Reflect on this ...
07 December, 2009
Part of my mission in life is to preach the essence of Infrared heating. And it always begins with and involves a ‘Holy Trinity’ of three factors – absorption, transmission and radiation. The misunderstanding of these three principles can lead to the misuse of ‘heat work’ as I call it – whether this is in the design and operation of thermoforming equipment or the design and operation of oven systems. The consequences – for energy, cost and capital plant – can be disastrous.Having understood the principle of the trinity, the next 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 - or in oven systems - a number of infrared ceramic heaters are typically mounted on reflectors which are then arrayed upon a platen or oven side which is part of the production line. The performance of these background reflectors - their material composition - and the performance of the whole system in general is vital in directing the infrared heating to the target material, whether this is items passing through an oven, or sheet plastic prior to moulding. This applies generally to infrared heaters, infrared ovens, custom infrared ovens, quartz heaters and ceramic heaters. Far too often, manufacturers resort to fighting the demands and design of their machine in order to get some efficient heat work done. Not enough thought has been given to either the design of the reflecting materials – or to their state in use. For example, stainless steel is not an adequate material for use as an infrared bulb reflector. It will absorb a high percentage of the emitted energy and will therefore, over time, cause burn-out of the electrical wiring behind the reflector. Polished aluminum on the other hand is in most cases the best reflector for ceramic infrared heating but at >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. ‘Heat work’ is most often a science but can often be an art – especially in designing the reflective heat elements to suit the specifics of each manufacturing job. Reflect before you design. And then design for reflection.
07 December, 2009
Part of my mission in life is to preach the essence of Infrared heating. And it always begins with and involves a ‘Holy Trinity’ of three factors – absorption, transmission and radiation. The misunderstanding of these three principles can lead to the misuse of ‘heat work’ as I call it – whether this is in the design and operation of thermoforming equipment or the design and operation of oven systems. The consequences – for energy, cost and capital plant – can be disastrous.Having understood the principle of the trinity, the next 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 - or in oven systems - a number of infrared ceramic heaters are typically mounted on reflectors which are then arrayed upon a platen or oven side which is part of the production line. The performance of these background reflectors - their material composition - and the performance of the whole system in general is vital in directing the infrared heating to the target material, whether this is items passing through an oven, or sheet plastic prior to moulding. This applies generally to infrared heaters, infrared ovens, custom infrared ovens, quartz heaters and ceramic heaters. Far too often, manufacturers resort to fighting the demands and design of their machine in order to get some efficient heat work done. Not enough thought has been given to either the design of the reflecting materials – or to their state in use. For example, stainless steel is not an adequate material for use as an infrared bulb reflector. It will absorb a high percentage of the emitted energy and will therefore, over time, cause burn-out of the electrical wiring behind the reflector. Polished aluminum on the other hand is in most cases the best reflector for ceramic infrared heating but at >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. ‘Heat work’ is most often a science but can often be an art – especially in designing the reflective heat elements to suit the specifics of each manufacturing job. Reflect before you design. And then design for reflection.
