Wet Wipes Case Packed via Robots at 160/min

Medline Industries of Northfield, Ill., is the largest privately held manufacturer and distributor of medical supplies, including medical-grade wet wipes. Not long ago, the medical resource provider realized that its existing system for case packing wet wipe products comprised outdated equipment that no longer fulfilled its needs.

To find new equipment to replace its aging machinery, including a 2004 Goodman gantry packer, Medline turned to Pearson Packaging Systems, which had acquired Goodman in 2008.

Medline was looking for a solution that could accommodate large- and small-scale operations at 150 products/min. They also wanted the ability to quickly scale production, anticipating rapid market acceptance of a test product.

Robotic Top Loaders use custom end-of-arm vacuum tooling to pick packs of wipes in groups of two, three, or four, according to the recipe.Pearson’s solution also needed to address the old machine’s limited two-axis, gantry-style movements, which caused the product’s corners to catch on the corrugated during packing. Additionally, product shingling during transfer at higher rates restricted the speeds at which the previous solution could pack product.

Through simplified and accelerated changeovers, decreased downtime and maintenance, and reduced dependence on low-skilled labor, Medline was hoping to achieve a significantly reduced Total Cost of Ownership (TCO).

With new equipment for secondary packaging that includes a Pearson CE15-T case erector, three Fanuc six-axis robots with continuous-motion conveying—all model M-10iD/12 robots—and a Pearson CS25-42T case sealer, Pearson was able to exceed Medline’s rate expectations, delivering 160 products/min. The system also includes an ergonomic hand-pack and hand-seal station with case start-and-stop foot pedals that allow for of small batches of test product without needed to program new recipes into the HMI.

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The flexibility innate to robotic solutions supports easy accommodation of different product types, rates, and pack patterns. The corner snagging issues were resolved through corner guards on the end-of-arm tools (EOAT) to protect product during packing and articulated motion to nimbly move the product into tight spaces. Product shingling was overcome using vision and line tracking to ensure proper spacing between products for a reliable pick.

Three EOATs per robot supported by automatic changeover enable quick and easy accommodation of new product runs, while continuous-motion conveying minimizes product damage, leading to increased uptime and reduced maintenance.

Additionally, the solution used a U-shaped floorplan, allowing a single operator efficient visual and physical access to the entire line.

Sequence of operation

Knockdown RSCs are stacked into the extendable, horizontal case magazine of the CE15-T. Blank suction cups advance to select the case, which is then indexed into the case-feed roller and transferred into the case-flight system. Opposed vacuum cups engage the case, and a pneumatic-operated set-up arm erects the case. The minor flaps are then closed and sealed with pressure-sensitive tape.

For smaller-scale productions, an operator station set up immediately downstream from the case erector includes a case escapement and a foot pedal to release cases. Empty erected cases exit the machine upright to be conveyed downstream to three Fanuc six-axis M10 Robotic Top Loaders (RTLs).

The new Medline case-packing line uses a U-shaped floorplan, allowing a single operator efficient visual and physical access to the entire line.While cases are being erected, a pre-feed conveyor transports product—seam up and short dimension leading—through the product conveyor. A regenerative vacuum blower jump transfers product onto the vacuum infeed conveyor. As the product passes over the backlit conveyor, a vision system determines the position and orientation of the product as it moves upstream toward the top loaders. Rejected product runs off the end of the product conveyor and collects in a discharge bin.

The RTLs use custom end-of-arm vacuum tooling to pick in groups of two, three, or four, according to the recipe. After picking the product, the robots rotate 90 deg and place it in the case in a single-layer pattern to maximize space and eliminate the chance of product corners snagging on case flaps during packing. Three EOATs included with each robot allow operators to modify pack sizes and patterns, reducing changeover time.

Full cases are discharged from the cell via the full case conveyor and are conveyed to the CS25-42T case sealer. The minor and major flaps are folded, and the case is sealed with the pressure-sensitive tape. For smaller-scale productions, an operator station set up immediately upstream from the case sealer includes a case escapement and a foot pedal to release cases. Finally, the cases are conveyed to an upward gravity conveyor where they are transported to the palletizing area for shipping preparation.