Metal working – Method of mechanical manufacture – Scrap recovering or utilizing
Reexamination Certificate
2000-09-11
2004-01-13
Chang, Richard (Department: 3729)
Metal working
Method of mechanical manufacture
Scrap recovering or utilizing
C029S403100, C228S119000, C228S262900
Reexamination Certificate
active
06675454
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
2. Description of the Related Art
Printed circuit boards play a very important role in many of today's electric and electronic appliances. Using a lot of energy these type of boards are made of different materials, for example plastics, fibre materials, metals etc. The electric and/or electronic components on the boards differ greatly, for example there are tranistors, capacitors, resistors, integrated switches, processors etc. Electric and electronic compliances pose a particular problem because not only do parts break down they also become technically out of date within a very short period of time. A classic example of this is the area of computer technology.
Different methods have been suggested to try to combat the waste of raw materials and environmental pollution through the ever increasing load of scrap electronic waste. As far as printed circuit boards are concerned the main problem remains in the fact that different materials are either glued, soldered or struck together. Methods requiring a high energy demand are needed to separate the materials so that they can be recycled.
These kind of methods involve shredding the printed circuit boards into an equipped, partly equipped and unequipped state. However, the first 2 cases are a cause of concern when considering the environment. In the last case the components can be removed by soldering, planing down, chiselling off, grinding down or other similar processes. After this the printed circuit boards or pieces thereof are burnt in metallurgy works, mainly abroad. In this process the base material, made up of glass fibre and plastic or similar such materials, is also burnt The resulting melted down material is then refined.
The melting down process of the printed circuit boards causes the energy requirement to be high. Refining the melted down materials also requires further complex proceedings. For this reason, it is important to consider the cost benefit ratio.
SUMMARY OF THE INVENTION
It is the task of the following discovery to develop a method of recycling printed circuit boards and using this technique to produce a result that also achieves a good cost benefit ratio.
An innovative method to recycle printed circuit boards appears to involve the stabil joining of component-free printed circuit boards to produce one composite board. Using this method it will not be necessary to melt down or burn the used printed circuit boards, thus reducing the energy requirement. As a result the final product shall achieve a good cost benefit ratio as far as the economic situation is concerned. When laid out next to each other or put in layers the used printed circuit boards can be made up into a composite board.
The outer conductor paths from the used printed circuit boards shall be carefully removed so that the material from the conductor paths can be recycles
The solder, for example tin, shall also be removed from the holes in the boards.
Furthermore several used printed circuit boards will be laid next to and layered on top of each other, resulting in a large composite board with any number of layers. The resulting composite board is very strong. The used boards shall be stuck together using a very strong glue.
The fibres within the used boards shall be so aligned to produce a layer in the composite board where the direction of these fibres is the same.
To make the processing easier the used boards could be cut into a single shape and size.
The used boards could also be shredded down and the resulting pieces pressed and stuck together forming a chipboard composite board.
Furthermore the used boards could be multilayer boards, that contain more than 2 levels with conductor paths, where a resulting additional effect is an electromagnetic shield.
It could also be possible to integrate at least one additional layer in the composite board. This additional layer could be made out of plastic, metal or a natural raw material. As a result the composite board could be strengthened, made more durable and/or an electromagnetic shield could be provided.
Using this new method a composite board will still be made out of component-free used board that are joined together. However, the result is produced without high energy requirement and can achieve a good cost benefit ratio, as the economic situation is concerned.
BRIEF DESCRIPTION OF THE DRAWINGS
The outer conductor paths from the used printed circuit boards are carefullly removed so that the material from the conductor paths can be recycled.
The solder, for example tin, can also removed from the holes in the boards.
Furthermore several used printed circuit boards are laid next to each other and layered on top of each other, so that a large composite board with any number of layers is made. The resulting composite board is very strong. The used boards am stuck together using a very strong glue.
The fibres within the used boards are so aligned to produce a layer in the composite board where the direction of these fibres is the same.
To make the processing easier the used boards could be cut into a single shape and size.
The used boards can also be shredded down and the resulting pieces pressed and stuck together forming a chipboard composite board.
Furthermore the used boards can be multilayer boards, that contains more than 2 levels with conductor paths, where a resulting additional effect is an electromagnetic shield.
Furthermore it is possible to integrate at least one additional layer in the composite board. This additional layer can be made out of plastic, metal or a natural raw material. As a result the composite board can be strengthened, made more durable and/or an electromagnetic shield can be provided.
The above mentioned discovery will be explained further using the following enclosed diagrams.
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patent: 4768699 (1988-09-01), Abbagnaro
patent: 5401689 (1995-03-01), Frei et al.
patent: 5715592 (1998-02-01), Mori et al.
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patent: 43 30 677 A 1 (1995-03-01), None
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patent: 196 19 965 A 1 (1996-11-01), None
patent: 195 48 213 A 1 (1997-06-01), None
Chang Richard
Oliff & Berridg,e PLC
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