Caution! Glass!

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Gentle container processing in filling and packaging lines thanks to individual transport

No matter whether syringes, cartridges, ampoules or vials, containers for pharmaceuticals are nearly always made of glass and are therefore fragile. If a container breaks during the filling and packing processes, this leads to delays in production. If the glass has cracks, the respective container must be sorted out. For this reason, measures are taken during production to prevent broken or cracked glass as far as possible. However, in the meantime not only breakages and cracks are rejection criteria, but also surface damage such as scratches and flaws are becoming more and more an issue in the pharmaceutical industry.
The special machine manufacturer Bausch+Ströbel has been looking into ways of processing containers gently for over 15 years and has provided customers with intelligent solutions - initially in the primary packaging sector and now also in the realm of secondary packaging. The keyword here is individual transport.

It is obvious that cracks in a syringe or ampoule cannot be tolerated. Occasionally such damage has led to product recalls as contamination of the product cannot be excluded. But how does a surface scratch or a flaw in the glass impair the quality of the product? "On the one hand", Werner Wieland (M.Eng) head of the Design Department at Bausch+Ströbel explained, "perfect packaging stands for the value of the contents". This can be observed not only in the pharmaceutical industry but also in other sectors. For example, abrasion rings on a conventional mineral water bottle are considered quite normal whereas high-quality gourmet mineral water comes on the table in flawless designer bottles. This has resulted from a change in consumer awareness which increasingly demands quality. And yet the matter goes further than just the cosmetic aspects. Surface damage could also be a cause for cracks - a fact that authorities are examining more closely at present.

Changed production processes

A further cause for the frequently occurring damage to glass surfaces can be seen in the changed production conditions which have led to increased stress on the material. This starts at the glass-makers. In the past, glass containers were packed in cardboard boxes and placed in storage for longer periods. Nowadays the containers are shrink wrapped straight after the annealing process and dispatched shortly afterwards. Directly after production no water molecules can be found on the glass surface and due to the impermeable packaging the protective film caused by the diffusion of water cannot be created, leaving the containers more sensitive and difficult to process. Already during shipment the glass containers rub against each other. Scratches occur and breakage inside the packaging is not uncommon.

Further stress is exerted on the glass containers on conventional filling and packaging equipment. They are subjected to a great variety of forces during loading, spacing, transfer to the various work stations, cleaning, sterilizing, depyrogenation, filling and closing, and later on during collation and loading into trays. These forces are exerted on the one hand by machine parts responsible for conveying the containers, such as feed scrolls or star wheels, and on the other hand by the contact with the other glass containers. The use of auxiliary production materials designed to reduce the friction is often no longer permitted.

In addition, the increased capacity of modern filling and packaging equipment causes higher stress for the containers. "The output of production lines has nearly doubled in the past decade and this has increased the stress on the packaging materials", said Werner Wieland. The ESA 1025 labeling machine processes up to 800 vials, cartridges or ampoules per minute.

How can the impact of these forces on the containers be minimized?
Firstly, materials with a lower friction factor and better shock absorption are being used in the machines - primarily synthetic materials. Another alternative are pucks which were originally introduced to convey unstable containers through the production line. However, as the containers stand freely in the pucks, the advantage in respect to gentle transport is only minimal because they collide with the puck if they are accelerated or decelerated and may even collide with adjacent containers.

For over 15 years, Bausch + Ströbel has been using individual transport systems for such applications. Syringes and cartridges are already inserted in tubs or trays by the glass manufacturer. They are lifted out by robots, loaded into the machine and returned to this packaging after processing. Apart from the gentle handing of the containers, this has the advantage that the start-up and running empty procedures are controlled, there is no loss of containers and no operator intervention is required.
In the production line, the containers have no contact with each other whatsoever. During transport the design ensures that only minimal forces are exerted on the glass.

Transport rails guide the containers through the sterilizing tunnel, and star wheels convey the vials or syringes from one processing station to the next, holding the containers by suction. Even during the processing (rinsing, filling, closing or labeling) the forces applied to the containers are minimal as they are held in plastic grippers.

The components of the line are synchronized precisely thereby making buffer tables - which cause friction stress - superfluous. This kind of container handling requires a more sophisticated logistics chain as the glass manufacturers have to supply their products in trays or tubs which may have to be returned to them for refilling. The level of automation of the production lines is higher - and thus also the initial purchase price.

This is compensated in part as less personnel is required. Moreover the individual transport excludes impact load as there is no relative movement between the container and the means of transport - and as a result no scratches, chips, breakage or glass particles. This eliminates production downtime required to remove damaged containers from the machine. Another advantage of the individual transport system: It easily allows 100 percent Track & Trace during production.

The gentle treatment of the packaging does not stop at primary packaging on Bausch+Ströbel machines but is also applies to tray-loading and labeling machines. Whether a pharmaceutical company opts for the gentle individual transport procedure depends on the quality required - and, of course, on the unit costs which in the long run could be less than on conventional lines despite the higher investment.

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