Tips to simplify designsDesign for Manufacturing and Assembly (DFMA) is an interpolation approach to product design methodology that can cut total manufacturing cost by 50% or more while improving quality rather than degrading it. To be effective, the technique must infuse every aspect of the product design process, from inception to long term, mass production.
Yet many engineers hesitate to fully integrate the comprehension of manufacturing outcomes into their process, preferring a ‘throw it over the wall to production’ approach. There is, too often, resistance to the simplifications of designs, through disconnect from outcome production efficiency, or fear of losing performance, durability, or perceived value.
That tension is understandable – but misplaced. DFMA is not about dumbing products down. It is about removing unnecessary complexity and replacing it with smart, intentional design choices made early, when changes are null-cost and flexibility remains within reach. When applied effectively, DFMA results in fewer parts, faster assembly, lower defect rates, and more robust products that scale cleanly into production.
Key takeaways
- DFMA integrates DFM and DFA to simplify products, reduce costs considerably, and improve quality, durability, and serviceability.
- Reducing total part count is the single most impactful DFMA technique – parts that don’t move relative to each other should be combined, wherever possible – or converted into upstream assemblies by overmolding; insert molding; alloy property transitions; compositing etc.
- In some cases, parts that do move relative to each other can be replaced with a one-step manufacture of a 4D, flexible parts.
- Self-locating features, snap-fits, and top-down (Z-axis) assembly simplify manufacturing without adding functional risk.
- DFMA should be applied during the concept phase; late-stage changes cost 10x to 100x more and typically create damaging delays.
- Early collaboration with manufacturing teams and suppliers is essential for successful DFMA.
- Simplification improves quality by reducing assembly steps, tolerance stack-ups, and failure points.
What is DFMA?
DFMA is a systematic underlying design methodology that combines two complementary disciplines:
- Design for Manufacturing (DFM): Making parts easy, repeatable, and cost-effective to manufacture.
- Design for Assembly (DFA): Making products easy, fast, and error-resistant to assemble.
Individually, DFM and DFA address specific problems. Together, they address the systemic issue of product complexity, before it becomes locked into tooling, supply chains, and production processes.
The core promise of DFMA is summarized in one basic concept:
Most product cost is designed in, long before manufacturing starts.
Numerous industry studies show that DFMA can reduce:
- Part count by 30-70%
- Assembly time by 40-60%
- Total product cost by 50% or more
Crucially, DFMA improves quality, functionality, and durability because fewer parts mean fewer interfaces, reduced tolerance stack-ups and opportunities for assembly error.
DFM vs DFA: How they work together
DFM focuses on how parts are made – process selection, tolerances, surface finishes, and materials.
DFA focuses on how products are assembled – part orientation, fastening, handling, and sequencing.
DFMA integrates both perspectives into a single design mindset: design the whole product to flow smoothly from raw material to finished assembly.
Core DFMA techniques for simplification
DFMA is not an abstract theory. It consists of clear, actionable design techniques that can be applied to almost any product.
Minimize total part count
This is the most powerful DFMA principle. Every part added to a design increases:
- Material cost
- Manufacturing operations
- Inventory complexity
- Assembly time
- Failure risk
A classic DFA test asks whether a part must exist:
- Does it move relative to adjacent parts?
- Does it require a different material?
- Does it need to be separate for assembly or service?
If the answer is no to all three, the part should be consolidated, wherever possible, so sub assemblies are converted into parts, evolving their assembly into a tooled and hands-free manufactured part.
For example, replacing a stamped bracket + fasteners with an integrated molded rib or machined feature often removes 2-4 parts and an assembly step – without impacting function.
Design multi-functional parts
Single-purpose parts are a hallmark of poor DFMA. Well-designed parts often perform multiple roles simultaneously:
- Structural support
- Alignment and location
- Fastening or retention
- Sealing or shielding
This does not increase complexity when designed with intentionality – it reduces interfaces.
