Collaboration between a customer and a supplier to design both a component and its manufacturing process.

Typically the customer provides cost and performance targets (sometimes called an envelope) with the supplier doing detailed design of the component and manufacturing process (tooling, layout, quality, etc.). The supplier often stations a resident engineer at the customer to ensure that the component will work properly with the completed product to minimize total cost.

Design-in contrasts with work-to-print approaches in which the supplier simply is given a complete design and told to tool and produce it.