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 (click pictures for close-ups) 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 it, the distance between the two 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. The engineers at Thermal Press International 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 Thermal Press International engineers to establish proper product design. By designing the tooling from electronic part files, the Thermal Press engineers 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.

Please Contact Us at Thermal Press for more information.