A technically brilliant PCB design can become a production nightmare if no one has considered manufacturability upfront. Workshop returns, last-minute modifications, cost overruns on production runs: the consequences of poor DFM (Design for Manufacturing) add up in time and money. Here are the 5 most common mistakes — and how to avoid them.
What is Design for Manufacturing?
Design for Manufacturing (DFM) refers to the set of practices that involve designing an electronic product with industrial manufacturing constraints in mind. The goal is straightforward: the board designed in the design office must be easy to manufacture, with a minimal defect rate and controlled costs at volume.
DFM is not a constraint imposed after the fact. It is a design philosophy that is integrated from the schematic stage, well before the first PCB routing pass. When this approach is ignored, problems most often surface during the first prototypes — at the worst possible moment and with the greatest impact on timelines.
The 5 most common DFM mistakes
1. A non-standard layer stackup
The stackup defines the structure of copper layers, dielectric and prepreg. A non-catalogue stackup forces the PCB manufacturer to produce in custom mode, which increases costs and extends lead times. Worse: a poorly chosen stackup can compromise signal integrity for high-frequency signals or cause thermal warping at the solder joint.
The rule: always work with the standard stackup from the chosen manufacturer, and validate it before starting PCB routing. A stackup file shared between the design office and the manufacturer prevents most surprises.
2. Pads too small for SMD assembly
Automated SMD (Surface-Mount Device) placement relies on pick-and-place machines that operate within precise mechanical tolerances. Undersized pads or insufficient spacing between components cause soldering defects: solder bridges, misaligned components, cold joints.
Component libraries must comply with IPC-7351 recommendations and be adapted to the soldering technology used (reflow oven, wave, selective). The same footprint may require adjustments depending on the process.
3. Missing ICT test points
ICT (In-Circuit Test) testing verifies electrical continuity and component values after assembly. To function, this method requires accessible test points on the bottom side of the board, with a minimum pitch (typically 2.54 mm) between points.
Forgetting test points in the design forces the workshop to perform manual tests that are slower, more expensive, and less repeatable. On production runs of a few hundred boards, the difference in test cost can represent several tens of thousands of euros.
4. Obsolete components in the BOM
Including end-of-life or short-supply components in the bill of materials (BOM) is one of the most costly mistakes. It can stall a production launch for weeks, or even force a partial redesign if the component is no longer available.
Proactive BOM management means verifying the lifecycle status of every component reference at the selection stage, and systematically defining a second source. This work must be done during the design phase, not after prototype validation.
5. Mechanical tolerances overlooked
The electronic board fits into an enclosure, a rack, or a mechanical assembly. Connectors must align with enclosure openings, screws must pass through the correct holes, heatsinks must have sufficient clearance. When mechanical tolerances are not integrated into the PCB design, manual adjustments in the workshop are inevitable.
Using a 3D PCB model (STEP or IDF) from the start of PCB routing makes it possible to detect these conflicts well before manufacturing.
How Codium integrates DFM from the schematic stage
At Codium, DFM is not a final step: it is a guiding thread throughout the entire design process. Here is how we put it into practice concretely:
- Stackup validation upfront — Before any PCB routing begins, we define the stackup with our PCB manufacturer partner to guarantee production without cost overruns.
- IPC-7351 certified libraries — Our footprints are validated for the soldering processes we use in the workshop, with appropriate pad sizes and spacings.
- ICT test points integrated during placement — Test points are planned during component placement, not added at the end of PCB routing when space is scarce.
- BOM verification against lifecycle alerts — Every component is checked for availability and lifecycle status, with a second source systematically defined.
- 3D modelling and mechanical validation — A STEP export of the PCB is provided with every design for validation by the client's mechanical design office.
The concrete benefits for your production runs
Adopting a rigorous DFM approach delivers measurable benefits across three dimensions:
Fewer workshop returns
A DFM-compatible design significantly reduces soldering defects, misaligned components, and wiring errors. On projects we support from schematic through to volume production, the first-pass yield rate (boards passing test on the first attempt) regularly exceeds 98%.
Controlled production costs
Savings come from testing (automated ICT vs. manual testing), reduced workshop rework, and guaranteed component availability. On a run of 500 boards, a poorly managed BOM can generate cost overruns of 15 to 30% of the initial production cost.
Deadlines met
Avoiding a last-minute redesign or a wait for unavailable components means meeting the time-to-market schedule. In an industrial context where delivery deadlines are contractual, this reliability has direct value for our clients.
Do you have an electronic board project to bring to industrial production? Our design office integrates DFM from the very first scoping meeting. Contact us to discuss your project.