DFMA: SHOULD COSTING
DFMA: PRODUCT SIMPLIFICATION
What is Design for Manufacturing?
Design for Manufacturing (DFM) is a methodology and set of practices used to design parts so they are easy to produce, consistent to quality-check, and economical at volume. It challenges early assumptions—process, material, tolerances, finishes, and features—so teams can converge to a manufacturable, cost-credible design before release.
DFM is most powerful early: the biggest share of lifecycle cost is committed during design, long before the first production build. It is sometimes called design for manufacturability, reflecting its focus on improving the manufacturability of each part—how feasibly, consistently, and economically it can be produced for a given process and volume.
- Manufacturability isn't binary. "Makeable" can still be fragile, slow, or expensive.
- Cost has drivers. Cycle time, setups, scrap, and secondary ops dominate outcomes.
- Iterate early. Small geometry/spec changes can unlock outsized savings.
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Benefits: reduce piece-part cost and late rework
DFM improves competitiveness by aligning geometry and specifications to the realities of production. Unlike approaches that only "negotiate a lower quote," DFM reduces the underlying effort and risk embedded in the part.
- Lower cycle time and fewer setups
- Reduced tooling/fixture complexity
- Fewer secondary operations (deburr/ream/EDM/hand finish)
- Less inspection effort from realistic tolerances
- Fewer manufacturing surprises late in the program
- Higher yield and more robust quality at scale
- Cleaner supplier conversations (clear assumptions)
- Faster design-to-release iterations
What actually drives manufacturing cost?
Teams often debate material price or a single tolerance. In production, the big money is usually in: time (cycle + setup), complexity (toolpaths/operations), and risk (scrap/yield).
- Cycle time (toolpaths, feeds/speeds, cooling, fill/pack)
- Setup time and changeovers
- Tooling/fixturing complexity and wear
- Scrap, yield, and rework loops
- Secondary ops (deburr, tumble, ream, EDM, hand polish)
- Surface finish and cosmetic requirements
- Inspection burden from tight tolerances
- Features that force small tools or hard-to-access machining
Core DFM principles
Use this DFM checklist to spot high-impact manufacturability improvements without changing function:
- Simplify geometry to reduce operations and tool changes
- Use generous internal radii to avoid tiny tools
- Design for access: avoid deep narrow pockets and awkward setups
- Minimize special features that force EDM or hand work
- Relax tolerances where function allows
- Specify finish only where it matters (mating/sealing/cosmetic)
- Standardize hole sizes, threads, stock, thicknesses
- Reduce variation to improve yield and sourcing options
These DFM guidelines apply across processes but take on specific forms for each—see the process-specific examples below. For the biggest total-cost wins, pair DFM with Design for Assembly (DFA) so part-level improvements don't miss architecture-level simplification.
Process selection: the hidden lever
The same geometry can be expensive in one process and efficient in another. Early DFM includes process screening: machining vs. casting vs. forging vs. molding vs. sheet metal—based on volume, tolerances, and constraints.
Good DFM doesn't pick a process once. It keeps process assumptions visible so you can compare alternatives as the design evolves.
DFM examples by process
DFM guidelines take specific forms depending on the manufacturing process. Here are common design-for-manufacturing examples showing how small design decisions drive cost and manufacturability in each process:
- Uniform wall thickness prevents sink marks, voids, and warpage—and shortens cooling time, the dominant cycle-time driver
- Adequate draft angles (typically 1–2° per side) allow clean ejection without sticking or drag marks
- Minimized undercuts avoid side-actions or lifters in the mold, reducing tooling cost and maintenance
- Generous radii at transitions improve material flow and reduce stress concentrations that cause cracking
- Internal corner radii ≥ 3× depth allow standard end mills and avoid slow, multi-pass small-tool finishing
- Limit depth-to-width ratios in pockets and slots to prevent tool deflection and chatter
- Avoid unnecessary tight tolerances—each jump in precision can add setups, slower feeds, and inspection steps
- Design for minimal setups by keeping critical features accessible from one or two orientations
- Bend radii ≥ material thickness prevents cracking and reduces press-brake wear
- Hole-to-edge and hole-to-bend spacing (typically ≥ 2× thickness) avoids distortion during forming
- Standard gauge thicknesses improve material availability and reduce lead time
- Minimize bend count and complexity to reduce setups and eliminate secondary forming operations
- Uniform wall sections reduce porosity and improve fill consistency
- Draft on all vertical surfaces (typically 1–3°) enables clean ejection without die damage
- Avoid deep cores and thin ribs that increase thermal stress and shorten die life
- Design for easy ejection to minimize secondary machining on as-cast surfaces
In every process, the pattern is the same: features that seem minor on a drawing—a tight radius, an extra setup, a cosmetic spec on a non-visible face—become real cost drivers in production. DFM makes these trade-offs visible before they're locked in.
