Design for Manufacturability Starts at Part Selection

Two weeks before a pilot build, a team learns that the board-to-wire connector, chosen months earlier for its current rating, has been moved to “not recommended for new designs” (NRND). The one distributor carrying it holds fewer units than the build needs, and the manufacturer quotes 40 weeks to replenish. The closest alternate mates with the same cable, but it uses a different footprint and stands about a millimeter taller.

So the electrical engineer reroutes the connector region. The taller housing now collides with an enclosure boss, and the mechanical designer has to move the boss and requote the tooling, causing the pilot build schedule to slip by several weeks.

All of that rework traces back to the original connector choice. The part came from a single manufacturer and was thinly stocked the day it was chosen, based on electrical specs alone. Nobody looked at it again until the NRND notice. Design for manufacturability (DFM) brings production requirements into those early decisions, keeps them under review through release, and, for most electronic products, has mechanical and electrical engineering settle them together.

Key Takeaways

• Early component, architecture, and manufacturing choices set a product’s major cost drivers, so consider production requirements when making those decisions.
• Check lifecycle status, package, and distributor stock when you first choose a part, then record a qualified alternate or a mitigation plan on the BOM.
• Cut unique parts with a preferred-parts list, and get the fabricator’s stackup options and impedance tolerances before you set the stackup.
• Early on, have mechanical designers and electrical engineers settle shared decisions such as connector selection and component heights.

Where Manufacturing Cost Gets Determined

A long-standing rule of thumb in cost-estimation research holds that roughly 70% of a product’s cost is determined during early design. David M. Anderson, author of Design for Manufacturability, describes the same pattern in budget terms: by the time a design is finished, only about 8% of the product budget has been spent, yet the design has already committed about 80% of the cost. Both are approximations, and both say the same thing: cost gets locked in early.

Each project phase builds on the decisions before it, so the later a problem is found, the more it generally costs to fix. A NASA study of error-cost escalation in large hardware and software systems quantified that growth, finding that a requirements error costing 1 unit to fix during the requirements phase costs 3 to 8 units during design, 7 to 16 units at build, and 21 to 78 units during integration and test.

Much of that committed cost comes from a handful of everyday design decisions. The following four practices address the ones mechanical and electrical engineers control most directly.

Four DFM Practices That Reduce Cost Before Layout Starts

1. Simplify the Design

Design for manufacture and assembly (DFMA), the method developed by Geoffrey Boothroyd and Peter Dewhurst, begins with part count, since each part removed eliminates its purchase, assembly, and inventory costs, as well as potential failure modes. Boothroyd Dewhurst reports that DFMA reviews of mature products typically cut cost by 15 to 40% without changing function.

Reducing total placements and unique BOM line items saves money in different ways. Fewer placements cut assembly time, while fewer unique line items can reduce feeder setups and inventory. Track both, and move them in the right direction by consolidating functions into fewer devices, questioning any resistor or capacitor value used only once on the BOM, and favoring snap fits over loose fasteners.

Simplification extends to the assembly line too. It covers packages with a pitch the assembler can reliably place and verify, clearance for inspection and rework around dense parts, and test points placed before routing fills the board.

2. Standardize Components and Materials

With a preferred-parts list, standardization becomes a daily habit. Anderson, who ran parts-standardization programs at Intel’s Systems Group, reports consolidating 20,000 parts to a preferred list of 500 and reducing 2,000 resistor, capacitor, and diode values to 35.

For a preferred list, useful electrical defaults include common passive packages such as 0402 and 0603, a short list of standard values, and one laminate and surface finish per product family. Mechanical defaults include standard sheet gauges, fastener sizes, and standoffs. Each still has to meet the product’s electrical, thermal, and reliability requirements. The parts your team has already bought, placed, and tested on its last three boards make a good starting point for that list, once rechecked for current lifecycle status and stock.

In one peer-reviewed study on material standardization in small-batch production, reducing the number of material items from 32 to 19 simplified supplier management and incoming inspection.

3. Choose Parts You Can Buy

A part’s availability, lifecycle status, and second-source options belong in the design spec alongside its voltage and current ratings, as all three can affect whether a layout will reach production without a redesign. Z2Data estimates the cost of obsolescence-driven redesigns at $20,000 to nearly $2 million, and its analysis found that 52% of the more than 620,000 parts that became obsolete in 2025 had no prior product change notification.

An initial sourcing screen checks four things:

• Lifecycle status: active, with no NRND or end-of-life notice.
• Stock: authorized inventory in the quantities the build needs.
• Lead time: short enough to fit the build schedule.
• Alternate: a candidate that matches on more than pinout, or a mitigation plan if none exists.

Defining the electrical envelope, including voltage, current, tolerance, and package limits, before choosing a part makes the screen easier, because a parametric search can then return candidate parts that meet those filters, including alternates from other manufacturers. The same sourcing risk applies to mechanical parts such as connectors, switches, and heat sinks, where a single substitution can change the board outline, the enclosure cutout, and the mating cable.

Screening at selection gives the team time to evaluate alternatives. Without that check, a sourcing problem may surface during pilot-build preparation, at which point a substitution can force changes to both the board and the enclosure.

