Braun Satin Hair 7 replacement fan (parameterized press fit)

thingiverse

CAUTION: Press fit alone does not seem to be a reliable solution for this problem. My fan came loose from the shaft even with a strong press fit of 0.13mm! Looking at the picture of the broken fan, it's clear that the connector was intact but simply fell off the shaft. Therefore, I highly recommend gluing the fan to the shaft as described here: https://www.thingiverse.com/thing:3791353 - this approach lasted several months before it eventually separated. I designed a parameterized press fit replacement fan specifically for the Braun Satin Hair 7. To simplify the design, I made some modifications compared to the original part. First, print the test print pieces (yellow cylinders in the picture). Each test piece has the inner diameter printed on it. In my case, the 2.4 diameter fitted smoothly onto the shaft, while the 2.35 and 2.30 were strong, but a bit too tight. I chose 2.27 as the optimal diameter for my setup. A good rule of thumb is to choose 0.13 less than the bore diameter, which still allows for an easy fit without excessive force. The diameter you select through testing should then be entered as the bore diameter in the design. To press the fan onto the shaft, I had to use both hands to apply gentle pressure - after disassembling the front air guide piece and placing the fan on a flat surface with its front side facing upwards. Note that it's essential to use fine resolution (0.1mm layer height or less) for both the test prints and the final fan print, as this will ensure an accurate press fit that can withstand normal usage. In version 0.3 of the design, I added an optional gluing gap, allowing you to glue the fan if desired. Additionally, I rounded off the blade edges to improve airflow. I now opt for gluing the fan (with the variant featuring a gluing gap) using installation glue (Montagekleber). Let's see how long it will last. Update: As of August 2020, with installation glue and a 0.1mm gluing gap, the fan lasted only three months before coming loose. The glue was still intact on the shaft, but the fan had somehow managed to pull away from it. In response, I increased the gluing gap to 0.7mm, hoping for improved durability.