Challenges with 3D printed parts for hydraulic experimental benchmarks: A perforated plate case study

Additive manufacturing using fused deposition modeling (FDM) or fused filament fabrication (FFF), commonly known as 3D printing, has become a popular method for prototyping method as it allows complex parts to be produced at a lower cost. Although FDM parts are increasingly being used in experimental analyses in all areas of engineering, there is limited information on their effects on fluid flow and how they compare with conventionally manufactured parts. This work is a cautionary tale for those using 3D printing for hydraulic testing and highlights the characteristics that can affect thermal–hydraulic analysis. Experimental investigations have been performed using perforated plates that are commonly used in hydraulic circuits fabricated by FDM and milling processes. In this study, precision-engineered perforated plates attached to an acrylic test section were used to measure the pressure drops caused by polylactic acid-printed and acrylic-milled plates. A 2D Laser Doppler Velocimeter (LDV) was used to analyze the fluid dynamics. High-precision dimensional and roughness measurements were performed to evaluate the effects of these parameters on the fluid flow. The results show that the pressure drop and velocity profiles of the FDM parts differ from those of their conventionally manufactured counterparts owing to the small differences inherent in the 3D printing process. These differences can be attributed to the geometric deviation, smaller average diameter, roughness, and the effect of the rounded edges on the perforated plate holes. It was also shown that milling the surface of the 3D printed part can reduce the rounded edge effect, but this can defeat the purpose of having a 3D printed part in a study. The conclusion from this exercise is that all dimensional characteristics of 3D printed parts should be carefully measured and assessed, especially when the data obtained are used to validate computational fluid dynamics simulations. •The study evaluated 3D-printed parts for hydraulic testing.•Significant differences found between milled and 3D-printed perforated plates.•Three factors investigated: dimensional accuracy, edge finish, surface roughness.•Dimensional accuracy and edge finish were most critical factors.•Study provided insights into limitations of 3D-printed parts for testing.