Drill file generation in PCB Design - Cell-by-Cell Formula Trace

Sample Data

This table lists the holes to be drilled on a PCB with their IDs, X and Y coordinates in millimeters, and hole diameters.

Cell	Value
A1	Hole ID
B1	X (mm)
C1	Y (mm)
D1	Diameter (mm)
A2	H1
B2	10
C2	15
D2	0.8
A3	H2
B3	20
C3	25
D3	1.2
A4	H3
B4	30
C4	35
D4	0.6

Formula Trace

GENERATE_DRILL_FILE(A2:D4)

Step 1: Read hole data from cells A2:D4

Step 2: Convert coordinates and diameters to drill file format (inches, format 2.4)

Step 3: Assign tool numbers based on diameter

Step 4: Create drill file lines for each hole

Step 5: Combine all lines into final drill file content

Cell Reference Map

    A       B       C       D
1 | Hole ID | X (mm) | Y (mm) | Diameter (mm)
2 |   H1    |  10    |  15    |    0.8
3 |   H2    |  20    |  25    |    1.2
4 |   H3    |  30    |  35    |    0.6

References: The formula reads all cells from A2 to D4 to get hole data.

The drill file generation formula uses the hole ID, X and Y coordinates, and diameter from cells A2 to D4.

Result

    A
1 | Drill File Output
2 | M48
3 | ;Layer_Color=9474304
4 | ;FILE_FORMAT=2:4
5 | T01C0.0315
6 | X03937Y05906
7 | T02C0.0472
8 | X07874Y09843
9 | T03C0.0236
10| X11811Y13779
11| M30

This shows the drill file content generated from the hole data. It includes header, tool definitions with diameters, hole coordinates, and footer.

Sheet Trace Quiz - 3 Questions

What unit conversion is applied when generating the drill file?

A Millimeters to inches

B Inches to millimeters

C Centimeters to inches

D No conversion

Key Result

GENERATE_DRILL_FILE reads hole data, converts units, assigns tools by diameter, and formats drill commands.

Practice

1. What is the main purpose of a drill file in PCB manufacturing?

easy

A. To specify the solder mask color

B. To provide instructions for drilling holes on the PCB

C. To define the copper layer layout

D. To list the components placement

Solution

1. Step 1: Understand the role of drill files

   Drill files contain instructions for drilling holes, including sizes and positions.

2. Step 2: Differentiate from other PCB files

   Other files define copper layers, solder mask, or component placement, not drilling.

3. Final Answer:

   To provide instructions for drilling holes on the PCB -> Option B

4. Quick Check:

   Drill file = hole instructions [OK]

Hint: Drill files tell machines where and how to drill holes [OK]

Common Mistakes:

• Confusing drill files with copper layer files
• Thinking drill files include component placement
• Assuming drill files control solder mask color

2. Which of the following is the correct format for specifying a drill tool in a drill file?

easy

A. DrillTool(1, 0.8)

B. Tool1:Diameter=0.8

C. T01C0.8 (Tool 1, 0.8 mm diameter)

D. 01T0.8D

Solution

1. Step 1: Recognize standard drill tool syntax

   Drill files use TxxCyy format where T is tool number and C is diameter.

2. Step 2: Compare options to standard

   T01C0.8 (Tool 1, 0.8 mm diameter) matches standard format; others do not follow typical drill file syntax.

3. Final Answer:

   T01C0.8 (Tool 1, 0.8 mm diameter) -> Option C

4. Quick Check:

   Tool format = TxxCyy [OK]

Hint: Look for T + number + C + diameter format [OK]

Common Mistakes:

• Using non-standard syntax like colons or parentheses
• Swapping tool number and diameter order
• Omitting the 'T' or 'C' letters

3. Given this drill file snippet:

T01C0.6
X10000Y20000
X15000Y25000
T02C1.0
X12000Y22000

What does this snippet specify?

