Call for Engineers: Tell us about your job! (2020)

NOT ALUMINUM FOIL!

Turns out it’s tough to Google for tin foil without getting swamped with aluminum foil results and/or reagent grade tin foil.

Aluminum won’t work. Reagent grade is too expensive.

But yeah…. Anyone got a source for plain old tin foil like grandma would have bought before aluminum foil was all the rage?

I want to create a receiver to always connect to the same transmitter all the time without having to scan for the device.

Is it possible to make it where I can override the old transmitter by using a combination of buttons?

I've seen this done with the Wii and Ps5 controllers work with their respective consoles. When you turn them on, they are already program to work with the console it came with. But you can always pair a new device to it letter should the first one break

I would like to build something like this or if it already exist, that would be awesome.

Thank you 🙏

Hi everyone,

I'm a mechanical engineer I recently received an opportunity for an interview for mechanical engineer at a hydraulic cylinder manufacturing firm from USA, the interview is with the director of engineering

I have close to 2.5 yrs of exp in design manufacturing and troubleshooting systems

I have studied but I wanna be more prepared Can you please please provide some technical questions?

Thanks in advance

We work with rolls of flexible vinyl, not exactly upholstery material, but similar. I need a gauge for width that can be used at the production line. Width is 6 inches. With 0.100 tolerance.

Suggestions for a go nogo design?

Source: https://nemesishd.gr/wp-content/uploads/2023/06/Su-57-Screws.webp

I'm currently working on a part that has a tapered bore that fits onto a tapered arbor that will spin. I have never toleranced a tapered bore before so I am not sure if the bore angle should be to the minus or plus side. I have gone through a ton of papers on this including my MFR engineer book and GD&T paperwork. Unfortunately we do not make the arbor here nor can i get any kind of print for that arbor because this is a reverse engineering project/new part. Assuming ill never find out which way the arbor is to be, is there any standard that says the male should be +.xxx or vise versa? Or would that all be determined by the original MFR and I am taking a guess?

Thanks for the help !

https://www.reddit.com/r/bestofinternet/s/57F5faWzAY

Im from Finland.

Is there a name for a fluid pump that draws fluid into one end, drops it into a reservoir, then pumps it back out from the reservoir into the same or another line? I’m looking to make fluid circulate in a tube for a project.

I know that during the later 19th and early 20th century there were ongoing experiments and designs for various forms of electrical analogue filters, that would only allow certain frequencies through or be picked up.

If this is the case, can you send multiple frequencies down the same telegraph line, mixing them together and them separating them out using the old analogue filters, like how fiber optic cables can send multiple messages using different light frequencies?

I know that fiber optics can do this because light and lasers don't interfere with one another, but what about electrical signals?

I’m a highschool student with a very limited understanding of electrical engineering. I created a generator using a 24V DC motor, which is being powered by pedalling a bike.  The output voltage fluctuates between 0-25V, but remains around 10-15V at normal pedalling speed.  I connected the motor to a 12V solar charg controller, which is then connected to a 12V, 150W inverter which has 5V 2.1 and 1 amp usb ports, and a 110V socket.

I am trying to charge my phone with this setup, and the inverter is indicating that there is current running through the wire, but there isn’t the green led indicating that is it’s charging or being powered.

Bike -> 24V DC Motor -> 12V Solar Charge Controller -> 12V, 150W Inverter

https://a.co/d/cBPJDim

https://www.canadiantire.ca/en/pdp/coleman-8-5a-12v-digital-solar-panel-charge-controller-0112008p.html

What can I do?

I have recently started a PhD in Engineering (Simulation and computational modelling), and I was wondering if people here had a recommendation for a good book (or other resource) which can provide a good mathematical foundation for modelling, optimisation, numerical/computational methods, and other relevant engineering maths principles. If there is something which contains all of this, that would be best, even if its a bit of a dense read, idm (ChatGPT ftw).

I obviously don't need to have the absolute basics taught to me, but I am coming to the PhD after a few years in industry and probably would struggle with a highly complex text, so something which provides at least decent explanations and depth would be great, thank you!

If it's of any use, my specific area of research involves climate, fire, and fluid modelling, including spatial (2D/3D) and data-driven modelling as well.

It seems like the N56c is maybe the same but just an older version?? But let’s say everything else on the nameplate is identical, would swapping a 56c with a n56c work? Thanks in advance

I am trying to understand what is necessary to join hardened shafts together. I am trying to install a transfer case to a transmission that it wasn't designed for, so we're looking at significant torque ranges (let's say up to 800ft lbs, occasional shock-loading).

