Understand the path from idea to product before you spend serious money.
A free, plain-language guide for inventors and small hardware teams: what happens in each phase of development, what really drives cost, and how to plan a sensible next step.
Explore the six phasesGet the planning kit
Written by Wayne Weber, a mechanical engineer and MBA working in product development and prototyping. No ads, nothing for sale.
The six phases of development
Every physical product moves through the same steps. Each one answers a single question.
- 1Project InitiationDecide what is being built, who it is for, and what "working" means.
- 2FeasibilityCheck on paper that it can work and can hit its price.
- 3Proof of ConceptBuild a rough version of the riskiest part to prove it works.
- 4PrototypeBuild a few complete units that work and look like the real thing.
- 5PreproductionPrepare the design and tooling so a factory can make it well.
- 6ProductionMake it at volume, ship it, and keep improving it.
Start where you are
Most people arrive with one pressing question. Pick the one closest to yours.
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A new idea
The development process
Learn the six phases and find out which one the idea is really in today.
Read the overview
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Worried about cost
Costs and timelines
Where development money goes, and why a prototype part can cost twenty times the production part.
See how costs work
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Ready to get help
The planning kit
A questionnaire and worksheet that turn an idea into something an engineer can respond to.
Open the planning kit
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Stuck on a term
Glossary
Plain definitions of BOM, DFM, tooling and the other words that show up in quotes and contracts.
Look up a term
Why nobody can price a new product on day one
At the start, the range of what a product could cost to develop and manufacture is very wide. Any single number inside that range is a guess, no matter who offers it.
Each phase of development answers a question and narrows the range. By the time a product reaches production, the cost is known. That narrowing is what development money buys.
Eight things worth knowing before you spend money
The short version of everything on this site.
A full price is not possible on day one.
Too much is still unknown at the start. A dependable estimate comes out of development; it cannot go in at the beginning.
Each phase buys certainty.
Every phase answers a specific question, and the estimate tightens as those questions are answered.
There are two unit costs, and they are far apart.
A part that costs cents in production can cost many dollars as a prototype. Quantity and tooling explain the gap. See the worked example.
Every requirement affects cost.
A written list of what the product must do is the most useful document in the whole process.
Each phase ends with a decision.
Pausing or stopping at the end of a phase, with a known amount spent, is a normal and healthy outcome.
Spend in the right order.
Learn what the product costs to make before committing large sums to patents, branding or packaging.
Business goals shape the engineering.
Licensing an idea, raising money and building a company each call for a different amount of development.
Not every firm covers every phase.
Some take a product all the way to production; others specialize in the early phases. Ask where a firm hands off, and plan for it.
Latest guides
In-depth answers to the questions inventors ask most. New guides are added every few weeks.
Guide
A prototype's unit cost is not the production unit cost
Why prototype parts cost ten to forty times more than production parts, a worked sheet-metal bracket example, how tooling and quantity drive the gap.
Guide
Why nobody can quote a new product up front
Why engineering firms cannot price a whole new product at the start, what the uncertainty curve is, what plus-or-minus 20% really means.