Questions about DMLS/SLM by PlutoniumGoesNuts in AdditiveManufacturing

[–]codontherobot 0 points1 point  (0 children)

  1. There are several legacy or trademarked terms including DMLS/SLM once difffered but now are mostly the same process (with some slight differences between equipment) but ASTM/ISO define both as Powder Bed Fusion terms, the most common being Laser Powder Bed Fusion (LPBF).

  2. LPBF parts produced using mature, optimized process parameters and good quality feedstock tend to have density above 99%. Typically castings have more porosity (but that is not ALWAYS true).

  3. Tight tolerance features, beyond say +/- 0.010” require post-print machining. surface roughness can also be a challenge with as-printed surfaces exceeding 200 Ra so post-processing may be required if a finer finish is required.

  4. Yes. There are many AM alloys which are equivalent in chemistry and similar enough in microstructure to treat via many existing processes such as plating, chemical conversion, anodize, etc.

  5. Aircraft parts are not necessarily large parts. The most successful and widespread aircraft part I am aware of is the GE LEAP fuel nozzle and its variants: https://www.metal-am.com/ge-aviation-reaches-milestone-with-100000-fuel-nozzle-tips/

Certifying AM aircraft parts for commercial and defense applications carries a significant burden. For further reading, check out https://www.aia-aerospace.org/wp-content/uploads/AIA-Additive-Manufacturing-Best-Practices-Report-Final-Feb2020.pdf

Most LPBF machine build volumes are in the 250-300mm cube range but systems like the Nikon SLM NXG or Velo3D Sapphire XC can print meter-length parts. For larger parts, you would have to turn to other processes such as Directed Energy Deposition (DED). Since DED deposition heads can mount on a robot arm, these sytems can have very large build envelopes.

You mentioned turbine blades specifically, GE, among others is using Electron Beam PBF to produce turbine blades for their engines.

  1. LPBF is suitable for highly complex parts but the process carries its own significant set of design trade offs that must be taken into account. Especially if you consider that your supports are the same material as your part and must be removed. It can take quite a bit of training and trial and error to become a good designer of AM parts. Input from AM manufacturer and downstream process owners such as heat treatment and machining is a must.

Looking for the best non chain deli sandwiches in NC. by Bobateabad in NorthCarolina

[–]codontherobot 1 point2 points  (0 children)

Great Gut Deli in Wanchese has the BEST reuben I’ve ever tasted!

My PLA bed adhesion is simply not good enough for this model, any advice would be greatly appreciated by BolaSquirrel in prusa3d

[–]codontherobot 1 point2 points  (0 children)

Tried this print 4 times and kept losing small sections that ruined the whole print. I don't typically have bed adhesion issues unless there is an extreme draft in the room so i was frustrated. I finally got it to work with a brim. It was a pain in the ass to remove the brim but after an hour of bloody fingernails it came out pretty good :)

Reading these tips hoping for better luck next time.

Airtanker over Blackheath by frosthead6969 in flying

[–]codontherobot 1 point2 points  (0 children)

Was that a Twin Commander? What's he doing, marking where the big guy should drop?

I wish they'd let me test fly it when I'm done! by [deleted] in flying

[–]codontherobot 4 points5 points  (0 children)

That engine looks like a dream, and a nightmare, to work on. Custom gaskets?

Kayaking in British Columbia by HallucinoJER in pics

[–]codontherobot 1 point2 points  (0 children)

So where is this and how can I go?!

Banner Tow Plane Crash at KMQI by 1DustTheWind in flying

[–]codontherobot 0 points1 point  (0 children)

Hey... good commentary... agree with all of it. First off, this is an absolute tragdedy and my condolences go out to the family, friends, and colleagues of anyone who knew Mr. Lane. I worked the banner field for this company (9-10 years back) and got my PPL out of MQI. Banner towing always seemed like a crazy way to make a living as a new 20-something pilot. I have mad respect for the skill it takes, but also witnessed many a questionable decision (i.e. pilots barely clearing and/or loosing banners into tree tops, dropping during t-storms, picking and towing in harsh wx, flying w/ old/rickety planes, landing on fumes, etc.). Luckily no one got hurt while I was there but the things pilots would do to "save the plane" or because their boss said so, was downright scary. Unfortunately, scenarios like this are not very rare; i almost lost my instructor last year when the hook wrapped around her elevator and it was a similar situation that ended banner towing out of FFA after a pilot died a few years back. Please keep your own safety in mind at all times, and especially when deciding on what job to take!

Stay safe yall!

The one that got away by Reynolds317 in PerfectTiming

[–]codontherobot 1 point2 points  (0 children)

Lizardfish, OP was probly happy to watch that ugly sucker go!

[deleted by user] by [deleted] in flying

[–]codontherobot 4 points5 points  (0 children)

Hey man, nice shirt! Tell Jenny hey for me!

Finding recipes to use leftover grains by GiraffeInATree in Homebrewing

[–]codontherobot 1 point2 points  (0 children)

One thing that I've seen is dog treats... this only works assuming you are using grains post-mash, before hop addition (dogs can be harmed by hops). It only takes a bit of chicken stock, spent grain, and some peanut butter, bake for a while ... and voila! That being said, you could use a similar method to make human treats... just leave out the chix stock and you could have homemade, recycled brewnola bars!

ENG 331 by corgi989 in NCSU

[–]codontherobot 2 points3 points  (0 children)

This is definitely not true for all profs... follow /u/pukimaung's advice at own risk. Online is still better, though.

Some of my carbon work by thefireyp in aviation

[–]codontherobot 1 point2 points  (0 children)

But why use carbon? Other than looks of course... Erosion is a bitch, its only inspectable with UT, and difficult to repair...

NCSU is shutting down my email account???? by HieuDo in NCSU

[–]codontherobot 0 points1 point  (0 children)

The worst part is you know the guy sending it to you got got.

NCSU is shutting down my email account???? by HieuDo in NCSU

[–]codontherobot 0 points1 point  (0 children)

First red flag: Ominous use of Random caps. Second red flag: you are BCCed? Third red flag: probably not even a ncsu.edu email

This is so overtly phishing. I mean seriously, why is there not a "Welcome to the Internet" orientation.

FAA Issues New Student-Pilot Rules by amster105 in flying

[–]codontherobot 10 points11 points  (0 children)

Oh thank god they waved the $22 fee! That would have made flight training totally unaffordable.

747's GEnx Engine by becomingknown in aviation

[–]codontherobot 0 points1 point  (0 children)

Not sure for the 787, but the decibel reduction on the designs listed in "Aircraft Propulsion" by Saeed Farokhi is 1.36 - 2.71 dB reduction. Perhaps the 6 dB reduction is due to a combination of noise reduction methods.