Infrared can unfreeze food & beverage line margins
27 Jan 2010
As Europe continues to enjoy its coldest snap for a while, Frank Wilson, founder of Irish-based infrared heating supplier, Ceramicx, offers some thoughts on the art of heat work involved in food & beverage packaging lines:
Cork, Republic of Ireland – Any plastics packaging thermoforming production system has its areas of opportunity and weakness - high-speed packaging lines for food & beverage applications even more so.
It is easily forgotten that the thermal systems installed as part of the thermoforming process are the engine of production. Without maintenance and without sufficient analysis, production output and quality will suffer. Infrared heaters, ceramic heaters, quartz heaters, and ceramic elements are all based on a specific and particular technology. The more understanding gained of infrared science, the better your production will be.
At Ceramicx we are used to listening to plastics processors and packaging users pointing to the heating system as a possible cause of packaging deformation and quality failure. But as a general rule, heat systems per se are very rarely the cause of production problems.
Instead, the complexity of the packaging part design; it’s dimensions, the depth of the thermoforming ‘draw’ and the characteristics of the material composition – these are the prime factors that must be calculated and overcome in order to make quality product.
Indeed, given the costs and the business issues at stake, it is somewhat strange that the principles of Infrared heating are so little understood by its users in packaging and thermoforming.
The essence of Infrared heating involves a ‘Holy Trinity’ of three factors – absorption; transmission and radiation. However, the misunderstanding of these principles generally leads many packagers to the misuse of the thermoforming equipment and the consequent expense in energy, cost and capital plant.
The practical key to a good infrared heating system is one in which incoming electrical wattage is converted into infrared output more quickly and efficiently.
In thermoforming production a number of infrared ceramic heaters are generally mounted on reflectors which are then arrayed upon a platen – or two – which is part of the production line.
The performance of the background reflectors - their material composition - and the performance of the platen in general – these factors are all vital in directing the infrared heating to the plastic. But too often, packaging processors of thermoforming machines end up fighting the demands and design of their machine in order to get some efficient heat work done.
For example, stainless steel is not an adequate material for use in infrared reflection work. It will absorb a high percentage of the emitted energy and will therefore over time cause burnout of the electrical wiring behind the reflector and will also start to discolour from 120degC. Polished aluminum on the other hand is in most cases the best reflector for ceramic infrared heating but > 500 C it also will start to fail. The business of thermoforming thin and clear plastic sheet needs some installation of passive ceramic tiles in the base of the platen in order to reflect back the heat. Every system, in some way, has its custom features.
Furthermore, in many cases, as a platen system starts to discolour and degrade in operation– with dirt and process plastic and other materials – so the reflectivity will be compromised and the machine operator will then typically be involved in a vicious circle of increasing the temperature in order to achieve the same performance. Regular review and maintenance could pre-empt the bother; the increasing lack of control and the extra cost.
Over 20 years of experience at Ceramicx suggests to us that a 30-40% improvement in operational efficiency of most packaging thermoforming systems can be achieved through this single and simple step of reviewing and renewing the infrared heating platen. The ideal control for this situation is to mount a thermocouple on the existing reflector system – keeping a temperature watch. When this starts to rise – taking more and more energy – the user should be alerted to take action.
This issue will continue to bear on the packaging industry to come as cost-down and higher quality demands continue. At Ceramicx we believe that the consciousness of the future packaging industries will no longer tolerate sub-standard parts and poor thermoforming design.
In these cost- and energy-conscious times, the food & beverage packaging sector should take the opportunity to investigate where its ‘heat work’ is letting production down – and also take the trouble to understand the principles of infrared a little better. The savings could be considerable.
