Mounting hole placement in PCB Design - Real Business Scenario

Scenario Mode

👤 Your Role: You are a PCB design analyst at an electronics manufacturing company.

📋 Request: Your manager wants a report showing the optimal mounting hole placements for a new PCB design to ensure mechanical stability and compatibility with the enclosure.

📊 Data: You have a dataset containing PCB dimensions, enclosure mounting points coordinates, and recommended hole sizes.

🎯 Deliverable: Create a dashboard that visualizes the PCB outline, enclosure mounting points, and suggested mounting hole positions with their sizes.

Sample Data

PCB_Length_mm	PCB_Width_mm	Enclosure_Point_X_mm	Enclosure_Point_Y_mm	Recommended_Hole_Diameter_mm
100	80	5	5	3
100	80	95	5	3
100	80	95	75	3
100	80	5	75	3

1

Step 1: Load the PCB dimensions and enclosure mounting points data into your BI tool.

Import the sample_data table with columns: PCB_Length_mm, PCB_Width_mm, Enclosure_Point_X_mm, Enclosure_Point_Y_mm, Recommended_Hole_Diameter_mm.

Expected Result

Data table with 4 rows and 5 columns loaded correctly.

2

Step 2: Create a scatter plot to visualize enclosure mounting points on the PCB outline.

X-axis: Enclosure_Point_X_mm, Y-axis: Enclosure_Point_Y_mm, add point size based on Recommended_Hole_Diameter_mm.

Expected Result

Scatter plot showing 4 mounting points positioned near the PCB corners with circle sizes representing hole diameters.

3

Step 3: Add a rectangle shape representing the PCB outline using PCB_Length_mm and PCB_Width_mm.

Draw rectangle from (0,0) to (PCB_Length_mm, PCB_Width_mm) behind the scatter plot points.

Expected Result

PCB outline visible as a rectangle with mounting points inside near corners.

4

Step 4: Create calculated measures to confirm hole placements are within PCB boundaries.

Measure: Is_X_Valid = IF(Enclosure_Point_X_mm >= 0 && Enclosure_Point_X_mm <= PCB_Length_mm, "Yes", "No") Measure: Is_Y_Valid = IF(Enclosure_Point_Y_mm >= 0 && Enclosure_Point_Y_mm <= PCB_Width_mm, "Yes", "No")

Expected Result

All mounting points have Is_X_Valid and Is_Y_Valid as "Yes".

5

Step 5: Add tooltips to the scatter plot points showing hole diameter and coordinates.

Tooltip fields: Enclosure_Point_X_mm, Enclosure_Point_Y_mm, Recommended_Hole_Diameter_mm.

Expected Result

Hovering over points displays mounting hole details.

6

Step 6: Create a summary card showing total number of mounting holes and average hole diameter.

Total Holes = COUNTROWS(sample_data) Average Diameter = AVERAGE(Recommended_Hole_Diameter_mm)

Expected Result

Summary card shows Total Holes = 4 and Average Diameter = 3 mm.

Final Result

PCB Outline (100mm x 80mm)
+------------------------------------+
| o                                o |
|                                    |
|                                    |
|                                    |
|                                    |
| o                                o |
+------------------------------------+
'o' = Mounting holes sized 3mm diameter

Summary:
Total Mounting Holes: 4
Average Hole Diameter: 3 mm

✓All mounting holes are placed near the PCB corners within the PCB boundaries.

✓Hole diameters are consistent at 3 mm as recommended.

✓The placement ensures mechanical stability and fits the enclosure mounting points.

Bonus Challenge

Add a filter to the dashboard to allow selecting different PCB sizes and dynamically update mounting hole placements.

Show Hint

Use slicers or dropdown filters connected to PCB_Length_mm and PCB_Width_mm fields to update visuals.

Practice

1. What is the main purpose of mounting holes on a PCB?

easy

A. To cool down the PCB components

B. To securely fix the PCB inside a device

C. To provide electrical connections

D. To increase the PCB size

Solution

1. Step 1: Understand mounting hole function

   Mounting holes are designed to hold the PCB in place inside a device.

