Comment The hidden production cost of
thinner casings By James Radcliff e, divisional manager, Interfood Technology
A
lower casing price is easy to measure, but the production cost of making that casing work is less clear. A saving per metre can disappear when operators are continually adjusting the clipper, output falls or a closure fails during cooking and a fi lled product is discarded.
This is where purchasing and production can
fi nd themselves with opposing targets. Buyers are asked to reduce packaging spend and production managers need to deliver the required volume of saleable product. If a replacement casing is approved on price before the line has proved it can run reliably, production inherits the risk. Casing changes do need production approval before committing.
WHAT CHANGES WHEN CASING THICKNESS IS REDUCED
Thinner does not necessarily mean poorer quality. A well-designed lightweight casing can perform reliably. Equally, a casing can meet its own specifi cation and still be unsuitable for a particular product, clipping machine or cooking process. The question is whether the proposed construction works within the line’s capabilities. Gauge, calibre and material construction
infl uence the amount and behaviour of casing gathered into the neck beneath the clip. Reducing
wall thickness at the same calibre generally reduces the material that the clip must grip. Changes in stiff ness, extensibility and surface characteristics can also change gathering and retention. Matching the fi lled diameter alone does not mean the casing is compatible.
For the production manager, the immediate question is whether an approved clip and closing setting can retain the new casing without damaging it, across standard production variation.
CLIP SELECTION HAS PRACTICAL LIMITS A clipping machine has a defi ned range of compatible clips and tooling. Closing adjustments work within that range - they do not necessarily give the operator a wide choice of fi nished closure sizes. A casing change can mean that the application no longer works with the combination. The Poly-clip ICA illustrates this limitation. It
specifi es four sizes of clip from small to large; S8735, S8740, S8744 and S8748 in the S8700 range and describes an additional S800 confi guration for thicker casings. The available choices depend on the machine’s confi guration. Each proposed casing must be assessed with the appropriate clip and tooling, rather than assuming the clip already fi tted will remain suitable.
For example, an application running on S8740 may need a smaller approved clip after a reduction
in casing thickness. Without adequate retention, the casing can slip from the closure during cooking. However, moving down a size is an application decision to be decided by trials, not an automatic response to every thinner casing. The clip must hold the gathered material securely without cutting or overstressing it. Increasing the closing setting does not always compensate for an unsuitable clip size. If no approved combination provides reliable retention without damage, the clip is unsuitable for the casing. That needs resolving before purchasing, rather than through repeated adjustments during a live order.
WHY A GOOD CLOSURE CAN FAIL LATER A clipped pack is produced by an interacting system - casing, food product, fi ller, clipping equipment and clip. Product temperature and consistency aff ect fi lling behaviour, whereas fi ll pressure, casing brake and portioning aff ect pack tension. The separator also needs to clear product from the closure area and gather the casing consistently.
During cooking, depending on the recipe and casing, product expansion and casing shrinkage can change the stresses on the pack. A marginal closure can appear satisfactory at the fi ller, but leak or lose retention during thermal processing. The handling that follows also needs to be considered. The fi rst sign of failure is clip movement during
fi lling, or casing damage after clipping. Other issues include irregular product shape and a rising number of operator adjustments. Record where the failure fi rst occurs, so the cause can be investigated.
Engineering should also check the condition and suitability of the punch, die and separator. Altering settings around worn or damaged equipment is an early warning that the tools may need replacing.
CALCULATE THE SAVING AGAINST PRODUCT LOSS
An example is - 10,000 metres of casing. A reduction of £0.01 per metre saves £100. If the change causes four additional cooked logs to be discarded at a production cost of £25 each, that saving has already gone. The same can be said about clips. Using non-OEM clips may look like
12
September 2026
www.convertermag.com
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