# Feasibility Study of Manufacturing Hydraulic Fittings Using Additive Manufacturing Technologies: Comparative Analysis of FDM and SLA Methods

## TL;DR

This study compares FDM and SLA 3D printing methods for manufacturing hydraulic fittings, finding that neither meets leak tightness requirements at higher pressures.

## Contribution

The paper evaluates the feasibility of AM for hydraulic fittings and identifies material and design limitations for achieving functional performance.

## Key findings

- SLA-printed parts showed 1% shrinkage, while FDM-printed parts showed 2% shrinkage.
- SLA samples had better thread quality compared to FDM samples with visible layer separation.
- Neither FDM nor SLA 3D-printed fittings achieved leak tightness beyond 0.5 bar.

## Abstract

This paper investigates the feasibility of manufacturing hydraulic fittings using additive manufacturing (AM) technologies, specifically Fused Deposition Modeling (FDM) and Stereolithography (SLA). The study addresses the environmental challenge of material waste in conventional fitting production by exploring 3D printing as an alternative manufacturing method. Hydraulic fittings were designed using CAD software: SolidWorks 2022 and fabricated using FDM with PETG (Polyethene Terephthalate Glycol) material and SLA with UV-sensitive photopolymer resin. In present studies, on-destructive leak testing was conducted in accordance with PN-EN 1254-4 and PN-EN 1254, at pressures ranging from 0.1 to 1.0 bar. Dimensional accuracy analysis revealed shrinkage of approximately 1% for SLA-printed parts and 2% for FDM-printed parts. Microscopic examination at 50× and 80× magnification showed superior thread quality in SLA samples compared to FDM, which exhibited visible layer separation and material porosity. Leak testing demonstrated that while the brass reference fitting maintained complete seal integrity, both 3D-printed variants failed to achieve leak tightness under operational pressures, with structural failure occurring at 1.0 bar during tightening. The study showed that FDM with PETG material and SLA with UV-sensitive photopolymer resin, despite achieving acceptable dimensional tolerances (±1–2%), do not meet hydraulic leak tightness requirements at pressures exceeding 0.5 bar in their raw state after printing. The results suggest that alternative material formulations (e.g., carbon fiber-reinforced PEEK for FDM or epoxy engineering resins for SLA) warrant further investigation. Potential avenues for improvement include advanced surface treatment, optimization of printing parameters, and modifications to thread geometry to reduce interthread gaps.