/r/engineering

Photograph via snooOG

r/engineering is a forum for engineering professionals to share information, knowledge, experience related to the principles & practices of the numerous engineering disciplines.

r/engineering is NOT for students to ask for guidance on selecting their major, or for homework / project help. Read the sidebar BEFORE posting.

If you see any post or comment that violates these rules, please report it so the moderators can respond in a timely manner. Thank you.

  1. No questions related to university, school, major selection, GPA, coursework, etc. NOTE: Asking for help on homework will result in an instant ban. DO NOT DO IT.

  2. No questions on "how something works" — try r/AskEngineers.

  3. All workplace topics and questions asking for career advice must go into the Weekly Career Discussion Thread.

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  • No posts about the 9/11 terrorist attacks. You can read about why this policy exists here.

  • Crowdfunding: Must be relevant to engineering and submitted as a self-post (not a link). You are allowed one submission, and you must be active in the comments to answer any questions.

  • Submission Flowchart

    Comment Rules
    1. Keep the discussion civil. Overly insulting or crass comments will be removed. Multiple violations will lead to ban. Racism, sexism, or any other form of bigotry will not be tolerated.

    2. Be substantive. No low-effort one-liner comments, memes, or off-topic replies. Limit the use of engineering jokes.

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    What is r/engineering for?

    r/engineering is a forum for engineering professionals to share information, knowledge, experience related to the principles & practices of all types of engineering: civil, structural, mechanical, electrical, aerospace, chemical, computer, environmental, etc.

    Questions about current engineering projects you are working on, how to interpret codes and standards, and industry practices are all encouraged. Engineers should help each other to make the world a safer and better place.

    Images and videos related to engineering are acceptable, provided they are relevant to engineering. Completed projects, destructive test results, and unique machinery and hardware are all acceptable and encouraged. Lead-in comments are required to provide context to the readers.

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    Pick an engineer from the list of volunteers below and send him or her a PM indicating that you would like to conduct an interview:


    Directory of Useful Subreddits

    Engineering Fields
    Engineering Topics
    • LearnEngineering: Learn & discuss engineering concepts
    • CAD: Computer Aided Design
    • CFD: Fluid Dynamics
    • FEA: Finite Element Analysis
    • PLC: Programmable Logic Controllers
    General Science
    Textbooks
    Other Links

    /r/engineering

    469,395 Subscribers

    1

    Possible ways to stop heat transfer in this project

    I have a project involving several heaters and thermistors. Looking at the image, there is a heater where I have crudely drawn the red box. It is wrapped around a plastic part (green) and then placed onto a stainless tube. However, I am getting quite a bit of heat transfer into the stainless rod into the centre which then transfers to the other heater/thermistor sections and throws the results off a bit.

    I am currently trying some Kapton tape wrapped around the rod and on the plastic part under the heater to see if that helps but I'm just posting this to see if anyone else has any ideas.

    dimensions are pretty tight. the OD is 21.3mm and the ID OD of the tube is 5.7mm so any solution has to be small.

    https://preview.redd.it/5z25y25wy4ic1.png?width=953&format=png&auto=webp&s=9f1ac2ecfc977caf7728bc6cc7f7c7ae9cd8435a

    1 Comment
    2024/02/12
    11:07 UTC

    1

    Weekly Career Discussion Thread (12 Feb 2024)

    Intro

    Welcome to the weekly career discussion thread, where you can talk about all career & professional topics. Topics may include:

    • Professional career guidance & questions; e.g. job hunting advice, job offers comparisons, how to network

    • Educational guidance & questions; e.g. what engineering discipline to major in, which university is good,

    • Feedback on your résumé, CV, cover letter, etc.

    • The job market, compensation, relocation, and other topics on the economics of engineering.

