Questions a Design Engineer Should be Asking

Most design problems aren’t design problems.

They’re questions nobody asked early enough.

We built a framework around five stages every product goes through — Define, Discover, Design, Develop, Deploy — and the specific questions a design engineer should be asking at each one.

The Define Stage

Before a single sketch gets drawn, the Define stage sets the boundaries a design has to live inside. Skip a question here and it usually resurfaces later as a redesign, a missed regulatory requirement, or a part that works great in the lab and fails in the field.

What industry or market will this be designed for?
Industry determines everything downstream — which regulations apply, what materials are acceptable, and how much documentation the design process needs to generate. An automotive component and a consumer electronics housing start from two completely different rulebooks.
Who will be the intended user?
The end user drives ergonomics, interface complexity, and even material choice. A design built for a trained technician looks nothing like one built for a first-time consumer.
Where is this design going to be used? (i.e. environment/context)
Environment dictates material selection, sealing requirements, and durability targets. A part exposed to outdoor weather, industrial chemicals, or extreme temperatures needs different engineering than one used indoors in a controlled setting.
How will the product be used?
Actual use conditions — frequency, force, duration — expose failure modes that a spec sheet alone won’t. Designing for intended use instead of assumed use is where a lot of field failures start.
Does a similar device or product exist in the market already?
Existing products are a shortcut to lessons already learned. Understanding what’s out there prevents reinventing a solution and helps position the new design’s actual point of differentiation.
Is there market, product, or device documentation or history available for review?
Documentation and history reveal what’s already been tried, tested, and standardized. It’s faster to build on existing knowledge than to rediscover it through trial and error.
Did the discovered products have any known successes and/or failures/design flaws and/or associated risks?
Known failures are free risk assessments. If a competitor’s product had a known flaw, that’s a design requirement in disguise.
Will there be an aesthetic value to the user? (i.e. Color, Form, Materials, etc…)
Aesthetics affect adoption and perceived quality, even in highly technical or industrial products. Color, form, and material finish can influence trust and usability just as much as function does.
Will there be user interface requirements? Will user training be required?
Interface complexity determines how much training and documentation the product will need to launch successfully. A design that assumes zero training will fail differently than one that assumes an expert operator.
Will there be performance requirements?
Performance targets need to be defined before design starts, not measured after a prototype fails. They anchor every material and geometry decision that follows.
Any regulatory / statutory requirements that need to be met, trialed, and approved by a governing body?
Regulatory requirements can dictate material selection, testing protocols, and documentation from day one. Discovering a regulatory requirement late in the process is one of the most expensive ways to delay a launch.
Have economic and cost aspects been considered?
Cost targets constrain material choice, tooling complexity, and manufacturing process from the outset. A brilliant design that can’t hit its cost target isn’t a viable design.
Is there an expected usage, durability, or lifetime of the device or product anticipated or required? Expected lifespan drives material selection and structural design. Overbuilding wastes cost; underbuilding creates premature failures — both come from skipping this question.
Have any databases been accessed for current or similar device history? (i.e. patent searches, fda.gov, etc…)
Patent and regulatory database searches protect against IP infringement and surface prior art that can shortcut development. This is diligence that’s far cheaper before design than after.
Any current or past trends, culture, psychological associations that could influence the design? Cultural and psychological associations shape how a product is perceived and trusted, sometimes more than its actual performance. A design that ignores these signals can be functionally sound and still fail commercially.
Any materials that need to be included/excluded to produce, use, store the product?
Material restrictions — chemical resistance, flammability ratings, regulatory exclusions, customer-specific bans — need to be known before concept work starts. Finding out a preferred material is disqualified after tooling begins is a costly correction.
What demographics would benefit from the design/product?
Demographics inform ergonomics, sizing, and usability requirements. Designing for a broad or narrow user base changes fundamental decisions about form and interface.
Any product information outputs? (i.e. U.I., alarm, data loss/storage, calibration, etc…)
Information outputs define what the product needs to communicate and how reliably. These requirements often carry their own validation and regulatory burden that needs to be scoped early.
Any product substance outputs? (i.e. chemical, waste, body fluids, emissions, etc…)
Substance outputs affect material compatibility, containment design, and disposal or handling requirements. This is a safety question as much as a design question.
Any product energy outputs? (i.e. noise, heat, radiation, electrical, magnetic, vibration, etc…) Energy outputs can trigger their own regulatory testing and affect user safety and comfort. Identifying them early prevents a redesign driven by an electrical, thermal, or acoustic failure late in development.

