Example Applications - RFID: Fundamentals and Applications in Contactless Smart Cards and Identification - page 375

The worn tool is first examined and measured in detail to determine its condition.
The tool is then serviced, sharpened and balanced on the basis of this data. After
every maintenance sequence the tool length and radius is updated and written to the
transponder, so that correctly dimensioned workpieces are produced by both new and
sharpened tools without intervention by the operator.
13.10.2 Industrial production
Production processes underwent a process of continuous rationalisation during the
development of industrial mass production . This soon led to production line assembly
('conveyor belt production'), with the same stage of production being performed at
a certain position on the assembly line time after time. For the present, a production
process of this type is only able to produce objects that are identical in function and
appearance. However, the days are numbered for machines that produce large quantities
of a single product with no variants.
If different variants of a product are to be produced at the same time on an assem-
bly line in an automated procedure, the object must be identified and its status clearly
recognised at every work station, so that the correct processes can be performed. Orig-
inally, this was achieved by objects being accompanied by process cards, which gave
the operating personnel all the information required at a particular work station — the
desired paint colour, for example. This was first achieved in electronic form using
coding pegs affixed to the revolving palettes so that palette numbers could be read
by the electronic control system. The position of these coding pegs could be sensed
by inductive proximity switches (Weisshaupt and Gubler, 1992). This procedure has
recently been improved by the use of barcode labels, which can simply be stuck onto
the individual objects.
RFID technology now provides an additional option — data carriers that can not
only be read, but also written. Now, in addition to recording the identity of an object,
it is also possible to document its current status (e.g. processing level, quality data)
and the past and future (desired end state) of the object.
Using modern identification techniques , production systems can now be realised
which can produce variants of a product, or even different products, down to a batch
size of one (Weisshaupt and Gubler, 1992). The automotive industry is a good example:
since vehicles are predominantly produced to order and it is rare for two identical
vehicles to be ordered, automatic material flow tracking is crucial to smooth operation.
A vehicle must be clearly identified at the individual manufacturing stages to avoid,
for example, an unwanted air conditioning system from being fitted, or the wrong paint
colour being applied during painting (Homburg, 1996).
There are two possible methods of controlling a system based upon object data:
centralised and decentralised control.
Centralisedcontrol In this approach, material flow and object status are continuously
monitored during the process and are stored in a database on a central computer
(Figure 13.49). This builds up an image of the current process data and system status
in the process control system of the central computer. It makes no difference whether
the status of objects in the process is determined using barcodes, radio, optical character
recognition, RFID or any other type of information coding and transmission.