    [Archive of past threads]


    Guidelines

    1. Before asking any questions, consult the AskEngineers wiki. There are detailed answers to common questions on:
    • Job compensation
    • Cost of Living adjustments
    • Advice for how to decide on an engineering major
    • How to choose which university to attend
    1. Most subreddit rules still apply and will be enforced, especially R7 and R9 (with the obvious exceptions of R1 and R3)

    2. Job POSTINGS must go into the latest Quarterly Hiring Thread. Any that are posted here will be removed, and you'll be kindly redirected to the hiring thread.

    3. Do not request interviews in this thread! If you need to interview an engineer for your school assignment, use the list in the sidebar.

    Resources

    0 Comments
    2024/02/12
    11:00 UTC

    63

    Who or what is holding your company back from being better or reach a higher potental?

    75 Comments
    2024/02/11
    16:10 UTC

    3

    Looking for a copy of the Royal Aeronautic Society Data Sheets from the 1940s

    0 Comments
    2024/02/08
    15:44 UTC

    2

    How to measure horizontal piping centerline?

    I am out at an install and they are quoting misalignment. Its a pair of piping built to their specs and drawings. This skid and the other person's skid are having an alignment issue with the top pipe. Its off by 3/4" of an inch horizontally. Their connection point is meeting our rubber ballon coupling coupling. 10" 250mm coupling

    This is the only 1 that is acting weird and not aligning. I have a been given a set of drawings with labeled centerline points.

    How can i easily find the horizontal centerpoint of these pipes.

    8 Comments
    2024/02/07
    04:11 UTC

    13

    PE stamped plans pricing

    Curious what everyone is charging for PE stamping basic, no frills designs? Think a spreader beam, rigging plan, frames/brackets etc. There’s some discussion at my company as to what should be charged for that. On the one hand it’s only a few hours of work, but on the other many feel there should be a minimum charge to PE stamping something due to liability, unseen admin costs, even for optics. No matter how simple the design, we typically won’t go less than $2k to stamp something. Outrageously low? Too high? Discuss!

    25 Comments
    2024/02/07
    01:03 UTC

    3

    What material is this spring mechanism made of?

    https://i.redd.it/fx1bq9a9w0hc1.gif

    https://preview.redd.it/l7t0ehpvw0hc1.jpg?width=3024&format=pjpg&auto=webp&s=73c7b8b44770dce05782b01669f330c99d2f84b8

    This knife has a push button slide mechanism that (I think) locks into the open and closed to positions by pressing outward into some internal slots the knife body. To slide it, you push down on the thumb pad.

    I've read that bending blue tempered spring steel is very difficult so I assume they're using a different type of steel here? What is it? And what are the limitations on using it as a spring? How much "springing" would be too much?

    Here's another knife with a similar looking steel piece that has a couple of bends that aren't used as springs (top and bottom) and then the bend in the face that is used to kind of tension the part inside the body.

    https://preview.redd.it/nldy1b8tx0hc1.png?width=382&format=png&auto=webp&s=281d4209cba0b4e9a81916de493a430206686bbe

    (Also this is my third post here as I'm trying to educate myself in DFM, please lmk if I'm being too much.)

    6 Comments
    2024/02/06
    20:25 UTC

    7

    Where to buy or have made small Stainless Steel Venturi Tubes

    Hi all, I'm having a hard time sourcing some small Venturi tubes like this from anywhere other than China/India. Does anyone have some North America based suggestions? Was hoping I could find something off the shelf that would be close enough but no luck. Closest I could find was Velocity Stacks for car turbos. Our volumes are pretty low ~200/yr so difficult to engage bigger suppliers for custom work.

    Thanks for any tips!

    https://preview.redd.it/8hjuuecnf0hc1.jpg?width=817&format=pjpg&auto=webp&s=95b73899ca2d30d89751ccb49523f6a831749bfc

    13 Comments
    2024/02/06
    18:46 UTC

    7

    Summary of Episode 052 | Field Oil Analysis with Lisa Williams

    3 Comments
    2024/02/06
    16:27 UTC

    2

    Electro Chemical machining. Other than making gun barrels, what are some other things to make? I do cad and 3d print, I’m stumped on what else to make.

