Drill file generation in PCB Design - Real Business Scenario

Scenario Mode

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

📋 Request: Your manager wants you to generate drill files for a new printed circuit board design to send to the fabrication house.

📊 Data: You have the PCB layout data including the coordinates and sizes of all drill holes for vias and component leads.

🎯 Deliverable: You need to produce a complete drill file in the standard Excellon format that lists all drill hole locations and sizes.

Sample Data

Hole ID	X Coordinate (mm)	Y Coordinate (mm)	Diameter (mm)	Type
H1	10.0	15.0	0.8	Via
H2	20.0	15.0	1.0	Component Lead
H3	30.0	25.0	0.8	Via
H4	40.0	35.0	1.2	Component Lead
H5	50.0	45.0	0.8	Via
H6	60.0	55.0	1.0	Component Lead
H7	70.0	65.0	0.8	Via
H8	80.0	75.0	1.2	Component Lead

1

Step 1: Organize the drill holes by diameter to group similar drill sizes together.

Sort the sample data by 'Diameter (mm)' column in ascending order.

Expected Result

Holes grouped as 0.8 mm, 1.0 mm, and 1.2 mm diameters.

2

Step 2: Assign a tool number to each unique drill diameter for the drill file header.

Map 0.8 mm to T01, 1.0 mm to T02, 1.2 mm to T03.

Expected Result

Tool list: T01=0.8 mm, T02=1.0 mm, T03=1.2 mm.

3

Step 3: Format the drill hole coordinates and tool assignments into Excellon drill file commands.

For each hole, write: 'X' + X coordinate in mils + 'Y' + Y coordinate in mils + 'T' + tool number. Use 1 mm = 39.37 mils.

Expected Result

Lines like 'X393Y591T01' for hole H1 at (10.0 mm, 15.0 mm) with 0.8 mm drill.

4

Step 4: Create the drill file header with units, tool definitions, and start commands.

Write header lines: 'M48', 'INCH', tool definitions (e.g., 'T01C0.0315'), and '%' to start data.

Expected Result

Header with correct units and tool sizes in inches.

5

Step 5: Add the drill hole commands from step 3 under the header.

List all drill hole commands sequentially.

Expected Result

Drill commands for all holes listed under header.

6

Step 6: Add the drill file footer to end the file properly.

Write 'M30' to indicate end of program.

Expected Result

Drill file ends with 'M30'.

7

Step 7: Verify the drill file by checking coordinates and tool assignments match the sample data.

Cross-check each hole's coordinates and tool number with original data.

Expected Result

All holes correctly represented with proper tool numbers and coordinates.

Final Result

Drill File Preview:

M48
INCH
T01C0.0315
T02C0.0394
T03C0.0472
%
X394Y591T01
X787Y591T02
X1181Y984T01
X1575Y1378T03
X1969Y1772T01
X2362Y2165T02
X2756Y2559T01
X3150Y2953T03
M30

✓Drill holes are grouped by size for efficient tool changes.

✓Coordinates converted from millimeters to mils for Excellon format.

✓Drill file includes proper header, tool definitions, hole locations, and footer.

Bonus Challenge

Create a drill map visualization showing hole locations color-coded by drill size.

Show Hint

Use a simple scatter plot with X and Y coordinates, and assign colors based on diameter.