Optimization of viscosity and composition of mixture of Cu powder and acrylate based resin for vat photopolymerization of metal components

Abstract

Vat photopolymerization is a technique that uses photocurable resin having photoinitiator (PI) to initiate polymerization reaction when exposed to UV light. This process forms long chains polymers by combination of small chains monomers and oligomers. Vat photopolymerization depends on various parameters. This work focusses on the optimization of viscosity and composition of acrylate resin-Cu powder mixture for vat photopolymerization of metallic samples. Anycubic acrylate-based photopolymer resin and fine copper powder is used. Five configurations (50%Cu-50%resin, 55%Cu-45%resin, 60%Cu-40%resin, 65%Cu-35%resin & 70%Cu-30%resin) are formed to determine the highest possible density in each sample. These samples are then sintered in order to optimize the sintering parameters like debinding and sintering temperatures, oxygen and carbon contents. Then, the sample with maximum Cu density is used to optimize the viscosity of mixture using ethylene glycol as diluent. It is observed that ethylene glycol is useable as it effectively reduces the viscosity of resin without altering the chemical nature and curing time of photocurable resin. By equating the viscosity of optimized Cu-resin mixture with pure resin, difference in curing times is calculated for finite thickness of layer. This shows that 28% increase in curing time is observed when Cu-resin mixture is used as compared to pure resin. Sintering profile used is good in terms of debinding and sintering temperatures however hydrogen curing environment is essential to reduce carbon and oxygen contents in final samples.

Keywords

• Photopolymerization
• Sintering
• Photopolymer resin
• Viscosity
• Density
• Debinding