Converting

There’s more to blister packing tablets and capsules than simply forming, filling and sealing. Lynda Searby finds out how the latest kit is coping with changing formats and tighter controls

In the words of one blister packing equipment supplier, “in an ideal world everybody would produce round tablets”. However, in the real world, with manufacturers introducing intricate shapes to prevent counterfeiting, the variety of formats is only going to increase.

“The number of product shapes has grown dramatically, from standard, round bi-convex tablets, to flat or elliptical and multi-faceted shapes,” says Brian Hansford, joint managing director of feeding systems specialist Electro-mec.

This trend clearly has major implications for the feeding and filling operation. Historically, the most common method of filling blisters was the brush box, whereby product is deposited on the web and brushed along into the forms. However, this method relies on product finding its own way into the form, so while it is still acceptable for standard-shaped tablets and capsules, this ‘free for all’ approach is far from perfect for irregularly shaped products.

Electro-mec says a typical solution is the use of individual feed tubes, which precisely position a single tablet or capsule in each form every cycle, as provided by its EMF range of feeders. It says this reduces mis-filled rejects and allows rapid, intermittent motion packaging.

In a recent example, installing an EMF1 feeder enabled a customer to increase line filling speeds by over 20 per cent. At the company in question, the EMF1 is working in conjunction with a Noack 623 blister machine, filling a variety of capsules into a number of blister formats, including a chevron layout. Prior to the installation of the EMF, filling speeds were between 35 and 40 packs/min. Now they are closer to 50 packs/min.

Logic TPS recounts a similar success story at a major UK generic manufacturer, where it installed two IMA Win Pack blister packing machines, fitted with inclined vibratory feeders to fill flat oval tablets into blister forms. “They were very tricky because if you stood them end-to-end and pushed they would lock within a track,” explains Logic’s managing director Keith Gooch. The installation increased output to 150 blisters/min, compared to the 80 packs/min the company was achieving with a brush box feeding mechanism.

The simultaneous feeding of different products into one blister pack presents another challenge for feeders. This can be achieved by the installation of multiple feeders over a single blister forming machine or the creation of split hoppers to allow multi-product feeding from a single tablet feeder.  

Similarly, large and awkwardly shaped capsules and caplets are prone to standing upright rather than lying down in the blister form. Electro-mec has addressed this issue via its Caplet Orientation Unit, which gently pushes each caplet into the forms.

It follows that the introduction of a wider variety of product formats has been accompanied by a marked shift away from dedicated high-volume lines and towards producing smaller batches of different products on more flexible lines. This has pushed shorter changeover times and easier cleaning to the top of equipment buyers’ wish lists.

“Minimising changeover and cleaning time is essential to profitability, particularly as we generally have to strip machines down much further at batch end to comply with more rigorous cleaning and verification procedures,” affirms Andrew Billington at contract packer Brecon Pharmaceuticals. “GMP-compliant design of blister machines and quick-change features are therefore essential.”

Brecon is the largest user of Romaco’s platen-sealing Noack blister packing machines in the UK, with four 760 units, five 623s, and further Noack lines on the way. The Noack 623 will be in action on the Romaco stand at the PPMA exhibition.

This heavy focus on changeover times means a blister packing machine’s efficiency is no longer judged on how many packs it can churn out every minute. “Increasingly, producers need to consider their overall production profile – the number of batches and typical batch sizes – when specifying a machine,” says Romaco’s UK sales director, David Dixon. “Start-to-finish batch times are the key here, and machinery manufacturers have worked hard to design machines which are easy to clean according to GMP regulations and fast to changeover.”

He says changeover times of less than 30 minutes are not uncommon today, thanks to lines with quick-release tooling, fewer format parts and operator guidance via the user interface.

Logic’s Gooch says user specifications usually stipulate a maximum changeover time of 15-20 minutes. He says Logic is able to meet these requirements by installing thermoform-fill-seal systems which are servo-motor controlled and incorporate industrial PCs. “This means when operators change between tablets or capsules, the system can remember exactly what conditions were in place before, so PVC temperatures, sealing temperatures and sealing pressures can all be repeated.”

IWK’s machines, meanwhile, have tool-less changeover, so a complete changeover and cleaning can be effected within an hour. The machines’ surfaces are smooth, with no gaps, crevices, countersunk holes or pipes, to assist quicker clean down.

The ratio of machine footprint to output has also become an important indicator when evaluating equipment. Logic TPS manufactures a small high-speed line, which can pack up to 300 cartons/min and is seven metres in length. High speed lines are usually about 10 metres long.

The new Giant1 integrated blister line from IMA is touted as the fastest micro blister packing line on the market. It achieves up to 350 blisters and 175 cartons/min and is only six metres long,  as the blister machine and the cartoner have been integrated for optimum efficiency.

Integrating the blister packing and cartoning operations has also allowed IWK to minimise the space occupied by its latest line. Blisters are transferred directly from the punch into the cartoning machine. As well as eliminating inefficiencies during the transfer process, this means IWK lines have a smaller footprint than older-generation machines.

The burden of ever-tighter regulatory controls in the areas of validation and child-resistant packaging as well as increased expectations in terms of product integrity have fallen on the shoulders of blister packing machinery manufacturers. Brecon’s Billington confirms that quality, regulatory and customer expectations have added to the complexity of operations at the firm. He cites more rigorous process measurement tests, leak integrity testing and wall thickness testing as examples of some of the additional functions that have had to be incorporated into its blister packing lines. “Machines now have a battery of detection devices, including high product sensors, eject verification, splice detection and Pharmacode reading,” he says. “We have fitted colour camera systems as standard on all new lines to ensure product integrity.”

In addition, following the move in the UK to make child-resistant senior-friendly (CRSF) packaging a legal requirement on certain blisterpacks, Brecon Pharmaceuticals has integrated pill-protect technology into its Noack 623 line. The system runs through a purpose-built reel holding unit and labelling head, which has been specifically designed and built for Brecon’s Noack machine and has been managed by Romaco. A reel of labels is used to supply the head and single labels are then applied in the correct position on the top of the already formed and sealed blister pack. Both are then die-cut to produce a clean one-piece finish.

Pill Protect offers a number of products that meet BS8404 standards; these range from a push-through barrier for everyday products to a peel-and-push solution for delicate items. This layer is then applied directly onto the backing foil of each pack during the blister process.

Seal of approval for Packaging Automation
Heat-sealing equipment manufacturer Packaging Automation has installed a twin-base rotary sealing machine at a prominent UK medical device manufacturer’s site in the north of England. It is using the machine to seal precision-engineered medical implants into sterile blister packs. The machine has two stations – one for loading and one for sealing – and has an automatic tool identification system which checks that the correct tool has been fitted. With seal integrity paramount, the machine is fitted with a direct pressure transducer, which records the seal force applied.

Packaging Automation says seal parameters can be easily set and accurately monitored and, if the seal force falls outside the pre-set parameters, the pack is rejected. A thermal printer is incorporated to provide a comprehensive record of the force applied, seal time, number of packs sealed, temperature and tool code to allow full traceability.