Automated bagging machine uses Mitsubishi throughout

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Pennine Healthcare has used a range of Mitsubishi equipment to automate the sterile bagging of medical devices.

Automated bagging machine uses Mitsubishi throughoutPennine Healthcare, based in Derby, UK, makes an extensive range of single-use medical devices, with all manufacturing undertaken in a medical quality clean room. With over 60million individual products made per year, automation is vital to help avoid contamination through human intervention, maintain quality and consistency, and contain costs.

A Yankauer is essentially a rigid extruded PVC tube, with one end attached to a suction line. The free end is chamfered to avoid sharp edges, has a series of radial holes and is angled for ease of use. Further back along its length, the bore diameter is enlarged (through an air injection during extrusion) and a larger hole is provided to allow suction control during use. As well as being used by surgeons, they are also used by dentists and vets.

Manufacture of these Yankauers has always been partially automated but, until recently, bagging them into poly sealed packaging was a manual process. Darryl Orridge, a plant and systems engineer with Pennine Healthcare, says: “We were aware that this was a production bottleneck, that the operatives had to maintain very strict hygiene routines and that inner packing was disproportionally expensive compared to the rest of the processes. So we were keen to look at automation.”

In-house expertise

Many of Pennine’s manufacturing processes are unusual, if not unique. Add to this the discipline for clean room operation and its engineering expertise has to be first class.

Orridge comments: “For us, manufacturing technology is not a commodity that can simply be bought in as required. It is a core skill within the framework of the company and we have a highly skilled team dedicated to the development of our own high-performance and sophisticated custom-built manufacturing systems.”

Pennine has long favoured Mitsubishi for control technology and systems and it was the launch of the new Q series programmable automation controller (PAC) that encouraged Orridge to consider the options for Yankauer packing.

He says: “The process can be broken down into distinct stages. We have to load the Yankauer into the packaging machine; make the bags from a roll of flat tube polythene; insert the product into the bag; then seal and label it. There is a 200W Mitsubishi J3 servo axis advancing the bag, the sealer/perforator, labeller, interlock, data handling and several other functions. In total there are 262 input/outputs, all handled by a Q01 PAC plus an E1032 HMI (human-machine interface) for local control and monitoring.”

The Q series is a flexible unit with dual central processors, which Pennine uses in a mutual redundant configuration, and a bespoke array of modules for each of the functions under control.

Because the machine is compact, loading requires the products to travel a route around several obstructions. This is achieved with a Mitsubishi RV3SB six-axis robot, controlled via the Q series. The main conveyor within the cell is controlled by small induction motors with Mitsubishi 0.18kW FR500 inverters for speed matching.

Orridge says: “This is the first time we have used the new J3. Previously it has been the J2. By comparison, the J3 is smaller, faster, more powerful and easier to programme; it is no harder to set up than a conventional AC motor.”

Fieldbus communications

In another innovation Orridge has also made considerable use of fieldbus communications. CC-link is used for communications between the robot bagging machine and packaging machine, while ASiSafe is used for the safety interlock. Orridge states: “Fieldbus has been a revelation for me. It is so easy compared to conventional wiring: just run the bus cable around the machine and link in the various devices locally. I reckon we saved several days of wiring up and troubleshooting in the build phase, and in-use repairs and alternations are the work of moments. We have decided that CC-Link is going to be the company standard from now on.”

Pennine’s commitment to automation matches its commitment to continuing manufacturing in the UK and the company will continue to automate its processes. Significantly this helps keep costs down so that exports are competitive, even when compared to products from low-cost economies. Currently half of all production is exported - a proportion that has been growing steadily for many years.

17 June 2008

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