Latest / Hardware Startups with Fexingo: Devices, Robotics, and Manufacturing Tech Companies / How Hardware Startups Use Selective Laser Sintering for Production
Transcript
- Lucas: Hardware startups are printing production parts now. Not just prototypes — actual end-use components going into products that ship to customers. Luna: And not on those $100,000 industrial machines, right? I've seen desktop SLS units for under $10,000 now. Lucas: Exactly. Selective laser sintering has crossed a threshold in the last two years. The price of the hardware dropped, but more importantly, the material quality and consistency improved to where you can trust it for production. Luna: Give me a concrete example. Because I still think of SLS as that grainy, slightly porous prototype material. Lucas: So there's this robotics startup — they make collaborative robot arms for small assembly lines. They needed custom gripper jaws for handling different part geometries. Each jaw was a unique shape, and they were ordering maybe 200 to 500 units per variant per year. Luna: Right. Too low for injection molding tooling to make sense. Tooling alone would be $5,000 to $15,000 per cavity. Lucas: Exactly. They were getting them CNC machined from aluminum at about $45 per part, with a lead time of 8 weeks. They switched to SLS in nylon 12, and now they're paying $12 per part with a 3-day lead time. No tooling. No minimum order quantity. Luna: And the parts hold up? Gripper jaws take repeated impact. Lucas: They do. Nylon 12 has excellent fatigue resistance and elongation at break — about 20 percent. The startup ran 5,000 cycles on the printed jaws and saw less wear than the machined aluminum because the nylon actually has better friction properties against the plastic parts they're gripping. Luna: Interesting. So the material choice was actually better for the application, not just cheaper. Lucas: That's the thing people miss. SLS isn't always a compromise. In applications where you want some compliance, damping, or chemical resistance, nylon 12 can outperform metal or ABS. The glass-filled variants push the tensile strength up to about 50 megapascals, which is competitive with many injection molded engineering plastics. Luna: What about surface finish? That's the classic knock on SLS — it comes out looking like a chalky white part that needs tumbling or bead blasting. Lucas: It's true — as-built surface roughness is around 10 to 15 microns Ra. But for functional internal parts, nobody cares. For cosmetic surfaces, you can vibratory tumble with ceramic media for 30 minutes and get down to 3 microns Ra. That's acceptable for most industrial products. Luna: And the dimensional accuracy? I've heard SLS can be tricky with shrinking. Lucas: It's about plus or minus 0.3 percent overall, with a lower limit around 0.1 millimeter for small features. That's fine for snap-fits and bearing housings. You wouldn't use it for precision optical mounts, but for 90 percent of mechanical parts, it works. Luna: So where does SLS make sense financially? I'd love a rule of thumb. Lucas: For volumes under 10,000 units per year, with part sizes that fit in a 300 by 300 by 300 millimeter build volume, SLS is often cheaper than injection molding when you factor in tooling amortization. The breakeven point varies, but for a typical part with a 10-gram shot weight, the crossover is somewhere around 5,000 to 8,000 units. Luna: And for higher volumes, molding wins on per-part cost. So SLS is really a bridge or low-volume production method. Lucas: Exactly. And that's where startups live — they don't know if they'll sell 100 or 10,000 units. With SLS, you can start at 100, validate the market, and if demand spikes, you can transition to molding without having wasted tooling money on a design that changed. Luna: That's the real killer feature: design iteration without sunk cost. You can revise the part geometry every batch if you want. Lucas: Right. And the material ecosystem is expanding fast. Beyond nylon 12, you've got TPU for flexible parts, PA11 for higher impact strength, and even flame-retardant grades for electronics enclosures. Some startups are printing entire drone frames in SLS because the weight to strength ratio beats CNC aluminum. Luna: What about throughput? SLS is still slow compared to molding — you're sintering layer by layer. Lucas: For a typical SLS machine like the Formlabs Fuse 1 or the Sintratec, you can pack a full build plate — maybe 200 to 400 parts depending on size. The print takes 12 to 24 hours. So you're getting 200 parts per day per machine. That's not mass production, but it's enough for a startup to fulfill orders while they scale. Luna: And you can always add more machines. They're cheaper than injection molding presses. Lucas: