Reverse and reduce

4 March 2019

Slitting and rewinding remains important for operations executives. Apart from the potential gains in efficiency and reduction of downtime, a good system will provide speedy return on investment and reduce waste. How can the manufacturers of the systems make this information easier to understand? Experts talk with Matthew Rogerson.

At its simplest, slitter rewinders sit at the beginning of a converting operation and cut a large roll of material into narrower portions. As each roll needs to be cut, aligned and sent down the line, this is a crucial step in the converting process, and one that has to work flawlessly every time. If the roll is not wound properly, or the cuts are made in wrong place, converters are left with a large useless roll that is waste. 

Recently, this has become truer for those in the flexible packaging market, where slitting and rewinding is the final stage. This is why it is so important the machines run seamlessly in order to get the product out the door to customers as soon as possible in as high quality as possible.

“Throughout my visits to flexible packaging converters worldwide one thing that always stands out is the large amount of work in progress (WIP) that is generated prior to the actual slitting,” said Barrie Homewood, Titan sales and marketing director at Atlas Converting . The solution is clear, “the best way to reduce the WIP is making the slitting process smoother and eliminating any backlog.”

 Look to the future, now

Removal of backlog or long periods of downtime is a must for the industry. It is an area which accounts for most of the wasted time and resources, and stands to see the biggest gains when managed properly. One company that has been at the forefront of innovation in slitting and rewinding systems is Kampf Machinery Corporation. The company’s director of business development, Randy Wolf, was clear that company is fully embracing industry 4.0.

“We have announced the launch of the Kampf Converting 4.0 advanced integrated data collection and process control system.  This allows for a smart data in the factory monitored and controlled remotely by cyber-physical systems,” said Wolf. “This process will enable operators and management to make real-time decisions through real-time data collection. Not only is slitting and rewinding becoming smarter, but the entire converting process is moving towards industry 4.0.”

Within the umbrella of industry 4.0, how would Wolf best define ‘converting 4.0’? 
“We see it as the next tool for productivity growth, and one that is driving machine and process development of the converting industry.” It is propelled by a number of key trends, including low cost data collection, the reduced cost for increased computing power, the ability for machines to connect over wide networks – even when made by different manufacturers – in addition to instructing physical converting machines from remote digital locations. 

“What this will mean for the converters is operators, computers and automation will all interact in new ways, remotely connected slitters, rewinders and other systems linked to computer systems equipped with machine learning algorithms that can learn and control the machine production, with input from both human operators and computers,” said Wolf.

Converting 4.0 is still in its infancy, however these digital technologies and data collections systems have been growing for some time now. Some are not yet ready for application at scale. But many are now at a point where reliability and lower cost are starting to make sense for applications in the converting industry. However, a lot of companies in the converting industry are not consistently aware or prepared for these emerging technologies. 

Wolf concluded, “There still remains a mentality even today in the converting industry that whatever errors occur in the printing, coating or laminating departments will be automatically corrected in the slitting process. This is a production and profit killer. The whole converting process must work together as a well-oiled and managed unit. Please keep in mind that the requisite tools are generally the last piece of capital equipment that will touch your materials before they get shipped to your customer.”

Go hard, win big

Albert Torrent, slitting brand manager at Comexi agrees. “All customers want to achieve a high return on investment (ROI). To achieve this, they look for reliable equipment that provides the best possible slitting quality. Time is money, so converters and customers also look for a high productivity ratio in order to reduce dead time or waste time. The packaging and flexible packaging market tends to ask for more automated solutions.”

Torrent adds that customers want solutions that increase the added value of the slitting process. As currently, they appreciate one shot laser perforation and reclosure labels while they are performing the slitting process.

“The company continues to focus on innovation in slitting equipment that offers high added value solutions, such as laser technology or automation systems,” continues Torrent. “Specifically, our laser technology allows converters to differentiate themselves from the competition quickly and easily, by providing a wide gamma of applications such as easy open windows, microperforations or code insertion. At the same time, automation systems allow converters to increase their productivity exponentially.”

