“Together we can fix anything”. For the last 20 plus years, iFixit has led the charge on the Right to Repair movement by making repair kits and guides for fixing almost every consumer product you can think of: phones, watches, laptops and more. As tinkerers and fixers ourselves, we at Intercreate had been using many of their kits as part of our hardware lab setup. So when iFixit came to us to design their Power Station and Soldering Iron, we were ecstatic to jump in and bring their first electromechanical product to market.
This project was perfect for us right from the beginning. Our expertise in low power consumer electronics and creating small, densely populated designs would be critical for the Soldering Iron to be small enough to fit comfortably in the end user’s hand. We also had the firmware knowledge to design the Power Station’s USB power delivery and graphical user interface and agreed to own both the electrical and firmware design.
After meeting with iFixit’s team to thoroughly understand the Iron and Power Station's features, we got started on the non-form factor (NFF) design to validate key aspects of the HW architecture and start building the firmware platforms. Our NFF phase led us to designing three PCBAs for the project, one for the Power Station main board, one for the vertically mounted Power Station user interface board, and one for the Soldering Iron itself. Through this phase we were able to determine some limitations of the NFF designs and make some important safety decisions, along with areas to reduce BOM cost. One of the more obvious changes coming out of the NFF phase was doing away with individually replaceable battery cells for a safer and still user-friendly way of replacing the entire battery pack.
After NFF we switched to our first form factor design (FF) where we reduced the electrical design down to its final dimensions to fit inside the Power Station and Iron. We knew it would be important to keep the Iron’s PCBA small enough to be handheld by the user, while still able to consume 100W. It’s in this phase of design where collaboration is key, we worked with the mechanical team to ensure our EE design fit within their required mechanical component outline (MCO).
Depending on the project, EE design may be considered complete after a successful FF design is tested and validated, particularly if the goal is to get working prototypes. Other projects start the transition of EE ownership from Intercreate to the JDM (Joint Development Manufacturer) where the JDM makes minor changes for BOM substitutions and test fixture access. In iFixit’s case, iFixit and Intercreate owned the EE and test fixture design throughout the scale up to high volume manufacturing.
In order to reduce the cost of the electrical BOM, our first task was to start sourcing and validating alternate components. This is especially important in case any component becomes obsolete in the future. This design work came at a particularly difficult time in the industry (2020 - 2022) when microcontrollers were in short supply. Knowing we had to secure enough STM32 MCUs to start our future EVT builds, Intercreate leveraged our contacts at various distributors to purchase these parts quickly and get ahead of the curve. Unfortunately, this strategy did not work for every component. When it became clear that our main battery charger and PMIC would not be available for over a year, we pivoted quickly and designed in a new battery charger / PMIC that had little supply risk.
Our final hardware push was to design and optimize the electrical test fixtures to meet the high manufacturing speed and yield expectations of iFixit. With three unique PCBAs in this product we opted for five different test fixtures: one bed of nails fixture for each of the two main boards, one functional test fixture for the user interface board, and two final assembly fixtures to test the final units after assembly. After using our initial fixtures on the EVT and DVT builds, it was obvious that optimizations in the test software could decrease the testing time and increase yield.
Increasing the test speed required us to redesign aspects of the fixture software interface and make some hardware changes but we were able to achieve a 50-70% decrease in test time for each of the stations. This was done throughout three trips to Taiwan in 2023 - 2024 and countless remote hours supporting the onsite engineers.
We really wanted to make this product stand out as a soldering iron and facilitate the best user experience possible. Safety was critical, and we implemented a series of fault handling controls to ensure both user and device safety. The Soldering Iron heater turns off, for example, if a user accidentally drops a hot Soldering Iron, or if the temperature increase in the tip doesn’t match what is expected based on the power being sent to the tip. We were able to have such a unique interaction between the Power Station and Iron by implementing a custom USB PD alt-mode that allowed for fast UART data transmission from the Iron to the Power Station using repurposed USBC pins. Our dynamic Power Station USB PD PDOs constantly monitor the state of the Power Station and in real time change the amount of power a specific Soldering Iron can consume based on other system-wide factors, such as battery state of charge, number of Irons in use, and the current needs of the Iron. The Power Station even doubles as a generic USB PD battery bank for other non-iFixit devices.
To date, iFixit’s Soldering Iron and Power Station tool has been one of our longest projects and thus one of the most rewarding. We really enjoyed being a part of this project from start to finish and helping iFixit scale up to launch.
Principal Engineer: Rob Helvestine
Services: Firmware Engineering, Hardware Engineering, Design for Manufacturing, Test Fixture Development and Mass Production Support
