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Ruggedized Tablet Testing

Ruggedized Tablet Testing

Nothing is more essential to building a rugged tablet than testing that rugged tablet thoroughly. Estone tech takes ruggedized tablet testing seriously. Learn more about some of the methods below, and how we ensure that those methods meet your needs with MIL-STD-810G standards.

Drop-Proof and Shock-Resistant Tablets

Tablet Drop TestingWhen building a tablet or piece of electronics to contend with rough situations, it makes sense to start at the beginning. Items get dropped sometimes, especially in a work setting. Objects being carried around juggled and manipulated are bound to be dropped sooner or later. Electronic devices ae no different, and in fact may be more likely to be dropped, since they’re often carried out in front and manipulated with one hand while they’re held by the other.

In order to ruggedize a device to contend with the trials of everyday life, it’s got to be carefully designed and constructed to stand up to those drops and bumps. There are two ways this is typically accomplished. With stronger frame components, and with soft, deformable components that can absorb the brunt of an impact so more delicate parts don’t have to. Electronics are usually rated for their most common and expected stresses – so tablets that are carried at arm’s height are usually rated for drops of 4 to 5 feet, though they may actually outperform this.

In a rugged tablet, weight and space are at a premium, so every piece that is reinforced and strengthened has to be carefully considered. Extrusions of metals like steel, zinc, and aluminum may be used at key points within the frame or on the case. These must not only take up as little room and space as possible, but also funnel heat away from trapped areas on the device. A properly ruggedized tablet will easily stand up to drops and shocks found in common use, without becoming too big, bulky, heavy or heat retaining to function properly.

All of our tablet designs visit our drop-testing devices, where they are reliably and repeatably dropped at different angles and orientations on different surfaces, to make sure you’re getting a tablet that is ready to meet your needs.

Our Testing Methods

Drop Test Conditions
• Drop Height – 48”
• Drop Surface – Plywood
• Total Drops – 26

Each tablet model we produce is dropped via drop apparatus a minimum of 26 times onto a plywood base from a height of 4 feet. The tablets are dropped on both front and back faces, as well as each edge and corner. Each edge and corner is dropped straight on, and also at positive and negative angles to ensure maximum durability. This testing method meets MIL-STD-810G standards.

Vibration Resistant Tablets

Vibration TestingWhile not a concern for every use case, some industries are less likely to see tablets dropped than they ae to see them heavily shaken and vibrated. Vibration that is damaging to electronics is usually regular and periodic, and might be found when a tablet is mounted in a vehicle or on a piece of machinery. When the vehicle or machinery is in motion, the regular moving of its parts creates a consistent vibration that can be very damaging to electronics. Wires and connections become loosened, components begin to shake free of fasteners, and even elements of integrated boards can fail.

Designing a tablet to withstand vibration means ensuring components are securely fastened, and sometimes, a little flexible themselves. Cables and wires will often be secured with a glue or epoxy that isn’t susceptible to minor mechanical strains. Nuts and bolts will often be fastened with a thread-locking compound to keep vibration from slowly “backing off”.

Vibration is one of the biggest concerns for tablets in the logistics and shipping industries, as well as any heavy manufacturing industries. Rolling mile after mile under the power of a large engine, touchscreen devices are susceptible to road-noise vibration. In an industrial environment, many pieces of machinery develop consistent vibrations as part of their regular operations, which can damage control screens, sensors, and other integrated electronics.

At Estone Technology, all of our tablet designs spend time on a specially designed Vibration Testing Table, being heavily vibrated at different speeds and frequencies, to ensure users don’t experience a failure when they hit the road.

Our Testing Methods

Vibration Test Conditions
• Vibration Scenarios – Field, Vehicle, General
• Vibration Conditions – Operating, Non-Operating
• Vibration Length – 1 hr/2 hr

Each tablet model we produce is tested for vibration durability in 9 different vibration tests that last one to two hours in length. In 6 of the tests, the tablet is tested while in operation, simulating use in the actual field. These tests are performed in three different tablet orientations. The remaining tests are performed with the tablet in non-operating mode, designed to check for structural failure due to vibration. In all cases, the tablet is placed in the appropriate orientation on a vibration platform and vibrated for 1 to 2 hours at a specified frequency. This testing method meets MIL-STD-810G standards.

