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IPC Annular Ring Formula:
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The IPC annular ring refers to the copper ring surrounding a drilled hole in a printed circuit board (PCB). It ensures proper electrical connection between the hole and the pad, and its width is critical for PCB reliability and manufacturability.
The calculator uses the IPC annular ring formula:
Where:
Explanation: The annular ring width is calculated as half the difference between the pad diameter and the hole diameter, ensuring sufficient copper remains around the hole for reliable electrical connections.
Details: Proper annular ring width is crucial for PCB reliability, preventing drill breakout, ensuring good solder joints, and meeting IPC standards for manufacturing quality.
Tips: Enter pad diameter and hole diameter in the same units. Both values must be positive, and pad diameter must be greater than hole diameter for valid calculation.
Q1: What are typical IPC annular ring requirements?
A: IPC standards typically require a minimum annular ring of 0.05mm (2 mil) for most applications, but specific requirements may vary based on PCB class and design.
Q2: What happens if annular ring is too small?
A: Insufficient annular ring can lead to drill breakout, poor solder joints, and reduced reliability in the finished PCB assembly.
Q3: Can annular ring be different for different layers?
A: Yes, annular ring requirements may vary between inner and outer layers, with typically stricter requirements for outer layers where components are soldered.
Q4: How does drill tolerance affect annular ring?
A: Drill tolerance must be accounted for in annular ring calculation to ensure minimum requirements are met even with worst-case drill misalignment.
Q5: Are there different calculations for plated vs non-plated holes?
A: Yes, plated through holes require consideration of plating thickness in annular ring calculations, while non-plated holes have different requirements.