    16 Comments
    2024/02/05
    15:28 UTC

    2

    Weekly Career Discussion Thread (05 Feb 2024)

    Intro

    Welcome to the weekly career discussion thread, where you can talk about all career & professional topics. Topics may include:

    • Professional career guidance & questions; e.g. job hunting advice, job offers comparisons, how to network

    • Educational guidance & questions; e.g. what engineering discipline to major in, which university is good,

    • Feedback on your résumé, CV, cover letter, etc.

    • The job market, compensation, relocation, and other topics on the economics of engineering.

    [Archive of past threads]


    Guidelines

    1. Before asking any questions, consult the AskEngineers wiki. There are detailed answers to common questions on:
    • Job compensation
    • Cost of Living adjustments
    • Advice for how to decide on an engineering major
    • How to choose which university to attend
    1. Most subreddit rules still apply and will be enforced, especially R7 and R9 (with the obvious exceptions of R1 and R3)

    2. Job POSTINGS must go into the latest Quarterly Hiring Thread. Any that are posted here will be removed, and you'll be kindly redirected to the hiring thread.

    3. Do not request interviews in this thread! If you need to interview an engineer for your school assignment, use the list in the sidebar.

    Resources

    13 Comments
    2024/02/05
    11:00 UTC

    0

    Books on designing in your garage

    I want to desing a cutting torch at home and want some general safety tips and guidlines.

    I will be using DIY approach and want to be safe and also ensure i have a good device.

    Any books I can check out?

    6 Comments
    2024/02/05
    04:04 UTC

    12

    Book recommendations for real fluids

    Hi,

    First off, I am not a regular user, so apologizes if this is the wrong place to post this.

    I am looking for a (text?)book that covers real (i.e., non-idealized) fluid physics. I have a lot of introductory and advanced fluid mechanics books, but none really discuss non-idealized topics. I’d really like a book that covers things like liquid surface tension, cavitation, non-Newtonian fluid mechanics/effects/observations, compressible liquids, non-ideal gases (i.e., in which P=rho*RT doesn’t hold and van Der Waals equations or other models must be used), things like that. Basically, things that my graduate AE degree didn’t have time to teach me. I have not found any books like this in my searching, but my favorite books generally come from recommendations anyway.

    Personally, I like books that introduce a topic with theory and then develop the ideas with practical and mainly qualitative discussion, for example “the effect of so-and-so increases with increasing temperature, but only to a point, before such-and-such effect begins to dominate.” I’m not sure if I’ll have much of a choice here, though.

    These topics have always been of interest to me and were always either glossed over in school (e.g., “we have to worry about cavitation which is related to vapor pressure when we design a rocket engine turbopump, because cavitation lowers effective mass flow rate through the pump”) or I learned about them on my own (e.g., the Weissenberg Effect [https://en.m.wikipedia.org/wiki/Weissenberg_effect]), but I had little further information on them.

    I’d find it hard to believe that there aren’t books out there that discuss these things, their trends, causes, stuff like that because of their relevance in engineering. Maybe not though because most of our data on these things seems to be empirical and maybe that’s not a money maker?

    Any recommendations, even on places to look, would be appreciated. Thanks.

    9 Comments
    2024/02/04
    19:36 UTC

    8

    Building a retractable laser light saber (proof of concept)

    4 Comments
    2024/02/03
    09:11 UTC

    4

    Bonding Neodymium Iron Boron Magnet to Kydex Plastic

    I am trying to find a good adhesive to reliably bond a neodymium iron boron magnet to Kydex plastic sheet. The magnet has the typical nickel plated finish. The adhesive joint has to be able to withstand thermal cycling as it will be outdoors.

    There is about a 10:1 coefficient of thermal expansion mismatch between the magnet and the plastic which is tough to deal with.

    I first tried using some JB Weld Plastic Bonder adhesive and some Parbond 905 adhesive to bond the magnets. Both of these are urethane based adhesives which produce a tough rubbery bond which I thought would do a good job absorbing the Cte difference between the magnet and the plastic.

