A New Life for Old Electronics
By Pia Tanskanen, Nokia Research Center
Upcoming EU legislation will set new formal requirements for end-of-life treatment of waste electronic products. In particular, producers will have the responsibility for obsolete product collection, pre-treatment, and recycling. To tackle these issues one must understand the nature of end-of-life processes and the treatment mobile terminals and other electronics need to undergo at the end of their useful lives.
The complex end-of-life system can be divided into three distinct stages, each with different characteristics and stakeholders. The first stage is the organization of the collection process. The second is the recognition, structural pre-treatment and fragmentation of the product. The third stage is the collection of the material content through recycling processes or by reusing the components.
View the entire end-of-life process
The financial burden of end-of-life treatment can be reduced by proficient design and through the active use of technologies such as active disassembly and automated sorting. In addition, the material content and product structure must be designed to be compatible for recycling. The tool for implementing these in the product creation process is Design for Environment.
Generally, the more materials are recycled the more value the product has at the end of its life. This so-called sustainable thinking aims for a closed material circle, where the same material is used again for making a new product.
Traditionally, end-of-life treatment of electronics products has meant shredding the product - preferably as whole - and automatically separating a limited number of material fractions from the shredded mass. This is usually combined with manual pre-treatment for separating out components containing precious metals or those requiring special treatment.
Disassembly of the product, however, leads to more efficient and safe recycling. With today's recycling technologies, disassembly is a necessary step for separating out plastics, components containing precious metals, or components requiring special treatment before recycling the rest of the product.
As manual disassembly is not very cost efficient, a new approach called active disassembly has been developed. An active disassembly mechanism is a built-in disassembly function that stays dormant during the use phase of the product and can be activated by some external trigger (e.g. heat) in the end of life stage. The active disassembly mechanism is usually connected to the fastening mechanism, such as a screw or a snap fastener, so it must be applied to the product in the beginning of the product creation process. Also, the disassembly trigger must be designed in such a way that it is highly unlikely that the product is exposed to these conditions during normal or even harsh use of the product.
Currently, research on active disassembly is being done in the European Union Fifth Framework research program called Active Disassembly Using Smart Materials (ADSM). The idea is to design around a recycling scenario in which the product disassembles itself into several sections with one disassembly operation. Thus far, the disassembly time in the best solution is two seconds, which is more than 50 times faster compared to the average time for the manual disassembly of mobile terminals. With developing material recovery systems this would result in efficient recycling of complicated electronics products.
Prototypes use smart materials
Several disassembly mechanisms using smart materials have been installed in Nokia 5110 mobile phones as prototypes. Smart materials can be specially molded into a particular shape for normal use and, with a certain external trigger like heat, return to their original shape. When the prototype is heated, the actuators made of smart materials are activated, and the phone is disassembled into four sections: printed wiring board (PWB), liquid crystal display (LCD), covers, and battery. The actuators can also be tuned to open at different temperatures to allow hierarchical disassembly.
One active disassembly mechanism is upper-cover removal. A Shape Memory Alloy (SMA) or Shape Memory Polymer (SMP) actuator opens the snap fixing that holds the changeable upper cover of the phone in place. In the case of SMA, a smart material is used as an insert in the snap fixing. When heated it curves and pushes on the fixing, thereby releasing it. An SMP can actually be used to form the whole snap-fixing part, which will open when heated. The SMP solution is an example of an integrated solution in which no extra parts are added and the disassembly mechanism is also used as the fixing mechanism.
Another disassembly mechanism is to undo the screws. Screw fixings can be built for active disassembly by making the boss or the screw out of a smart material. The latter option, where the screw releases its threads, has been presented in literature (Chiedo et al). It represents the drop-in solution where an existing part is simply replaced by the similar part with different material properties. In the first option, shape memory plastic is worked into a circular shape to form a boss and it "remembers" the original flat shape when heated. When activated the boss will open as the material resumes its original form, and the screw and the insert are released. In this case, the plastic casing remains free from metallic impurities, which helps the recycling of the materials. This is also an integrated solution with no extra parts. However, it requires changes in the manufacturing process of the mechanical parts.
These mechanisms have been presented in more detail at the invited session of the Care Innovation congress in Vienna November 2002.
In addition, part of the prototype development focused on creating disassembly mechanisms for arbitrary mobile terminals. This kind of concept allows a terminal to be designed around the disassembly mechanism without any constrains from the existing mechanical design. This solution, called Shock, was presented at the International Electronics Recycling Congress 2002 (Tanskanen, Takala). The concept was designed in cooperation with the Helsinki University of Technology and the School of Industrial Art and Design, Helsinki.
The prototypes demonstrate that the integration of active disassembly fasteners into a product does not require larger product volume and that the product can be disassembled without any physical contact - by heating it. However, hand-made prototypes do not necessarily reflect the issues in mass production. Therefore, mechanical reliability of the solutions, among other things, is not yet clear.
The upcoming European legislation on the producer responsibility for electronics waste will require organizing the collection of the waste from the consumers. The aim of the legislation is to move the flow of obsolete products from landfill to recycling. Collection systems in each European country are slowly being set up. The missing part is the smart collection point, which could motivate people to bring back their old products and also do some kind of sorting of the returned goods. Also, the information about the amount and type of collected goods is important, as each country will be reporting this to the EU.
Nokia Research Center and Tomrasystems Oy, who are known for their reverse vending machines for bottles, have set up a cooperative project with the Helsinki University of Technology and the School of Industrial Art and Design, Helsinki. The project has resulted in a working prototype of an automated take-back machine for mobile phones and accessories as well as a potential business case.
When returning waste products, electronics are difficult to identify by analyzing the shape or material as is done for plastic and glass bottles and aluminum cans. This recognition could be possible by using image recognition technologies. In the prototype, the idea was to replace the smart properties of the machine partly by the smart users. This makes the return process slower, but as electronics waste is not returned in large quantities, like bottles, that is not a problem.
When the user returns his/her mobile phone (the prototype is limited to Nokia products), it is weighed and photographed. He/She then compares the picture of the phone to the models the machine shows to be similar, and, by comparing these, the user selects the model he/she is returning. Alternatively, he/she may enter the model number straight away. After the machine accepts the product, it is possible to get an SMS receipt, for example, with discounts or other incentives. Also, the manufacturer can receive information on what models have been returned for recycling.
The products are separated according to the database in the collection machine. Separation increases the value of the returned waste products. For example, the magnesium in some older models, which may start a fire in normal recycling process, needs to be separated. Batteries must also be separated according to their chemistries (NiCd, NiMH, Li-ion). As there is no simple way to automatically recognize the different chemistries, the user is again asked to help out. He/she should also remove the battery from the phone, which would normally be done at the recyclers, and in the future will be paid for by the manufacturers.
The upcoming legislation and other requirements for the treatment of electronics waste create challenges for technology and engineering process development. To tackle these challenges, ongoing research has produced a number of technologies that promote end-of-life treatment. Similarly, engineering processes have been amended to include Design for Environment and material checks at key design milestones.
Future research opportunities in technology development include several new possibilities in the design of disassembly triggering mechanisms. Also, the mass production of these mechanisms needs to be evaluated. In the take-back arena, a feasible business case for collection and recycling of mobile terminals needs to be demonstrated with actual figures.