Heat Staking of Antennas in Handheld Devices
As the world of electronic components continues to miniaturize, so
do the electronic devices that contain them.
Many devices such as cell phones, PDAs, laptops and MP3 players
are in great need of real estate within the products' enclosures to mount
critical components and hardware. In the past, locating a component within
.100" of another was considered close tolerance placement to allow the device
to perform correctly. Now, the tolerances have shifted to a degree of .005
inches and smaller. This creates great challenges to the engineers involved in
providing a manufacturing solution.
The performance of components such as an antenna can be greatly
improved if their proximity to other live components can be controlled to
within .005-.010 inches. The ability to do so can become expensive and
difficult to maintain. If these obstacles can be achieved with proper tooling
and equipment, the products success and reliability in the marketplace will be
realized while profits are retained.
In the two before and after examples shown, a cell phone antenna
must be bent to conform to the curved shape of the housing they are to be
attached to. By bending the antenna @.050" away from the PCB to be mounted
directly above increases by almost 100%. This increase in distance is very
significant in the performance of the antenna.
There are two ways to achieve this increase in distance. One, is
to pre-bend the antenna from the antenna supplier. This is rather expensive and
requires special packaging to eliminate damage during packaging and shipping.
The other, is to invest in quality tooling and equipment to perform the bending
during the assembly process. This investment is quickly realized in greater
yields and savings of raw components.
Many heat stake machines and tooling sold on the market today do
not provide the accuracy and repeatability to perform such precise heat staking
needs. Their manufacturers feel that by offering an inexpensive piece of
equipment, profits have been retained by their customer and all is well. We do
not feel that the savings end here. Nor do we feel that they even begin here.
We feel that the real savings and educated investment involves not only the
equipment and tooling cost, but the accumulated cost of simplified components,
ease of assembly and reliability of the product itself.
In both of the examples shown, the manufacturers were able to
purchase antennas at the lowest price available with shortest lead times. This
is due to the fact that both antennas are flat and all bending is left to the
tooling and the heat staking equipment. There was an investment of time by both
parties to work with us to establish proper product design. By designing the
tooling from electronic part files, we were able to calculate the degree of
bending required and incorporate this into the heat stake tool as a feature.
The success of this has been so great that this is now considered standard
protocol for design of similar products.
See these articles for more information:
Attaching Metal Grilles and Screens to Plastic
Cell Phones Assembly Machines
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