    To test my adhesive joint, I boiled the test assembly in water for 2 minutes and then dropped it into an ice bath to generate a thermal shock. I repeated this boiling water - ice bath cycle 10 times. I then used a pair of pliers to twist the magnets I bonded, and I got a purely adhesive failure at the adhesive / magnet interface with low force. There was a shiny clean break with no adhesive left on the magnet. The urethane adhesive remained bonded very well to the Kydex sheet though.

    I am thinking about trying a high shear strength epoxy like the orange epoxy 04007 from Sanford which claims to have high peel strength and a tough and flexible cured state.

    Any other ideas for adhesives ? Am I being too aggressive with my boiling water / ice bath test ?

    8 Comments
    2024/02/03
    04:56 UTC

    5

    Laser vs GMAW

    The vast majority of automotive structural components are mig welded.

    Laser welding has some applications but they seem few and far between.

    Recently I've seen so many videos on social media of hand held laser welders laying visually perfect beads.

    It seems like this would be super easy to automate, and you don't need to pay for weld wire.

    Will laser welding eventually replace mig welding? Why or why not?

    10 Comments
    2024/02/03
    00:48 UTC

    133

    What do you think will be the future of engineering?

    Do you think certain technologies will be present or others fade? Do you have any ideas for something you need that doesnt exsist but might later? Will firms resist change

    171 Comments
    2024/02/02
    19:20 UTC

    5

    Simulation Software

    Good day! Hi, I am a student who is currently doing research that involves the use of simulation software. I can't go into much detail but our research involves heat and electrical output. Currently, we are already in our implementation period have already created our models and are about to start the simulation process, but sadly we can't continue to simulate the model as the simulation software, which is the student version of ANSYS Workbench, has limitations and we aren't capable of purchasing the full software. We do have a backup which is COMSOL Multiphysics but it seems like it is also over our budget. I am not sure if this is the right place to ask about this but if someone knows a software that is capable of analysing heat and electrical output please let me know through a comment or by directly messaging me. On behalf of my groupmates, I express my deepest gratitude to whomever. Have a nice day.

    14 Comments
    2024/02/02
    13:25 UTC

    1

    Cybersinew - Contruction and Design of Artifical Muscles

    (21/1/24)

    Honestly im just here to keep myself in check but also place some updates and maybe get some feedback on some ideas, but i just want to make this cuz ive had this idea stuck in my head for a while now.

    Long story short, i dont like the current designs for prosthetics, they feel too "robotic" and dont emulate the movement/flexibility of actual muscles. so im starting a design for (firstly) a robotic arm using expanding and contracting materials for its movement instead of motors. Nitinol is what im going for in term of contracting materials, and i have a solid grasp on the design for the fast twitch muscles, not so much the slow twitch and an expanding material (im still researching for either semi-liquid one thats not to expensive to make/acquire, if not ill figure it out) . also i want to patent my idea but not sure when to do it or at what stage, but ill figure it out. so far i have:

    -Weave pattern for fast twitch mucles

    - general design on the joint design

    - general design for the mucle placement

    By general design i mean i have like 5 drawings and a few compiled medical/mechanical docs for reference. anywhooo, i might make this project into a yt channel but not sure how to start on that either. ill figure it out eventually. if anybody knows any resources for expand on my knowledge over artificial muscles, please let me know. so far im still in the design stages, but if anybody is interested i will update with skematics/code. (just in case, i dont want to make a superhuman arm, i want to make the closest thing we can get to actual muscles like in anime/comics/video games and reduce the amount of motors needed).

    0 Comments
    2024/02/02
    02:59 UTC

    3

    Document Review Cycle

    Are there any document review cycle plug-ins for Teams that don't suck? I'm looking for reviews.

    2 Comments
    2024/01/31
    17:07 UTC

    27

    How is this manufactured (the metal bends specifically)?

