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Introduction
Introduction
The designers’ choice of materials for a product is critical in ensuring that it is fit for purpose. An example of this is the selection of materials appropriate for a drinking vessel. In order to manufacture a successful product there has to be a match between material, shape or form of the product, function, scale of production and cost (selling price).
Example - Choice of materials and processes
Example - Choice of materials and processes
Lets lookat the drinks can as an example.
It is made from two parts (three including the ring pull): the can body and the top. The body is made of a single piece of Aluminium alloy with no seams so there is no time or cost wasted on welding.
The material has to be stretched (drawn) so Aluminium has been alloyed with small amounts of manganese and magnesium which increases ductility. See Unit 1.4 for more information on deep drawing.
The body begins as a disc of Aluminium that has been blanked from sheet material. The manufacturer needs as little waste material from this process as possible as the sheet is already the right thickness and surface finish and, although recyclable, it will cost time and money to recycle the metal back into useable sheet.
The discs are first cupped then deep drawn by forcing the materials through a series of ironing rings.
The advantage of the drawing process is that as the shape forms the thickness of the can sides is reduced to about a third of the thickness of the base (which hasn’t changed).
Blanked disc of aluminium
The much reduced thickness of the can wall is still capable of supporting the can shape and withstanding forces from the pressurized liquid inside. In fact the liquid works with the material to give the walls strength. It is only when the can is empty that the sides become weak enough to collapse which helps with recycling.
Discussion time:
In the two products below, how has the product function or appearance influenced the choice of materials and manufacturing process? Write down your thoughts or discuss with a partner.
Do you think the material and manufacturing process influenced the design or the other way around?
The six R’s of sustainability
The six R’s of sustainability
It is essential that the recycling of materials is maximized to maintain future resources and reduce levels of landfill. This is particularly important for materials from non-renewable sources such as most polymers and metals.
Local councils are now responding to this by supplying different coloured bins to help consumers separate their waste into categories for easier recycling.
Some materials, such as Aluminium, are easier to recycle than others while one PVC bottle contaminating a batch of 10,000 PET bottles could result in the resulting product being unusable.
Recycling is linked to the methods of manufacture incorporated in products and later in the unit we will consider disassembly as a means of encouraging the wider use of recycling.
Legislative leverage from directives such as the End of Life Vehicles (ELV) and Waste from Electrical and Electronic Equipment (WEEE) has been crucial in making manufacturers consider how products can be recycled.
Dyson has historically operated a scheme where they will collect any of its vacuum cleaners when customers buy a new model, often with a discount in price on the new model for doing so.
The concept of ‘cradle to grave’ which we will look at in a later unit is commonly used so that designers and manufacturers consider all aspects of production. This includes the extraction and processing of raw materials (birth), manufacturing and shipping, consumables during the products use and what happens to the product at the end of its ‘life’, when it is no longer usable or repairable.
Is it possible to use less material and energy so that there is not as much depletion of resources?
A major area is the reduction of packaging materials for products especially plastic packaging. Take an chocolate egg as an example. It is a hollow chocolate shell wrapped in aluminium foil, set in a vacuum-formed shell than placed in a cardboard box with a cellophane window as well as other decorative materials.
When designing products for manufacture we can also look at how small changes to the design might help to reduce waste. In the image, a folding chair was made slightly smaller without affecting its aesthetics or performance. As a result, sixteen of the chairs fit exactly within a standard 8’x4’ plywood sheet with almost zero waste.
As consumers we can make choices about the products we support or purchase. When asked if we want a carrier bag, we can refuse or supply our own reusable bags.
We can also make choices in other areas such as refusing to buy:
cars with high fuel consumption or high levels of omissions
single use water bottles rather than refillable ones
timber products from unsustainable or irresponsible sources
snacks packaged in layers of plastic
electrical products with a poor energy rating
electrical products that are non repairable or expendable
inefficient light bulbs such as incandescent bulbs. LED's are a better choice.
oil based polymer products over bio polymers
products that made from materials that cannot be recycled
In the previous century it was common to have household appliances repaired when they became faulty. However, due to legal disputes as a result of accidents from trying to repair products without sufficient skill or training, manufacturers have made it more difficult for most appliances to be repaired by their owners.
They have done this in a few ways:
sealed plugs that cannot be changed
sealed units so access cannot be gained without damage
components soldered on PCB’s so they cannot be upgraded or replaced with incompatible parts
complicated disassembly procedures that would require specialist training
lack of ‘off the shelf’ parts so appliances need to be repaired by the manufacturing company.
These are not necessarily bad things but it has resulted in products like TV’s being thrown away rather than repaired as the parts and labour can cost more than buying a new product.
Some products are too expensive to replace and need regular user maintenance to keep them fully operational. Smartphones can have software upgrades and computers can have upgradeable parts. Cars need the owner to maintain them so they have some parts (bulbs, wipers, trims etc.) that can easily be replaced. There are tyre and body repair kits available, but a repair to a major component such as an engine or gearbox still requires the skills of a specialist.
Rather than being a process we can follow, this asks us as active consumers to reconsider or 'rethink' our attitudes to purchasing, using and disposing of products and change behaviours.
Examples include:
cycling or walking to work rather than driving
having solar panels fitted at home or work
keeping a phone for longer before upgrading
using a water butt to collect rainwater for the garden
buying low energy appliances. only buy A+ and above rated products
buying loose fruit and veg from a market rather than a shop
composting waste and using it as fertilizer
joining a car share scheme
Products can often be reused or repurposed but it is not something that comes naturally in a consumer society that has developed to expect items to be cheap, disposable and easy to replace. One major trend in recent years is that of the ‘bag for life’; a reusable shopping bag to reduce the use of disposable carrier bags (Thailand famously banned carrier bags in 2020).
Websites such as Freecycle encourage people to give their unwanted goods to others and previous generations used to have ‘hand me down’ clothes where an older sibling gave their clothes to a younger sibling once they had grown out of them.
Can you imagine sharing the clothes your parents of siblings had grown out of?
Can you imagine sharing the clothes your parents of siblings had grown out of?
Upcycling
Upcycling
Not one of the 'official' 6 R's, Upcycling is the creative reuse of unwanted products and materials, resulting in outcomes with a higher quality or environmental worth than the original. It is often undertaken at a domestic level rather than in industry. It could include:
making furniture from shipping pallets
glass jars used as lights
personalised messages from scrabble letters
re- styling old furniture to make it look more modern
Restaurants, bars and offices are also increasingly adopting the upcycled look.
Exam Question (34)
Exam Question (34)
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