Upcoming job interview

So, I have my first real job interview...

Just graduated as a junior industrial automation engineer. This is my first "real" job interview and man I never thought it would be this exhausting. Can't really imagine how further exhausting it will be to land a full-time job where your brain is constantly "on". Love the field though.

I have to go through a handful of tests: Some personality and IQ tests and lastly I have to solve a case and then present it. The case is actually what I fear the most because I don't really know how to solve it with the little information they've given me in the task. I feel really stupid but I have zero experience with parcel conveyors so I kinda lack the imagination of how one should be designed.

I don't have to design everything from scratch. I have the layout of the whole system. But I need to think about where to place the sensors (for gap detection purposes), mind the required spacing between the parcels (250mm), parcel length (300x300x100mm) and main speed of conveyor of 2.1 m/s.

Here's the exact task:

Your task is to meet the customer requirement of 4000 parcels/hr. in the
dimension 300x300x100mm.

1. Main conveyor feeding line speed can maximum be 2,1 m/s to be within the specifications of the sorter line. Line sorter speed = Main conveyor line speed. The line sorter and main
conveyor feeding line has to run continuously

2. Spacing between parcels must be a minimum of 250 mm upon handover to the line sorter.
3. No conveyor in the system are designed to have a velocity higher than 3,5 m/s or an
acceleration above 4,0 m/s^2.


As a minimum include your thoughts on:

1. sensor placement (how many and where?)
2. max. capacity for a single BOM feeding line.
3. critical areas that would require attention during development/commissioning

So, there I have it. I'm just puzzled how to figure out the max capacity when I don't have more info of the conveyor dimensions? Maybe I'm missing something? I'm pretty nervous about the interview so my brain is already cloudy ☁.

I changed profession three years ago because I wanted to try something new. Always dreamed of being an "engineer" but never got to do anything about it (because girls just weren't engineers at the time I was a teen in the early 2000s). So I ended up working with HR. The learning curve has been steep but I've managed to get good grades but the "real world" is just so much more complex than what you learn in the university.

I'm not looking for solutions handed to me but maybe some guidance of where to start? If you need an overview drawing of the system, please let me know.

Edit: attached drawing of the layout

Thank you in advance

/Melissa Miranda


I have to add that I've been seeking help on this subject on other PLC/Automation forums also. I'm just trying to gather as much input as possible.

Thanks for your time in advance


Sometimes an inexperienced or fresh set of eyes can bring a whole new perspective to the task at hand. I see this quite frequently in industrial applications. (I also see some very unusual and quirky attempts at thinking outside of the box, and one wonders how those attempts make it into production.)

Anyway, some of us respondents are kind of reluctant to help with "homework" problems like this. These kind of assignments should be taken as opportunities to research and expand your horizons. If you've been studying in the field for a while, you likely (should have) encountered some trade journals (though not so many are printed these days, there are still plenty of them available digitally). I can't tell you how many things I have learned over the years by reading trade journals--not so much the articles, but the advertisements. If a company wants you to buy their product, they are going to be very good at explaining why their product is better than others--and in the process they quite often do some very good explanations of subtle and even not-so-subtle idiosyncrasies of processes and equipment and devices. (I discovered trade journals when I was researching topics for papers I had to write in university--and I would spend hours and hours poring over them, increasing my knowledge and thirst for knowledge greatly in the process. What I once thought of as "useless" advert papers became my "mentor" on many subjects, causing me to research some things further.)

Many years ago, when I had an opportunity to work in an engineering office environment I watched some of the older, more experienced engineers reserve some time during the week to "clear their desk" and pull out the (printed) trade journals they subscribed to (they were most often free), and read them, earmarking pages, cutting out ads and articles, photocopying pages, and then, usually, they would open one of the cabinets in their office and place the trade journal on a stack of past copies. These guys were, in my opinion, some of the best engineers and were innovative and forward-thinking. (Their managers weren't always receptive to their ideas or suggestions or design changes, but it was always an interesting discussion.)

