Castle Creations' Electronics Speed Controller (ESC) Assembly Videos for Engineers
A few weeks ago, I posted a video of a manufacturing plant that builds smart meters. It is always cool to watch the automated pick-and-place machines pick surface mount components from tape reels and precisely place them on the printed circuit board. This video shows the assembly line for microprocessor-controlled motor controllers for brushless electric motors at Castle Creations. Business development manager Lee Estingoy starts out showing the silkscreening process for the solder mask, then moves on to the tape reels where the electronic components are fed to the pick-and-place machine. You get to see the amazing speed at which the robotic head places the parts onto the PCBs. He tells how a vision system verifies that each part is the right size and value and is oriented properly for placement. This particular speed controller has a daughter board assembly that gets inserted by a separate machine because of its relatively large size and weight. Some parts still need to be hand-assembled because they do not lend themselves to automated assembly (although there are machines to do the job if the budget can be justified). After all the parts are on the board, the assembly is fed into a reflow oven that melts and then cools the solder paste according to a temperature profile that has been optimized to assure proper flow and adhesion without thermally stressing the components or PCB and minimizing residual mechanical stress. A Quality Assurances operator then does a visual inspection with the help of a computer vision inspection system prior to applying power during electrical test. This helps avoid failures due to misalignment and solder bridges between pads, and provides a second level of component orientation and part number verification. Finally, the ESCs are electrically tested. You get to see a glimpse of the 3-phase controller waveforms during the test portion (BTW, I made a short video of the modulated pulse width waveforms that drive the brushless motor). It's good to see in-house, domestic production!
Many moons ago (early 1980s) while working at Westinghouse (now Northrop Grumman) in Maryland, I took an in-house course on the new-fangled surface mount components and what the company was doing to incorporate them into designs. We designed and built towed sonar arrays and MkII torpedo sensors at the Oceanic Division (Annapolis) where I worked, and the Electronic Systems Division (Baltimore) division built airborne and ground-based radars for the military. In those days, nearly all the manufacturing was done on site, both electrical and mechanical. One session of the class was spent on a presentation by engineers who were pioneering one of the first visual inspection systems for automated assembly. They were developing both the hardware and the software to do the job. We also were given an introduction to ESD handling procedure necessitated by the small components and their increased vulnerability to static discharges. It was not really a problem for the passive components, but in moving to SM packages for silicon devices, die sizes were shrunk to a minimum (for the day), which made gate sizes and conductor separation small enough to invite arcs and subsequent damage. We were on the proverbial bleeding edge.