| Creating a Successful Test Strategy |
Creating a Successful Test Strategy
key points and facts about how to build and create a test strategy, write
a test strategy document and save considerable sums of money in the electronics
production and test process.
The development of a test strategy or testing strategy for an
electronics product is just as important as the development of the product
itself. It is an unfortunate fact of life that not all products will work once
they have been manufactured and it is necessary to test the product before it is
shipped to ensure that it is operational.
The test strategy will need to be developed around the
product, and the available equipment. When creating a testing strategy it is
necessary to take account of many other aspects of the product including its
design, the complexity of the boards and many other factors. It may be necessary
to ensure that elements of the design are changed to enable testing to be
accommodated more easily and in a more cost effective manner. As a result it is
necessary to develop the test strategy from the earliest stages on the
development of the product.
Elements of creating a test strategy
In order to create a test strategy, it is necessary to start at the beginning of
a project and then carry the development and implementation forward throughout
the whole of the development and production lifecycle. In order to ensure that
the testing strategy is carried forward, it is wise to create a test strategy
document, and update this as the development and production elements of the
project move forward.
The main elements of the test strategy lifecycle may include
the following:
- Analyse the product: One of the first tasks to undertake
is to completely review the proposed product. It will be possible to gain a
good idea of the construction of it, and form a view of the anticipated
components and technologies it should be possible to estimate the
anticipated failure rates.
- Review available test equipment: While many would like
to tailor the test equipment to the product and buy new test equipment, this
is not normally possible. It is normally necessary to re-use existing test
equipment and to design the product so that it is optimised for the test
equipment that already exists. With a knowledge of the technologies used in
the proposed product it will be possible to asses the existing test
equipment to ensure it will be suitable for testing the new product.
- Review test opportunities: It will be necessary to
review the areas in which assemblies can be tested, both during the pilot
production runs when more failures would be expected as well as later in its
life when the processes will have matured and the line settled down.
- Create test strategy document: In order to define what
needs to be achieved it is necessary to create a test strategy document.
This will set down the aims of the test strategy in a form that can be
reviewed and then implemented. It is vital that all parties agree to this so
that any design for test strategies can be implemented during the early
design stages for the product.
- Implement test strategy: It is necessary to implement
the test strategy from the earliest stages of the deign of the product.
Elements of design for test will need to be implemented from the concept
stages of the product through to the time when printed circuit boards and
ASICs are committed. By ensuring that any design for test measures are
introduced, the testing of the product can be greatly simplified and the
test coverage increased to a level where few failures are missed.
- Collect metrics: One key element of any test strategy is
to collect metrics. In this way commonly occurring problems can be seen and
rectified. In this way the production process can be improved and costs
reduced. Only by collecting metrics and analysing them quickly can process
improvements be achieved.
- Review and change test strategy and testing: One of the
key elements in any test strategy is to incorporate regular reviews of the
product and be prepared to change even after the product ahs been in
production for some while. This costs additional money and once a product
has completed its development, this is rarely available and as a result
costs may be higher than necessary because the testing is not continuing to
be optimised. It is normally advisable to make changes to the test strategy
once a product has been in production. It may be possible to omit some tests
which rarely produce results or it may be necessary to introduce others to
reduce fault find time. These improvements to the test strategy can only be
implemented if funding is available.
Summary
By adopting a sound test strategy from the early design stages of a product,
production costs can be kept to a minimum while maintaining a high quality
product. This is exactly where some of today's top manufacturers score, and are
able to deliver cheap reliable product.
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