Obviously, the easiest way to do this would be to order an intermediate shaft built to specs, but I have easy access to the appropriate transfer case input and transmission output shaft for far less money than a custom job with splines and hardening. With access to a lathe, I could machine different kinds of connections between these two existing components, perhaps with a third shaft interposed.

What I don't understand is exactly what kind of joints I need to be thinking about to handle these torque ranges. Would a sleeve and a keyway suffice? Should I pin it? From what I've read online, a welded joint on case-hardened shafts is unreliable and introduces too much deformation. I've heard extraordinary things about freeze-fit interference joints. What kind of torque capacity can I realistically get out of something like that?

I’m having a super hard time visualizing this mechanism. The goal is to have a door that is normally horizontal with a hinge at one end that opens vertically, and this is tied to a platform that is parallel to the doors plane when it is closed. As the door is opened, the platform raises linearly. I’ve tried sketching a bunch of different combinations of sliding hinge points and fixed rotations and can’t come up with something that I think works, but I’ve only tried single links. Can anyone show a mechanism that would accomplish this?

Hello everyone, I have a thought experiment I can't figure out. When a non compressible fluid such as water hits a 'Tee' in a closed-loop system and flow essentially is stopped in one direction, is there a resultant thrust? I'm trying to figure out if flow rate will increase tension on the piping supplying water to the 'Tee' or if it's just a function of piping design pressure times cross sectional area. Please let me know your thoughts!

I need to make an aluminum box with a tight lid but need help understanding the tolerances. The lid of the box will be removable and slide right over the top of the base, like the kind of box that an iPhone or Mac (or really any apple product) comes in. I really want it to be such a close fit that you can feel the air vacuum when you try to remove the lid from the bottom/base.

The pass/fail criteria should be that if you hold the box upright and are grasping only the lid (I.e. no hand stopping the base from falling down to the floor), the base/bottom will slowly fall downward until the vacuum is released and then it free falls downward.

I tried reading the ANSI guidelines but can’t even figure out where to start. I am using Fusion 360 to make the box so I do have precise control. Thanks!

If so, what are its drawbacks (pun not intended) and how powerful would it be if strength wasn't an issue

For the purpose of presenting in front of a crowd of customers, I need to revive my created hydraulic circuit diagram (Boiler, Accumulation tank, hot water heating, solar heating and its regulation). There is no problem with the scheme as such.

Making a scheme is easy, I have that. I would like to revive this scheme so that the flow of water moves from the boiler to the storage tank, which would "warm up and change color" over time. With such visuals, I wanted to approximate the function of the device.

I tried Gemini, chatbot to get some solutions, but did not figured it out. IM looking for free-software. Or maybe AI which can "make it" for me.

Thank you for all of your advice .)

I'm thinking about making a Corsi-Rosenthal box for fun, but it seems weird that the box fan would end up being so much louder than official air purifiers with smaller fans and smaller filters. Because it'd be a fun project I'd be okay with modding the box fan with a quieter motor, different fan blades, or other "smart" features.

As a reminder, /r/AskEngineers normal restrictions for career related posts are severely relaxed for this thread, so feel free to ask about intra-office politics, salaries, or just about anything else related to your job!

I would love to ride a bike but don’t have a garage, and the idea of my bike being stolen is nightmare fuel. I’ve been designing an impenetrable storage box for motorcycles or other high-value items. Here’s the concept, and I’d appreciate any feedback on the design, particularly the lock system.

Box Design

The box is designed to be resistant to all forms of physical and explosive attack:

Materials and Layers

• Outer Layer: 35 mm of AR600 steel (used in military tanks) for abrasion and cutting resistance.
• Inner Layer: 35 mm of AR500 steel for added reinforcement.
• Core Layers:
  • Ceramic tiles for energy dispersion.
  • Kevlar, Dyneema, polypropylene strands, and fiberglass to snarl up blades or resist grinding tools.
  • Air gap between layers for blast mitigation.
• The corners are reinforced with additional steel to prevent vulnerabilities.

Structural Design

• The outer and inner steel layers are tied together with supportive tags to eliminate weak points.
• The door uses a recessed, shielded piano-style hinge.
  • Six deadbolts secure the door along the opening side.
  • Additional bolts lock the top and bottom corners of the door.
• The lock mechanism is protected behind a physical barrier, similar to a shipping container which has recessed hinges too..

