Increasing Packing Line Throughput

With a desire to automate its packaging line and improve upon its existing packaging methods, Don Wagner, general manager at AWP’s Kingwood facility, began searching for stretch hood equipment suppliers.
By Joseph Albert | December 11, 2019

Appalachian Wood Pellets Inc. in Kingwood, West Virginia, produces and packages wood pellets into 40-pound plastic bags, distributing them around the U.S. Originally, the 50,000-ton-per-year plant deployed a method of securing and protecting its palletized products by using stretch wrap, which was applied by semi-automatic stretch wrapper in conjunction with top sheets or pallet bag covers. The top sheets and bags were applied manually, and maximum throughput was approximately 26 pallets per hour.

With a desire to automate its packaging line and improve upon its existing packaging methods, Don Wagner, general manager at AWP’s Kingwood facility, began searching for stretch hood equipment suppliers, with the goal of finding a supplier whose equipment improved his line’s efficiency, load integrity and appearance, and reduced cost per load and cost of ownership of the end-of-line packaging. After screening various stretch hooding equipment manufacturers, he narrowed his search to Signode and its Lachenmeier stretch hood equipment line. The new machine was integrated in line with an upstream automated bagging line along with a robotic palletizing system.

Wagner says he thinks the most impressive feature of the Lachenmeier Power Flex T1 stretch hooder is its ability to automatically lower the top hood applicator down to floor level, which eliminates the safety risk of an operator having to climb to the top of the machine to complete routine maintenance.

“Previously, when any of my employees were going to conduct work off the ground, it was typically a two-person process, which takes twice as long,” Wagner says. “This increases down time, costs and safety risks. The workers must be harnessed in or tied down to the equipment to prevent the risk of falling.”

The stretch hooder’s four-legged structural support provides more machine stability, allowing the stretch frame to travel smoothly up and down, while applying the film over the load. Traditional models use two-legged support structures and cantilever design, which can be less stable and cause the top of the machine to sway when the stretch frame starts and stops during the film application process. The cantilever design can create pinch points and binding when the stretch frame is attempting to apply the film.

Finally, the machine’s film delivery system allows for complete control of the film-stretching process before it begins applying it to the load, as well as during the application process, with the benefit being that the film is flatter to the top of the load, thus reducing the risk of the film gussets being exposed to wind while in transit. It also reduces the film consumption per load, reducing the cost per load. 

Moisture Protection
Water that gets trapped between the layers of film adds weight to each pallet load. A customer of Signode’s reported that previously, trapped water and moisture absorbed into product added an additional 150 pounds to each pallet—significant, as the company ships 28 pallets on a truck.

Multiplied by 150 extra pounds per pallet, that equates to an additional 4,200 pounds per shipment.
Because the stretch hood is one solid piece of film, consisting of a sealed top and four sides, there is nowhere for rain, dirt, animal dropping, etc. to get inside the hooded load. Top sheets and stretch wrap are very easily penetrated by these contaminants, which can work their way between the layers of film. The result is a load with poor visual appearance, dirty and potentially damaged products.

Besides the waterproof packaging, the film used for wrapping is a colored film preventing the actual product bags from getting “hurt” by the UV light from the sun when being stored outside.

Clinging, Tearing
No cling, a characteristic of Signode’s stretch hooding film, is another important factor when loads are being moved and transported onto a flatbed truck or into a box trailer. To increase storage space or reduce freight costs, loads are generally very close to each other, causing them to rub. Stretch film can be very clingy, and often, it will tear when rubbed by another load. As a result, the loads may have to be rewrapped. For those loads that were already shipped, the tears will not be evident until they reach the distributor, box store, etc., a point at which it is too late. The load appearance is poor, the film is torn, and the ultimate result may be a leaning load, potentially damaged products, an unhappy customer and unanticipated costs to the supplier. Customers overwhelmingly prefer the arrival condition and appearance of a stretch hooded load versus a stretch wrapped load.

 “Since installing the Lachenmeier system, the end-of-line packaging process has operated much more efficiently,” Wagner says. “The finished products are more stable, much more appealing to the eye and have saved us on operating and labor costs and have reduced cost per load. In general, all the drawbacks of our former stretch wrap equipment have been offset.”

Author: Joseph Albert
VP of Sales, Americas