The Design Stage

Once Define sets the boundaries, the Design stage turns them into an actual part. Abstract requirements become dimensions, materials, and specs — and a design engineer’s decisions start locking in cost, manufacturability, and risk.

Have the physical characteristics and attributes been considered and/or determined?
Physical characteristics — size, weight, geometry, wall thickness — are the foundation every other decision builds on. Locking these down early prevents downstream conflicts between form, function, and manufacturability.
Have performance requirements been detailed? (i.e. human factors/ergonomics, waterproof, etc…) Performance requirements translate what the product needs to do into measurable targets an engineer can actually design against. Vague requirements produce vague designs that are hard to validate later.
Have safety and reliability requirements been detailed?
Safety and reliability targets define the margin the design has to work within before it becomes a liability. These requirements are far cheaper to build in at the design stage than to retrofit after a failure.
Have criteria that affect fit, function and durability been identified?
Fit, function, and durability criteria are what separate a part that works in isolation from one that performs correctly in the full assembly, over its full service life. Missing one of these is a common source of late-stage redesigns.
Have potential failures and concerns of the product/device been discussed and addressed? Identifying potential failure modes during design, rather than after prototyping, gives the team room to engineer around them instead of reacting to them. This is where a lot of long-term reliability gets built in or lost.
Has compatibility with other devices been considered? (i.e. auxiliary devices, accessories, software, etc…)
A part rarely exists in isolation — it has to interface with other components, systems, or software. Compatibility gaps discovered after tooling are among the most expensive to fix.
Have the material characteristics been considered? (i.e. Toxicity, biocompatibility, environmental reclaim, etc…)
Material characteristics affect regulatory compliance, environmental impact, and end-of-life handling, not just mechanical performance. Choosing a material without weighing these factors can disqualify a design late in the process.
Are there requirements for special handling? (i.e. sterilizing, etc…)
Special handling requirements – cleaning, sterilization, chemical exposure, extreme storage conditions – can dictate material and design choices well before the product ever reaches the end user. These requirements need to be known, not assumed.
Have packaging and labeling been considered?
Packaging and labeling are part of the product experience and, in many industries, a regulatory requirement in their own right. Treating them as an afterthought risks shipping delays and compliance gaps late in the program.
Is budgetary cost analysis needed?
A design that hits every technical requirement but misses its cost target still isn’t a viable design. Running cost analysis alongside the technical design, rather than after it’s finalized, keeps the program financially realistic from the start.

The Discover Stage

This stage is where the research happens based on the answers from the Define phase. We start by studying current trends — what’s working, what can be improved. Then we look beyond the immediate market, sometimes even to nature itself, using cross-analysis to bring a fresh angle to the design. So, there are no predefined questions to sort through.

The DEVELOP Stage

Develop is where a design gets pressure-tested — mathematically, materially, and physically — before it’s committed to production tooling. It’s also where manufacturing input has to enter the conversation.

