So where is the LeetCode for mechanical engineering? Kaggle?
I apologize if I am losing you in a slurry of data science and coding jargon. The reality is that there isn’t truly a holy grail of preparation materials, videos, and challenges that a burgeoning mechanical engineer fresh out of college can use at their disposal to prepare for technical interviews in hardware engineering.
At this point in my young career, I have been fortunate enough to have had a fair share of internships as well as experience in two full time engineering roles. Each time I sought employment at various stages of my career, preparation was required for both technical and behavioral portions of interviews. While the interview process can look drastically different depending on the companies you may be applying to (early stage startups to mid size companies to massive corporations), HR (or lack thereof) protocol, and the nature of the role and industry, there are some standard starting points you should look into. I’ll start with giving my two cents based on a few years of experience working in both the LA/Orange County vicinities as well as the Bay Area.
Tip #1: Your interviewer is human too. Leverage that.
Believe it or not, your interviewer is a walking, talking body of water and air too, with thoughts, feelings, and priorities that are likely quite similar to yours. A good interviewer will not want to see you fail - they don’t want to spend time going through hundreds of candidates - they want to find the best fit fastest.
I have seen way too many students trip over themselves at career fairs at UCLA and Berkeley where it takes four hours just to get in because the queue of nervous students dressed in business blazers and dress shoes is about 200 people long. Once one actually makes their way into the big top, there are *wait for it* even MORE queues with eager students waiting to talk to reps from Amazon, Google, Apple, and so on. After a long day of meeting many students, those reps are REALLY tired. Trust me, I’ve been in their shoes. Don’t be a robot even if you research or develop them in your free time. Remember your social cues and courtesy. Opening with a “how is your day going and how are you enjoying being on campus?” goes a long way. Don’t immediately launch into your list of accomplishments developing bioinspired tactile sensor skin, or how you built the composite body for the Formula SAE racecar last season (as cool as that really is!). As you build rapport with your rep, find common ground and ask about their own background and passions. You’re not just being nice and courteous - USE those tidbits of information to present your own accomplishments and passions after you’ve given them a chance to share about themselves.
This applies to real interviews too outside of career fairs. It is always a good idea to come off as genuine and enthusiastic and learn about your potential future manager or teammate. After all, you could be spending 40 hours a week with him or her for years.
Tip #2: Your portfolio is your best friend.
Well first of all, make sure you are getting or have gotten hands on, project-based experience outside of the classroom. I personally was in the Battlebots club at UCLA and did robotics research on the side. These combined experiences coupled with internships gave me well-needed hands on experience outside the classroom that I could speak to in mechanical engineering interviews. But it’s not enough to just talk about them abstractly. Most engineers are quite visual and love to whiteboard or look at concrete images and data.
Create a portfolio. I’d recommend investing some money in creating a Squarespace or Wix site to host a private and personalized domain, but a PDF portfolio that you can send to recruiters and interviewers is totally acceptable too. I did that for a years before building my own website. If you are going to share information or pictures from internships, make sure to obtain the necessary permissions from your managers or HR at those companies - the last thing you want to do is to breach a contract. Showcase your projects in a clean and concise manner. Avoid verbosity and use lots of high quality images (hopefully you would have taken some great pictures of your projects during design, build, testing, and final phases unlike me over the years).
When in an interview, reference your portfolio. Send a link or the PDF to your interviewer ahead of time so they can skim through it and ask personalized technical questions. This works in your favor! No one should know your project as intimately as you right?! Plus, if you loved what you were doing, your passion and excitement will shine through, which interviewers love to see.
IMPORTANT: Do not use “we” if discussing a team project. Jump straight to what YOU personally did on that project as selfish as it sounds. Using “we” only indicates that you did not do much of the work yourself and hung onto the coattails of other team members. Make sure you can speak concretely and specifically to what you achieved. Use numbers and metrics where possible.
Technical:
Through my own good fortune, I have had mentors and friends older and wiser than me over the years share secret google docs, and useful lecture notes….content that summarizes a range of topics from mechanics of materials and beam bending, to mechanism and linkage analysis, to understanding of power transmission systems, motors, and basic robotics depending on the role one is applying for.
