Cherry Pitter

During a previous internship, I designed and built a motorized cherry pitting machine. The project combined mechanical design, food safety, and a lot of trial and error. The work began with a set of 2D mechanical drawings left by an engineer who had retired over a decade earlier. My first step was to translate these drawings into 3D CAD models, and then develop them into a fully functional machine.

The 3D models in question

Once in 3D, I was able to make adjustments for manufacturability and hygiene. For example, we chose a food-grade rubber that was easy to sanitize, and flexible enough for quick removal and replacement during cleaning. Initially, I was concerned about the cups being positioned so close to the edges of the trays. However, this turned out not to be a problem, even after extensive testing. In fact, the slight deformity where the cups met the tray edge actually helped with unloading the cherries, like the spout on a water pitcher.

A later batch of cherry trays

2D drawing example

All of the stainless steel parts were designed in SolidWorks, then cut using SICAM Punch. Stainless steel was the obvious choice for its corrosion resistance and compliance with food handling standards. 

To keep prototyping fast and economic, I leaned on the office's 3D printer. Only a few metal parts were kept in place for structural integrity during tests, while the rest of the assembly was printed in plastic. This let us iterate on fit and function rapidly, often printing a part in the afternoon and testing it the same day. The low material cost of plastic compared to stainless steel and rubber made experimentation far less intimidating. 

Early prototype

By the end of the internship, the retired engineer's sketches had evolved into a robust, modernized machine. On top of performing great, the updated materials and design resulted in a product that could be easily cleaned and maintained. And while it was satisfying to see the cherries neatly pitted and collected, the real reward was watching an old concept come to life.

Functional late-stage prototype