Surface Roughness Measurement Device

Project:
Surface Roughness Measurement Device

Main role:
Team Lead

Jan. 25, 2023 - Dec. 1 2023

The project focused on creating a cost-effective surface roughness measurement device using a surface friction concept. Employing a linear actuator and load cells, the device autonomously moved a probe across a specimen of different milled sections, collecting data to quantify surface roughness.

Initial Design Concepts

Methodology

Issues with the stylus designs involve expensive costs for the stylus tool itself. A non-contact laser has a very complex setup with potential scatter error in results. Even though the friction device contains the greatest feasibility and cost effectiveness, the concept has the lowest accuracy compared to other designs.

Construction

There was a need to 3D print essential components vital for the mounting and attachment system of the linear actuator. One of these components, the actuator bracket with a hex hole, and its counterpart, the actuator bracket, were intended to undergo printing with an approximate 25% infill. Additionally, the load cell actuator attachments demanded a higher 45% infill due to the inclusion of brass threaded inserts for M5 threads.

Results

The figure incorporates 8 suitable sections of the test plate with different surface roughnesses and their corresponding measured coefficients of friction. The blue and orange curves represent outer bounds of the possible coefficient of friction range for each surface, and are used to find an uncertainty range of measured surface roughnesses within the LabVIEW program.

Procedure

A linear actuator, connected to a load cell, is strategically positioned to exert force along a test arm carrying a predefined weight. Simultaneously, another load cell is affixed to a resin-tipped end on the test arm. As the actuator propels forward, the resin tip comes into contact with a metal surface, generating a frictional force that is meticulously measured by the load cell on the actuator. Concurrently, the second load cell on the test arm records the normal force. The coefficient of friction is then calculated by determining the quotient of these two forces. This data is systematically processed and outputted for a mean value for further analysis.