Are special considerations required regarding design development? (i.e. FEA, other simulation/testing)
Simulation and analysis catch structural and performance issues while they’re still cheap to fix. Skipping this step means finding those same issues in a physical prototype, or worse, in the field.
Are the materials being considered conducive to the intended use, and are they manufacturable?
A material can meet every performance requirement and still be impractical to mold, machine, or assemble at scale. Confirming manufacturability alongside suitability prevents a design that only works on paper.
Has manufacturing processes been considered?
The manufacturing process shapes what geometry, tolerances, and features are actually achievable. Designing without process in mind leads to parts that need significant rework before they can be built.
Will there be manufacturing representation in the development phase?
Manufacturing input during development catches design-for-manufacturability issues before they’re locked into tooling. This is the point where a design engineer and a process engineer should be looking at the same part together, not sequentially.
Will special analysis of the materials be required?
Some applications demand material testing beyond standard datasheet values — chemical exposure, fatigue, long-term aging. Identifying this need early prevents a late-stage scramble when a material doesn’t perform as expected.
Will a Design FMEA need to be developed for manufacturing?
A Design FMEA forces the team to systematically identify failure modes and their manufacturing impact before production starts. It’s one of the most effective tools for catching risk that a visual design review would miss.
Have all special characteristics been identified?
Special characteristics — features tied to safety, function, or regulatory compliance — need extra process controls and monitoring. Missing one means it won’t get the scrutiny it needs during production.
Have all tolerances, specifications and limits been incorporated?
Tolerances and limits define what “correct” actually means for every dimension on the part. Without them fully specified, manufacturing has no objective standard to build or inspect against.
Are tolerances compatible with accepted manufacturing standards?
Tolerances that exceed what a process can reliably hold drive up scrap rates and cost, even if they’re technically achievable. Matching tolerances to real process capability keeps the design both functional and affordable to produce.
Are product characteristic and requirements defined to provide sufficient detail for data/print generation?
Prints and data packages are only as good as the requirements behind them. Gaps here get passed downstream to manufacturing, where they become questions, delays, or incorrect assumptions.
Have all design requirements been factored for engineering and functional prototypes?
Prototypes are only useful if they reflect the actual design intent and requirements. A prototype built to incomplete requirements can pass testing and still fail to represent the production part.
Have service and maintenance issues been considered and/or determined?
Serviceability affects total cost of ownership and end-user satisfaction long after launch. Designing for maintenance access and part replacement up front is far easier than retrofitting it later.
Will any type of product testing be done in-house?
Knowing where testing will happen affects timeline, cost, and how quickly issues can be identified and resolved. In-house testing capability can significantly shorten the feedback loop during development.
Is test loading sufficient to provide all conditions? (i.e. product validation, end use, etc…)
Test conditions need to represent real-world use, not just a convenient lab setup. Insufficient test loading can let a design pass validation and still fail in actual service.
Is the specified test sampling size and/or frequency feasible?
Sample size and frequency determine whether test results are statistically meaningful or just a snapshot. An infeasible sampling plan either doesn’t get followed or doesn’t produce data anyone can trust.
If required, has customer approval been obtained for test equipment?
Customer sign-off on test equipment prevents disputes over whether validation results are acceptable after the fact. This is a coordination step that’s far cheaper to handle before testing starts than after.

The Deploy Stage

Deploy is where the design hands off to production. Every decision here determines whether a design that worked in prototype form translates cleanly into a repeatable process, or turns into a string of launch delays.

Has manufacturing processes been considered/determined?
By Deploy, the manufacturing process needs to be locked, not still under discussion. An undefined process at this stage puts the entire launch timeline at risk.
Is the necessary equipment available for manufacturing?
Equipment availability — press tonnage, tooling, secondary equipment — has to be confirmed before a launch date is committed to. Discovering an equipment gap after the fact turns a planning problem into a schedule problem.
Will a Design FMEA be provided to manufacturing for consideration?
Manufacturing needs visibility into the failure modes identified during design so process controls can be built around them. Without it, the production team is working blind on risks the design team already knows about.
Will there be specific inspection, monitoring and submission requirements of the manufacturing process?
Inspection and monitoring requirements determine how the process will be controlled and how quality will be proven to the customer. These need to be defined before production starts, not improvised once parts are already running.
Have leadtimes for raw materials been reviewed and considered?
Material lead times can be the longest pole in the launch timeline, especially for specialty resins or custom colors. Reviewing them early prevents a finished tool from sitting idle waiting on material.
Will assembly or other secondary processes be needed?
Secondary operations — assembly, welding, printing, finishing — add time, cost, and potential failure points beyond the base molded or machined part. Planning for them at Deploy keeps them from becoming an unplanned addition after launch.
Are there requirements for controlled environment or clean room manufacturing conditions? Controlled environment requirements affect facility selection, process capability, and cost, and they need to be confirmed well before production is scheduled. Finding out late that a part needs cleanroom conditions can force a manufacturing site change.
Have packaging, labeling, and shipping processes been reviewed to maintain product or device integrity?
Packaging and shipping are the last line of defense protecting a part after it leaves the manufacturing floor. A part that’s perfect at the press and damaged in transit still fails the customer.

Get the PDF below

Download the entire PDF for FREE

Download