To brush up on mechanical engineering conceptuals, I love reefing through these Youtube playlists in addition to my messy notes and few select textbook chapters from college:
In addition, MIT, Stanford, and other universities with a strong online academic presence host courses online for free that you can audit. A quick search for “mechanical engineering” on the EdX.org website yields a slew of courses in really exciting topics like Supply Chains for Manufacturing, Dynamics, and Introduction to Haptics. I encourage piquing your curiosity by going through any of these during your free time, but I personally like brushing up on core material with the MITx series on Mechanical Behavior of Materials.
Well-intentioned advice from said peers and mentors is not written down in a concrete set of open-source materials that all of us young mechanical engineers have access to unfortunately. It usually is bounced back and forth through various grapevines. Reach out to me though and I will be happy to share a few choice documents with you depending on the role you are applying for.
Given this, it is very likely you will be asked about the following general fundamental questions:
Make sure your beam bending knowledge is solid. You’re bound to be asked about cantilevers and will probably be asked to draw a FBD and describe factors that influence (increase, decrease) deflection.
The interviewer could bring out a component and ask you what material it’s made from and how it was manufactured. Make sure you understand various manufacturing processes related to metals, ceramics, and polymers. For a design position, you’ll potentially be asked about injection molding as it is so commonly employed for plastics manufacturing at scale.
For example, I was once asked in an Apple interview how an Iphone SIM card tray was manufactured and how it might be fixtured. I did not get the right answer at all. I didn’t even realize the part was anodized aluminum. I totally BOMBED but it’s ok because I learned how to manage questions where you have no idea what the right answer is. If you’re handed a part, feel free to handle it however you need to. Bend it gently to check how much give it has, smell it if you need to, DO NOT taste it. But show that you are critically thinking about material properties like elasticity, malleability, etc. to arrive at an informed decision even if it’s wrong. Feel for ridges, planar features, grooves, and other key features that will give you hints.
Know your stress strain diagrams cold. If you have never seen the following image, that’s a problem. You’ll almost always be asked about it and be asked to identify the point of yield stress, ultimate tensile strength, rupture, toughness and where and why work hardening and necking occur. You will probably be asked how stress strain curves differ between metals, ceramics, and polymers as well. Make sure you conceptually understand these fundamentals well and aren’t just spewing out definitions for your interviewer. They will immediately be able to tell if you’re reading off of Wikipedia. See below.
Interviewer: Can you tell me about necking?
Interviewee: Yes, necking is a mode of tensile deformation where relatively large amounts of strain localize disproportionately in a small region of the material.
Interviewer: Mhhm.. what else?
Interviewee: ….. Uh. I don’t know.
Interviewer: * awkward silence *
Hint: when stuck, don’t rely on diagrams and formulas. Your interviewer cares a lot more about your reasoning and how you think through problems than arriving at the right answer (although that’s always a good thing). Use your engineering intuition and explain what assumptions you are making. Whenever possible, whiteboard (if doing a video call, pull up Paint and share your screen). It goes a long way to visualize the thought process. This applies well to “whiteboarding” problems where the interviewer will think up abstract problem statements and see how you think through a design idea or mechanism.
This list is not comprehensive. It is a good idea to understand various additive and subtractive manfufacturing processes (injection molding, casting, machining, 3D printing, etc.), and joining processes of various permanencies and their benefits and disadvantages (welding, adhesives, fasteners, snap fits, etc.). Feel free to reach out for more specific information depending on the role you are applying for. I will likely have a pretty strong idea of what you should prepare for and refresh technically depending on whether you are going into robotics, energy storage, biotech, or other mechanical engineering industries. While you should not be underprepared, you could also overwhelm yourself by relearning material that may not be relevant to the role you are applying for. Ex: I would not normally look back into thermodynamic vapor compression cycles but the last company I worked for specialized in energy efficient refrigeration systems. BIG CLUE for interview studying. I held off on the robotics end effectors and actuators deep dives for that one.
Finally…
All the very best in your search for the right role for you! I know it can be daunting and scary, but don’t give up. I hope you, like me, have created a network of peers and mentors who will guide you through the process of landing your first few roles. Over the time, the process becomes more and more comfortable. And of course, if there are certain aspects of interviewing or networking that make you squeamish or that you would like to know more about, you are more than welcome to drop me a line. I would love to hear from you about your own mechanical engineering journey! Good luck!