Quantified micro-case: small changes, big drivers
Part: aluminum bracket (milled) | Goal: reduce cycle time without changing function.
- Increase internal corner radius from 1 mm → 3 mm
- Open a deep pocket slightly to improve tool access
- Relax finish on a non-mating face
- Localize a tight tolerance to the functional interface only
- Avoid tiny tools and long toolpaths
- Reduce passes and setup sensitivity
- Drop or simplify secondary finishing
- Lower inspection burden
| Driver | Before | After | Impact |
|---|---|---|---|
| Tooling / toolpaths | Small tool required | Larger tool possible | Cycle time ↓ |
| Secondary operations | Finish requirement broad | Finish localized | Ops removed |
| Inspection effort | Tight tolerance on large area | Tolerance localized | Inspection ↓ |
Illustrative outcome: cycle time reductions of ~12–18% and piece-part cost reductions of ~9–14% are common when changes remove small-tool paths and secondary ops. Actual results vary by geometry, rates, volume, and routing assumptions.
Real-world DFM results
DFM-driven redesigns consistently produce dramatic savings when cost-driver visibility is paired with product simplification. Here are documented outcomes from DFMA implementations:
- 85% part count reduction
- $1.1M annual labor savings
- DFM should-cost analysis guided a full redesign, slashing assembly time and supplier count
- 40% total cost reduction
- 50% labor reduction
- International Game Technology used DFM analysis to redesign a critical electronic enclosure
- 81% part count reduction
- 78% cost reduction
- Integrated teams used DFMA and Six Sigma to re-engineer key structures, cutting parts and weight
DFM vs DFA vs DFMA®
DFM optimizes parts. DFA simplifies product structure. DFMA combines both so teams optimize total product cost and avoid local optimizations.
| Discipline | Primary focus | Typical questions | Outcome |
|---|---|---|---|
| DFM | Part feasibility & piece-part cost | Which process & parameters minimize cost while meeting spec? | Optimized geometry/specs and credible process assumptions |
| DFA | Assembly structure & labor | What can be eliminated or combined to reduce assembly effort? | Lower part count, fewer fasteners, faster builds |
| DFMA® | Total product cost | What architecture and part designs minimize total cost? | System-level savings and faster convergence |
Explore: DFMA Should Costing, DFMA Product Simplification (DFA), and What is DFMA?
How to execute DFM: a practical workflow
- Define intent: function, loads, risk, volume, and target cost
- Screen processes and pick credible routings (don't assume)
- Expose cost drivers: cycle, setup, tooling, yield, secondary ops
- Iterate: change geometry/spec to remove the biggest drivers first
- Validate: supplier feedback + real constraints + quality/inspection
- Close with DFA: ensure part optimizations don't miss assembly wins
If you're trying to hit a price target, DFM provides the fact base for "why this should cost what it costs"—before the RFQ. For a deeper look at using cost models in supplier negotiations, see Should Cost Analysis.
Frequently asked questions
What is Design for Manufacturing (DFM)?
DFM is the practice of designing parts so they are feasible to make and economical to produce. It works best early, when geometry, tolerances, materials, and process assumptions can still change quickly.
How is DFM different from DFA and DFMA?
DFM focuses on part-level feasibility and piece-part cost. DFA focuses on simplifying product structure to reduce assembly time and complexity. DFMA combines both perspectives to optimize total product cost and producibility.
Does DFM replace supplier quotes?
No. DFM accelerates iterations and makes supplier conversations more productive by revealing key cost drivers before RFQs. Quotes still validate final pricing and supply conditions.
When should we apply DFM?
Apply DFM during concept and early CAD iterations, before design freeze, tooling commitments, or supplier selection. That's when changes are cheapest and impact is highest.
What are the most common DFM cost drivers?
Cycle time, setup time, tooling/fixturing, scrap and yield, secondary operations (deburr/ream/EDM/hand polish), inspection effort, and process constraints like draft, wall thickness, and minimum radii.
Which processes does DFM cover?
Machining, sheet metal, injection molding, multiple casting methods, forging, powdered metallurgy, extrusion, welding/joining, PCB fabrication and assembly, and manual or automated assembly.
What is manufacturability?
Manufacturability is the degree to which a part or product can be produced efficiently, consistently, and economically given a specific process, material, and volume. DFM is how teams evaluate and improve manufacturability during design—catching issues when changes are cheapest.
What is a DFM checklist?
A DFM checklist is a structured set of process-specific guidelines—covering geometry, tolerances, materials, and features—that designers review to catch manufacturability issues before release. Effective checklists are organized by process (machining, injection molding, sheet metal, etc.) and focus on the cost drivers that matter most for each.
Want to see DFM applied to your part?
Bring a cost-critical part. We'll show how process assumptions and cost drivers change with geometry/spec iterations—so you can converge faster and hit target cost.
