Design and Development of an Automated Contact Angle Tester (ACAT) for Surface Wettability Measurement

TL;DR

The paper presents the design and development of ACAT, an automated robotic system for precise, safe, and high-throughput measurement of surface wettability on 3D-printed materials, enhancing manual testing limitations.

Contribution

It introduces a fully integrated robotic platform combining hardware and software for automated contact angle measurement, improving accuracy, safety, and throughput over manual methods.

Findings

Achieved high precision and repeatability in contact angle measurements.

Demonstrated system safety and compliance with industrial standards.

Enabled automated, high-throughput surface wettability testing.

Abstract

The Automated Contact Angle Tester (ACAT) is a fully integrated robotic work cell developed to automate the measurement of surface wettability on 3D-printed materials. Designed for precision, repeatability, and safety, ACAT addresses the limitations of manual contact angle testing by combining programmable robotics, precise liquid dispensing, and a modular software-hardware architecture. The system is composed of three core subsystems: (1) an electrical system including power, control, and safety circuits compliant with industrial standards such as NEC 70, NFPA 79, and UL 508A; (2) a software control system based on a Raspberry Pi and Python, featuring fault detection, GPIO logic, and operator interfaces; and (3) a mechanical system that includes a 3-axis Cartesian robot, pneumatic actuation, and a precision liquid dispenser enclosed within a safety-certified frame. The ACAT enables high-throughput, automated surface characterization and provides a robust platform for future integration into smart manufacturing and materials discovery workflows. This paper details the design methodology, implementation strategies, and system integration required to develop the ACAT platform.