Silkscreen placement rules 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 a report showing how silkscreen markings are placed on the PCB to avoid overlaps and ensure readability.

📊 Data: You have data on component positions, silkscreen text locations, and keepout zones where silkscreen cannot be placed.

🎯 Deliverable: Create a dashboard that visualizes silkscreen placement relative to components and keepout zones, and calculates the percentage of silkscreen text correctly placed without overlap.

Sample Data

ComponentID	X_Pos	Y_Pos	Silkscreen_X	Silkscreen_Y	Keepout_X1	Keepout_Y1	Keepout_X2	Keepout_Y2
R1	10	20	11	21	9	19	12	22
C1	30	40	31	41	29	39	32	42
U1	50	60	55	65	48	58	52	62
L1	70	80	71	81	69	79	72	82
D1	90	100	95	105	88	98	92	102
Q1	110	120	111	121	109	119	112	122
R2	130	140	131	141	128	138	132	142
C2	150	160	151	161	148	158	152	162

1

Step 1: Create a table that checks if silkscreen text is inside the keepout zone for each component.

For each row, check if Silkscreen_X is between Keepout_X1 and Keepout_X2 AND Silkscreen_Y is between Keepout_Y1 and Keepout_Y2. If yes, mark 'Overlap', else 'Clear'.

Expected Result

R1: Overlap, C1: Overlap, U1: Overlap, L1: Overlap, D1: Overlap, Q1: Overlap, R2: Overlap, C2: Overlap

2

Step 2: Calculate the percentage of silkscreen texts placed without overlap.

Count of 'Clear' silkscreen placements divided by total components times 100.

Expected Result

0% (0 out of 8 components have clear silkscreen placement)

3

Step 3: Create a scatter plot showing component positions and silkscreen text positions with color coding for overlap status.

X-axis: Component X_Pos, Y-axis: Component Y_Pos; Overlay silkscreen positions with different color for 'Overlap' (red) and 'Clear' (green).

Expected Result

Scatter plot with red dots for overlap near components (no green dots since no clear placements).

4

Step 4: Add a filter to the dashboard to show only components with silkscreen overlap.

Filter visual to show only rows where silkscreen status = 'Overlap'.

Expected Result

Dashboard updates to show only components where silkscreen text overlaps keepout zones.

5

Step 5: Summarize findings in a card visual showing total components, overlaps, and clear placements.

Create three cards: Total Components = 8, Overlaps = 8, Clear = 0.

Expected Result

Cards display correct counts matching data.

Final Result

Scatter Plot

↓

Cards

↓

Filter

✓100% of the silkscreen texts overlap with keepout zones and need repositioning.

✓No clear silkscreen placements found in the current data.

✓Using this dashboard helps quickly identify and fix silkscreen placement issues.

Bonus Challenge

Add a calculated measure that suggests new silkscreen positions by offsetting overlapping texts by +5 units on X and Y axes.

Show Hint

Use a conditional formula: If overlap, new position = Silkscreen_X + 5, Silkscreen_Y + 5; else original position.

Practice

1. What is the main reason for following silkscreen placement rules on a PCB?

easy

A. To make the PCB waterproof

B. To increase the electrical conductivity of the PCB

C. To keep markings clear and avoid covering pads or vias

D. To reduce the cost of PCB manufacturing

Solution

1. Step 1: Understand the purpose of silkscreen on PCB

   Silkscreen provides markings like labels and component outlines on the PCB surface.

2. Step 2: Identify the importance of placement rules

   Placement rules ensure these markings do not cover pads or vias, keeping them clear and readable.

3. Final Answer:

   To keep markings clear and avoid covering pads or vias -> Option C

4. Quick Check:

   Silkscreen clarity = avoid covering pads/vias [OK]

Hint: Silkscreen must not cover pads or vias to stay clear [OK]

Common Mistakes:

• Thinking silkscreen affects electrical conductivity
• Assuming silkscreen reduces manufacturing cost
• Believing silkscreen makes PCB waterproof

2. Which of the following is the correct minimum clearance distance for silkscreen from pads and vias?

easy

A. 0.05 mm

B. 0.15 mm

C. 0.5 mm

D. 1.5 mm

Solution

1. Step 1: Recall the standard clearance rule

   The minimum clearance to keep silkscreen from pads and vias is 0.15 mm to avoid overlap.

