Service for Testing:
We can perform 100% board-level testing for each PCB unit we build -and we mean, 100% testing. we can perform board-level testing as well as 100% system testing to ensure high quality. The test services we provide include:
PCB AOI Testing:
Continuing miniaturization of components and increasing complexity of boards is driving the need for PCB AOI Testing:
Checks for missing components, offset, incorrect parts, polarity
Checks solder paste
Checks components down to 0603mm (0201")
PCB Parts Inspection
PCB Parts inspection is a computerized function that compares the image of a PCB captured by a CCD camera with the image of a good PCB memorized in advance, and determines whether it passes inspection or not.
This determination is performed at high speed by the specification of the portion to be inspected, the inspection of the existence of parts, positional divergence of parts, wrong parts, etc. As color factors are also inspected, objects which cannot be discriminated between good and defective by brightness alone can still be judged reliably.
PCB Solder Print Inspection
PCB Solder print inspection is a function that inspects the status of a solder printed surface by examining its area, place and form. Data processing is carried out in natural light, as in the previous parts inspection. Moreover, no special hardware is required.
The reference data for the solder printed surface to be inspected may be GERBER data, automatic sampling, or a manual designation.
PCB Solder Fillets Inspection
A captured image is processed by high-speed rendering. After the process, only the fillet parts are extracted from the image and judged to be good or defective.
PCB X-Ray Testing
We offer high-resolution pcb x-ray inspection of:
Chip scale packages
Large board capability is also suitable for inspection of bare boards
Opens are usually caused by insufficient reflow, missing balls, doming, popcorning or contaminated board surface conditions.
Shorts are easily found using X-ray.
Insufficient reflow is usually a little more difficult to spot. Some of the characteristics of a solder joint, which has not reflowed properly, include rough grainy appearances on the edges of the solder joint and an irregular shape of the joint.
Doming is a defect common when a package has not been stored in nitrogen or other types of non-humidity chambers. The characteristics of the doming effect are the center solder joints of the BGA are slightly smaller than those on the outside edge.
Potato chipping occurs when a component's outside edge lifts up from a pad. This will cause the center joints to appear squashed as a result of overheating the component.
Voids are usually found on boards which have not been through reflow long enough. They are typically created by flux gases that are unable to escape.
PCB In-circuit Testing
STG Electronic offers in-circuit test and turnkey test program development and fixture fabrication services.
Standard PCB Program Development
The Standard programs are cost effective and offer a fast turn-around. This service is most suitable for customers with standard technologies or limited time and budget. The Standard programs can be upgraded to an Advance level at a later date if required.
Advanced test programs The Advanced programs are designed for complex boards and for customers that require the maximum fault coverage possible at the ICT stage. The Advanced programs include steps listed in the Standard Programs as well as the following steps if applicable:
Combination PCB In-circuit & Functional Test Programs
Recognizing that most products will require some form of functional test before shipment to customers, a more logical approach would to be to combine when possible In-Circuit Testing (ICT) and Functional Testing (FBT) into a single stage.
Combination of functional test with ICT can also be used to achieve higher fault coverage that may not be possible with ICT only test strategy. Single stage test strategy using a single test fixture can save test-time and capital expenditure, and reduces the potential for errors and damage caused by excessive board handling.
Single Stage PCB Test Strategies
The In-Circuit Test systems are basically designed to detect manufacturing process faults quickly and accurately and often lack the necessary capabilities for functional testing. As such, the ICT system capabilities can be expanded by integrating off-the-shelf test and measurements instruments (GPIB, VXI or PXI) as well as adding the necessary electronics into the fixture to make functional test possible.
Once the scope of the functional testing is defined, then the necessary instruments are selected; integrated with the target system or in the test fixture, test fixture is designed and built, and test programs are developed and fully debugged integrated with the ICT system software before they are installed at the customer site.