Thermal relief for through-hole pads in PCB Design - Real Business Scenario

Scenario Mode

👤 Your Role: You are a PCB design engineer working on a new circuit board layout.

📋 Request: Your manager wants you to analyze the impact of thermal relief patterns on soldering quality and heat dissipation for through-hole pads.

📊 Data: You have data on pad sizes, thermal relief spoke counts, solder joint temperatures, and heat dissipation measurements from test boards.

🎯 Deliverable: Create a report with charts showing how different thermal relief designs affect solder joint temperature and heat dissipation, and recommend the best pattern.

Sample Data

Pad Size (mm)	Spoke Count	Solder Joint Temp (°C)	Heat Dissipation (W)
1.0	4	230	1.2
1.0	6	225	1.4
1.0	8	220	1.5
1.5	4	235	1.3
1.5	6	228	1.6
1.5	8	222	1.7
2.0	4	240	1.4
2.0	6	230	1.8
2.0	8	225	2.0

1

Step 1: Organize the data by pad size and spoke count to prepare for analysis.

Create a pivot table with Rows = Pad Size (mm), Columns = Spoke Count, Values = Average of Solder Joint Temp (°C) and Average of Heat Dissipation (W).

Expected Result

Pivot table showing average solder joint temperature and heat dissipation for each pad size and spoke count combination.

2

Step 2: Create a line chart to visualize how solder joint temperature changes with spoke count for each pad size.

X-axis = Spoke Count, Y-axis = Average Solder Joint Temp (°C), Series = Pad Size (mm).

Expected Result

Line chart showing decreasing solder joint temperature as spoke count increases for all pad sizes.

3

Step 3: Create a second line chart to visualize heat dissipation changes with spoke count for each pad size.

X-axis = Spoke Count, Y-axis = Average Heat Dissipation (W), Series = Pad Size (mm).

Expected Result

Line chart showing increasing heat dissipation as spoke count increases for all pad sizes.

4

Step 4: Calculate the percentage change in solder joint temperature and heat dissipation from 4 spokes to 8 spokes for each pad size.

Percentage Change = ((Value at 8 spokes - Value at 4 spokes) / Value at 4 spokes) * 100 for both metrics.

Expected Result

Table showing percentage decrease in solder joint temperature and percentage increase in heat dissipation for each pad size.

5

Step 5: Summarize findings and recommend the optimal spoke count balancing soldering quality and heat dissipation.

Review charts and percentage changes to identify spoke count with best trade-off.

Expected Result

Recommendation to use 6 spokes for best balance between lower solder joint temperature and improved heat dissipation.

Final Result

Thermal Relief Analysis Report

Pad Size (mm) | Spokes | Solder Temp (°C) | Heat Dissipation (W)
---------------------------------------------------------------
1.0           | 4      | 230              | 1.2
1.0           | 6      | 225              | 1.4
1.0           | 8      | 220              | 1.5
1.5           | 4      | 235              | 1.3
1.5           | 6      | 228              | 1.6
1.5           | 8      | 222              | 1.7
2.0           | 4      | 240              | 1.4
2.0           | 6      | 230              | 1.8
2.0           | 8      | 225              | 2.0

Key Insights:
- Increasing spoke count reduces solder joint temperature by up to 6.25%.
- Heat dissipation improves by up to 42.9% with more spokes.
- 6 spokes offer a good balance between thermal relief and heat transfer.

Recommendation:
Use 6 spokes for thermal relief on through-hole pads to optimize soldering quality and heat management.

✓Solder joint temperature decreases as spoke count increases, improving soldering quality.

✓Heat dissipation increases with more spokes, enhancing thermal performance.

✓6 spokes provide the best balance between temperature reduction and heat dissipation.

✓Larger pad sizes show greater improvements with increased spoke count.

Bonus Challenge

Analyze how different spoke widths affect solder joint temperature and heat dissipation for a fixed spoke count.

Show Hint

Add spoke width as a new variable in your data and create similar pivot tables and charts to compare its impact.