It may be too late for this assignment, and I don't think it's really clear what your need is (how to calculate parcels-per-hour?), but it seems you may be over-thinking this. As a fresher, you're not going to be expected to come up with the most efficient or most elegant design/idea(s)--what they're probably looking for is more of a thought-process type of solution: What is the candidate thinking and how is the candidate thinking? What kind of logical thought processes does the candidate possess and use? And, in the process, they might even be surprised by one or two aspects of the design/ideas presented. Sure, you want to prove your knowledge and ability--but without a lot of experience they can't (shouldn't) expect a lot from a fresh graduate (though some are pretty smart, and you may be one of them).

Try to step back and prioritize your needs at this point. If it's parcels-per-hour as your most important, how would you measure traffic flow on a street? (Is it that different from parcels passing a point on a conveyor?) By controlling the distance between cars (parcels) and the speed of the cars (speed of conveyor) can you safely increase the amount of traffic on the street (number of parcels passing a point per hour)?

Anyway, I may have missed the most important requirement you have, but I hope I have given you some ideas. As a fresh graduate with little, maybe no, experience in a particular field a company can't really expect a candidate to design a perfect system. (I work on gas turbine control systems, and in the process, had to learn about how the company I worked for designed and built and controlled and protected their machines, and then how the control systems did their jobs. The company did a lot of training (back in the day--not today, unfortunately!) and hired people with varied engineering backgrounds and degrees--but they knew they had to do training because the skills they needed weren't taught in many universities, only the basics of engineering and the "lingo" of the profession. Would they have liked to hire experienced people out of college/university? You bet! But, by training and mentoring their new hires they knew they had a good chance of success, rather than just taking someone fresh out of a mechanical engineering or electronics engineering program and throwing them in a job (either in a desk or in the field).)

You are starting on a journey. The piece of paper you have received for your efforts in school opens doors. In effect, that piece of paper says: I set a goal for myself. It was a long-term goal, too. I did what I had to do to achieve that goal; I may have done some things I didn't want to do, and I may not have gotten to do all the the things I though I might, or would, do--but I focused, and worked hard (you said you achieved good grades!) and I completed my task, I achieved my long-term goal. (And, in this new world, people that can work on a task, focus and complete the task are what employers are really looking for. Today's jobs are more about projects (tasks) than they ever were.) Setting and achieving that long-term goal, and completing all the things required to do so, sets me apart from many other people--who, though they might have better skills than I do, didn't set a goal and do the things required to achieve that goal over a period of time. (That's what college/university is really about--focusing; completing tasks; learning the jargon (lingo) of the field you want to work in; perhaps getting some hands-on experience (either in the school lab or on an internship or similar); and recognizing what is required to achieve the goal; and achieving the goal' AND learning to think logically as well as critically--the most important aspect of school!) And, that's why many employers have required a degree--to separate the people who did from the people who might. (Of course, employers today are offering people jobs without degrees.... Employers should be more open to both--people with and people without. But, you were in HR, so you have some experience with that, I imagine.)

What you do when that piece of paper opens the door for you is up to you. Go forth and prosper. And remember--you have skills, and abilities, you haven't even tapped yet.

Best of luck!

Thank you for your thourough and very helpful take on this. I reall appreciate it.

What made me nervous and insecure was that the manager said "Here, use 15-20 minutes on this and give me a 10 presentation next week".

I'm currently interning at another company full-time and I'm pretty bombarded when coming home from work and picking up my kid afterwards in daycare. That's not an excuse. I was just baffled by the low amount of time he said I should use to solve it. I would need hours - more like days to gather all the information I need because I want to have overview of every single detail (I'm very process oriented), but I also somewhat know that I'm overthinking it but my first thought was, "Am I fit for this job if I can't solve it within an hour?


I'm still trying to figure out the exact placement of the sensors across the system.

