State of the Art of Components Reuse

Over the last two decades, spectacular advances in technology have led to a dramatic increase in our reliance on electronic products. Televisions, computers, wireless phones, copiers, fax machines, telephones, etc. are just some of the electronics that have become a central part of our everyday lives. As product innovations multiply and electronic product use increases, the lifespan of electronic equipment has decreased. Televisions and fax machines may operate for many years, but several electronic products quickly become obsolete when newer, quicker, or better equipment and software is released. This is why there is an increasing concern about the volume of end of life electronics, and the fact that much of it is consigned to landfill. The limited availability of landfill, and the need to adopt a more sustainable approach to materials consumption has lead to greater attention being given to the problems associated with end of life electronics.
Printed circuit board (PCB) is the typical and fundamental component for almost all electronic products. With the development of electronic products, the amount of waste PCBs is increasing sharply and has caused severe environmental problems.

Benefits of reuse of electronics

The most environmentally sound management of solid waste is achieved when approaches are implemented according to the preferred order of European Union's waste treatment laws: waste prevention first, recycling second and disposal last. Reuse is the environmentally preferable option for managing older electronic equipment. The main benefits of reuse are:

• Diverts materials from disposal: electronics reuse and recycling save bulky equipment from landfills and incinerators.

• Provides social benefits: the amount of workersneeded to close the loop is very high.

• Conserves natural resources and reduces pollution: electronic products are made from valuable resources, including precious and other metals, engineered plastics, glass and other materials, all of which require energy to source and manufacture. Many electronic products also contain parts that could be profitably refurbished and reused with little effort. Extending the life of old products minimizes the pollution and resource consumption associated with making new products.

Recovered components could be used in new products with the same original application or with a different one (i.e. lower value applications), or also in used products as spare parts at lower price in repairing shops, specially when a new component is not available because it is not manufactured yet due to the rapid technology change.
However, currently electronic components reuse from PCBs has some difficulties to be accepted due to:

• Reused components have bad image in market mainly because of uncertainly in their life span and reliability during the second use time.

• High recovery cost

• Lack of collection systems that guarantee constant supply

• Quite often product design does not allow easy disassembly of discrete electronic components.

• Lack of simple and effective disassembly processes for small or medium recycling industry.

• Absence of accepted quality standards for recovered components.

• Reticence of electronic industry to accept reused components in new products for technical and quality reasons. Reused components must fulfil the same requirements as new ones and also fit into standard manufacturing processes.

• Absence of established markets for recovered components

In general, a basic disassembly process of electronic components from PCBs (lead containing or lead-free) for reuse purpose can be divided into three main steps (Figure 1):

• Components identification on boards: by means of visual inspection or automatically with artificial vision systems. In the first case, the target component and its position are previously detected on the board visually. In the second case, the system identifies automatically valuable components and their location on the board comparing their codes with a database.

• Desoldering and removal: traditional procedure (manual) or by means of other technologies (laser beam, infrared radiation, hot gas or vapour) combined with removal systems (vacuum extractors or robots with specific picking tools). An important aspect to be considered when components are desoldered for reuse purpose is to avoid high temperatures on the package (>220-230ºC) for a long time (several seconds). High temperatures could kill some sensitive components.

• Quality control (based on checking physical characteristics) [Stobbe]: packages and connection leads must not be damaged. Leads have to fulfil requirements of co-planarity and alignment. For these purposes vision systems can be used for quality control.

Figure 1: Reuse technologies

Quality assurance

Recovered components from PCBs must have quality comparable to the new ones (without damages in packages and leads, and also in working conditions) to be re-assembled again and to operate successfully during the second life. Therefore, a desoldering procedure must guarantee quality in recovered components in terms of electrical functionality and reliability in connections and package:

• Co-planarity: all leads must fulfil the tolerances in three planes.

• Lead position: leads must have certain orientation with respect to each other.

• Popcorn effect: it occurs if package material pops up due to the inner pressure of heated moisture vapour what could destroy the component.

Disassembling initiatives for components reuse

Currently, PCBs disassembling for components reuse, if it is done anyway, is mainly a manual or semi-manual process and focussed on production rejects without considering post-consume equipment. According to the state-of-art, some initiatives for components reuse exist.
In Austria, the organization SAT [Kopacek] has developed an automated component disassembly methodology for the dismantling of components from scrap, redundant or malfunctioning PCB assemblies. The disassembling cell (Figure 3) consists of four stations:


Figure 3. Disassembly cell

1. Vision system: initially the PCB goes through an artificial vision system in order to identify the components to recover and their position. This system reads the identification letters and numbers on top of the components and compares them to a database. This database provides also with information on the most suitable disassembling method for each component.

2. Laser: the most valuable components are recovered using this technique. It consists of two laser beams directed to the solder so that the components is protected from the heat. Once the solder is melted the component is recovered using a suction system.

3. Robot: the components in sockets are recoverd by this method. The robot uses grippers to pull out the components.

4. Infrared: this technique is used for through hole components. The board is heated from the opposite side to the components so that the heat is not applied directly to them. When the solder is melted the components are recoverd using a suction system or grippers.

The AutDem project (Automated disassembly of PCBs, including visual proof and quality control of desoldered packages, BeCAP, Berlin Center for Advanced Packaging) has the objective to close the technological gap for these reverse processes in order to provide reusable components in adequate quality under commercial conditions [Dembowski]. The pilot reuse line (Figure 4) can be divided into several stations:


Figure 4. Pilot Reuse Line

Identification of components: this station defines the type, dimension and location of the components to recover. It is also provided with a database of components demanded in market.

Desoldering process: it uses hot air to melt the solder according to a desoldering profile.

Automatic inspection: an optic recognition automatic system measures the deviations on components specifications.

Quality control: the geometric quality of recovered components is analysed as well as their resoldering possibilities.

Companies in the reuse business

In Internet there are some companies related to electronic components reuse, however nor the recovering system nor the quality assurance process they use are mentioned. Some of these companies are:

• Covertronics (www.covertronic.de): they remarket electronic components and parts of devices coming from redundant or scrap production as well as end of life equipment.

• Jabil (www.jabil.com): they repair elctronic components for reselling.

• AER worlwide (www.aerworlwide.com): they provide a reused components database.

• Retronixs (www.retronix.com): they recover SMD components from obsolete or scarp equipment for reuse. Some of the services offered are: lead straightening, BGA reballing, component salvage, device scanning...

• Service Electronics (www.separts.com/sei_about.html): they provide an
  array of after-market services related to sourcing, processing, repairing, emanufacturing, demanufacturing, managing, distributing and remarketing computer systems, parts and peripherals.

• Vicor (www.vicor-berlin.de): they recycle end of life electronic equipment. They sell repaired and reconditioned modules and printed circuit boards.

 Desoldering Procedures for Electronic Components from PWBs [next chapter]