Shock Resistant Tablets

While drops are a concern for tablets, it is also a risk that something will be dropped on the tablet, as it may be placed in harm’s way, or even used as a blunt instrument! Shock testing is the method used to make sure that your device stands up to the bumps and blows of every day use. A shock is any sudden impact, jar, or change in orientation that can damage the look or function of a device. They are common in shipping, storage, and every day use.

Because it’s hard to anticipate what might strike a tablet, and from what angle, shock testing is performed a number of times in a number of orientations. Each time, the tablet is secured, and then struck with a metal mass designed to simulate an impact. This is done to the touchscreen, the rear case, and the sides of the tablet. Any damage, like dislodging of components, or screen cracks, indicates failure of the test, and our engineers go back to the drawing board to create a more durable tablet.

Our Testing Methods

Shock Test Conditions
• Test Weight – 40g
• Test Impact Speed – 11ms
• Test Total – 18 Total Shocks

The shock test, unlike the drop test, is designed to determine whether a tablet can take blows and impacts expected during shipping and use. In the shock test, the tablet is struck with a metal mass moving at a specific speed, from multiple directions and orientations. In total, the test article is struck 18 times, and any damage that prevents proper function or operation of the tablet indicates failure. This testing method meets MIL-STD-810G standards.

Tumbling Resistant Tablets

Tumbling is something between drops and vibration, and puts a unique type of stress on an electronic device. While tumbling, devices are subject to a series of small blows something less than a full-fledged drop, but something more than regular vibrations caused by road or equipment noise. It is harder to predict when a device might be subject to tumbling, but it is important to be prepared for it. A drop down a flight of stairs, or a bobble down a hill or embankment could lead to a tumbling tablet. As opposed to the single-impact stresses of a drop, repeated, small, torqueing impacts can spell disaster for unprepared electronics.

Tablets equipped to deal with tumbling need to be built with secure fasteners for all pieces of equipment so that they won’t shake loose during a tumble. I/O ports, buttons, and internal devices need to be securely mounted, and wires or cables need to be fastened so they remain unmoved and out of the way.

At Estone Technology, we have specialized Tumbling Testers that all of our tablet designs must pass through. The repetitive up-and-down tumbling action ensures a robust tablet design.

Our Testing Methods

Tumbling Test Condition
• Tumble Period – 1.2 minutes
• Tumble Speed – 10 Rotations / Minute

The tumble test is designed to ensure that the tablet can withstand repeated, randomized blows from different directions and orientations. The test article tablet is placed into the tumbling tester device which is rotated about once every 6 seconds to simulate the tumbling experienced during shipping, handling, and mishandling of a device. Tumble testing is not part of the MIL-STD-810G method requirements, but Estone Technology fulfills it to make sure we’re delivering you the highest quality rugged tablet.

Extended Button Life for Tablets

Button Life TesterNothing puts the limits on electronic lifespans quite like the destruction of the human interface. If a user can’t properly interact with the device, it doesn’t matter if it’s still technically functional. Though tablets and touchscreen devices usually rely on their capacitive touchscreens for primary interaction, many feature hardware pushbuttons for some common features, like a power button, buttons to activate scanners or devices, and programmable buttons for a frequently used software process.

Because these parts are so essential for proper tablet function, they need to last at least as long as the device itself is intended to be used – tens of thousands of cycles. This means selecting pushbuttons and rocker switches that are robustly manufactured, with just the right amount of travel, and securing them behind and appropriate flexible cover.

At Estone Technology, we test our pushbuttons to extremes, through many thousands of cycles, to ensure that they don’t fail because of frequent use. We have specialized button testing devices just for switching devices on-and-off, far more than a user ever would.

Our Testing Methods

Button Life Testing Methods
• Frequency – 60 Cycles/Minute
• Length – 3000 Total Cycles
• Pressure – 500g

Button Salt-Spray Testing Methods
• Test Temperature – 35°C, 92% Humidity
• Air Pressure – 1kg/cm2
• Saline Concentration – 5%

Buttons are tested rigorously in a specialized button testing apparatus. This is designed to ensure that buttons can withstand even forceful presses, repeatedly, for the expected life of the product, without fail. At 500 grams, buttons are subjected to far more force than is expected from an average user, and up to 6 buttons an be tested at once.

In the saline test, buttons are tested against a pressurized saline spray for intrusion and corrosion. Entrance of saline into the system could be catastrophic, so this test is essential, and more rugged than mandated.

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