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August Locks Down Quality with Instrumental

August engineers use Instrumental Dev to discover and fix unexpected issues on 10% of their development units.

As part of August’s mission to make homes more secure and life simpler, they set out to create a smart lock that anyone could afford. They wanted to ship the new lock in time for the holidays, so August’s team relied on Instrumental’s system to help them catch and fix issues during development.

The August Smart Lock allows you to use your phone as the key to your home, auto-unlock your door as you approach, and auto-lock when you leave. It notifies you if your door is left open and even lets you grant visitors keyless entry to your home directly from the August app.

The Problem

The August Smart Lock was going to be an all-new product, with an entirely different form factor from the original Smart Lock Pro. To streamline their supply chain, August planned to reuse several key components from the Pro. This constraint, coupled with the new Smart Lock form factor presented new design challenges for August’s engineers.

Before the Smart Lock’s EVT build, the August team was concerned. One specific concern was the gears: each unit has seven gears that need to align and to have the right amount of grease in the right locations – exactly the kind of assembly process that’s difficult to control over time. The biggest worry was that any gear issues that occurred would be dark yield: they might be missed by functional tests on the assembly line and could cause units to fail after making it to customers. The August team also anticipated that the shaft-to-shaft distances would be critical for proper function of the gears, and wanted traceability during development to be able to correlate any gear train performance issues with the gear assembly. Taking measurements of every unit on a development line is difficult: traditional vision systems require a lot of setup, but the design is still in flux, so that setup may have to change over and over again.

Quality hardware and great customer experience are core elements of August’s brand, so in addition to functional performance, product cosmetics are important. The team was concerned about cosmetic defects like gaps, offsets, scratches, and surface. The lock’s enclosure is made of blasted anodized aluminum, a highly spectral surface that can be difficult to inspect, making it likely that some defects would be missed. On previous programs, August’s team used emails and spreadsheets to monitor performance and cosmetic issues; they needed a more efficient way to see what’s happening on their assembly line.

The Solution

In order to meet their quality requirements on a tight schedule, August’s engineers looked to level up their current process before starting EVT. Instrumental engineers teamed up with August to analyze the plans for the new lock’s assembly process, taking into account the highest risk features. Together, they created a plan to set up four strategically placed inspection stations on August’s line, taking a total of eight images of each unit. Several weeks later, Instrumental engineers had the whole system up and running in time for EVT.

Being able to look at units as they come in and showing the team at headquarters that issues are ‘real’ is very cool!


Three stations enabled the direct inspection and review of the lock’s gears and shaft bosses at different stages of assembly. Instrumental stations automatically created a 100% traceability record so that the August team could review the images from those stations to identify other gear-related issues, such as too little or too much grease. In addition to looking for anomalies, the August team used Instrumental’s built-in measurement tools to virtually take precise, ad hoc measurements to confirm that parts were placed correctly, from anywhere in the world.

One of these three stations also provided a view of the lock’s circuit board. August’s engineers used images from the station to make sure the board was placed correctly and that the board connectors were fully seated. An intermittent connection caused by a non-fully mated connector would be missed by functional tests and could result in field performance issues. Instrumental helped August identify several of these so that process changes could be made to ensure they didn’t happen again.

The August team used Instrumental to identify dark yield defects, like this connector that may be mated well enough to pass a functional test, but may become disconnected after light use.

The final station captured images of the finished units, enabling engineers to track important cosmetic issues like scratches, offsets, and imperfections in the blasted anodized finish.

The Results

Instrumental was on August’s known issues. They were then able to conduct failure analysis and iron out those issues before moving into mass production.

During development, August’s engineers used Instrumental to discover issues in about ten percent of the Smart Lock units that they would have been unlikely to find without it. Issues ranged from the expected—gear assembly and lubrication variation, for example—to the unanticipated, like misrouted flex cables and debris in enclosures. Those units enabled the team to learn faster during development, making design changes and putting process in place earlier than they would have normally, resulting in better quality by the end of PVT.

With Instrumental’s system on their line, August’s engineers moved smoothly through each build of the Smart Lock. Because they caught critical issues early in development, they were able to validate design and process fixes quickly and transition the new lock into mass production easily, without sacrificing quality or schedule.

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