By Roberto Rocca
In the context of automated testing, the complexity of new technologies has brought challenges that both the flying probers and bed of nails testers are facing to the highest level. The increasing demand for functional testing, as well as on board programming, JTAG tests and testing through dedicated hardware, compel the user towards well thought-out choices within the test strategy. Add to this that the significantly most pressing concern is, beyond all doubt, related to achieving short test times at reduced costs.
Seica has revolutionised the concept of the bed-of-nail test, combining the best distinctive features and the throughput of the Compact line bed of nail testers, with the flexibility and innovation of the Pilot4D line flying probers. The outcome is the Pilot4D FX, the missing link between standard bed of nails and flying probe test systems.
The core of Pilot4D FX technology is a mobile head, capable of accommodating a 12x12cm mini fixture, controlled in the four degrees of freedom. XYZ and W. A SMEMA-compliant conveyor can load, lock and download the board in a production line. The mechanics of the test system is controlled by the consolidated VIVA software, monitoring test programming and motion, ensuring that the fixture can fit any board arrangement within a panel. The head of the Pilot4D FX is substantially a mobile receiver, capable of housing a minimised fixture implementing the system resources required to test a single board. The receiver and fixture are both designed in accordance with automotive standards.
Therefore, this type of solution is conceived for the shared use of test resources for board panels. The strategy for fixture construction will be carefully verified and selected, not only based on the number of boards to test, but also depending on the cost of the required equipment. In fact, the higher is the test cost per board, the higher benefit is gained by using the Pilot4D FX. Unlike a standard bed of nails tester, the hardware resources are integrated only once. The mobile head of the system will move the test resources from one board to another within the panel. On-board programming and functional integration with specific communication protocols are just some examples of what the Pilot4D FX can be used for.
Due to the high speed provided by the lack of mechanical handling time, a bed of nails in-circuit tester is the best choice for maximised throughput. However, this method incurs recurrent development costs. While flying probing provides minimal throughput, it reduces development costs. Pilot4D FX is an intermediated solution, capable of delivering productivity levels which are comparable to those of an ICT tester.
The system architecture provides different possible configurations, a customisation for the specific use by the customer. The solution of a fixture contacting from bottom side may be completed with an upper contrast on the opposite side, either mechanical or integrated with other fixed channels. Alternatively, the solution may be manufactured implementing a reversed architecture, that is, with a mobile head on the upper side of the board and a fixture providing contact capabilities from top to bottom, which could be suitable for a non-SMEMA conveyor solution of the UUT. An additional possible configuration is to have the solution equipped with a second head and a fixture on the upper side to provide top/bottom test capability via two mobile fixtures. Optionally, a marking system can be installed in order to certify the positive result of the test.