medium

A. Tool 1 drills 0.6 mm holes at (1,2) and (1.5,2.5), Tool 2 drills 1.0 mm hole at (1.2,2.2)

B. Tool 1 drills 0.6 mm holes at (10000,20000) and (15000,25000), Tool 2 drills 1.0 mm hole at (12000,22000)

C. Tool 1 drills 6 mm holes at (10,20) and (15,25), Tool 2 drills 10 mm hole at (12,22)

D. Tool 1 drills 0.6 mm holes at (10,20) and (15,25), Tool 2 drills 1.0 mm hole at (12,22)

Solution

1. Step 1: Interpret tool and coordinates

   T01C0.6 means tool 1 drills 0.6 mm holes. Coordinates X10000Y20000 mean 10.000 mm, 20.000 mm (units usually in thousandths of mm).

2. Step 2: Convert coordinates to mm

   Coordinates like 10000 mean 10.000 mm, so (10000,20000) = (10,20) mm, similarly for others.

3. Final Answer:

   Tool 1 drills 0.6 mm holes at (10,20) and (15,25), Tool 2 drills 1.0 mm hole at (12,22) -> Option D

4. Quick Check:

   Coordinates in thousandths mm = (10,20) [OK]

Hint: Divide coordinates by 1000 to get mm positions [OK]

Common Mistakes:

• Reading coordinates as raw numbers without unit conversion
• Confusing tool numbers with hole sizes
• Assuming coordinates are in mm without scaling

4. You find this line in a drill file:
T01C0.8
X10000Y20000
X15000Y
What is the problem with this drill file snippet?

medium

A. The second coordinate line is incomplete, missing Y value

B. Tool number is missing in the second coordinate line

C. Hole diameter is not specified for the second coordinate

D. Coordinates use wrong letter case (should be lowercase)

Solution

1. Step 1: Check coordinate line format

   Coordinate lines must have both X and Y values, e.g., X15000Y25000.

2. Step 2: Identify missing value

   The line X15000Y lacks a Y value, making it incomplete and invalid.

3. Final Answer:

   The second coordinate line is incomplete, missing Y value -> Option A

4. Quick Check:

   Coordinates need both X and Y [OK]

Hint: Check each coordinate line has both X and Y values [OK]

Common Mistakes:

• Assuming missing Y is allowed
• Thinking tool number is needed on every coordinate line
• Believing letter case matters for coordinates

5. You need to generate a drill file for a PCB with two hole sizes: 0.5 mm and 1.2 mm. The holes are at positions (5,10), (15,20) for 0.5 mm, and (10,15) for 1.2 mm. Which drill file snippet correctly represents this?

hard

A. T01C0.5\nX5000Y10000\nX15000Y20000\nT02C1.2\nX10000Y15000

B. T01C0.5\nX5Y10\nX15Y20\nT02C1.2\nX10Y15

C. T01C0.5\nX0.5Y0.5\nX1.5Y2.0\nT02C1.2\nX1.0Y1.5

D. T1C0.5\nX5000Y10000\nX15000Y20000\nT2C1.2\nX10000Y15000

Solution

1. Step 1: Confirm tool and diameter format

   Tool lines must use 'TxxCyy' format, e.g., T01C0.5 for tool 1 with 0.5 mm diameter.

2. Step 2: Convert coordinates to drill file units

   Coordinates are in thousandths of mm, so (5,10) becomes X5000Y10000, etc.

3. Step 3: Check all lines for correctness

   T01C0.5\nX5000Y10000\nX15000Y20000\nT02C1.2\nX10000Y15000 uses correct tool format and coordinate scaling; others have wrong formats or units.

4. Final Answer:

   T01C0.5 X5000Y10000 X15000Y20000 T02C1.2 X10000Y15000 -> Option A

5. Quick Check:

   Tool format + coordinates in thousandths mm = T01C0.5\nX5000Y10000\nX15000Y20000\nT02C1.2\nX10000Y15000 [OK]

Hint: Multiply mm by 1000 and use TxxCyy format [OK]

Common Mistakes:

• Using mm directly without scaling
• Incorrect tool number format (missing leading zero)
• Mixing decimal and integer coordinate formats