Cooling issue before mass production
Some SLUSHi units struggled to reach recipe temperature targets, including orange juice. The recorded behavior included power spikes, early kickdowns, and warmer end temperatures.
With two weeks remaining before mass production, a solution also had to fit the release schedule. I owned two workstreams: a short-term airflow baffle and a longer-term PWM fan / PCBA update.
Release constraint
Develop a part with a manufacturing lead time compatible with the approaching production date.
System constraint
Evaluate airflow alongside the unit’s power and temperature behavior, then coordinate the electrical changes required for fan control.
Airflow experiments
I started with low-fidelity cardboard baffles, then compared opening patterns and measured airflow. The iterations changed hole size, count, and pattern to characterize how the baffle affected CFM.
That experiment provided a practical reference for the next design step: the fan work used an external power supply and tachometer, with similar baffle airflow observed at 6 V.
Pursue a manufacturable airflow restriction for the immediate release, while developing a controllable fan solution for the longer term.
Baffle & PWM fan validation
01 — Baffle for the approaching production release
Cardboard experiments progressed to 3D-printed and laser-cut prototypes. Mounting features included screw holes and press-fit spherical features. Comparative traces showed reduced power spikes and a colder final condition with the baffle.
02 — PWM fan and PCBA update
The longer-term path required an updated fan and board connections. A reworked PCBA with jumper connections supported evaluation of the PWM arrangement. The recorded comparison again showed reduced power spikes and a colder end temperature.
Drawings & engineering changes
Baffle
Released engineering drawings to the China team for die-cut manufacturing.
Fan / PCBA
Initiated an engineering change order for the new PCBA; the résumé also documents the fan update and coordination with electrical engineering.
The outcome combined prototype data with manufacturing timing. It demonstrates both mechanical iteration and integration with electrical hardware.
Evidence and scope
The plots show comparative performance for the documented tests. The project record does not establish a fleet-wide improvement, test repeatability, or a complete causal thermal model, so the project does not claim those results.