2. Step 2: Differentiate from other PCB features

   Electrical connections and cooling are done by traces and heat sinks, not mounting holes.

3. Final Answer:

   To securely fix the PCB inside a device -> Option B

4. Quick Check:

   Mounting holes = Secure fixing [OK]

Hint: Mounting holes hold the board physically [OK]

Common Mistakes:

• Confusing mounting holes with electrical vias
• Thinking holes cool components
• Assuming holes increase PCB size

2. Which of the following is the correct way to specify a mounting hole position on a PCB?

easy

A. Using x and y coordinates on the board

B. Using the hole diameter only

C. Using the color of the hole

D. Using the number of pins

Solution

1. Step 1: Identify position parameters

   Mounting holes are placed by specifying their x and y coordinates on the PCB layout.

2. Step 2: Exclude irrelevant options

   Hole diameter defines size, color and pin count are unrelated to position.

3. Final Answer:

   Using x and y coordinates on the board -> Option A

4. Quick Check:

   Position = x,y coordinates [OK]

Hint: Positions need x and y coordinates [OK]

Common Mistakes:

• Confusing hole size with position
• Using color or pins to locate holes
• Ignoring coordinate system

3. Given a PCB with mounting holes at coordinates (10, 20), (50, 20), (10, 60), and (50, 60), what is the distance between the two holes at (10, 20) and (50, 20)?

medium

A. 30 units

B. 60 units

C. 50 units

D. 40 units

Solution

1. Step 1: Identify coordinates of the two holes

   The holes are at (10, 20) and (50, 20), so they share the same y-coordinate.

2. Step 2: Calculate horizontal distance

   Distance = |50 - 10| = 40 units since y is the same.

3. Final Answer:

   40 units -> Option D

4. Quick Check:

   Distance = 50 - 10 = 40 [OK]

Hint: Subtract x values when y is equal [OK]

Common Mistakes:

• Calculating vertical distance instead
• Adding coordinates instead of subtracting
• Mixing x and y values

4. A PCB designer placed mounting holes at (15, 25), (15, 75), (65, 25), but forgot one hole to complete the rectangle. Which coordinate should be added to complete the mounting hole placement?

medium

A. (65, 75)

B. (15, 50)

C. (40, 75)

D. (65, 50)

Solution

1. Step 1: Identify existing hole coordinates

   Holes are at (15, 25), (15, 75), and (65, 25). Two share x=15, two share y=25.

2. Step 2: Find missing corner to form rectangle

   The missing corner must have x=65 and y=75 to complete the rectangle.

3. Final Answer:

   (65, 75) -> Option A

4. Quick Check:

   Opposite corner = (65, 75) [OK]

Hint: Complete rectangle with missing opposite corner [OK]

Common Mistakes:

• Choosing midpoint instead of corner
• Mixing x and y values incorrectly
• Ignoring rectangle shape

5. You need to place four mounting holes on a PCB sized 100x80 units. The holes must be 5 units from each edge. What are the correct coordinates for the holes?

hard

A. (5, 0), (95, 0), (5, 80), (95, 80)

B. (0, 0), (100, 0), (0, 80), (100, 80)

C. (5, 5), (95, 5), (5, 75), (95, 75)

D. (10, 10), (90, 10), (10, 70), (90, 70)

Solution

1. Step 1: Calculate hole positions from edges

   Each hole is 5 units from left/right edges (x=5 and x=100-5=95) and top/bottom edges (y=5 and y=80-5=75).

2. Step 2: List all four corner coordinates

   Holes are at (5,5), (95,5), (5,75), and (95,75).

3. Final Answer:

   (5, 5), (95, 5), (5, 75), (95, 75) -> Option C

4. Quick Check:

   Edges minus 5 units = hole coords [OK]

Hint: Subtract 5 from edges for hole positions [OK]

Common Mistakes:

• Using 0 or full edge coordinates
• Adding 10 units instead of 5
• Mixing x and y values