Since Wal-Mart's sustainability initiatives were ﬁrst introduced in 2007, sustainability is a subject manufacturers ﬁnd hard to avoid. For packaging manufacturers and suppliers, the added pressure to "go green" has only escalated over the years, with customers unwilling to lower their expectations for suppliers to meet varying sustainability goals.
However, more companies are also realizing that implementing sustainable practices isn't just improving the environment, but also their bottom-line. For example, companies using petroleum-based products are being greatly aﬀected by rising oil barrel costs and have had to reduce usage to minimize costs. For stretch-wrap users, these factors are all too familiar.
While packaging sustainability is focused on reducing primary packaging material and increasing cube utilization, the end-of-line stretch wrapping process is critical to achieving optimum product delivery and reducing waste. As another step in the supply chain, it can't be ignored if companies are looking to meet industry demands and achieve greater overall production eﬃciency. Advancements in ﬁlm, equipment and technology are making it easier to reach sustainability goals while minimizing costs.
Reduction of materials is practiced in the name of sustainability. The reduction in primary packaging has put greater demands on stretch wrapping operations. Manufacturers are no longer just wrapping boxes of canned goods. For most manufacturers, stretch wrapping has become essential for products that create unstable loads, such as water bottles and open-top display boxes.
As we have gone from boxes to trays to pads to nothing but shrink wrap, manufacturers have become more reliant on the end-of-the-line stretch wrap to make sure their product makes it to their customer intact and unharmed. Stretch wrapping may be the last operation before the product leaves the production facility, but it is the ﬁrst thing the customer sees when it enters their facility.
Therefore, increasingly, stretch wrapping has become recognized as a critical component in making sure a product arrives in its intended condition. Most companies have already made signiﬁcant investments upstream of the stretch wrapper, but any improvements (and the costs) will be wasted if the product arrives damaged.
It's easy to understand how reducing ﬁlm consumption is good for the environment. Less waste in landﬁlls, reduced oil demands of producing plastic resins and decreased energy costs associated with manufacturing the ﬁlm are all green beneﬁts to help meet growing sustainability initiatives. However, reducing ﬁlm usage when stretch wrapping while avoiding load damage can be a challenge.
Here are a variety of solutions to minimize ﬁlm usage, optimize load containment and improve eﬃciencies while at the same time improving sustainability impact.
Thin is in
The most obvious way to reduce ﬁlm consumption is to use a thinner ﬁlm. However, moving to a thinner ﬁlm without properly analyzing if it will work for the particular application will often result in an overall increase in ﬁlm usage. In addition to the likelihood that a manufacturer has to compensate by using additional ﬁlm to maintain the integrity and security of the package, a thinner ﬁlm that is inappropriate for the application also creates the possibility for ﬁ lm breaks. This will almost certainly increase overall ﬁ lm consumption and labor costs, while slowing productivity.
The good news is that recently several high quality, thinner ﬁlms have come to market that can eﬀectively reduce ﬁlm usage without compromising the integrity of the load. When evaluating any new ﬁlm, thorough testing with the new ﬁlm and intended application is essential, as well as performing an ASTM standardized force-to-load test. Similar testing can also be performed to ensure the proper number of wraps are being applied.
Load tension can be adjusted
One often-overlooked opportunity to limit waste is by applying proper tension to the load. To put it simply, most stretch wrapping machines have a tension adjustment that aﬀects how tightly the load will be wrapped. It is important because if you don't apply enough tension, you run the risk that the loads will topple over in transit. If you apply too much tension, it can "squeeze" the ﬁlm too tight around the load and damage the product or increase the probability that the ﬁlm will break.
When ﬁlm breaks occur, it is common for operators to "ﬁx" any stretch wrapper issue by lowering the tension. In a study by ITW Muller, a customer could see a 12 percent increase in ﬁlm usage when wrapping a load under low tension settings versus high tension settings. This is because when it is kept under high tension the ﬁlm retains its stretch while low tension allows the ﬁlm to recover and spring back.
Spitting out ﬁlm at low tension may be good for wrapping empty PET bottles that are prone to crushing under the lightest of force, but the majority of loads would be better served by allowing for optimal tension throughout the wrap cycle. By applying just the right amount of tension at various points on the load, manufacturers can be assured that they are reducing product damage while simultaneously lowering ﬁlm costs. Variable tension control allows for increased tension at locations on the load that require extra hold (the base of a sturdy box) and lighter tension where reduced force is beneﬁ cial (sharp corners, the top of an open box). For example, ITW Muller not only oﬀers variable tension control on its Octopus machines but, integrated with the OctoMAX system, users can also monitor the settings-making it easy to view how previous loads were wrapped and quickly identify where changes need to be made. The variable setting control eliminates ﬁlm breaks and reduces usage by optimizing the settings based on the load conﬁguration and containment needs.
As ﬁlm type, load dimensions or pre-stretch requirements change, the wireless function and monitoring system further make it easy to adjust to new settings. The wireless control also minimizes components and maintenance, adding additional cost-saving beneﬁts.
Measure, monitor and act
To really understand and quantify the beneﬁts of any change made, having a way to record the performance of the ﬁlm and equipment is essential. With retailers increasingly looking for proof that a manufacturer is making strides in its sustainability promise, stretch wrap equipment manufacturers are beginning to add monitoring systems to their machines that will measure and display at the HMI the precise amount of ﬁlm that was applied to each and every load.
Monitoring tools enable the user to keep a close eye on ﬁlm usage and machine settings to drive down the cost of stretch-wrapping operations and simplify maintenance. It can even be used to compare the performance of two diﬀ erent types of ﬁlms. As the old adage says, "What gets measured, gets done" and this is a way to ensure that the pre-stretch performance promised is actually delivered.
Optimize the system
True optimization and savings comes from looking at the stretch-wrap operation in its entirety-ﬁlm, equipment and service. The return on investment in a simple service audit of your existing equipment can be tremendous. Speaking to suppliers and ﬁnding out what upgrades are available is an essential component to improving sustainability.