The control of industrial processes
The control of industrial processes requires carrying out measurements, tests and analyses at each stage of production, generally integrated into quality management procedures.
The parameters which characterise the quality objectives for a substance or an object entering or leaving a production stage are given acceptability criteria defined in specifications.
These can be set within a company to control its production processes or shared with suppliers or customers in the context of a supply contract or for qualifying a new product reference.
The numerical value of a control parameter is meaningful only if the methodology, the equipment used and the procedure applied are known.
When industrial production is concerned, the sampling procedure and the statistical treatment of the results are also important to define, according to the situation.
Parameters to control
For bottling processes, the parameters followed will obviously depend on the step concerned in the overall process.
To enable the different components to be correctly assembled, for example, applying a cap on the finish of a bottle, dimensional characteristics are particularly important.
For a finished bottled product, the parameters under control would be those necessary to guarantee people’s security and the performance for the end-user, for example, absence of leakage, trouble-free opening, aesthetic aspect, etc. These must take into account the conditions that the finished product may encounter between leaving the filling plant and being consumed by the end customer. The tests concerned may thus include a simulation of reasonably possible extreme conditions during transport, intermediate storage and use phases,
given that these conditions cannot be entirely controlled by the producer. Such simulations may require accelerating physical or chemical processes involved,
in particular by increasing the temperature, in order to evaluate through a laboratory test over a limited period of time the variation of the performance during the expected lifecycle of the product.
Harmonised test methods
In all cases, harmonised test methods are clearly a prerequisite for establishing corresponding quality criteria.
Test methods have thus been a subject of standardisation since the first standardisation bodies were created at the end of the 19th century in response to this need. In the field of bottling, the Cetie is in a privileged position for establishing pertinent and consensual test methods between the different interested parties.
Even if a specific version of a given test may be imposed by a filler on his suppliers for a specific reason,
it is clear that overall industrial efficiency is best served by test methods shared and employed by the majority of the bottling value chain concerned.
PET working groups
As an example, a specific Cetie working group has been developing since 2013 a manual of qualification tests for flat top plastic closures for PET bottles, the quality Guideline n°18
. Based on an existing document published by the ISBT (International Society of Beverage Technologists) in 2003, much extended, this action has been an opportunity to establish more general relations with ISBT on reference documentation in areas of common interest. The document developed by the Cetie group is thus currently under final verification by an ISBT
This collaboration enables extending participation to certain American and other experts and promote international recognition of the manual when published by the two organisations. The manual includes 39 test methods classified under “dimensional”, “performance” and “reference”, the latter being less systematically used in qualification procedures.
The use of the tests for different types of the bottled product is indicated in a matrix, as are the qualification tests appropriate to use according to the main element of new development. Although qualification of new products is the main intended use of the manual, the tests which are also suitable for production quality control are identified.
The manual is expected to be published in early 2019 after the completion of the document release procedures in the two organisations.
Decoration of glass flacons
In a different field, the decoration of glass perfume flacons is the subject of a working group initiated in 2016.
Decoration, and more general techniques used to obtain specific aesthetic effects for perfume flacons, are part of the normal competitive positioning of perfume brands and their glass flacon suppliers. However, the objectives of qualification tests for new decorated product developments are clearly the same for all interested parties.
It is thus anticipated that the harmonisation of these tests will generally contribute to the efficiency of new product developments and the time to market.
An initial phase to collect information on currently used tests for lacquered flacons confirmed the usefulness of the work item with, for example, more than 40 versions identified of the test for the resistance to bulk (i.e. the product contained), depending on the brand. Differences were sometimes small (e.g. a temperature of 40 °C, 42 °C or 45 °C) but each combination of test conditions had a historical reason for the brand, now often no longer known. The group has thus initiated test programmes in order to objectively clarify the selection of harmonised test conditions, in a first instance for the test of the resistance to water and resistance to bulk.
Although the group is specifically oriented to the perfume market, lacquering is also used for other markets and the glassmakers supplying spirits bottles have expressed interest to participate in this action.
"Action in Cetie to harmonise test methods indeed contributes not only to guaranteeing the quality of bottled products but also to ensuring industrial efficiency and cost reduction opportunities for the sectors concerned."
Revision of the bottling guides
More generally, all the Cetie bottling guides reference specific test methods for supplies and finished products.
At each revision of these guides, new needs for harmonising test methods are identified and taken into account.
For example, the working group currently revising the Guide n°3 “Tirage and final corking for quality sparkling wines produced in specific regions (QSWPSR)”
has formalised a test for the cork extraction force/torque, both for testing corks as received and the final corked product.
The group revising the different bottling guides for aluminium screw capping (Guides 2, 6 & 9) has produced several test methods as separate documents, e.g. DT34
for the compressibility and elastic recovery of laminated liner materials and FS16 describing specific test methods for the pressure resistance of this closure system.
Other test methods are in preparation, in particular for measuring the opening torque of aluminium screw caps.
The most recently formed working groups – WG “Bartop stoppers
”, WG “Plastic cap ovality
” and WG “PET finishes for Home and Personal Care products
” – obviously include in initial considerations the specific measurement methods and tests in their respective work programmes.
Action in Cetie to harmonise test methods indeed contributes not only to guarantee the quality of bottled products but also to ensuring industrial efficiency and cost reduction opportunities for the sectors concerned.
N. Harris - Cetie General Secretary for french Magazine Liquides & Conditionnement N°395
- Liquides & Conditionnement N°395 (FR)