Tips on Maximizing Converting Line Productivity
Boxmakers tend to focus on the boxmaking equipment in their converting lines, and little attention to end-of-line bundling system design. It’s understandable because making quality boxes is Job Number One. But a well-conceived and well managed bundling operation can help maximize line throughput and ultimately, the success of the plant.
The first challenge in successful bundler management is to develop the right specifications. Know the largest and smallest products the flexo can produce and be sure the bundler can handle the full size range. Be sure that the bundling system can keep pace with flexo output. Keep in mind, bundlers process bundles, while flexos count kicks or individual boxes, so the box-per-bundle-count is important to consider. There are a number of factors that affect bundle production. While the number of boxes per bundle is obviously important, most flexos also have an output curve that is a function of box size, so anticipated product mix is important. Also, with a trend to a higher proportion of smaller boxes, companies are turning to bundle breakers or twin box slitters to optimize flexo throughput. The bundler may see more bundles than the counter ejector does, and this must be considered.
Type of bundler is a key consideration. Once the physical requirements are determined, the buyer has to choose the type of bundler he needs. Solutions range from simple bundle strappers, to more sophisticated squaring bundlers, to tandem systems that offer high output with back-up capability to help assure uninterrupted operation. Given the relatively small investment for bundling systems compared to the total project, and the high cost of unproductive line time, an increasing percentage of buyers are opting for higher-end bundlers that offer quicker setups and backup capability for maximum uptime assurance.
Trend toward Integrated Squaring-Bundlers. As part of the trend to more sophisticated bundling systems, the popularity of squaring bundlers has increased. These systems allow more leeway at the counter ejector while still delivering a good looking bundle to the load former. However, as the bundling system becomes more sophisticated, so do bundle management requirements.
Squaring bundlers must be aligned with the center of the incoming bundles. This may be accomplished by adjusting the bundler position as box sizes change, or by installing centering conveyor between the counter ejector and bundler.
Bundle pacing is also an important consideration. Some counter ejectors may release bundles unevenly, which at high outputs, can disrupt bundler operation. A pacing conveyor entering the bundler helps manage uneven bundle flow and improve automatic bundler performance.
Setup tasks and times should also be considered. As flexo setup times have shortened, high speed lines can sensibly produce shorter box runs. Matching bundler setup capability to operating intentions is important. Simple bundlers may require some re-positioning of the strapper and a timer adjustment to put the strap in the bundle center. Squaring bundlers require centering, positioning of the squaring paddles to optimize cycle speed and placing the backstops to align the strap line with the bundle center. This can be done manually or with varying degrees of automation. Spending the time to understand options and selecting the level of sophistication that is consistent with overall line operation pays off when production starts.
A final bit of advice: When installation time comes, be sure to make time to adequately train maintenance personnel and operators on bundler operation and care. No doubt the critical part of a line upgrade or new installation is the flexo and related box forming equipment, but strapping system installers often struggle to get time and attention from plant personnel more engaged in learning the upstream equipment. Bundler issues can be easily avoided with sufficient training. Finding a way to fulfill the training requirement, on all shifts isn’t easy, but it definitely pays off.
A new bundler may not generate the goose bumps that a new flexo does, but it is a necessary, and we would argue, beneficial part of the overall production line. It can improve bundle appearance, protect the product and add to the quality aesthetic of a finished unit load. Most importantly a well designed and maintained bundling system contributes to the output of the line and the success of the investment. Time spent getting bundling right, is time well spent.