However, I did a quick calculation of the max capacity of a single BOM line with a package dimension of 500x500x200mm and a required gap .


element speed (m/s)
total parcel length (including min. req. gap) X 3600 (s/hr)

3.5 m/s X 3600 s/hr = 13263 parcels/hr

54,77% over customer requirement.

If you only have 10 minutes to do a presentation, I would presume the Manager understands you can't possibly put together a full-blown process and instrumentation explanation. Maybe he's just looking to see, one, if you will over-commit and under-deliver, and, two, if you'll ask for more information (and what kind of information) or ask if you will be a part of a team that's working on this together.

If you've had personality and IQ tests, well, that's a reflection of the world we live in today, eh? (Sad; but true.) I knew a woman in HR in the high-tech world and we used to have long talks about hiring, mostly because the Managers just wanted to hire the first "good" candidate with the best qualifications they interviewed--and didn't consider how that person would fit into the team and the Corporate environment. She was opposed to doing that, and once her "business partners" (as the Managers were called) realized and understood she was helping to find good candidates who weren't just warm bodies but could be integral parts of and contributing members of teams they were happy to listen to her recommendations. (She also had to tell some of those same Managers they couldn't fire someone just because they weren't doing what they were supposed to be doing--that the Manager had to sit down and have difficult conversations with those employees and have them multiple times and document them before they could sack them. She had to remind several of them of such episodes, some repeatedly.)

Anyway, do your best. You also have a life, and responsibility for yet another life (your child's). While this may be a great opportunity, it might or might not be the right one for this time. Only you can tell. And interviewing is a skill (for both the -er and -ee!!!). Always remember this experience, and if you get the job you can always ask the Manager what he/she was looking for and if you gave the 'correct' response. And, if you don't get the job, you can still ask the same question--letting him/her know you are trying to learn and improve. Who knows, you might a call back for another position at that firm???

Best of luck! I'm not an industrial automation engineer, just a power generation controls engineer. With a few years under his belt.

Please write back to let us know how this turns out for you!

And give your child and extra big hug today--and tomorrow.
As an ex-control engineer I gave it 10mins.
One might say it should take as long as takes if you are lacking experience.

It does help to get your facts right..
"Your task is to meet the customer requirement of 4000 parcels/hr. in the
dimension 300x300x100mm". You later mention parcel size 500x500x200mm.
The drawing refers to 6000 parcels/hr.
However if you do brief calculations (as you have done) there is no difficulty in reaching the customer requirement if the conveyor runs at 2,0 m/s; so variations in parcel size and expectations don't matter too much.

You have given no information on either the sorter or main conveyor to feed line diverts, so assume you
have little to go on. But as a mechanical handling system the divert would dictate conveyor speed/throughrate/
parcel gapping. Likewise for the sorter the divert would dictate conveyor speed/throughrate/parcel gapping.

The only thing you could seriously think about is creating gapping between parcels if 250mm is not achieved.
This could be done with one sensor and either gating system or a conveyor that stops/starts fairly promptly.

If I were at the interview I would expect you to take an interest in how the feed line divert system would work.
At the point where 6000 parcels/hr is shown on the diagram I would be looking for a bar code reader or something similar to determine which parcel goes where, despite your remit apparently not asking for it.

"The line sorter and main conveyor feeding line has to run continuously", but has to be capable of being stopped
quickly if there is 'queueback' downstream (or whilst commissioning parcels jam on diverts or go the wrong
I can give you some tips on getting ready for the interviews. First of all, wear the right clothes. A classic suit is a right thing you should wear on a job interview. Try to sleep well the night before the interview, and also try to come at least half of an hour earlier, in case you will have the possibility to enter earlier. Also, the smell is essential. Don't smoke and perfume yourself before the interview. You can find lots of helpful information on how to get a job on the web.

Sorry, but I do not understand the repeated suggestions to "...perfume yourself..."

Some people (more and more these days) are extremely sensitive to scents used in detergents, soaps, perfumes, deodorants, and even after-shave lotions. If an interviewer was one of these people, how would they react to a "perfumed" candidate???

Odd, repeated recommendation.