Open circuits and short circuits are common issues that PCB manufacturers encounter, often leading to shipment delays, customer complaints, and costly production interruptions. With over 20 years of experience in the PCB manufacturing industry—covering production, quality management, process optimization, and cost control—I have gathered valuable insights into addressing these challenges. Below is a summary of the main causes of PCB open circuits and corresponding improvement methods, which I hope will serve as a helpful reference for production and quality management personnel in the industry.

Main Causes of PCB Open Circuits and Improvement Methods

PCB open circuits primarily result from the following causes:

1. Open Circuits Due to Exposed Substrate

Causes:

• Scratched copper clad laminate (CCL) before warehousing.
• Scratches during the cutting process.
• Scratches caused by drill bits during the drilling process.
• Damage during transportation.
• Scratches on the copper surface during copper deposition and full-board electroplating.
• Damage from improper handling when passing through leveling or grinding machines.

Improvement Methods:

1.1 Scratches Before Warehousing

• Inspection: Implement thorough IQC (Incoming Quality Control) inspections. Check for scratches or exposed substrate on the copper clad laminate before entering the warehouse.
• Action: If scratches are found, contact the supplier promptly and determine appropriate corrective action based on the extent of the damage.

1.2 Scratches During Cutting

• Cause: Hard or sharp objects on the cutting machine table can scratch the copper foil during the cutting process.
• Solution: Clean the cutting table carefully before each use to ensure it’s free from debris and sharp objects that can damage the copper surface.

1.3 Scratches by Drill Bit During Drilling

• Cause: Worn drill nozzles, debris in the nozzle, improper nozzle installation, or insufficient lift height during drilling can cause the drill bit to scratch the copper foil.
• Solutions:
  • Replace worn drill nozzles based on their usage record or wear level.
  • Clean the nozzle regularly following proper operational procedures.
  • Ensure the drill is installed correctly, and the drill height is set appropriately to prevent surface damage.

1.4 Damage During Transportation

• Cause: Boards may be scratched when too many are transported at once, dragged instead of lifted, or handled roughly during reorganization.
• Solution: Ensure that personnel handling PCBs lift them without dragging and place them neatly to avoid board-to-board friction.

1.5 Scratches During Stacking After Copper Deposition

• Cause: Improper stacking of boards after copper deposition can lead to the corners impacting the board surface due to gravitational force, causing scratches.
• Solution: Handle boards with care during stacking, using appropriate methods to reduce the risk of impact on the board surface.

1.6 Scratches from Horizontal Grinding Machine

• Causes:
  • Contact between the grinding machine’s baffle and the board surface.
  • Sharp objects or damaged stainless steel transmission shafts can scratch the board.
• Solutions:
  • Regularly inspect and maintain machine baffles, ensuring they do not have protrusions that can damage the PCB.
  • Repair or replace damaged transmission shafts to prevent surface scratching.

Open circuits in PCBs can often be traced back to mechanical damage during various stages of production—whether from scratched copper clad laminate, improper handling, or worn tools. Implementing the outlined improvement methods can significantly reduce the occurrence of these issues, improving both product quality and production efficiency.

As a leading PCB manufacturer, members of our printed circuit board (PCB) design service team are practical partners working with you on every project and can help you achieve your goals at any time. They can complement your engineering expertise, which helps speed up time to market, reduce the time from concept to production, and ensure that quality is integrated into the manufacturing process to maximize your profits.