Davis-Standard stretch film line redefines efficiency
Davis-Standard has engineered a stretch film line of which they believe redefines modular efficiency for high-grade film operations. Installed in early 2017 for a large-scale North American film producer, this technology is the new standard for stretch film line configurations due to multiple operator and production advantages. These include a compact machine arrangement, ease of operation and servicing, excellent profile control, consistent roll quality and an intuitive control package.
The system is engineered for producing thin films from 31-to 51-gauge (7.8µ to 13µ) at high speeds. Davis-Standard’s side-by-side DS S3 overlapping winder is essential to this capability. The S3 winder enables maximum slit widths for hand-wrap, machine-wrap and jumbo rolls, supporting multiple market segments on one winder. Films discharge out the front of the line to a common side to simplify roll packing and future automation. Cores are also same-side loaded from the back to prevent disruption of packing activities. There is an auxiliary lay-on roll to eliminate top-wind waste during transfer, optimizing roll quality and eliminating outer wrap transfer waste.
High-volume core bins minimize refilling frequency and feature a simultaneous core set discharge of multiple core lengths while also decreasing cycle time, improving slit-width flexibility and net film utilization. Core widths can be changed on the fly to maximize uptime. There is a 30-second cycle time regardless of the number of slit widths, which is ideal for hand-wrap products. A pull-through trim system eradicates trim jams into the granulator regardless of line speed or film thickness. Motor-driven web support rollers with an air-venting finish improve film transport at high line speeds, providing quality winding and wound roll formation. The air-venting idler roll finish locks film on the rolls at low tension for excellent tracking and roll edge straightness.
In addition to system components, an over-the-line mezzanine accommodates a smaller footprint, while also enabling safe servicing of the extruders, screen changers, melt pipes and associated control systems. With the unique “through-the-mezzanine feedblock riser,” there is safe and convenient access to the selector plug for layer-sequencing changes. Selector plugs can be changed with minimal downtime allowing product flexibility in layer-sequencing to easily accommodate production schedules.
The customer has been pleased with overall performance and reports very few medium gels and no large gels in films, which is paramount to thin film production. The combined IR web measurement system, profile control, melt delivery and gravimetric rate control has resulted in a deviation of less than one percent, regardless of film thickness, resulting in superior roll quality.