Latest / Hardware Startups with Fexingo: Devices, Robotics, and Manufacturing Tech Companies / Accelerated Life Testing for Hardware Startups
Transcript
- Lucas: So there's a stat that stuck with me from a reliability study last year: nearly 40 percent of hardware startup failures are linked to field defects that could have been caught with proper stress testing before shipping. Luna: Ouch. Forty percent — that's a huge number of preventable product deaths. Lucas: Right. And one of the tools to avoid that is accelerated life testing — specifically a method called HALT, which stands for Highly Accelerated Life Testing. It's been around for decades in aerospace and automotive, but a lot of consumer hardware startups skip it because they think it's too expensive or only for big companies. Luna: So what does HALT actually involve? Like, do you just bake the thing in an oven? Lucas: Partly, yes. But systematically. You put a prototype or early production unit into a chamber that can ramp temperature rapidly — we're talking minutes to go from -40 degrees Celsius to +85 degrees — while also applying six-axis random vibration. The goal is to find the product's fundamental design limits: at what temperature does a solder joint crack? At what vibration level does a connector shake loose? Luna: And you're doing this before you commit to a thousand units, ideally. Lucas: Exactly. The classic example I heard recently was a startup making environmental sensors for smart agriculture. Their first batch was failing about 8 percent of units in the field after six months. The failures clustered in cold climates — sensors just stopped transmitting. They ran HALT and found that the potting compound used to seal the electronics was becoming brittle at -20 degrees and cracking, which let moisture in. They switched to a different epoxy, reran the test, and the failure rate dropped to under 1 percent. One material change, no redesign of the PCB. Luna: That's a huge win. But how do you even afford a HALT chamber as a startup? Aren't those things six figures? Lucas: The systems themselves are — a new chamber can run $80,000 to $150,000. But almost nobody buys one early on. You rent time at a contract test lab. For a couple of days of testing, including technician time, you're looking at maybe $3,000 to $5,000. If you have a prototype, you can do a full HALT sequence in three to five days if the lab has capacity. Luna: So for less than the cost of a small production run, you can de-risk a major failure mode. Seems like a no-brainer. Lucas: It should be, but a lot of founders I talk to say they didn't know it existed, or they thought certification testing like FCC or CE already covered reliability. Those are about emissions and safety, not durability. Luna: Right. That's a different thing entirely. So after HALT, there's also HASS — Highly Accelerated Stress Screening. That's for catching manufacturing defects once you're in production, correct? Lucas: Exactly. HASS takes the limits you found during HALT and applies a slightly less aggressive stress to every unit coming off the line. For example, if HALT showed your design fails at 80 degrees, you might screen each unit at 70 degrees for a short cycle. Any unit that fails that screen has a latent defect you don't want to ship. Luna: That makes sense. You're basically proving the manufacturing process is consistent. And if a batch starts failing HASS, you know something changed in your supply chain or assembly line. Lucas: Precisely. One medical device startup I know uses a 10-minute HASS cycle for every unit of a wearable vital sign monitor. They found that 1 in 200 units had a cold solder joint on a flex cable that only showed up when vibration and temperature happened together. Without that screen, those would have failed in the field, and for a medical device, that's both a safety issue and a regulatory nightmare. Luna: Yeah, that's the kind of failure that can sink a company. And regulations like ISO 13485 or even just good warranty math would push you toward screening. Lucas: Now, one question I get a lot is: should you do HALT on every product, or just complex ones? My rule of thumb is, if it has a battery, a connector, or a seal of any kind, you should at least do a limited HALT on one or two prototypes. Those are the three worst failure categories in consumer hardware. Luna: Battery failures are huge, especially with Li-ion. And seals — that's how you get water damage or dust ingress. Lucas: Right. The other thing is, you don't need to test everything to destruction. HALT is about finding the weakest link. Often you'll see a product survive fine until a specific threshold, then fail dramatically. That's your design margin. If your target operating range is -10 to 50 degrees, but HALT shows the device fails at 60 degrees, you've got good margin. But if it fails at 55, you're cutting it close. Luna: So you adjust your specs or your design. And that's the value — you get data before you go to production, not after. Lucas: One thing I want to mention — if you're a small team, you can also run simplified thermal shock tests with a cheaper setup. For example, a two-chamber method: a hot oven and a freezer. Transfer the unit back and forth manually. It's not as controlled, but it can catch gross issues like incompatible CTE — coefficient of thermal expansion — between components. I know a drone startup did that with a toaster oven and a chest freezer to test their camera module. Found a lens mount that popped off after 10 cycles. Luna: That's resourcefulness. But HALT is really the gold standard because it combines stresses. Lucas: Yeah, and the cost of a proper HALT at a contract lab is often less than the cost of a single field failure when you account for replacements, shipping, customer support, and brand damage. If you're selling a $200 device and 2 percent fail in warranty, that's $4 per unit. For a run of 10,000, that's $40,000 in direct costs. A $5,000 HALT that eliminates half those failures pays for itself immediately. Luna: And that math is exactly why showing this kind of data also helps with investors. It shows you're thinking about manufacturing risk. Lucas: Absolutely. When I hear a founder say 'we did HALT and our failure rate is under 1 percent,' that signals they understand hardware is hard. It builds confidence. Luna: Speaking of building confidence — if these conversations are useful for what you're building or running, a couple of dollars a month is genuinely what keeps these going. Buy me a coffee dot com slash fexingo, if you've gotten something out of them. Lucas: Yeah, it makes a real difference. Keeps the show ad-free and lets us dig into these detailed manufacturing topics. Luna: And it's a small amount that adds up. So back to HALT — what about interpreting the data? How do you know if a failure is a one-off or a design issue? Lucas: Great question. In HALT, you typically test three to five units. If two or more fail at the same stress level, that's a systematic issue. If only one fails, it might be a build anomaly. But you'd want to investigate anyway because a sample size of five is small. The key is to document the failure mode and fix the root cause, not just the symptom. Luna: And you repeat the test after the fix to confirm the stress margin improves. Lucas: Exactly. That iterative process — test, fix, retest — is what creates robust products. And for a startup, it can be the difference between a product that survives in the wild and one that becomes a recall statistic. I'll add that many contract labs will also help you design the test profile based on your product's expected environment. If it's a smart lock for outdoor use, they might focus on UV, humidity, and temperature cycling, not just thermal shock. Luna: So you customise the stress profile. That makes sense. What about vibration? Is random vibration always needed? Lucas: If your product will be shipped or used in a vehicle, yes. For a stationary device like a thermostat, vibration might be less critical. But even shipping vibration can cause issues with heavy components like transformers. I've seen a startup's speaker enclosure rattle apart because they used a heavy magnet that wasn't glued. Random vibration at 5 to 10 G would have caught that. Luna: So it's all about matching the test to the real-world use case. And doing it early enough that you can make changes before tooling. Lucas: That's the whole point. Once you cut steel for injection molds, a design change costs ten times more. HALT is cheap insurance when you're still in the prototype phase. Luna: I think the biggest takeaway is that reliability isn't something you test in after the fact — it's something you design for and prove before you commit to volume. Lucas: Well put. And the tools are accessible. Contract HALT, HASS, thermal shock ovens — they exist for startups. You just have to know they're out there and budget for them. A third of all hardware startup failures are preventable with a $5,000 test. That's the message.