3D Printed vs. Machined Parts Testing Tip:
As 3D printing capabilities continue to increase and become more affordable, test engineers are increasingly using 3D printed parts in their test setups. 3D printing can produce complex, customized anatomical geometries relevant to medical device testing applications not possible with other machining methods and can also create test fixtures with intricate contour shapes less expensively compared to the alternative 5-axis CNC machining method.
For medical device testing, “dummy” samples are often created using 3D printing for test setup, setting test parameters and establishing contact points. 3D printing is often a great option for non-loading or low-load applications such as barb fittings and bending blocks, and the availability of clear printing material may simplify visual inspections and mounting. Sample grips and anchoring fittings made of 3D printed parts may also be used for feasibility testing or for quick assessment of design iterations. However, for higher-stress,long-term, high-cycle fatigue testing, machined parts remain the better option. If parts will be subject to bending or shear forces, machined parts tend to be more reliable than 3D printed components due to the isotropic properties of the base material. Many 3D printing materials can also swell or warp significantly when submerged in saline.
Stress analysis of 3D printed parts can provide useful information and guide your decision about whether to use 3D printing vs. machined parts in your test setup. A generally-accepted practice for machined parts is that the stress level should be 1/3 or less the material yield strength. For 3D printed parts, the stress level should be 1/5 or less the yield.