Believing in DfM Is Not the Same as Doing It
Most development leaders agree that Design for Manufacturing belongs in early product development. The logic is clear. Cost, quality, and scalability are shaped long before design transfer.
Yet many organizations that intellectually support early DfM still struggle to execute it effectively.
In practice, early process development is often assigned to design engineers who are primarily measured on functional performance and schedule. They make reasonable manufacturing assumptions, but they rarely have deep process expertise or the incentive structure to challenge their own design decisions through a manufacturing lens.
The result is a subtle gap. DfM exists in principle, but process development lags product development. Manufacturing considerations are reviewed rather than co-developed.
Closing that gap requires more than awareness. It requires a different operating model.
Process Development Begins During Design
Process development starts as soon as architectural decisions are made and matures alongside the product definition. It includes material selection, outlining process flows, identifying critical process parameters, establishing inspection strategy assumptions, conducting preliminary pFMEA work, and outlining a process validation pathway.
These activities do not require finalized production equipment. They require clarity about how the product will be assembled, inspected, controlled, and validated at scale. When process development is deferred, these elements are reconstructed later under schedule pressure, often after critical design decisions have been constrained.
Parallel Product and Process Evolution
Effective parallel development operates with synchronized product and process workstreams.
Product Development Track
- System architecture definition
- Detailed design and tolerance strategy
- Risk analysis and mitigation
- Verification planning
Process Development Track
- Process flow definition
- Assembly sequencing
- Equipment and fixture concepts
- Capability assumptions
- Measurement strategy
- Validation planning
These streams intersect continuously. Architecture influences assembly feasibility. Tolerance strategy determines process capability expectations. Material selection affects inspection approach and control strategy. Verification protocols must reflect realistic process performance.
Resolving these interactions early allows tradeoffs to be addressed while flexibility remains available.
The Paired Engineer Model
The most effective mechanism for integrating product and process work is pairing design and manufacturing engineers at the system or subsystem level.
In this model, manufacturing judgment is applied as design decisions are formed. The design engineer brings a deep understanding of functional intent and performance tradeoffs. The manufacturing engineer evaluates variability exposure, process capability, assembly feasibility, and validation implications. Together, they assess whether tolerance targets are realistic, whether assembly sequences introduce unnecessary variability, whether automation assumptions are credible, and whether inspection strategies align with the product’s risk profile.
This pairing changes the cadence of design reviews. Manufacturing considerations are incorporated as the design evolves rather than introduced after major decisions have been made. Earlier reconciliation of product and process assumptions reduces the likelihood of redesign, unexpected validation complexity, or yield instability during transfer.
Critical Synchronization Points
Several development milestones require explicit reconciliation between product and process artifacts. Architecture freeze, material selection, tolerance stack confirmation, design for assembly reviews, and verification protocol approval all demand joint evaluation.
A tolerance decision without a capability assumption leaves risk undefined. A verification plan without a validation pathway introduces uncertainty downstream. Maturing these artifacts together increases confidence before formal verification begins.
Sources of Manufacturing Expertise
Manufacturing insight may originate internally or externally. Internal engineers often understand equipment constraints, supplier performance history, and established operational strengths. Their input ensures alignment with real-world manufacturing capability.
External contributors can broaden perspective by introducing alternative process architectures, automation strategies, and cross-industry best practices. This perspective is particularly valuable when entering new technology domains or scaling beyond prior experience.
The effectiveness of parallel development depends less on where expertise resides and more on when and how it is applied.
Summary
Designing product and process together improves predictability across cost, quality, and scale. The paired engineer model provides a structured way to apply manufacturing judgment while design flexibility remains high.
When product and process artifacts mature in parallel, tradeoffs are resolved earlier and transitions into verification and production proceed with greater stability. Parallel development aligns decisions that already determine downstream outcomes and addresses them while change remains manageable.
Free Design for Manufacturing Review
If you have an active or upcoming medical device development program, we offer a free 30-minute Design for Manufacturing review.
This peer-level discussion focuses on:
- Reviewing your current design and development plan through a manufacturing lens
- Identifying where early DfM decisions could reduce variability, quality risk, or cost later
- Highlighting design assumptions that may limit scalability or complicate validation
- Suggesting targeted adjustments while change is still inexpensive and flexible
Email: sdonnigan@a65consulting.com
Or schedule your design for manufacturing review online
References
- U.S. Food and Drug Administration (FDA).
Design Transfer (21 CFR 820.30(h)).
https://www.ecfr.gov/current/title-21/chapter-I/subchapter-H/part-820#p-820.30(h) - Boothroyd, G., Dewhurst, P., & Knight, W. A.
Product Design for Manufacture and Assembly (3rd ed.). CRC Press, 2010.
https://www.routledge.com/Product-Design-for-Manufacture-and-Assembly/Boothroyd-Dewhurst-Knight/p/book/9781420089279 - Ulrich, K. T., & Eppinger, S. D.
Product Design and Development (6th ed.). McGraw-Hill Education, 2015.
ISBN: 978-0078029066
Cooper, R. G.
Winning at New Products: Creating Value Through Innovation (4th ed.). Basic Books, 2019.
ISBN: 978-1541617804