2. Step 2: Compare options with the rule

   Only 0.15 mm matches the recommended clearance; others are either too small or too large.

3. Final Answer:

   0.15 mm -> Option B

4. Quick Check:

   Minimum clearance = 0.15 mm [OK]

Hint: Remember 0.15 mm clearance keeps silkscreen clear [OK]

Common Mistakes:

• Choosing too small clearance causing silkscreen overlap
• Selecting too large clearance wasting PCB space
• Confusing clearance units

3. Given a PCB pad at coordinates (10,10) with a radius of 1 mm, which silkscreen placement is correct if the silkscreen line is at (10,11.1)?

medium

A. Incorrect, because silkscreen is too close to pad

B. Correct, because silkscreen is 0.1 mm away from pad edge

C. Correct, because silkscreen is more than 0.15 mm away from pad edge

D. Incorrect, because silkscreen overlaps the pad

Solution

1. Step 1: Calculate distance from pad edge to silkscreen

   Pad radius is 1 mm, so pad edge at y=11. Silkscreen at y=11.1 is 0.1 mm away.

2. Step 2: Compare distance with minimum clearance

   Minimum clearance is 0.15 mm, but silkscreen is only 0.1 mm away, which is too close.

3. Final Answer:

   Incorrect, because silkscreen is too close to pad -> Option A

4. Quick Check:

   Distance 0.1 mm < 0.15 mm clearance [OK]

Hint: Check if silkscreen is at least 0.15 mm from pad edge [OK]

Common Mistakes:

• Ignoring pad radius when measuring distance
• Assuming 0.1 mm clearance is enough
• Confusing center-to-center distance with edge clearance

4. A designer placed silkscreen text overlapping a via hole on a PCB. What is the best fix to comply with silkscreen placement rules?

medium

A. Increase the font size of the silkscreen text

B. Place silkscreen text directly on the via hole

C. Remove the via hole

D. Move the silkscreen text at least 0.15 mm away from the via hole edge

Solution

1. Step 1: Identify the problem with silkscreen placement

   Silkscreen overlapping a via hole violates the minimum clearance rule.

2. Step 2: Apply the correct placement rule

   Moving the silkscreen text at least 0.15 mm away from the via hole edge fixes the issue.

3. Final Answer:

   Move the silkscreen text at least 0.15 mm away from the via hole edge -> Option D

4. Quick Check:

   Maintain 0.15 mm clearance from vias [OK]

Hint: Always keep silkscreen 0.15 mm away from vias [OK]

Common Mistakes:

• Increasing font size does not fix overlap
• Removing via hole is not practical
• Ignoring clearance rules

5. You need to place silkscreen markings on a PCB with dense components and many vias. Which approach best follows silkscreen placement rules while maximizing readability?

hard

A. Place silkscreen only on open PCB areas, maintain 0.15 mm clearance, and use readable fonts

B. Place silkscreen over pads to save space and use small fonts

C. Ignore clearance rules and place silkscreen anywhere for maximum labels

D. Remove silkscreen markings to avoid placement issues

Solution

1. Step 1: Understand constraints of dense PCB layout

   Dense components and vias limit space for silkscreen markings.

2. Step 2: Apply silkscreen placement rules for clarity

   Placing silkscreen only on open areas, keeping 0.15 mm clearance, and using readable fonts ensures markings are clear and compliant.

3. Final Answer:

   Place silkscreen only on open PCB areas, maintain 0.15 mm clearance, and use readable fonts -> Option A

4. Quick Check:

   Clear markings + clearance + readable fonts = Place silkscreen only on open PCB areas, maintain 0.15 mm clearance, and use readable fonts [OK]

Hint: Use open areas, 0.15 mm clearance, and readable fonts [OK]

Common Mistakes:

• Placing silkscreen over pads or vias
• Using too small fonts reducing readability
• Removing silkscreen entirely