4. Design Within What the Fab Can Build

Stackup, controlled impedance, and via structures are where DFM and signal integrity overlap. When the fab can reliably build the stackup as designed, the finished traces stay closer to what the simulation predicted. In a Sierra Circuits article, signal-integrity specialist Rick Hartley of RHartley Enterprises advises designers to learn the fabricator’s capabilities and build their designs around them.

That comes down to a few recurring choices:

• Symmetric stackups limit bow and twist during lamination and reflow.
• Stocked dielectric thicknesses avoid special-order material and its added lead time.
• The simplest via structure that meets routing and assembly needs keeps fabrication cost down. Specify filled and capped vias only where the via structure requires them, such as via-in-pad and stacked microvias.
• Realistic impedance tolerances match the fab’s process. Sierra Circuits, for example, can hold ±10% and ±5% in special cases.

A design that requires tighter tolerances than the fab can reliably achieve risks a redesign and a second fabrication cycle. With the stackup and parts settled, layout rules can enforce the remaining constraints, as covered in our article on the eight common DFM problems that design rules catch.

Where Mechanical and Electrical DFM Meet

Several of the practices above involve parts and features that belong to both disciplines: connectors, tall components, the board outline, mounting holes, and the standard hardware that holds the assembly together.

Agreeing on those interfaces at the block diagram and first enclosure sketch, and then refining them before detailed placement and enclosure tooling commitments, keeps the two designs aligned. Adding the shared parts to the preferred-parts list carries that alignment into the next product. Once CAD work is under way, a synchronized electronic and mechanical CAD (ECAD-MCAD) workflow can keep it current, as described in our article on ECAD–MCAD collaboration.

Checklist: DFM Practices to Apply Before Layout Starts

The four practices above cover a lot of ground, but the decisions that matter most tend to cluster around the same recurring checkpoints. Use this list to make sure nothing slips through before layout begins. 

• Set targets for both total placements and unique BOM line items, and track them at each review.
• Build a preferred-parts list from the parts on your last three boards.
• Screen lifecycle status, authorized stock, and lead time for each new part when you select it, and recheck before release.
• Record a qualified alternate or a mitigation plan on the BOM for every single-manufacturer part.
• Settle connectors, tall components, and the board outline jointly across mechanical and electrical design before detailed placement begins.
• Get the fabricator’s stackup options and impedance tolerances before you set the stackup.
• Choose the simplest via structure that meets routing and assembly needs, and specify fill and cap only where the structure requires it.
• Confirm inspection access and test-point placement before routing fills the board.

How Octopart Supports Manufacturable Part Selection

The sourcing screen goes fastest when lifecycle, stock, and package data are available in one place. Octopart’s parametric search can filter parts by package, mount type, and dimensions and shows lifecycle status, stock, and lead time in the results. Octopart pulls pricing and availability for tens of millions of parts from hundreds of distributors. Each part page lists current offers and, where available, inventory history indicating whether a part has stayed reliably stocked or run thin over time. Datasheets and available symbols, footprints, and 3D models help engineers evaluate the part, including its fit and clearance. Part pages also show how many distributors stock each part. One carried by a single distributor, like the connector in the opening example, is a single-source risk to resolve before layout.

Once parts move onto a BOM, the Octopart BOM Tool shows lifecycle status, pricing, and stock for every line, so the team can find alternates for risky parts before layout starts.

Before your next design moves into detailed layout, run the sourcing screen on its BOM and confirm the stackup with your fabricator, while both are still easy to change.

Search your next part on Octopart to check its lifecycle status, distributor stock, and alternates before layout starts →

Frequently Asked Questions About Design for Manufacturability

What is design for manufacturability (DFM) in electronics?

DFM is the practice of designing a product so it can be fabricated, assembled, and tested at the lowest practical cost. In electronics, it covers component selection, stackup and via choices, layout rules, and the mechanical features the PCB shares with its enclosure.

How is DFM different from design for assembly (DFA)?

DFA focuses on the assembled product, asking whether each part is necessary and how easily it can be handled and inserted. DFM focuses on how each remaining part, including the bare board, is made. Boothroyd Dewhurst combines the two as DFMA and applies DFA first, since a part that can be eliminated does not need its manufacturing optimized.

What should an engineer check before adding a part to a BOM?

Look past the datasheet to the part’s lifecycle status, stock depth at authorized distributors, current lead time, and whether equivalents are available from other manufacturers. For a single-manufacturer part, carry either a qualified alternate or a documented mitigation, such as an agreed inventory buffer or a planned redesign path.

How does DFM apply to mechanical design?

Mechanical DFM for electronics covers the board outline, mounting features, component heights, connector placement, and enclosure fit, as well as the fastener and hardware choices that determine assembly time.

How does DFM shorten time-to-market?

DFM reduces manufacturing-related delays caused by fabrication rejections, assembly rework, and late part substitutions. Standard parts, well-stocked components, and fab-compatible stackups also shorten quoting, procurement, and assembly setup, so the first build reaches the line sooner.