A desktop SLS system runs $8,000 to $15,000. A small injection molding press with auxiliary equipment is $50,000 to $100,000. So the capital barrier is much lower. Plus, you don't need a dedicated operator — the machine runs unattended. Luna: So the startup we mentioned — the robotics company — they're now printing all their custom grippers in-house. What about post-processing? That's often the hidden cost. Lucas: They do a 30-minute tumble to remove excess powder, then a quick bead blast for uniform finish. No supports to remove, no machining. The powder that doesn't get sintered is recyclable — about 50 percent virgin powder mixed with 50 percent used powder maintains consistent properties. Luna: That's efficient. And no tooling storage, no mold maintenance. It's a clean supply chain. Lucas: And that's why we're seeing more hardware startups dedicate a corner of their lab to SLS. It's not just a prototyping tool anymore. It's a production tool for the first 5,000 units. Luna: Speaking of tools that help builders — we keep this show ad-free and listener-supported. A handful of listeners chip in monthly through buy me a coffee dot com slash fexingo, and that literally funds making this many episodes. If you find these production strategies useful, that's the way to keep it going. Lucas: Yeah, it's a small group that makes it possible. No pressure — just if you're getting value, that's how it stays sustainable. And we really appreciate it. Luna: Alright, back to SLS. Lucas, you mentioned TPU for flexible parts — are startups actually printing end-use rubber-like components? Lucas: Yes. TPU with a Shore hardness of 80A to 95A is available for SLS. We're seeing startups print gaskets, bumpers, vibration dampeners, and even custom shoe soles. The layer adhesion is excellent because it's a thermal fusion process, not just UV curing. Luna: So an SLS TPU gasket could actually seal — no porosity issues? Lucas: For static seals, yes. With proper wall thickness — at least 1.5 millimeters — and a closed-cell structure, it can hold air pressure up to about 2 bar. For dynamic seals, you'd still want molded TPU, but for many applications it's sufficient. Luna: What about conductive or dissipative materials? Some startups need esd safe parts for electronics handling. Lucas: There are carbon-filled nylon powders that provide surface resistivity in the 10^4 to 10^6 ohm per square range — that's esd safe. We're seeing startups print custom jigs and fixtures for PCB assembly lines. It's a niche, but growing. Luna: So the SLS material palette now covers structural, flexible, and conductive. That's basically all you need for a hardware product except maybe optical-grade transparent parts. Lucas: Transparent SLS exists too — there's a polycarbonate-like material that's translucent after tumbling. Not optical clarity, but good enough for light pipes or diffusers. The point is, the technology has matured to where a startup can consider SLS as a primary manufacturing method, not a backup. Luna: Let's talk design rules. What's different about designing for SLS versus injection molding? Lucas: The biggest difference is that you don't need draft angles. SLS parts can have vertical walls with zero taper. You also don't need uniform wall thickness — you can vary thickness freely because there's no flow or cooling issues. And undercuts are free. Luna: So you can design internal channels, lattice structures, and nested assemblies without worrying about tooling constraints. Lucas: Exactly. One startup designed a robotic joint with an integrated helical cooling channel inside the arm — impossible to mold, trivial to print. They reduced the part count from 12 to 2. Luna: That's the kind of advantage that justifies the higher per-part cost. You're not just substituting material — you're redesigning the architecture. Lucas: And that's where hardware startups win. They don't have legacy tooling. They can adopt SLS from day one and design for it. By the time they need to scale to molding, they've already proven the design and can transfer it with confidence. Luna: One last question: what's the single most important tip for a startup considering SLS for production? Lucas: Start with the part function, not the process. If the part needs to be produced at 10 cents each in infinite volume, SLS is wrong. But if you need 500 parts with complex geometry and you want them next week, SLS is the fastest path to revenue. Don't let perfect be the enemy of shipped. Luna: That's a good note to end on. SLS is a tool for shipping, not just for iterating. Lucas: And the technology is only getting better. Powder costs are dropping, machine speeds are increasing, and new materials are coming every quarter. It's a good time to be a hardware builder.