Why Functional Testing?
Purpose of the functional test in the assembly of components

Why function testing in assembly?

The purpose of the function test is to systematically check and permanently ensure the basic function of all electronic components and their interaction.

With the help of the function test, CrossTEQ systematically and reliably checks the overall or partial function of an assembly or an entire system. The function test includes both the final test after production of an assembly and after installation of the respective assembly in the finished device. 

Test requirements and test instructions for functional testing at CrossTEQ


CrossTEQ ensures that personnel are properly trained in performing functional testing. Only regularly trained production personnel may perform the functional test (and burn-in test and factory acceptance test).

Test environment and precautions

CrossTEQ quality personnel (production manager and production engineering manager) maintain and implement work instructions, test environment guidelines, and any precautions for functional testing (especially for electrostatic sensitive devices!).

Testing software

The test application software guides the tester through the various test steps and executes the automated test section where possible. The test application documents and creates digital test reports, which the tester must sign.


Deviations/defects are to be noted on the test report. Any corrective actions and the subsequent regression tests shall be described in detail at the request of the test application software.

Per the Supply Agreement, CrossTEQ archives reports as part of the Device History Record (DHR). Each report must be traceable to the component by part identification number and serial number. 


Only after testing is successful, assembly of the assembly or device is completed. Our quality personnel perform the Quality Assurance (QA) buyoff for product release and confirm proper manufacturing, testing and reporting by electronic signature before delivery to the customer.

Applications and examples for functional tests

X-ray image function tests for radiation therapy imager

In this functional test, we test the acquisition of X-ray images in the darkroom, with the aim of discovering errors caused by the interaction of the components.

Foto zeigt einen Computerbildschirm in unserer Cross Assembly für den Burn-in Test von medizinischen Baugruppenngsprüfung  in unserer Cross Assembly

Functional test of a large-area, highly sensitive image sensor during incoming goods inspection

Our quality personnel are specially trained to test and assemble large area and sensitive sensor panels, as unclean handling can cause the glass to strike the frame components or flex cables to catch on the PCBs and be damaged. 

Foto zeigt die Testeinrichtung in unserer Cross Assembly für den Function Test von medizinischen Baugruppen 

When such panels are received, the workplace and devices are first cleaned with ionized compressed air and the device grounding is ensured. Before the actual panel function test, the vacuum handling device is tested first. For this purpose, the image sensor with the fixture is removed from the packaging and placed in image sensor test fixture.
After the image sensor is placed in the test fixture, it is neatly aligned with the PCBs and all flex cables are plugged into clamps and closed. The image sensor is covered as light-tight as possible when it is connected to the test station and the test is performed.

At CrossTEQ, we specialize in the demanding quality assurance of electrostatic sensitive assemblies and devices.

We assemble, test and adjust complex assemblies and highly sensitive microelectronics with permanently highest precision and reliability.

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Foto zeigt einen Computerbildschirm in unserer Cross Assembly für den Burn-in Test von medizinischen Baugruppenngsprüfung  in unserer Cross Assembly

Burn-in testing of assemblies before the start of mass production

Accelerated life test for testing the load capacity of components, assemblies or complete devices in continuous operation.

Application example of CrossTEQ: Frequency acquisition of dark field images and generation of drift images with radiotherapy imager during 48 hours.

Foto zeigt die Röntgenkammer in unserer Cross Assembly für den FAT Factory Acceptance Test von medizinischen Baugruppen

Finaler Factory Acceptance Test (FAT)

To validate equipment operation and ensure that order specifications and customer quality and functional requirements have been met.

Application example at CrossTEQ:
Final acceptance test (X-ray test) to acquire X-ray test images with radiotherapy imagers.

CrossTEQ AG, Madam Hanna Eberli
1 December, 2022
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