Design Engineer Interview Questions UK: 8 Real Questions and What Interviewers Want

Applying for a Design Engineer job in the UK? Here is what you are likely to be asked. These questions come from our Design Engineer question bank of 25 questions, written for UK employers at mid-level level.

Eight Design Engineer interview questions, and what the interviewer is thinking

1. Talk me through your design process, from receiving a customer requirement to releasing a design for production.

Why they ask: They want to see that you work in a structured, stage-gated way and don't just jump to CAD.

2. What does a typical day as a design engineer involve?

Why they ask: They want to check you understand the mix of CAD, analysis, testing and liaison with other teams.

3. Which CAD systems have you used, and how do you approach building a robust parametric model and assembly?

Why they ask: CAD competence is the core tool of the job and they want to see that your models are built for change.

4. Tell me about a time a design of yours failed in testing. What did you do?

Why they ask: Everyone has failures in design; they want to see how you investigate and respond, not whether you were perfect.

5. How would you design a bolted joint, and what factors affect whether it stays tight?

Why they ask: Fasteners are everywhere and bolted joint failures are a classic source of field problems.

6. What design rules do you follow when designing a plastic part for injection moulding?

Why they ask: Moulded parts are very common and they want to see that you know what makes a moulding manufacturable.

7. What do you need to think about when designing a sheet metal part?

Why they ask: Sheet metal is a staple of mechanical design, and the practical rules are easy to get wrong.

8. Your prototype fails a critical test two weeks before the planned product launch. What do you do?

Why they ask: They want to see calm prioritisation, proper root cause analysis and honest communication under pressure.

A sample answer to question 1

Talk me through your design process, from receiving a customer requirement to releasing a design for production.

I start by making sure I understand the requirement. I'd ask the customer or product manager questions to clarify function, loads, environment, volumes, target cost and regulations, and write it up as a product design specification that everyone signs off. Next comes concept generation: sketches, quick calculations and perhaps a decision matrix to choose between two or three concepts. Once agreed, I move into detailed design in CAD, with hand calculations or FEA to check strength, and consider manufacturing and assembly from the start. I'd then make a prototype, test against the specification, and iterate. A design review comes before release, involving manufacturing, quality and purchasing. Finally, I'd release drawings and the bill of materials through the change control system, support the first build, and capture lessons learnt. Each stage has a gate, so problems are found early when they are cheap to fix.

Common mistake to avoid: Jumping straight to CAD; ignoring manufacturing input before release

Want the rest?

Full model answers, key points and common mistakes for all 25 questions are on the Design Engineer interview questions page. The first five are free, no sign-up needed.