# Feasibility Study on Reusing Recycled Premixed Multi-Material Powder in the Laser Powder Bed Fusion Process for Thermal Management Application

## TL;DR

This study explores reusing leftover mixed metal powder in 3D printing for thermal applications by designing structures that compensate for material performance loss.

## Contribution

The novelty lies in proposing structure design as a solution to reuse multi-material powder for non-critical thermal applications.

## Key findings

- The reused Cu-Ni powder mixture showed good homogeneity and flowability similar to pure Ni.
- Cu-Ni specimens demonstrated good energy absorption and ductility, suitable for thermal applications.
- The Cu-Ni heat exchanger performed nearly as well as pure Cu, with less than 1.3% deviation in heat transfer effectiveness.

## Abstract

Large-scale applications of multi-material manufacturing technology face many challenges. One major issue is how to reuse the mixed powder left after printing. In this study, we propose using an effective structure design to compensate for the performance loss of reused materials, thereby achieving the purpose of reusing premixed waste powder in certain non-critical thermal management applications. Taking Cu and Ni premixture powder as an example, some explorations were then conducted on the feasibility of the proposed concept. The morphological inspection confirms that the powder mixture exhibits satisfactory homogeneity, while the Hall flow rate measurements reveal that its flowability is closer to that of pure Ni. The compression tests show that the fabricated Cu-Ni specimens have good energy absorption, whereas tensile tests reveal their favorable ductility. The numerical analysis indicates that the effect of convection heat transfer is much greater than that of conduction heat transfer. Heat transfer experiments show that the Cu-Ni heat exchanger exhibits comparable performance to pure Cu, with a heat transfer effectiveness deviation of less than 1.3%. Previous results indicate that effective structure design can offset the loss of material properties, allowing premixed powders to be utilized in heat exchanger production as a means of recycling waste powders.