Stretch wrap: Is it time for lean packaging?
September 01, 2011 - MMH Editorial
Pat Lancaster, the chairman of Lantech, has been around stretch wrap machinery as long – or longer – than anyone else in the industry. Now in his 70s, Lancaster says his focus these days is on research and development and not on selling equipment. As a result, he spends a fair amount of time visiting customer sites with his technicians. There, he gets a chance to see what happens to a stretch wrapper out in the field. “I’ve even been known to turn a wrench,” Lancaster says.
When we spoke earlier this week, he talked about two different subjects that are on his mind as a result of customer visits.
The first is what Lancaster described as “the degree to which film companies influence the decision-making process when customers purchase stretch wrap equipment.”
The other is that when it comes to the transport packaging that is applied at the end of the line, there are few of the process controls in place that you would otherwise find in a lean manufacturing process.
At first, these seemed like two different topics. But to Lancaster, they are connected and lead to a question: Why don’t lean manufacturers use lean principles when it comes to their unitized loads?
First things first. Talk to an end user or a stretch wrap film supplier, and they’re likely to mention how much they pre-stretch the film, the gauge of the film and whether they use cast or blown film. “Those are all important when it comes to the price of the film,” says Lancaster. “But at the end of the day, what really matters is containment force.”
Containment force is basically how tightly the film is wrapped around the load – regardless of the gauge of the film or how much it’s pre-stretched. “Containment force is like putting on torque with a wrench,” Lancaster says. “At the end of the day, I don’t care which film you use. If you put on the right amount of containment force, you’re load is going to ship just fine. If you use too little containment force, you’re going to have a problem with load failures. If you use too much containment force, well, you’re just wasting money.”
Lantech advises customers to determine the right combination of gauge, pre-stretch and containment force that delivers the performance they’re looking for with a tolerable number of film breaks per roll – remember that the more you stretch the film and the tighter it is wrapped, the more likely it is to break. “If you want 5 pounds of containment force and one break per roll of film, you can see what percentage of prestretch and gauge will deliver the performance you’re looking for,” Lancaster says. That is true whether you use a Lantech machine or a stretch wrapper from one of Lantech’s competitors.
Lancaster’s second observation is that most of the sophisticated consumer goods manufacturers he visits have embraced lean methodologies to improve the quality of their manufacturing processes and products. But lean seems to stop at the end of the line before a carton is placed on a pallet.
“Before a beverage manufacturer fills a container, the product has gone through a tremendous amount of process control,” Lancaster says. “They know the temperature of the product and the thickness of the plastic bottle,” Lancaster says. “There are processes on the line to insure that the flaps on the corrugated containers are square.”
Meanwhile, when it comes to the stretch wrapper, “I’d say that 20% of big companies have a specification for wrapping a load,” Lancaster says. “Of those, almost no one has a specification for containment force, a quality check to insure that their wrap specifications are being met or a process to correct a load if it’s not.”
The result: It’s not unusual to see 15 or 20 deliveries a day that need assistance to get loads that have shifted off the truck.
I asked Lancaster how Lantech is addressing the issue. He says the company is making machines that hold the load to tighter tolerances and notify an operator with a change on the readout screen if a metric has changed that could cause a failure to the load.
But more importantly, Lancaster believes its time that manufacturers extend their lean processes and process controls beyond the end of the line to palletizing and transport packaging.
“Big companies do a remarkable job of producing great products,” Lancaster says. “In a lean process, if something doesn’t meet the specification the way it’s supposed to, they shut down the line until someone figures out what to do to fix the problem. We need to apply that kind of thinking to stretch wrap and transport packaging.”
Equipment 101: Unitizing equipment
There are many ways to unitize a load, but the common goal for most operations is to stabilize and protect products while they are in motion.