A plastic housing boss that:
- Locates a PCB
- Acts as a fastener point
- Controls standoff height
…eliminates separate spacers, brackets, and alignment features.
Use standard and off-the-shelf components
Custom components feel elegant in CAD – but they are expensive in reality. DFMA strongly favors standardized components where possible:
- Fasteners
- Bearings
- Springs
- Connectors
Standards reduce cost, shorten lead times, and reduce risk.
A standard part often outperforms a custom part in total system cost and reliability.
- Torx drives offer the highest self location and bit durability in fastener driving.
- The thread profile is a thread-forming type that rolls the screw pillar wall rather than cutting it. This produces lower residual stress, no swarf, and a firmer engagement or stronger pullout resistance.
- The type A-B tip enables good self starting.
- The screw pillar has a relief at the entry point that serves to engage the screw in position, soften the start torque required, and prevent potential for screw pillar splitting by integrating a collar at the pillar that is not screw distorted.
- The pillars are drafted on the outer face, to ease ejection.
- The core pins that form the screw holes are draw polished, to reduce ejection forces.
- The screw hole is parallel to ensure good screw engagement and the resistance to ejection is obviated by a) draw polishing the core pin and b) mounting a sleeve ejector onto each pillar to ensure high local force and low distortion risk.
- The screw head receptacle has a small collar that improves engagement between the upper and lower features to reduce misalignment (poka-yoka).
Optimize for ease of assembly
Designs should assume either human or automated assembly, not idealized lab conditions. DFMA favors:
- Top-down (Z-axis) assembly
- Minimal reorientation
- Self-aligning geometry
- Clear, mistake-proof sequencing
Each reorientation, tool change, or ambiguous part orientation adds hidden cost.
Example:
A housing that assembles from one direction with gravity-assisted locating requires fewer fixtures and less operator skill.
Implement error-proofing (Poka-Yoke)
Poka-yoke means designing out the possibility of error. In DFMA, this often involves:
- Asymmetrical geometry that prevents incorrect orientation.
- Features that only mate one way.
- Assembly sequences that physically block incorrect steps.
Error-proofing improves quality without inspections – arguably the best kind of quality improvement.
Replace traditional fasteners
Fasteners are expensive:
- They require inventory
- They add assembly time
- They increase failure modes
DFMA encourages replacing screws and bolts with:
- Snap-fits
- Living hinges
- Press-fits
- Self-locking tabs
When designed correctly, these features reduce cost and improve consistency.
Benefits of implementing DFMA
DFMA is a systematic engineering approach that simplifies products to reduce manufacturing cost, complexity, and risk. By minimizing part count, standardizing components, and designing with process capabilities in mind, DFMA shortens production cycles and lowers defect rates. It encourages early collaboration between design, manufacturing, and supply chain teams, ensuring materials, tolerances, and assembly methods are aligned from the outset.
Broadly applied, DFMA improves reliability, enhances scalability, and accelerates time to market. The result is not just cheaper production, but more robust products, clearer workflows, and stronger competitiveness across high-volume and precision manufacturing environments.
Lower production costs
Cost reductions come from multiple directions:
- Fewer parts
- Shorter assembly time
- Reduced tooling complexity
- Lower scrap rates
Each simplification removes entire cost categories – not just marginal savings.
Improved quality and reliability
Contrary to common fears, simpler designs are more robust:
- Fewer component interfaces mean fewer points of potential failure.
- Reduced tolerance stack-ups result in higher certainty of successful assembly and wider tolerance allocations to components, resulting in lower cost process applicability.
- Less assembly variation, or increased tolerance of component variations that result in lower risk of hitting boundaries case obstructions or operational failures.
Many DFMA processes reduce the risk of warranty claims even as costs fall.
Faster time to market
Simpler designs:
- Prototype faster, allowing increased design evaluation without ramping outsource prototype costs.
- Tooling is typically faster and lower cost to produce.
- The ramp-up to production will usually go more smoothly, as fewer obstructive challenges must be overcome in establishing, stabilizing and growing production.