Moreover, Torrent notes some of the main trends that have marked the slitting sector and the flexible packaging industry in recent years have been targeted effectively by Comexi, “Currently, runs are becoming shorter and the explosion of new market niches has led to the appearance of personalised and differentiated products: containers that extend shelf-life, which are more sustainable, ecological, easy to use and formed by more complex laminated structures”, he explains.

Therefore, converters frequently bet on high-quality equipment that provides the highest productivity and the ability to respond quickly to new market needs. All this promotes focus on machines that can work with higher tensions that offer more automation, turrets, great ergonomics and maximum efficiency.

The skeleton key to productivity

Further insight was provided by Uli Jorgens , sales and technical director for the slitter and rewinder division of Karlville. He started by emphasising that productivity is key, claiming, “It is vital to continuously enhance key capabilities of our systems, like improved slitting, fast and efficient rewind systems that do not tangle, all within healthy tension control parameters. In addition ensuring the same roll quality consistently is a major benefit for our customers.

“As we move towards 4.0, the ability for the operator to remotely access and intervene in the machines’ human machine interface (HMI) becomes increasingly important. The aim is to expand on the scope of available data and commands available with this feature,” said Jorgens.  

In addition, another key benefit of a good slitter and rewinder is the cutting accuracy benig consistent, while keeping high-quality tension control to produce a brilliant finished roll first time every time. The machine is the final peice in the production process of flexible packaging material – and the last chance for a quality check.

The manual setup time of slitting knives is time-consuming, error-prone and unsafe. Selecting semi or fully-automatic knife positioning is safe, precise and reduces setup time significantly. Another improvement is to reduce the operator-influenced time of rewind roll change. There are quite a number of solutions offered, such as turret rewinders, rewind roll push-off and unloading systems, auto-finished roll labelling and packing concepts.

Lastly, but vitally, the industry continually sees the machines overlooked as a line item during a plant refurbishment or expansion. This means buyers have a smaller budget and focus too much on time to deliver the system than on what it actually does once in situ. It is critical to research the machine thoroughly and investigate extra features that can be used in the field, before the machine is locked into the line, as there are always savings to be gained through planning. As each factory is different, companies need to tailor the machines to perform to their best, and that needs advance planning for best results.

When asked about what trends they are seeing in the slitting and rewinding part of the converting process, Wolf and Torrent agree that productivity and profitably are key. “There is a big trend at the moment to focus in on material handling,” Wolf said. “Included with your slitter and rewinder should be material handling features and options that will increase the pure productivity and profitability of your slitter and rewinder. You could have the fastest machine available on the market, but if you can't get the finished rewind rolls off and reload the new cores onto the rewind shafts then the money you spent for that speed is totally lost." He explains that the material handling options can include rewind shaft finished roll pushers that will automatically push the finished rewind rolls off the cantilevered rewind shafts onto a rewind unloading unit that can automatically marry up to the rewind shafts and then automatically pivot away and turret over for the proper unloading height.

Torrent agrees with Wolf about material handling. "Machine upgrades can be improved if we automate all the steps that occur after slitting such as labelling, wrapping or palletising, using robots connected to our slitters. This improvement is one of the main ways to reduce any downtime. In that sense, it is possible for all machines to be connected to a cloud system that will help improve efficiency and performance."

Torrent also sees a few other emerging trends in the slitting, rewinding and flexible packaging arena. "Things such as shorter printing runs, automation, the current explosion of new market niches, demand for personalised and differentiated products, the emergence of eco-friendly packaging and packages that are more sustainable and lengthen the useful life of food are some of the trends we are seeing," he said. "But above all, slitting equipment that offers productivity and the ability to respond efficiently to the latest market needs is what customers want."

Companies are being forced to lead with complexity and a rise of stock keeping units (SKUs). So, companies need slitters and rewinders that are able to deal with more complicated jobs and able to avoid being stopped and downtime. Changeover is critical

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