In-house functional testing: Ensuring quality products every time

In this blog we provide an overview of GRiD’s approach to in-house functional testing, the process that each and every one of our rugged laptops or tablets goes through before it is delivered to the customer. With this approach, military operators can be confident that their systems perform to the very highest standards, and that the chances of failure have been vastly reduced.

When a customer selects GRiD as a supplier for its rugged computing requirements, they can be safe in the knowledge that the assembly and functional testing of our ruggedised hardware is all done in-house by our specialist UK engineers, and that we have highly efficient processes in place to guarantee each piece of equipment delivers on the performance that we promise.

Our in-house functional testing capability is utilised for all components that enter our workshop and every assembled GRiD tablet or laptop that leaves our UK facility. This testing is based on a layered approach, from the individual components such as Printed Circuit Boards (PCBs) up to system level and even environmental functional testing if required by the customer.

Credit: Defence Media Ltd.

Component Level Functional Testing

Functional testing starts with pre-build testing at the component level, because after all, there is no point in configuring a laptop to then find further down the line that a piece of wiring does not work and is preventing the whole computer from powering up. And this can easily be avoided by testing the performance of each component.

A bench test rig based on an open frame is used to carry out these functional tests, which replicates the tablet/laptop and allows for the different components to be plugged in so that checks on them can be carried out.

Components tested include wiring looms, each of which needs to be checked before installation. Each signal within the system that is connected to a pin is wired, and there can be hundreds of wires per system, all of which need to be working.

Our printed circuit boards – or PCBs – are designed by GRiD and fabricated by our partners in the UK, so we carry out tests on each one when it is delivered to our facility to ensure that it is performing as required before it enters our stores.

There are lots of tracks on the PCBs, so this approach serves to de-risk the process at an early stage in the build. PCBs are then stored in an anti-static bag and are temperature and humidity controlled throughout storage to ensure that performance is not impacted.

We also test mechanical features such as keyways within the system. The same connector within a laptop or tablet can have different keyways, so each one needs to be functionally verified.

System Level Testing

When the laptop or tablet has been assembled by our expert engineers and the relevant BIOS and operating system has been configured, another layer of checks takes place.

This is known as a final test procedure (FTP), and covers mechanical, firmware, configuration, operation and power management checks.

At a very basic level, the system needs to be checked to see if it matches the configuration ordered by the customer. This includes the memory, processor, hard drive, resolution and so on.

Powering is also verified – does the system switch on and off? It may sound simple but there are many complex power states in a computer, all of which require confirmation that they are working correctly.

There is even a shake test where the laptop or tablet is physically shaken to ensure that loose parts are not missed, and if anything has come loose, we can quickly fix it before it becomes an issue. While this sounds like a basic test to carry out, it can be overlooked if a company does not have a stringent functional testing process in place, and that has future consequences for the end users.

Environmental Extras

Environmental stress screening (ESS) can also be carried out at the request of the customer, which is functional environmental testing and differs from qualification testing – such as IP67 – that determines if the system adheres to particular military standards and ratings.

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ESS testing involves placing the system in environments of extreme temperatures and vibration levels and provides yet another layer of assurance that the system performs as it should.

FTP testing is carried out before and after the ESS in this case. The second FTP is essentially a repeat of the first one, ensuring that the ESS process has not altered the system in anyway. If there is no ESS element, only one FTP is typically required.

Burning In

The final part of the testing to take place before the hardware is ready to be shipped is a system burn-in. This serves to essentially push the system to its limits, trying to induce a failure.

The burn-in sees components within a fully assembled laptop or tablet operated at 100% over a period of 36 hours, including the screen, graphics, RAM and hard disk.

The system-level FTP checks are carried out both before and after the burn-in, checking for any problems that can be rectified beforehand, and likewise, if the burn-in has produced any problems that need to be dealt with afterwards.

The whole testing process from FTP through to burn-in takes approximately 48 hours in total, assuming no problems are found and testing does not need to be repeated for any reason. This is carried out on every piece of equipment that is delivered by GRiD, so that our customers know that they are receiving a fully-tested, mission-ready laptop or tablet every time.

GRiD is so confident in the reliability of its systems – as a result of its stringent testing and extremely ruggedised designs – that extended warranties of some 20 years are possible. And our in-house functional testing capability is often utilised on legacy customer products that are being upgraded or are going through obsolescence management, so the customer can rest assured that it will go through all of our rigorous testing procedures again before it is returned.

If you are interested in learning more about our testing methods and the products we produce, give our team a call on +44 (0)1628 810 230 or drop an email to