Fast paced test management
The automotive environment remains one of the most difficult and complicated markets to face for those who manage the testing of electronic products. By Paolo Bertoldo, Technical Sales Support for Seica Italy.
The fast introduction of new technologies, the increased complexity of systems and the reduced time-to-market of the new products, combined with the high quality level demanded by the automotive industry, are all elements which require quick response time and significant innovation.
With increasing frequency, technologies from the consumer world ranging from mobile communication, touch screens and LED-based optical systems are coming into the car. These solutions have cycles of innovation and a time-to-market concentrated in to a few months, and hence require a prompt and immediate reaction by those who intend to integrate them. In addition, the end-users expect that the benefits from these new technological solutions deliver the same performance level as those they are already accustomed to and use in everyday life.
So, it is essential for the players in the industry, as well as for those who manage the issues of internal test, to locate the most suitable and qualified partners to implement the solutions needed to keep up with the consumer world. This is especially valid when discussing automated test equipment.
One of the most important characteristics to be considered in the selection of a test partner is the expertise acquired from working in different electronics sectors, from the simplest product in the consumer world up to complex military systems. This ‘wide angle’ exposure often makes it possible to spot and anticipate technical solutions and possibly market trends which may be transversal, and consequently can be applied to different customers and sectors.
Certainly, specific knowledge of the issues can lead to the optimisation of manufacturing costs and integration of testers in production lines. In fact, very often the technologies being faced for the first time by the automotive world are already a consolidated reality in other industries. Think, for example, mobile phones and satellite localisation modules.
The same expertise can also be used in the initial stage of design and, above all, to optimise the definition of test specifications, which today represents one of the most time-consuming steps in the process.
It is also certain that the automotive environment uses specific solutions which require dedicated expertise; the CAN vehicle protocol for example or, more recently, communication via MOST. In this sense, a partner who has had the opportunity to see situations and critical conditions working in other sectors is a step ahead when it comes to suggesting the most suitable solutions and, in many cases, the most original.
A challenging environment
The evolution of the car has led to raised market expectations from integrated capabilities. Airbags, power steering and headlight controls are now considered to be an integral part of the vehicle itself, as is their reliability. To achieve this result, the automotive component manufacturers must resort to all of the best solutions available on the market, from the best chip suppliers all the way up to the best manufacturing strategy. The decisions concerning test are clearly an important part of this last consideration.
Compared to other sectors, the test process in the automotive industry consists of a set of test solutions which are very articulated within the production line. Great attention is placed on the organisation of the test sequence, with the goal of achieving the 0ppm goal (0 faulty parts per million of products).
When the assembly process of the electronic circuits is completed, the first test stage is in-circuit test. This step may also include the task of programming micro-controller as well as the related device-embedded memories to guarantee the availability of the proper code. In many cases, these two operations are integrated into the same system, if the time-cycle of the line allows it, with the aim of reducing the number of required tasks.
The next stage is the functional testing of the product before it is completely assembled with all of its parts, including the mechanical ones. Here the aim is to assess the compliance of the product itself to the defined operational specifications. However, the advantage of carrying out this type of test at this point is the optimised accessibility to the circuit under examination, allowing better diagnosis of the known critical conditions.
Once it is completely assembled, the product is subjected to an additional test before it’s sent to the customer for installation in the vehicle. This station, commonly defined as End-of-Line, aims to assess the product in its final configuration, with normal access via its external connectors, which partially limits the diagnostic options. This stage normally requires the integration of additional, specific instrumentation, able to appropriately simulate the sources external to the product. The use of resistive loads or GPS simulators are common examples of specific instrumentation.
Finally the product is inserted into another test station, where it is subjected to a prolonged stress cycle in the real operating conditions of the device. This way it is possible to diagnose possible endemic problems or those categorised as ‘infant mortality’; that is, those which occur when the product is first subjected to real component strain. Given the typically long cycle times of this type of test, this may be applied on a ‘sample’ basis, rather than the total number of devices manufactured.
What makes the situation even more complex is the need to manage multiple variants of the same product, not only for different models of vehicle, but also based on the final market where the product is sold, in addition to the not less important requirement of complete traceability of all the stages of the process to enable fast intervention in the event of critical situations (for example, a recall campaign).
In order to reach the required 0ppm target it is necessary not only to address defects related to the assembly process implementing the aforementioned solutions, but also to reduce to a minimum the chance of human error by the operators working in the line. These so-called fool-proof solutions start, for example, by limiting the opportunity to insert the product on the wrong fixture (through appropriate mechanical constraints), then ensure the activation of the correct test program (based on barcode readers) sometimes arriving at the complete automation of the process using in-line systems.
Along with maximum performance, the tester should also be engineered to optimise system ergonomics with respect to operator comfort and the precepts of lean production, with the flexibility to allow the introduction of new solutions to better meet the requirements of the industry customers. Not less important is the necessity to guarantee high test throughput to comply with the increasingly stringent production cycle-times.
Based on a unique hardware and software platform common to all its products, Seica’s product portfolio covers all of the test levels required in a standard production line, from the simple in-circuit to the most complex end-of-line functional test. This architecture optimises return on investment, ensuring that systems are readily interchangeable and training is optimised across different test steps, reducing to a minimum the need for specific operator know-how.
The whole is of course completed by the integration of the basic technologies in automotive electronics, such as, for example the management of the most common communication protocols ranging from a standard CAN to the LIN and k-line serial interfaces, up to the support for the innovative Ethernet-based standards. SEICA also offers the option for true parallel test, to maximum test throughput.
The Seica COMPACT product line includes a full range of solutions, from entry-level systems (Compact TK) or combinational testers with full integration of external instruments (Compact Multi). These systems are available in several different configurations including the fully automated, in-line version, (Compact SL) and independent, multi-fixture versions.
Seica’s PILOT line of flying probers complete the range of test solutions, providing in-circuit and complex functional test wherever a fixtureless solution is required or preferable, for example in a prototype or repair stage.