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Smart baggers optimize efficiency

The Nypro Healthcare plant in Gurnee, IL, which has 28 injection molding machines that produce in excess of 2 billion parts a year, is a dedicated Sharp PackNypro bagger1.jpgaging Systems facility. Thirteen of the machines are equipped with baggers, and all of the baggers are Max Plus units from Sharp Packaging Systems Inc.


Founded in 1955, Nypro is a leading global solutions provider in the field of manufactured precision plastic products. The company operates 44 locations in 15 countries, employing more than 17,000 people. Sales for the most recent fiscal year were approximately $1.1 billion. Integrated into the Nypro Worldwide Quality System are 12 healthcare plants that manufacture products for the healthcare industry. Combined, the plants operate more than 394 presses and encompass 442,000 square feet of assembly area.


"We started using Sharp equipment 10 years ago, and our usage has expanded since then," says automation/project engineer Greg Johnson. "We now have replaced all the baggers in the plant with Sharp's Max Plus baggers, which have Windows XP operating system and Panasonic's PLC systems on board."

 

Molding machines run 64 cavities

In a typical operation during Packaging DigesNypro infeed.jpgt's visit, a molding machine from Netstal Machinery Inc. was producing small polypropylene vials for a global medical OEM. All production is made in an ISO Class 8 molding environment. Resin is delivered from an overhead hopper into the molding machine that produces parts off 64 cavity tooling.

 

At the completion of the cycle, the finished pieces are picked up by a robot from Wittmann/Battenfeld and transported to an integral automation cell. The robot places the pieces on stems in the cell where they are leak tested. The robot then picks up the pieces and drops them into a channel that delivers them to a Max Plus bagger. 


Poly bags, which are also manufactured by Sharp Packaging in a continuous web with perforation between each bag, can be delivered on a roll or folded in a box. In either case, the bagger pulls the bags through a series of tensioning rollers into the bag filler. At this point, the bag passes a labeler that prints and applies a thermal-transfer label.

 

The label contains date and time, lot code and a sequential code, allowing individual bags to be tracked. The labeler, which is supplied by Sharp as part of the bagging system, actually is manufactured by Datamax-O'Neil.

 

The bags then enter the filling zone, where the molded parts are loaded. The intermittent-motion bagging machine stops during the fill cycle and remains stopped until the bag has received the set quanypro-print.jpgntity of pieces. In this case, the bag contains 502 pieces, which is eight molding-machine cycles. 


The Max Plus incorporates Sharp's positive entry funnel system in which an option selectable air blast and/or vacuum cups opens the bag, the funnel moves into the open top, and the molded parts discharge into the bag. After the bag is filled, the funnel moves away and fingers move outward to pull the top tight and the bag is heat sealed. It then discharges onto a take-away conveyor.


The bagger features Sharp's Recovery Mode system, in which it can be programmed to try to open the bag multiple times before it discharges from the machine. "Recovery Mode is a real benefit, because we don't throw away parts or stop the production cycle," Johnson says.


If a bag to be filled does not open, this is detected by a bag open sensor, which stops the product from discharging. The defective bag is discharges the same as if it were filled and is removed downstream. A new bag replaces the bag that failed to open and production continues uninterrupted. 

 

Integrated controls

The controls on the bagger and the automation cell are integrated, so the bagnypro-weigh.jpgger knows how many items a bag is supposed to contain, and it knows when that quantity has been filled. At that point, it momentarily stops the filling cycle, discharges the filled bag and delivers the next bag. "We had problems when we first installed the baggers, because we didn't want to stop or delay the molding process while the bag discharged, and there was nowhere to hold the parts. Sharp came up with way to accumulate parts above the bagger during the bag filling cycle," Johnson says.


Customers for the parts require that samples be taken periodically for inspection, so the system is set up to discharge the product from one cycle (64 pieces in this operation) into a separate bag. The system control is set up to accomplish this at set intervals. Other than the number of pieces in the bag, the process is similar to the regular operation. The system is programmed to print a specific label for the sample bag. 


The controls for the labeler, printer, bagger and molding machine are all integrated so that when the machine operator selects the product to be run from the menu on the bagger HMI, it will also set the bagger and labeler controls accordingly. 

 

"We worked with Sharp to develop software and to standardize HMI and PLC programs on all of the machines, so that the operator can select a product from the menu on the HMI, and all of the equipment is set up accordingly," Johnson says. "Sharp has also expanded the software so that HMI can display parts lists, service requirements, as well has any Nypro imported documents, work instructions, pictures and video. All of which can be viewed at the bagger HMI."

 

Fill bags by weight

Some of the molding operations at Nypro package parts by weight rather than by count. These use the Sharp Max Plus baggers equipNypro - robot.jpgped with net weight scales from Weigh Right Automatic Scale Co. Products from the molding machine discharge via robot into the hopper on the scale and a vibrating pan discharges the products into a weigh bucket. The weigh-scale uses the "bulk and dribble" method of vibrating the majority of the desired weight quickly into the weigh bucket (bulk speed), and the rest slowly (dribble speed) to provide an accurate weight. 


Once the set weight is present, the bucket discharges into the open bag, which then is sealed. The label is applied prior to product loading. The scale system is integrated into the control system for the former and bagger, so the operator only needs to select the product at the beginning of the operation.


"We have a good relationship with Sharp engineering," Johnson says. "We share ideas and they help us solve problems. I've mentioned the accumulation system that Sharp came up with. In another situation, we had a problem with large bags, and Sharp developed a vacuum open system to solve the problem. 


"Sharp provides great service and training. In the end, however, the biggest factor in our conversion to Sharp technology is simply that competitive baggers weren't as smart."


Datamax-O'Neil, 800-816-9649. www.datamax-oneil.com
Netstal Machinery Inc.,
978-772-5100. www.netstal.com
Sharp Packaging Systems Inc.,
262-246-8815. www.sharppackaging.com
Weigh Right Automatic Scale Co.,
800-571-0249. www.weighright.com
Wittmann Inc.,
860-496-9603. www.wittmann-ct.com

 

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