# Evaluation of Surface Roughness Reduction in TPU 95A Samples Using Ferromagnetic Liquid Machining

## TL;DR

This paper explores using a ferromagnetic fluid with abrasives to reduce surface roughness in 3D-printed TPU 95A samples.

## Contribution

A novel tool using neodymium magnets and a ferromagnetic abrasive medium is proposed for surface finishing of 3D-printed materials.

## Key findings

- Series D showed the most significant reduction in surface roughness parameters Sp and Sz.
- The use of carbonyl iron and silicon carbide in a ferromagnetic fluid improved surface finishing.
- The designed tool with asymmetrically arranged magnets offers an unconventional approach to surface treatment.

## Abstract

Additive manufacturing technologies are characterised by the capability to produce components with complex geometries that are difficult to achieve using conventional methods. Despite the wide range of available materials and additive manufacturing processes, fulfilling design requirements related to surface structure parameters remains a considerable challenge. This paper presents the findings of an investigation into the influence of abrasive treatment of a ferromagnetic fluid on the surface roughness of MEX-printed samples. The samples were fabricated using TPU 95A material. The abrasive medium employed in the study comprised carbonyl iron and silicon carbide. A dedicated tool was designed for the experiments, incorporating neodymium magnets arranged in four asymmetrically distributed slots. The proposed tool represents an unconventional approach in comparison with existing practices. Tests were conducted in three measurement series—B, C, and D—while series A served as the control group. Analysis of the experimental results revealed that, for the parameters Sp (height of the highest apex) and Sz (maximum height, defined as the sum of Sp and Sv, representing the height of the highest apex and the maximum pit depth, respectively), the most significant reduction in parameter values was observed for series D.