We just received the first samples for our initial small production run! Here’s a bit about our experience with the manufacturer and our immediate impressions of the samples…
Experience: Working with our motor manufacturer has been a great learning experience. It was essential for us to be in China for the initial production run, and our biggest takeaway was to visit the manufacturer early in the process and sit down with the engineer overviewing the production run.
We sent our initial motor designs in early November, and prior to visiting, the manufacturer seemed to review the motor design part by part, rather than holistically. So, they would send us an email with a suggested design change, we’d exchange several emails to resolve the problem, and then they’d come to us with another issue and that process would repeat itself. In hindsight, we should’ve scheduled a visit a week or so after sending the initial designs because the email back and forth was an extremely inefficient way to make design changes.
We scheduled a visit in late November and this in-person meeting forced them to thoroughly review the design (on top of the changes we already made). We were able to meet with the engineer in charge of the production of our motor and discuss the remaining changes to finalize the design. It was also very interesting to walk around the manufacturing facilities and see rows of CNCs, the assembly line, QC testing, etc. We found the motor coil winding machines particularly impressive.
Impression: Once both parties agreed on the final design, it took about three weeks to get samples. We needed to continually check in to make sure everything was on schedule because we were leaving for the US on December 17th. Fortunately, the samples arrived two days before departure, and we were so excited to finally have our own motors. Our initial reaction was that they look awesome!
Before this, we were buying off-the-shelf motors and retrofitting our tech to the bottom with 3D-printed “backpacks.” They proved the viability of our technology, but they were ugly and overheated frequently (our circuit board was covered by plastic). Now, the motors look great and the ESCs are heatsunk to the stator aluminum, so we shouldn’t have any issues with heat. Also, we’ll be able to hone our technology to work perfectly with these specific motors, rather than making one-offs.
Issues: When it came time to test the motors, we had one primary issue: the magnetic field wasn’t strong enough for our position sensor, so the motors didn’t operate as well as we had hoped. We disassembled the module and found that the magnet wasn’t aligned properly within the shaft, weakening the magnetic field. To address this issue, we will manually replace the magnet with proper alignment. If the magnetic field is still too weak after this, we will need to design a custom magnet or get a more sensitive sensor.
Overall, we’ve been pleased with our motor manufacturing partner and will do our full production run with them. As for the ESC, it’s a relatively straightforward circuit board, and we were happy with our most recent manufacturer’s work. We realize that the manufacturing process comes with challenges, but we’re confident that having gone through this process once already has prepared us well for a large production run following the campaign!