PCB Prototyping Pitfalls: 5 Must-Check Details for Engineers to Avoid Wasting Time and Money

1. Introduction: Have You Experienced the Pain of Prototyping Failures?

Many engineers spend a week on PCB design, only to have the prototype fail due to a small oversight during prototyping—like forgetting to mark silkscreen direction (causing reversed component soldering) or choosing the wrong board material (resulting in insufficient high-temperature resistance). PCB prototyping costs little, but repeated rework seriously delays project progress. Today, we’ll share 5 details to check before prototyping.

2. 5 Details to Check Before Prototyping

1. Detail 1: Silkscreen "Clear and Non-Overlapping" to Avoid Soldering Errors

    

   Silkscreen guides soldering. Blurry, overlapping silkscreen or incorrect polarity markings (for diodes, capacitors) cause reversed component soldering and direct board failure.

    

   Check Method: Enable the "3D View" in design software (e.g., Altium) to see if silkscreen covers pads or overlaps with other components. Focus on checking "±" or "PIN1" markings for polar components to ensure clarity.

2. Detail 2: Board Material "Matches Application Scenarios"—Don’t Blindly Choose Expensive Ones

    

   Different scenarios require different PCB materials. For example, FR-4 works for ordinary consumer electronics, while FR-4 high-Tg (Tg ≥170℃) is needed for industrial high-temperature environments (temperature >85℃), and PTFE high-frequency materials for high-frequency communications (e.g., 5G). Choosing the wrong material causes PCB deformation or performance degradation in use.

    

   Selection Advice: Use FR-4 (Tg 130-150℃) for general projects, FR-4 high-Tg (Tg ≥170℃) for industrial projects, and PTFE or Rogers materials for high-frequency projects. Clearly note the material model and parameters in the prototype order to avoid wrong deliveries.

3. Detail 3: Copper Thickness "Meets Current Requirements" to Avoid Board Burning

    

   Copper thickness determines the PCB’s current-carrying capacity. Too-thin copper causes copper foil overheating and burning when high current passes through. For example, 1A current requires at least 1oz (35μm) copper, and 2A requires 2oz (70μm). Many beginners default to 1oz copper, ignoring current needs.

    

   Calculation Method: Use the formula "Current Capacity (A) = Copper Thickness (oz) × Trace Width (mm) × 0.8". For example, a 1oz copper trace with 2mm width has a current capacity of ~1.6A. If current exceeds 2A, switch to 2oz copper or widen the trace.

4. Detail 4: Hole Size "Matches Component Pins" to Avoid Insertion Issues

    

   Too-small through-holes or pin holes prevent component insertion; too-large holes cause cold soldering. For example, for a component with 0.8mm pins, the pin hole diameter should be ~1.0mm, and the through-hole diameter ~0.6mm (with a 1.2mm pad diameter).

    

   Check Method: Refer to the component datasheet in the design software to confirm pin diameter. Make pin holes 0.2-0.3mm larger than the pin diameter, and through-holes 0.1-0.2mm larger. Avoid holes smaller than 0.3mm (difficult for manufacturers to process, prone to drill breakage).

5. Detail 5: "Panelized Design" Reserves "Process Edges" for Easy Production

    

   Omitting process edges for panelized prototyping (multiple small PCBs combined) makes machine soldering impossible—only manual soldering is feasible, which is inefficient and error-prone.

    

   Design Requirement: Reserve 5-10mm process edges around the panel. Add positioning holes (3mm diameter, no copper) on the edges for machine alignment. Connect PCBs in the panel with "V-CUT" or "mouse-bite holes" for easy separation later.

3. Conclusion: The "Final Step" Before Prototyping—Confirm with the Manufacturer

Before prototyping, send Gerber files to the manufacturer and ask their engineers to check for design issues (e.g., whether hole size, copper thickness, and material meet processing capabilities). Many manufacturers offer free DFM (Design for Manufacturability) checks, which effectively avoid rework. Remember: Spending 10 minutes checking before prototyping is better than 10 days of rework later.