Team 03 - HP Chill Puck

Note to Instructors: Final report and executive summary can be found under "Documentation."

HP Chill Puck

Nathaniel Goldberg, Nathaniel Liu, Jayant Mathur, Kristen Matsuno

CAD of the final Chill Puck assembly 

Introduction

Inkjet printing relies on the use of many micromachined nozzles to shoot ink droplets out of the printhead. This process inevitably causes some amount of ink to leak onto the surface of the printhead. If this puddling remains for a long enough period of time, the liquid components of the ink can evaporate, leaving behind a tacky residue. This issue, known as crusting, can cause the printhead to malfunction. It is therefore important that the fundamental physics of ink evaporation be studied.

An image of undesirable inkjet crusting. 

HP Inc. (formerly Hewlett-Packard) has commissioned this team to create a portion of an experimental apparatus to help study ink evaporation. Known as the Chill Puck, this device is to keep a silicon coupon roughly 3 cm square at a temperature much below that of a stream of hot air that blows across it. It is to be lightweight and to have very little vibration, if any, as the balance it must rest upon is very sensitive. By enabling fundamental studies of ink evaporation, the Chill Puck will not only advance science, but will also help create lower-cost, more reliable inkjet printers.

Project Requirements

The basic set of requirements for the final Chill Puck deliverable are as follows:

• Maintain a constant, cold substrate temperature in a heated airflow environment

• Produce substrate temperatures as low as 30o C in a 5 m/s, 80o C airflow (worst case operating conditions)

• Weigh less than 200 g

• Possess an operating life of at least 1 hour

The more advanced, but secondary requirements are as follows:

• Extreme operating lifespan (on the order of 4 hours)

• Possess wireless communications suite for contact-free measurement and data transmission

Results and Final Performance

The completed Chill Puck was found to be capable of satisfying each of the basic criteria, as well as the advanced, stretch goals. The final deliverable not only maintains constant temperatures for extended periods of testing, but also weighs less than 150 g and possesses a Bluetooth-based wireless data communications suite. The graphs below show the final design's robustness in achieving various required setpoint temperatures and reliability when operating for extended durations.

Left: Temperature controlled for an hour-long test. Right: Test of Chill Puck functional temperature range.

For further details about the final design, please visit the Final Design portion of the website.