Silkscreen placement rules in PCB Design - Dashboard Guide

Dashboard Mode - Silkscreen placement rules

Goal

Understand key rules for placing silkscreen on a PCB to ensure clear labeling without interfering with components or soldering.

Sample Data: Silkscreen Placement Guidelines

Rule ID	Description	Minimum Distance (mm)	Applies To	Example
1	Keep silkscreen away from pads to avoid soldering issues	0.25	Pads	Text 0.3mm from pad edge
2	Do not print silkscreen on solder mask openings	0	Solder mask openings	Silkscreen outside openings
3	Place reference designators clearly near components	1.0	Component body	Designator 1mm from component edge
4	Avoid silkscreen on component pads or pins	0.25	Component pads/pins	No silkscreen on pins
5	Use clear, legible font size for readability	1.0	Text height	Text height at least 1mm
6	Keep silkscreen within PCB outline	0	PCB edge	Text inside board edge

Dashboard Components

• KPI Card: Minimum Distance from Pads shows 0.25 mm as critical clearance to avoid solder bridging.
• Bar Chart: Silkscreen Distance Requirements visualizes minimum distances for each rule ID.
• Table: Silkscreen Rules Details lists all rules with descriptions and examples.
• Pie Chart: Rule Application Areas shows percentage distribution of rules by applies to category (Pads, Component body, etc.).

Formulas/Expressions

• KPI Card Value: MINX(FILTER('SilkscreenRules', 'SilkscreenRules'[Applies To] = SELECTEDVALUE('SilkscreenRules'[Applies To])), 'SilkscreenRules'[Minimum Distance (mm)])
• Bar Chart Y-axis: 'SilkscreenRules'[Minimum Distance (mm)], X-axis: 'SilkscreenRules'[Rule ID]
• Pie Chart Values: COUNTROWS(FILTER('SilkscreenRules', 'SilkscreenRules'[Applies To] = EARLIER('SilkscreenRules'[Applies To]))) grouped by 'SilkscreenRules'[Applies To]

Dashboard Layout

+----------------------+----------------------+
|      KPI Card        |      Pie Chart       |
|  Min Distance: 0.25  |  Rule Application    |
|                      |      Areas           |
+----------------------+----------------------+
|                      Bar Chart: Silkscreen Distance Requirements                      |
|                                                                                   |
+-----------------------------------------------------------------------------------+
|                           Table: Silkscreen Rules Details                          |
|                                                                                   |
+-----------------------------------------------------------------------------------+

Interactivity

A filter slicer on Applies To allows users to select categories like Pads or Component body. When a category is selected:

• The Pie Chart updates to show only selected categories.
• The Bar Chart filters to show minimum distances for rules in the selected category.
• The Table displays only rules applying to the selected category.
• The KPI Card updates to show the minimum distance among the filtered rules.

Self Check

Try this: Add a filter for Applies To = Pads. Which components update and what changes?

• The Pie Chart will highlight only the 'Pads' category.
• The Bar Chart will show minimum distances only for rules applying to Pads (Rule IDs 1 and 4).
• The Table will list only rules 1 and 4.
• The KPI Card will update to show the minimum distance from these filtered rules, which is 0.25 mm.

Key Result

Dashboard shows silkscreen placement rules with minimum distance requirements, application areas, and detailed descriptions.

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