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fresh air in packaging design Neil Kirby Brian Gabbitas Neil Kirby is an engineering designer, employed as an associate on the Teaching Company Scheme between Great Western Packaging and Southbank University. He took the original concept and produced a design methodology that led to the commercial exploitation of a new packaging. Dr. Brian Gabbitas is the senior academic supervisor of the Teaching Company Scheme between Great Western Packaging and Southbank University. His task was to use his expertise in material selection and research techniques, and provide general project supervision. This paper describes how the Great Western Packaging Company (GWP) used a forward thinking and innovative approach to produce a patented concept for both a new product and the design method used to create it. The recent EC Directives on environmental issues relating to packaging have altered the methods by which electronic equipment is protected during transit. What was originally seen by GWP as a problem, has been turned into an exciting project, which has culminated in a bespoke product and design techniques far removed from GWP's usual sphere of business. Introduction As a result of EC legislation tightening the control of waste disposal, many European countries instigated their own legislation for the recycling and disposal of packaging waste, introducing financial penalties for both industrial and domestic waste collection. In October 1992, German companies advised many of their suppliers, that by January 1993 the disposal of all packaging exported to Germany containing expanded foams, or similar difficult to dispose of products, would remain the responsibility of the supplier of the packaged product. In response to this, the Great Western Packaging Company Ltd. (GWP), embarked upon a programme of research and development investigating alternative forms of protective transit packaging. The aim being to produce a product of equal or superior performance (compared with expanded foams), reduction in cost, an emphasis on re-usability, whilst reducing the impact on the environment. As a result of the proposed bespoke nature of the packaging, CADCAM design and manufacturing techniques were fused together. Background In the UK, the Environmental Protection Act 1990 sets out targets for the recovery of household waste by the year 2000. The EPA seeks voluntary agreements that will meet the EC goals of 50 to 65 per cent packaging waste recovery, and 25 to 45 per cent waste recycling. 1 Germany has taken even further steps, with the German Chamber of Commerce and Industry creating the New German Packaging Law 2, including the Green Dot recycling system, and initiating massive recycling programmes, with waste collection and disposal controlled by strict guidelines. Many companies assumed that this kind of policy decision based on environmental grounds was going to become a common reality throughout the EC. As such they brought their packaging philosophy into line, specifying that all packaging (with the exception of specialised items such as anti-static foam or moisture barrier bags) would have to be either reusable or recyclable. The main problem with this arrangement, was how to achieve a sufficient level of cushioning, as well as meeting all the required environmental conditions. Ideally, for a package to have a very low impact on the environment, it must be reusable, and to be practically reusable, the package must be capable of being returned to the supplier. With most forms of protective packaging, their very nature gives them a high volume to weight ratio, and as such, the costs of transporting large volumes of packaging material back to the suppliers usually exceeds the cost of producing virgin packages. Working on the theory that the packaging needs to have enough volume and cushioning properties to protect the product during transit, and also that after this has been achieved, the volume can be substantially reduced, a concept was developed for new packaging, which resulted in the filing of a patent application by GWP. This patented concept is Pneumatic Cushion Packaging, with the product name of Q-CELL. Design concept The basic principles of Q-CELL are very simple. By controlling the flow of air around a network of inflated cushion cells placed around a load, the deceleration of this load, when dropped on a hard surface, can be minimised and the level of protection optimised. This is achieved by welding seams into two flat sheets of plastic film to form a collection of different sized cushion cells, rectangular in nature, joined by apertures of varying sizes to allow differing air flow around the network. The flat sheets and layout of the welded seams are designed so that once inflated, the system will wrap around the desired area of the product and protect it from shock force and vibration. This principle means that the Q-CELL system can be tailored to suit a particular product i.e. it is of a bespoke nature. On impact, deceleration is controlled by the release of air from the impacted cell into adjacent cells. When the product eventually stops, the impacted cell is re-inflated by the increased pressure in it's neighbouring cells, creating the original balance of pressure through the network protecting against further impacts. This concept is shown in Figure 01. Re-use is achieved because once the product has reached its destination the packaging can be deflated to a flat state and either palletised for return or posted back to the supplier. Each Q-CELL system is bar coded and labelled, for identification and traceability, giving control over the number times they are re-used to the manufacturer. Before they are re-used, each system is given a Quality Control check, and then delivered ready to package new products. At the end of it's useful life, the Q-CELL would be recycled by the manufacturer, hopefully into new Q-CELL systems. Design methodology The initial stage of the design process is to assess the optimum style of packaging required for the product. For the majority of products, end caps will be the optimum means of protection, and as such, a design method has been adapted for this form. Q-CELL is designed from a number of parameters specified by the object to be packaged. These are:
The variables that are altered within the Q-CELL system to optimise the protection level are:
