Designing and Placing Silkscreen on your PCB with Altium Designer

Zachariah Peterson
|  Created: June 14, 2019  |  Updated: July 27, 2021

Planning for manufacturing and assembly of your next printed circuit board requires drafting a number of deliverables for your manufacturer. One of the important aspects of planning for assembly is ensuring that your assembler has the instructions they need to place components in the right locations and with the right orientation. When you use the right PCB editor with top-quality CAD tools, you can place silkscreen directly in your PCB layout and use a design rule check to verify appropriate clearances. Altium Designer gives you these tools and plenty of other features to help you prepare for manufacturing and assembly.

ALTIUM DESIGNER®

A unified PCB design package with the best CAD tools for PCB layout and silkscreen placement.

Silkscreen refers to a set of labels that are printed on the surface layer of a circuit board. Silkscreen includes each reference designator for your components, identifiers, company logos, switch settings, test points, part numbers, and any other information that an assembler needs to ensure they place the correct components in the correct locations. Silkscreen can also contain component outlines or points that are used to indicate the correct orientation of DIP packages or ICs that are mounted on BGAs.

If you’re designing a Printed Circuit Board that includes a number components with similar or identical packages, or multiples of the same IC with various orientation, you’ll want to include silkscreen on your PCB so that your manufacturer and assembler does not make any mistakes during fabrication. Your manufacturer will likely place silkscreen for you, but it is in your best interests to place silkscreen yourself in order to prevent any confusion.

Silkscreen communicates a significant amount of information required to properly assemble your board, and you should include this information in your PCB layout. With the right CAD tools in your PCB editor, you can easily place silkscreen in your PCB layout once you’ve finished arranging your board. This is one of the final design steps before planning for manufacturing.

Common Mistakes with PCB Silkscreens

Silkscreen is placed on the component layer, or it can be placed on the bottom layer of a PCB. One common mistake when placing silkscreen on a Printed Circuit Board is to place it too close to a pad, or even underneath a pad. The best PCB design software will display your intended pad size in your PCB editor, which will ensure that you can properly place your silkscreen. You need to maintain the correct clearances between your silkscreen and your exposed pads. A good rule is to place at least 3 mils of clearance between a pad and silkscreen.

The IPC standards require PCB manufacturers to place a manufacturer’s mark and a lot number using silkscreen. This allows a board to be traced throughout the supply chain in the event of a recall. Manufacturers generally place these marks away from critical areas, such as on the back side of a board or near the edge away from critical components. One common mistake is to neglect telling your manufacturer where these markings should be placed on your board. Make sure to specify this if it should be kept away from specific areas.

If you do use silkscreen on the top layer of your board, one simple mistake is the use of ambiguous symbols, odd fonts, and small text. This significantly increases the difficulty involved in manual testing and assembly. Silkscreens are the primary means for an assembler to see information they need to correctly place and solder components. The polarity and orientation, and first pin on an IC package should be clearly marked.

Fabrication and Assembly Instructions

Aside from silkscreen and assembly instructions, your manufacturer will need a bill of materials that lists components that include reference designators. These reference designators must match your silkscreen in order to ensure that components are placed in the correct locations. This prevents unnecessary errors during assembly and makes your board easier to test and troubleshoot.

The IPC Compliant Footprint Wizard in Altium Designer

Creating compliant proprietary components in Altium Designer

How to Make Readable Silkscreen Layouts in Altium Designer

Creating a silkscreen layout in Altium Designer takes layout tools that make it easy to add a silkscreen layer to your layout. Working with a PCB editor that includes multiple viewing modes allows you to show and hide silkscreen during your layout. You’ll want to use silkscreen DRCs in your PCB editor to check whether silkscreen will appear on conductors, in holes, and has the clearances you specified in your design rules.

This all happens during the layout phase after you have arranged your components. It is a good idea to finalize your layout and thoroughly simulate its behavior before placing silkscreen. Any changes to the component arrangement may require changing the silkscreen layer as well, so be sure that you are happy with your PCB layout.

Defining Silkscreen Clearance as Design Rules

When your design software is built on a rules-driven design software, you can easily define the clearances you need and check them as you design your board. The best PCB design software will allow you define solder mask and silkscreen clearance as a design rule, ensuring that your manufacturer won’t have to spend time modifying your design before fabrication. Manufacturers will appreciate it when you can anticipate whether silkscreen will overlap with a pad in your layout.

Unfortunately, not all design programs will show you the information you need to verify these important clearances. Annular rings on vias and pads on SMD components should appear directly in your layout so that you don’t have to calculate this clearance by hand. With the right design tools for vias and pads, as well as layout tools that check against your design rules as you create your board, you can ensure that your silkscreen and solder mask will have the right clearances before you send your board off for fabrication.

Screenshot showing the PCB Rules and Constraints editor in Altium Designer

Defining solder mask rules and constraints in Altium Designer

Design and Manufacturing Preparation in a Unified Environment

Silkscreen is just one important design element that will help you plan for a successful manufacturing run. You should also place fiducial markers if your manufacturer requires them so that your board can be run through pick-and-place machines and other automated manufacturing tools. You’ll need to source components and ensure that you only procure the most up-to-date, highest quality components for your board.

Design tools that integrate directly with your documentation and production planning tools allow you to easily create a complete documentation package for your design in a standard format. You’ll also be able to manage your supply chain and prevent the procurement of obsolete or counterfeit components. Instead of writing up a bill of materials with sourcing information by hand, you can quickly import distributor information into your bill of materials and match your component selections with your silkscreen reference designators.

Altium Designer: Unifying Design, Fabrication, and Assembly

Only Altium Designer includes your design, documentation, and supply chain management features in a single program. Your design tools need to communicate using a single data structure that integrates your data with all your design, analysis, documentation, and supply chain management features.

With other PCB design platforms, your features are separated into different programs, and some important features required to properly place silkscreen may not be present in your design. Instead of risking your productivity and potential redesigns with other programs, Altium Designer gives you access to all the design and production planning features you need in a single program.

There are plenty of design aspects to consider in any Circuit Board, and Altium Designer includes the tools you need to create the highest quality boards in a single program. You’ll be able to operate at peak efficiency when you have access to design, production planning, verification, and data management features in a unified design environment.

While other design programs leave you to figure things out on your own, Altium gives you the resources you need to get started and finish strong. You’ll have instant access to the AltiumLive forum, webinars and podcasts given by industry experts, design tutorials, and an extensive knowledge base with plenty of design tips and examples. No other PCB design software company gives you this many resources for success.

Altium Designer sets the standard for PCB design and is leading the way in design integration. This environment gives you the tools you need within a single program and without the data errors that can cripple other design software. Don’t settle for other design platforms with separates features that force you to work between different programs. If you want to work with the best design and production features, then it’s time to make the switch to Altium Designer.

About Author

About Author

Zachariah Peterson has an extensive technical background in academia and industry. He currently provides research, design, and marketing services to companies in the electronics industry. Prior to working in the PCB industry, he taught at Portland State University and conducted research on random laser theory, materials, and stability. His background in scientific research spans topics in nanoparticle lasers, electronic and optoelectronic semiconductor devices, environmental sensors, and stochastics. His work has been published in over a dozen peer-reviewed journals and conference proceedings, and he has written 1000+ technical blogs on PCB design for a number of companies. He is a member of IEEE Photonics Society, IEEE Electronics Packaging Society, and the American Physical Society, and he currently serves on the INCITS Quantum Computing Technical Advisory Committee.

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