measurement. The system can operate at up to 750ft/min and accommodates interchangeable assemblies for razor, score and shear slitting.
Each cantilevered Smartwinder-2000 position produces spools up to 12in wide x 15in OD on 3 and 6in cores. It operates completely independent of all other positions and has a computerized, fully adjustable, servo driven traverse that will vary pitch, stroke length and end dwell, and is capable of a wide range of spool sizes and winding patterns.
Precise adjustable rewind tension is speed controlled by an independent closed loop follower drive system through the IMC dancer/tension controller, with a 50:1 tension range and diameter measurement. The operator touchscreen has recipe storage for setting all winding parameters and operating adjustments. All adhesive contact points are coated with a non stick finish.
Gauge gives greater control of film thickness
NDC Infrared Engineering has developed an infra red film thickness gauge said to give greater production control. Benefits claimed for the FG710 system include reduced scrap volumes, shorter start-up times, improved product quality, greater productivity, fewer customer returns and a low cost of ownership.
The FG710 is said to be superior to nucleonic sensors in the measurement of most products, offering high speed measurement, simple calibration, minimal maintenance and excellent measurement performance characteristics. It can be used to measure mono-layer films, and up to four separate co-extruded layers simultaneously, for accurate measurement of barrier or tie layers, for example. It is also capable of measuring a wide range of film thickness (from 12 micron to 5mm) and types, including voided, hazed, pigmented, and filled.
The new gauge is also able to detect streaks as narrow as one mm, allowing the control system or operator to intervene and eliminate the cause. Its short and long term measurement repeatability and stability are said to allow for tighter control of the film to the target weight. This also gives line operators the confidence to reduce film weight towards the lower production limit.
The FG710’s design allows internal and continuous standardization, eliminating the need for off-sheet standardization. This is especially critical during start-ups or after product grade changes, when getting the film thickness profile back into tolerance quickly is important in ensuring minimal scrap.
Fast cast five
Davis-Standard recently developed what it claims is “the industry’s most advanced” 4m cast film line for processing industrial pallet stretchwrap.
The five-layer system is capable of processing speeds ranging from 450-600m/min with outputs between 2,500 and 2,800kg/hour.
Sold to a customer in Spain, its advantages are said to include faster cycle times that eliminate off-line rewinding for handwrap, and a single roll handling system that simplifies winding logistics by only requiring one robot for unloading.
Reifenhauser rolls out a special service system
With the establishment of its RQS Quality Service, Reifenhäuser says it is offering a modular service system that provides fast and competent assistance worldwide. This includes a hotline that “eliminates a telephone answering machine and makes ‘live’ contact with someone from the Reifenhäuser headquarters in Troisdorf “365 days around the clock”.
Another module of the RQS concept is eliminating possible problems before they arise. Reifenhäuser will contact customers to arrange a “preventative action” visit by a technician or engineer. Any unnoticed problems (such as with parts wear) that may have crept in can be found and eliminated by the installation of spares, thus avoiding unplanned production downtime.
Metallizing matters in Malaysia
Valmet General has supplied a vacuum metallizer to Daibochi Plastic and Packaging, one of Malaysia’s largest manufacturers of flexible packaging film for the snack foods, beverages, confectionery, biscuits and bakery markets.
Over the last few years, metallized film has become popular as a cost effective substitute for foil packaging. It is of major importance to Daibochi’s Malaysian customers, as the country has a high humidity level that demands good barrier packaging to prolong the shelf life of products.
The metallizer supplied by Valmet General has the capacity to process rolls of up to 1,250mm width to a diameter of 1,000mm. It is equipped with a plasma treater to improve coating-to-web adhesion during the metallizing process.