Real Engineering
3 HN recommenders · recommended in 3 months, 2019–2024
15:00 · 2.7M views · Oct 26, 2019
Real Engineering explains the materials science behind metal 3D printing, including crystal structure, laser sintering, and why printed parts develop fatigue cracks. It shows how process imperfections limit the strength of printed metal.
Commenters point to it whenever 3D-printed metal parts come up, as a clear explanation of why they have poor fatigue life and material defects.
4 comments from Hacker News
I was going to write a reply saying that I don't see why we can't use it in many places as long as we understand the parameters of the product, but as so often happens I found an excellent source that actually explains your stance in details.[1] The TL;DR is that there are lots of imperfections in 3D printed parts, which means they typically fail at much lower stresses. It actually includes some pretty good video illustrating this at a microscopic level. That said, there are apparently new techniques being researched and discovered that have promise to increase the quality of 3D printed parts. One way to thing of it is that we have hundreds to thousands of years of experience in material science with forming metals in other manners, and we've just started with additive engineering, so there's a lot of room for improvement. 1: this video
“Our hybrid 3D printing method has opened up the possibility of fabricating 3D electronics so that devices and robots used in healthcare and nursing care could become significantly better than what we have today.” And right there, the PR operation blew their credibility. Here's a useful video on the metallurgy of 3D printing metal.[1] Actual X-ray movies of what's going on during laser sintering, why 3D printed metal parts have crack growth problems, and what's being done about it. [1] this video
Great Real Engineering video with a lot of discussion of the issues with material properties, crystalline structure, and fatigue cracks related to metalized 3d printing: this video
Took me a while, but I tracked down the conversation. Turns out it wasn't a research paper, and I wasn't linked to it but found it on my own in researching the discussion I was having[1]. It was an a video about engineering and cost effectiveness of sintering metals and the current downsides, which (at the time) there were attempts to counter by using specific laser patterns, but even with that the fatigue life was lacking compared to other manufacturing methods. This is, of course, four years out of date, and I can't state for certain how accurate the review of the problems that video provided were, but it did a very good job of explaining what caused those problems, so I wasn't left with many questions as to why sintering wasn't as well suited for some situations. That said, I'm not in this industry, I just noticed some relation to a prior conversation I had and the topic is interesting to me. 1: [LINK] 2: this video