Understanding the Extrusion Process
Robert Tewksbury, vie president of Pearl Technologies, Inc., is excited to help educate the industry about the extrusion process.
Q: What new equipment features or technologies are being introduced to this sector of the industry?
A: Blown film extrusion has always been driven by a demand for better film at higher outputs. Reduced friction and ability to cool the bubble play increasingly important rolls.
As soon as the industry provides a solution to overcome these issues, the market drives the resin manufacturers to formulate new compounds that yield beneficial features to the marketplace while inadvertently creating new processing hurdles. This is a common experience as films continually are downgauged (thinner) and often times tackier.
Higher quality is not only measured in gauge uniformity and web flatness, but also clarity and roll quality. This is extremely important for converters because of the high quality packaging requirements from today’s customers.
The pre-nip chiller/spreader is one of the newest products introduced to chill the bubble on both sides prior to entering the nip rolls. This allows for both higher outputs and reduced use of process enhancers, such as anti-block and slip agents, which can lead to compromises in film’s physical properties such as clarity or strength. Pre-nips are just one technology introduced to boost extrusion performance leading to quick paybacks on investment.
Q: Any generic pointers on how can a company make the highest quality extruded blown film possible?
A: There are two simple words to remember, basics and benchmarking. High quality film always begins with collapsing geometry and nip-to-die alignment. Too often extrusion lines are not benchmarked and over time subtle changes are made to influence the bubble as it travels from the extruder to the primary nips. This is where stresses placed on the bubble manifest themselves into less than desirable quality results such as wrinkles and bagginess. I'm being kind by using the phrase “subtle changes,” because this usually entails lots of tape and cardboard.
Q: What's missing from this sector, or the flexible packaging industry as a whole? What would you like to see improve?
A: I'd like to see more training, seminars, literature, editorials and education on blown film extruding. Simple benchmarking of new extrusion equipment, so producers can go back to their starting point as the years go by.
By training and benchmarking your extruders, not only will the blown film producers benefit from higher outputs, but in turn their customers will benefit from higher speeds in converting their film into quality packaging.
Pearl Technologies, Inc.
(315) 365-3742; www.pearltechinc.com