Come risolvere i problemi di sovrapposizione tra maschera di saldatura e strati serigrafici nella progettazione di PCB

In TOPFAST’s Progettazione PCB review and manufacturing experience, overlap between solder mask and silkscreen layers is one of the common design issues that can lead to soldering defects and affect product reliability. Properly addressing this issue is key to ensuring PCB manufacturability and final quality.

Core Risks Posed by Overlap Issues

1. Soldering Quality Risks
   Silkscreen ink is insulating. If it covers solder pads, it directly hinders effective bonding between the solder and the copper layer. This can lead to cold solder joints, insufficient solder joint strength, or incomplete soldering, potentially causing failures during vibration or high/low-temperature cycling tests.
2. Manufacturing Process Conflicts
   In the PCB production process, the solder mask layer usually has process priority. Silkscreen ink in overlapping areas may be etched or partially removed, resulting in incomplete, blurred, or misaligned characters, affecting assembly accuracy and subsequent repair and debugging.
3. Reduction in Product Professionalism
   Messy, overlapping silkscreen not only reduces the readability of the circuit board but also reflects oversight during the design phase, impacting the overall image of the product.

Systematic Solutions Recommended by TOPFAST

I. Preventive Rule Setting

• Key Rule Settings:
  In EDA tools such as Altium Designer or Allegro, it is essential to establish the “Silk to Solder Mask Clearance” rule. TOPFAST recommends:
  • General Designs: Minimum clearance ≥ 0.15mm (6mil)
  • High-Density Designs: Can be negotiated down to 0.1mm (4mil), but process capability must be confirmed in advance
  • High-Frequency/High-Voltage Boards: Recommend ≥ 0.2mm (8mil) to ensure safe clearance
• Rule Implementation Example (Altium Designer):
  1. Design → Rules → Produzione → SilkToSolderMaskClearance
  2. Set matching objects (First Object: Silk layer; Second Object: Solder Mask layer)
  3. Run a comprehensive Design Rule Check (DRC) after applying the rule

II. Design Verification & Manual Refinement

• Layer Stack Visual Inspection:
  In the PCB editor, display only the silkscreen layer + solder mask/pad layer and use colour contrast to visually identify overlapping areas.
• DRC Error Closed-Loop Processing:
  Manually review and adjust each overlapping point flagged by DRC, including:
  • Moving/Rotating character positions
  • Simplifying non-essential markings (retain designators, polarity, and interface labels only)
  • Standardising character orientation and font size (recommended line width/height of 5/30mil)

III. Manufacturing Collaboration Recommendations with TOPFAST

1. Confirm Process Details in Advance
   Before submitting board files, provide design files to TOPFAST for a Design for Manufacturability (DFM) Review. We will provide feedback on:
   • Optimal silkscreen-to-solder mask spacing parameters for your design
   • Process adjustment suggestions for specific materials/surface finishes
   • Silkscreen optimisation solutions for high-density areas
2. Utilise the “Solder Mask Priority” Principle
   During production, TOPFAST strictly adheres to the principle of “solder mask opening accuracy taking priority over silkscreen integrity” to ensure pads remain absolutely clean. It is recommended to treat active silkscreen avoidance of pads as an iron rule during design.
3. Standardised Design Output
   It is recommended to deliver files in IPC-2581 o Gerber X2 format with layer property descriptions to reduce interpretation errors at the production end.

TOPFAST Process Capability Reference Table

conclusioni

At TOPFAST, we believe that “design determines the manufacturing ceiling.” Regarding the overlap issue between the solder mask and the silkscreen layers, we recommend:

1. Lato design: Strictly enforce clearance rules and utilise DRC tools to eliminate risks at the design source.
2. Review Side: Use TOPFAST’s free online DFM inspection tool or submit files for expert review to obtain customised recommendations.
3. Production Side: Clearly label clearance requirements for critical areas and select design parameters that match TOPFAST’s process capabilities.

Through the dual assurance of design prevention + manufacturing collaboration, TOPFAST helps you eliminate “minor issues” like silkscreen overlap, improving the first-pass yield of PCBs and the reliability of end products.

Need TOPFAST to provide tailored recommendations for silkscreen clearance rules for your design?
Feel free to upload your design files or contact us for a free DFM analysis report. We will provide optimisation solutions based on actual production capabilities.

Common Core Issues in PCB Solder Mask Design

In PCB manufacturing, solder mask design directly impacts product reliability and yield. Based on manufacturing experience, TOPFAST summarises the five most common solder mask design issues beyond silkscreen overlap, along with solutions:

Need complete solder mask design rules or DFM review?
Upload design files to TOPFAST for customised solutions based on production expertise.