    Thanks everyone that commented on my last post! I'm brand new to DFM and have lots of questions so this is extremely helpful (I've also sent my design files to a couple manufacturers but the feedback here is much quicker and so far much more useful).

    I'm trying to design a simple, cheap part but have inadvertently created a not-so-simple-to-produce, probably not very cheap part in the process. I have been using the product below as inspiration.

    How is the part below made? Specifically the bends - I've been told that my part's flanges are too small to bend, but they're about the same as the flanges that wrap around the utility blade here, so... how are they doing it?

    (Link to the product if you want to see more: https://screwpoptool.com/screwpop-rons-utility-knife-2)

    https://preview.redd.it/hwg7p7024tfc1.png?width=507&format=png&auto=webp&s=d782d7eb2b089041e50352997c019c6a03baab17

    https://preview.redd.it/vkmvyrr53tfc1.png?width=507&format=png&auto=webp&s=34bfac8922f9fd1f022962925995eadadaede01d

    https://preview.redd.it/14v31gyc3tfc1.png?width=507&format=png&auto=webp&s=b9901e585ca54c087412830f1b6f8e2c4ce1e75f

    And here's the part I designed for reference:

    My part

    34 Comments
    2024/01/31
    17:02 UTC

    1

    Tolerance for aluminum parts

    I was hoping someone here could help me with a small question I have. I need to epoxy two aluminum parts together. Basically I am taking an aluminum pipe and inserting a plug into the end and I want to epoxy it in there. I am planning on using Loctite AA H003 which is made for aluminum to aluminum bonding. I'm assuming there is a tolerance that would be best for the epoxy to work optimally (OD to ID) but I have not been able to find it in any literature. (I could have just missed it) I'm assuming too tight and I push it all out, too loose and it pushes the limits of the epoxy. Anyone have any insight into something like this? Thank you.

    7 Comments
    2024/01/31
    16:43 UTC

    9

    Canbus - transmission distance

    I’ve got a challenge on my hands - the r/Canbus guys are all automotive focused so I’m hoping someone here can help - I’ll try r/electronics too - I have a long distance simple end to end Canbus that may be beyond the limitations of the PHY. I have been experiencing signal loss errors. Nodes at either end are signalling at Low Speed Fault Tolerant (LS-FT) 125kbs - there are no other nodes on the bus. The ‘industry’ limitations (ISO11898) are 500 metres cable length BUT… is this the length of the actual physical copper cable (I.e. straightened out) or is this the notational length of a typical twisted pair Cat5 cable? Is there a way to measure the cable latency / signal propagation delay or use say a Time Domain Reflectometer to measure the cable length? The Canbus is already installed, cannot be measured by following the cabling routing as it’s a very complex installation. Help gratefully received- I’m trying everything before switching to F/O and using media converters

    10 Comments
    2024/01/31
    11:56 UTC

    8

    Is it possible to manufacture this?

    I'm a designer and am working on a part that I was thinking could be laser cut and bent, but I've been told my flanges are too small to allow bending. They can't be bigger otherwise the part won't work.

    Is it possible to produce this part? Any advice?

    Here's a CAD image of my part (~1mm thick stainless steel):

    https://preview.redd.it/yxess9dcpmfc1.png?width=1316&format=png&auto=webp&s=20da8b42b426e8d88d04ed153fbd828bf9c296c7

    Here are a couple similar parts with small bends/flanges that I was using as inspiration:

    https://preview.redd.it/twb30mw7qmfc1.png?width=1000&format=png&auto=webp&s=88eedf7ce61bef38e969cdece7b63abbf57a0123

    https://preview.redd.it/so8wk9hromfc1.jpg?width=760&format=pjpg&auto=webp&s=756e2290e12a29560ee42be11e95580574138708

    https://preview.redd.it/73ied82ypmfc1.png?width=686&format=png&auto=webp&s=b4ca3568367b4c593158a0abb16d78c9a2d39cf4

    30 Comments
    2024/01/30
    19:33 UTC

    9

    Material selection?

