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Launch HN: Bucket Robotics (YC S24) – Defect detection for molded and cast parts
Hey Hacker News! We’re Matt and Steph from Bucket Robotics https://bucket.bot https://bucket.bot Bucket transforms CAD models into custom defect detection models for manufacturing: https://youtu.be/RCyguguf3Is https://youtu.be/RCyguguf3Is
Injection molded and cast parts are everywhere – 50% of what’s visible on a modern car is injection molded – and these molds are custom created for each part and assembly line. Injection molding is a process where small plastic pellets are heated - primarily by friction from an auger - and pushed into a mold - usually two big milled out chunks of aluminum or steel - that are pushed together by somewhere between 10 tons and 1000s of tons of pressure. Once the plastic cools the machine opens up the mold and pushes the newly formed object out using rods called ejector pins. Look at a plastic object and you can usually find a couple round marks from the ejector pins, a mark from the injection site, a ridge where the faces of the molds meet, and maybe some round stamp marks that tell you the day and shift it was made on. (Link to a great explainer on the process: https://youtu.be/RMjtmsr3CqA?si=QjErT_rOU9-_TQ8d https://youtu.be/RMjtmsr3CqA?si=QjErT_rOU9-_TQ8d)
Defect detection is either traditional ML based – get a real-world sample, image it, label defect, repeat until there’s a big enough set to build a model – or done manually. Humans have an 80% success rate at detection - that gets worse throughout the day, because decision fatigue leads to deterioration in performance near lunch/end-of-shift (https://en.wikipedia.org/wiki/Decision_fatigue https://en.wikipedia.org/wiki/Decision_fatigue). Creating an automated system usually takes somewhere between 2 days and 2 weeks to collect and label real world samples then build a model.
Injection molding is currently a 300 billion USD market, and as vehicle electrification increases, more of the total components of a car are injection molded making that market even bigger. And because so much of that surface area is customer-facing – any blemish, scratch, or burn is considered defective. Speaking to folks in the space, you can see a defect rate as high as 15% for blemishes as small as 1cm^2.
Our solution to this problem is to build the models off of CAD designs instead of real world data. An injection mold is usually machined aluminum or steel and can cost anywhere from $5k to >$100k - usually with a significant lead time. So when customers send out their designs to the mold makers - or their CNC if they do it in-house - they can also send them to us in parallel and have a defect detection model ready to go long before their mold is even finished.
On the backend we’re generating these detection models by creating a large number of variations of the 3D model - some to simulate innocuous things like ejector pin marks and most to simulate various defects like flash. Once we have our 3D models generated we fire them off to the cloud to render photorealistic scenes with varied camera parameters, lighting, and obscurants (shops are dusty). Now that we have labeled images it’s a simple task to train a fairly off the shelf transformer based vision model from them and deliver it to the customer.
Running the model doesn’t require fancy hardware - our usual target device is an Orin Nano with a 12MP camera on it - and we run it purely on-device so that customer images don’t need to leave their worksite. We charge customers by the model — when they plan a line change to a new mold, ideally they’ll contact us and we’ll have their model ready before retooling is complete.
Injection molding is as error prone as it is cool to watch. For example, flash is a thin layer of extra plastic - usually hanging off the edge of the part or overhanging a hole in the part which makes parts defective aesthetically or can even prevent parts from joining up properly. It can happen for so many reasons. Too high an injection pressure, too low a clamping pressure, a grubby mold surface, mold wear, poor mold design, and that’s just to name a few!
Steph and I have a history of working on tasks performed manually that we want to automate – we’ve been working together for the last five years in Pittsburgh on self-driving cars at Argo AI, Latitude AI, and Stack AV. Before that, I worked at Michelin’s test track and Uber ATG. We really, really love robots.
Our first pitch to Y Combinator was, “build a better Intel RealSense” since it’s a universally used (and loathed) vision system in robotics. We built our first few units and started building demos for how folks could use our camera - and that’s when we found defect detection for injection molding and casting. Defect detection is understood and highly automated for things like PCBs – where a surface defect can indicate a future critical failure (hey that capacitor looks a little big?) but defect detection for higher volume/lower cost parts is still too high a cost and effort for most shops.
We’re excited to launch Bucket with you all! We’d love to hear from the community – and if you know anyone working in industrial computer vision or in quality control, please connect us! My email is matt@bucket.bot – we can’t wait to see what you all think!
- chfritz 2y agoNice use case! Can you elaborate a bit more on robotics piece? What role does the robot play? I assume it's required to turn the part around for inspection. If so, how do you (automatically?) compute the grasping pointing? Also feel free to find me on LinkedIn if you want to chat more about growing a robotics businesses and/or geometric reasoning for manufacturing.
- lasermatts 2y agoYou nailed it - when the part comes out of the mold, it slides down a chute onto a conveyor belt. From here, the arms themselves change depending on the supplier (Kuka/Fanuc/Universal Robotics/Yaskawa...there are a lot of players in the space,) but they're all used to hold the part in the air so we can take images on all sides -- then the arm moves the part to its correct spot (good bin/bad bin) for computing the grasping position -- your mileage may vary depending on which axis/face matters the most for an object (in an automotive part, you want to grasp the side that's not customer-facing because people care less about a scratch there) but it's a real challenge. Luckily EtherCAT + protobuf's adoption has helped keep the comms integration low -- even a few years ago we'd need to make a weird hop from camera --> PLC --> arm but things are slowly getting easier
- jjk166 2y agoI'm an engineer at company that injection molds parts for medical and industrial devices. This seems extremely promising. Can your scene generator handle things like custom tooling? For example if I were to place a part to be inspected on a clear acrylic jig, could the model be trained to look through the acrylic? We're currently already using a vision system to measure certain features on the parts, can your models be applied to generic images, or does it require integration with the camera? How does the customer communicate the types and probable locations of potential defects? Or do you perform some sort of mold simulation to predict them? Likewise how does the customer communicate where defects are critical versus non-critical? Finally how does pricing work? Does it scale based on part size, or does the customer select how many variations or do you do some analysis ahead of time and generate a custom quote? Is it a one time cost or is it an ongoing subscription? Could you ballpark a price range for generating a model for a part roughly 3.5 inches in diameter and 1.5 inches tall with moderate complexity? Feel free to reach out to the email in my profile if you'd like to discuss a little more in depth.