DFMA reduces risk during launch – the most expensive time to discover problems.
When to Apply DFMA: Timing matters
DFMA delivers the greatest impact when applied from early in the product development cycle, ideally during concept design. Decisions made at this stage determine most of a product’s total lifecycle cost.
Applying DFMA after detailed design limits its effectiveness, as major geometry, material, and architecture choices are already fixed. Early integration enables smarter part consolidation, tolerance alignment, and process selection before tooling or capital is committed. In short, the earlier DFMA begins, the greater the cost, quality, and schedule benefits.
The cost of late changes
Industry data consistently shows:
- Concept phase change: ~1× cost
- Pre-tooling change: ~10× cost
- Post-production change: 100× cost
Once tooling is ordered, most cost decisions are already locked in.
Apply DFMA during concept development
The best DFMA decisions happen before geometry is detailed:
- Before tolerances are frozen
- Before suppliers are locked
- Before tooling assumptions harden
Waiting until “manufacturing problems appear” is already too late.
How to simplify product design without sacrificing quality
This is the core concern DFMA must address.
Start with functional requirements
Simplification does not mean removing required functions. DFMA begins by asking:
- What does the product actually need to do?
- Which features are performance-critical?
- Which features exist out of habit or legacy?
Function defines design – not the other way around.
Use the minimum part criteria
Every part should justify its existence using the DFA test. If it does not:
- Move relative to other parts
- Require a unique material
- Enable assembly or service
Then it should be merged, removed, or redesigned.
Apply realistic tolerances
Over-tight tolerances are one of the most common cost drivers. DFMA encourages:
- Tight tolerances only where functionally required.
- Looser tolerances elsewhere.
This improves yield and reduces manufacturing cost without compromising performance.
Validate through prototyping
Simplification must be validated – not assumed. Rapid prototypes, pilot builds, and functional testing ensure:
- Performance is preserved
- Assembly assumptions are correct
- Quality metrics improve, not degrade
DFMA is evidence-driven, not aesthetic-driven.
Cross-Functional Collaboration: The key to successful DFMA
DFMA fails when design is isolated from manufacturing reality.
Involve manufacturing teams early
Manufacturing engineers understand:
- Process limits
- Cost drivers
- Common failure modes
Their input during design prevents expensive downstream corrections.
Early supplier involvement (ESI)
Suppliers often know:
- Which features cause scrap
- Which tolerances drive cost
- Which designs scale cleanly
Ignoring this expertise is one of the costliest mistakes teams make.
Direct supplier communication is essential for DFMA. Platforms like Jiga enable engineers to engage manufacturers early, get DFM feedback during design, and maintain those relationships from prototype through production- exactly the collaboration DFMA depends on.
Joint design reviews
Regular, structured design reviews with manufacturing stakeholders surface:
- Simplification opportunities
- Assembly risks
- Cost hotspots
DFMA is most effective when decisions are shared and visible.
Finding manufacturing partners who support DFMA
Not all suppliers support DFMA equally.
What to look for in a partner
- DFM feedback capability: Willingness to challenge designs constructively.
- Process expertise: Deep understanding of how parts are made.
- Engineering access: Direct communication with technical staff.
- Prototype-to-production continuity: Knowledge preserved across phases.
Why early engagement matters
When suppliers are brought in after designs are frozen, DFMA opportunities are lost. Early engagement allows manufacturability to shape the design – not just react to it.
Jiga connects engineers with suppliers who provide proactive DFM feedback and support early-stage collaboration. Direct communication enables DFMA-driven design discussions before tooling commits.
Summary
DFMA is not about cutting corners – it is about cutting unnecessary complexity. By minimizing part count, designing multi-functional components, using standard parts, optimizing assembly, error-proofing designs, and reducing fasteners, teams can lower costs dramatically while improving quality.
The key is timing: apply DFMA early, involve manufacturing expertise, and validate through prototyping. Done well, DFMA delivers simpler products that are easier to build, easier to scale, and more reliable in the field.
