The Manufacture of Transponders and Contactless Smart Cards - RFID: Fundamentals and Applications in Contactless Smart Cards and Identification - page 322

Figure 12.2 Size comparison of a sawn die with a cereal
grain. The size of a transponder chip varies between 1mm 2
and 15mm 2 depending upon its function (photo: HITAG
Multimode-Chip, reproduced by permission of Philips Elec-
tronics N.V.)
Figure 12.3 Manufacture of plastic transponders. In the figure an endless belt is fitted with
transponder coils wound onto a ferrite core. After the transponder chip has been fitted and
contacted, the transponder on the belt is sprayed with plastic (reproduced by permission of
AmaTech GmbH & Co. KG, Pfronten)
to the normal insulating paint. The winding tool is heated to the melting point of
the baked enamel during the winding operation. The enamel melts during winding
and hardens rapidly when the coil has been removed from the winding tool, causing
the individual windings of the transponder coil to stick together. This guarantees the
mechanical stability of the transponder coil during the following stages of assembly.
See Figure 12.3.