Foundation and Anchoring

• The box is embedded into a 2.5-meter-thick reinforced concrete slab, which extends 2 meters beyond the box footprint on all sides.
  • Concrete is designed to withstand a 20 GPa blast force and explosive impacts equivalent to 20 kg of military-grade munitions.
  • High-performance concrete includes polypropylene fibers and multi-layered steel rebar to prevent spalling or delamination during extreme heat or impacts.
• Flared Base Design: Steel sides extend 1 meter below ground and flare outward to prevent digging or prying.

Weight

• Steel Weight: Approximately 20.57 metric tons.
• Concrete Weight: Approximately 337.92 metric tons.
• Total Weight: Approximately 358.49 metric tons.

Advanced Security Features

1. Blast Resistance:
   • Ceramic and Kevlar layers absorb and disperse explosive forces.
   • Steel design deflects and mitigates impact.
2. Vibration Sensors:
   • Detect tunneling or seismic activity, sending alerts to the owner and authorities.
3. Drainage System:
   • Prevents water accumulation for long-term durability.

Think this is designed to be virtually impenetrable. With its weight and reinforced foundation, lifting or digging under it is impossible without industrial-grade machinery and significant time. It’s aimed at also capable of withstanding extreme attacks, including military-grade explosives.

I’d love to hear your thoughts, especially regarding the lock system or any potential vulnerabilities I might have overlooked.

I have a few. An ROV control system that ended up on TV. An IP based logging system on over 5000 sites.

Hey,

I have to design an air intake system for an engine with exhaust turbo chargers. The motor specifications state:

• pressure drop (total) at rated power before turbocharger: 0,3 psi
• max. allowable pressure drop (total; power derating) before turbocharger: 1,5 psi

Does that mean that the tc itself causes 0,3 psi of pressure drop an the air intake system could cause an additional pressure drop of 1,2 psi without reducing the engines power or does it mean that power derating starts at 0,3 psi and over 1,5 psi it's not working anymore?

I was reading some posts about people having issues with the 12v battery on their ev. (It powers electronics etc.)

Seems like dc-dc power supply from the big battery would eliminate the need for the "normal" battery.

Since they are typically made of lead it seems it would: Save weight, Save space, Eliminate a wear item,

Seems to me to be an opportunity for improvement...

Edit: thanks for the good onsite of 48v system is disconnected in emergency, and 12v is still needed,

And for charging from dead.

And supply chain! I.e. why 12v for electronic, when most chips are 5v, or ~3v. (But that is a different question)

We're studying Bode Plots for the first time, and we set the real part of the complex frequency to 0. I'm wondering, doesn't this automatically imply we're studying the behaviour of the circuit with sine waves?

This next topic is something I have not studied, and more like a hunch: I've heard that signals can be decomposed as sum of multiple sine waves (is it related to Fourier, right?), that would answer to my doubts, but if that were to be the case, what about the real part? Like, does it get ignored?

In our fabrication shop, we need to roll ss plates to fabricate a tank. As we have CS rollingachine, I am concerned about the mating surface between different materials. What options can we utilize?

Those resistive heaters are much more effective, especially when the car is first started. What reason(s) are there to not use them on the front? My guess is that the heaters are more likely to fail than hot air, which necessitates having hot air as a backup, and if you're doing that, the marginal benefit of resistive heaters is not deemed to be worth the added cost. I'd like to hear from somebody who actually knows the answer(s), though. Thanks!

Edit: Thanks to everyone who answered. This question can be considered closed.

Edit 2: Please do not comment that a specific make or model has this feature. It is not answering the question. It is not helpful in any way.

GM has been able to squeeze some large displacement out of a small-block, in part because they're not having to also fit massive OHC heads onto that engine. But that does mean they're limited to only adjusting the intake and exhaust valve timing together.

What if there was a second cam in the V of the engine, one for the intake lifters and one for the exhaust lifters. Both would have their own VVT gear and bolt setup. Would this be enough of an advantage over the single cam to be worth the extra several machining steps?

Hi!

I'm making a sim racing cockpit and my main roadblock right now is that I do not know how to "properly" measure my body so I could accurately determine and estimate the position of certain components in my CAD model.

Results online so far have only given me more general guidelines on system designs suited for fitting a variety of workers (i.e. Industrial Engineering). I'm aiming for a more tailor-fit design since I'll be the only one using this rig and the frame is not as adjustable compared to rigs based on 4080 aluminium extrusions.

What would be the best approach to get the most accurate data for this process?

Thank you!