Using simple applied mechanics, the minimum allowable cushion cell thickness is approximated, i.e. the minimum distance, measured at the centre of each cushion cell, between the outer box and the packaged product. Once the cushion thickness has been approximated, the next stage is to calculate the dimensions of the Q-CELL end caps, and determine which style is best suited to the product. The product is measured, and the decision taken as to the optimum location of the end caps, from which the controlling edge is determined. The controlling edge being the longest side of the face of the product where the end cap will be positioned. From these product dimensions, the size of the Q-CELL end caps can be calculated, for numerous different styles. Q-CELL end caps are grouped into a number of main styles, determined by the number of cushion cells along each face of the packaged product. The Q-CELL dimensions are calculated using a mathematical model, together with dimensional analysis curves formed form experimental data. With the optimum size and style of the Q-CELL end caps calculated, stage one of the design is complete. The next stage is to determine the size and position of the apertures between all the cushion cells. Two sets of Q-CELL end caps can be exactly the same size and shape, but have markedly different protection performance qualities. By adjusting the size and position of the apertures, as well as the inflation pressure, (although this has a minimal effect) the system can be made very stiff, for heavy products, or very soft, for fragile delicate products. The apertures are designed into the system with the aid of historical data, held in a database, formed from experimentation with standard size Q-CELL systems. When the position and size of the apertures has been finalised, within the optimum dimensioned style, the design process for the Q-CELL system end caps is complete. Software design tool In line with the design procedure for Q-CELL pneumatic packaging, a software tool has been developed which will perform the majority of the calculations and analysis. From an input screen where the details of the product dimensions and specifications are entered, the software will generate an output, of the Q-CELL dimensions, style, inflation pressure and aperture positions and sizes. The software tool will produce drawings of the cushion cell layout, fully dimensioned, labelled and with the costs estimated, which will be printed directly from the computer. This software tool will be extremely useful when going out to sell Q-CELL, as with a minimal input, the whole system can be designed, cost estimated and presented almost immediately. Materials and manufacture One of the most significant areas of the design project was the selection of a suitable material, which would satisfy the following criteria. . It must be wear, tear and puncture resistant, good resistance to gas permeability, stable for varying climatic conditions such as heat, cold and changes in humidity, economically viable and ecologically sound. The material that matches these requirements the closest, is a Thermoplastic Elastomer, Poly Wreathing (PU) film. However, a major drawback is the high cost of this material., and therefore, co-extrusions and engineered laminates are also being investigated. This examination has taken the form of various material tests performed on small samples of different materials, to build a property profile, using the results from the PU film as a base, against which other materials can be compared. Typical tests involve tensile, puncture, burst, tear, friction and slip, as well as a number of tests exclusive to the Q-CELL Pneumatic Packaging System. Once the optimum material has been selected, the appropriate manufacturing process can be chosen. For PU film this would be High Frequency (HF) welding. For most coextruded or laminate films, unless a layer is used purely as a welding medium, this would be Heat Impulse Welding. Total packaging management The aim of total packaging management is to reduce the impact of the packaging on the environment, and at the same time, evoke an economic benefit to both customer and supplier. The basic concept, shown in Figure 03, is as follows:
Performance criteria The performance of the Q-CELL end caps was measured in terms of the G-value actually realised by the packaged product in free fall drop tests, and by the resonance, and damping effects in a frequency swept vibration experiment. The Q-CELL results were compared with results from other recognised forms of protective packaging, such as expanded Poly Ethylene foam. The Q-CELL shows an improvement in performance over the foam of 14.47 per cent, i.e. a reduction in the G-value felt by the packaged product of 14.47 per cent. For the vibration tests, the resonant peak is 42 per cent lower, and the damped frequency drop off point is 62 per cent lower for the Q-CELL compared with the foam. This means that the vibration applied to the outer box during transit, is more effectively damped out with Q-CELL than with the foam. Another major advantage over the foam is that the Q-CELL demonstrated a 100% memory, that is, the results were the same on the tenth drop as the first, whereas the foam showed a 4.27 per cent decrease in performance by the tenth drop. Other advantages gained over the foam were a reduction in the required outer box size of 23.15 per cent and a reduction in weight of up to 14.28 per cent, both of which would save in transit costs. Regarding storage space, Q-CELL requires over 70 per cent less space than expanded foam, due to the fact that the end caps can be stored flat prior to use. Conclusion This paper was constructed to outline the philosophy of the Q-CELL Pneumatic Packaging System currently under development at Great Western Packaging. Q-CELL is a novel method of protecting packaged products during transit and storage. Q-CELL offers benefits in performance over conventional cushion protection methods, and due to it's genuine ability to be returned and re-used, substantial economic and environmental savings. The design process of Q-CELL is to examine the product properties, and then pursue the method stage by stage to produce production drawings direct from the theoretical approach. Samples can then be made and performance verified through simple practical experimentation. The design calculations are based on sets of graphs formed from standard experimentation, and a database of historical data formed from experimentation on standard size Q-CELL end cap systems. The software development will produce a stand alone package that will perform calculations, and come up with an estimated Q-CELL solution for a particular set of product properties. Q-CELL has been field tested by sending dummy packs on several practical trials, including a courier trip to Bermuda and back, via Boston USA. The performance was assessed using a variety of recording devices, all of which indicated that the packaged product had seen no undue stress, even though the outer box was badly damaged. References Stonestreet B., (July 1994) Chief Executive Officer REPAK (The
UK Fibreboard Transit Packaging Recycling System),
Packaging - The Environment - Legislation: A Resume. Deutschland
European Plastics,
News, (July/August 1991), Recycling - Duales System,
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