    Hi All - looking for advice. Need to choose a thermoplastic material for a “popsicle stick” shaped part that is 6” x 1” x 1/4”. It will be supported for 3” and 3” will be cantilevered with a distributed 20lb static load. The 1/4” thickness will support the load. The Part will need to be impact resistant because it will be attached to a off road vehicle.

    It will need to survive outdoors. So -20 to 150 degrees Fahrenheit.

    Would be nice to 3d print during prototyping and use the same material during production. But if that is not possible I’d prefer to chose the production material.

    Eventual volumes could be 5000 “popsicle sticks” per year.

    Appreciate the advice.

    20 Comments
    2024/01/30
    03:25 UTC

    10

    What drafting software to use to design a cottage/cabin

    Hi Everyone, I’m a mechanical engineer with some experience using NX, Solidworks, and Catia.

    For a personal project I want to design and build a cottage/cabin. I’m hoping to generate engineering drawings of the building in order to make the construction go by smoother.

    What I’m looking for is to be able to think through the design and have everything correctly dimensioned before we start cutting material. Also it would be nice to be able generate renderings to visualize everything.

    Do you have some reccomendations for Software to use? Revit? AutoCAD architecture? I suppose the simpler the software the better, provided it has the features required.

    I imagine I could do it quickest in SolidWorks. However I’m just thinking one of the architectural based ones would make it so much smoother if they already have pre-installed libraries of things such as: windows,doors, plumbing piping, joists, etc. Plus the rendering and visualization may be a lot simpler

    28 Comments
    2024/01/29
    16:21 UTC

    3

    Weekly Career Discussion Thread (29 Jan 2024)

    Intro

    Welcome to the weekly career discussion thread, where you can talk about all career & professional topics. Topics may include:

    • Professional career guidance & questions; e.g. job hunting advice, job offers comparisons, how to network

    • Educational guidance & questions; e.g. what engineering discipline to major in, which university is good,

    • Feedback on your résumé, CV, cover letter, etc.

    • The job market, compensation, relocation, and other topics on the economics of engineering.

    [Archive of past threads]


    Guidelines

    1. Before asking any questions, consult the AskEngineers wiki. There are detailed answers to common questions on:
    • Job compensation
    • Cost of Living adjustments
    • Advice for how to decide on an engineering major
    • How to choose which university to attend
    1. Most subreddit rules still apply and will be enforced, especially R7 and R9 (with the obvious exceptions of R1 and R3)

    2. Job POSTINGS must go into the latest Quarterly Hiring Thread. Any that are posted here will be removed, and you'll be kindly redirected to the hiring thread.

    3. Do not request interviews in this thread! If you need to interview an engineer for your school assignment, use the list in the sidebar.

    Resources

    21 Comments
    2024/01/29
    11:00 UTC

    1

    TVAC thermal reference advice

    Hey folks, I’m currently navigating the complexities of thermal vacuum chamber (TVAC) testing and could use some wisdom. My setup involves a cold plate for conduction and a thermal shroud for radiation, each with its own coolant loop and chiller setup.

    Every time I go to implement one of these tests, I have to argue with the systems engineers over their selection of Thermal reference points (TRP‘s). they typically choose TRP‘s that are far from good conduction paths. this is fine for steady state detect, but screws up my control, algorithms, and make ramp rates impossible to hit.

    I’m of the opinion that the interface temperature, particularly at the cold plate, should be Sup our primary TRP for control purposes. It’s where the device under test directly interfaces with our system, making it the most logical point for precise temperature control. However, there’s some disagreement among the team, especially with system engineers, on this approach.

    I’m looking for any established guidelines or standards, maybe something from NASA or similar authoritative sources, that could help clarify the best practices for selecting TRPs in TVAC testing. Any shared experiences or pointers to relevant documentation would be hugely appreciated to help bring clarity to this debate.

    3 Comments
    2024/01/28
    17:34 UTC

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