Circuit Board Mounting: A Step by Step Guide

This article explains circuit board mounting steps, the materials to use, and best practices for the project’s success.

How do you properly fasten a PCB to a casing or surface? Also, what tools and hardware do you need? This article is your complete guide to circuit board mounting. In the guide, we explain the process, step by step, from the beginning to the end.

What is Circuit Board Mounting?

Circuit board mounting means securing assembled PCBs to enclosures, chassis, or other spaces. The process prepares the boards for integration into an electronic product or system. You can place your PCB in various places, such as:

• Data cabinets
  
• Consumer electronics
  
• Office machinery
  
• Industrial systems
  
• Electrical cabinets
  
• Junction boxes
  
• Automotive systems
  
• Flat surfaces like walls
  
• Custom box build assemblies
  
• Testing and prototyping enclosures
  

Mounting methods vary. Options range from threaded parts and snap-locks to press and push-fits. Others are easy-to-use fasteners like adhesives, trays, and card guides or slots.

The application determines the mounting techniques, the rules to observe, and other requirements. In all instances, the installer must observe good practices.

Why is Proper Circuit Board Mounting Important?

Correct mounting process steps ensure your board performs superbly and meets your expectations. It helps you avoid various installation problems, including the following.

• Misalignment resulting from wrong positioning and fastening
  
• Loose boards vibrating and causing solder joint problems
  
• Electrical safety issues that may lead to shocks and electrocution
  
• Electrical noise and other EMI problems
  
• Cooling inefficiencies that could affect the board’s performance and durability
  
• Challenges in accessing the board for removal, repair, or servicing
  
• Inability to meet industry and application standards.
  

Circuit Board Mounting Hardware

Printed circuit board mounting hardware comprises temporary and permanent options. They are usually plastic, metal, or ceramics. They include the following grouped by their design and function.

Screws and Mounting Blocks

Screws are threaded components you insert into holes. They tightly secure the board, making them the most popular type. Most circuit board mounting screws come with washers to prevent damage when tightened.

On the other hand, blocks mount PCBs and their connectors, providing electrical and mechanical interfaces. They can be different materials and sizes or shapes, just like screws.

Stand-offs and Spacers

Stand-offs and spacers raise the PCB off the installation surface. They provide electronic components clearance, thermal insulation, and electrical isolation. They also create room for air circulation to aid cooling.

The two parts differ in design. Stand-off types have threads on either side, while spacers have no thread but come with through holes. Their material options include metal, plastic, and ceramics.

Clips, clamps, and Brackets

These are temporary fasteners and are more straightforward to use. They also make the board less challenging to remove for repair or upgrade since they do not use threaded parts.

They are helpful in applications involving regular dismantling and adjustments, such as modular electronic systems. The hardware is usually metallic or plastic and of various sizes or shapes.

Adhesives and Mounting Tape

Adhesives and tapes hold lightweight boards to surfaces. Unlike other hardware types, they save space. They are also easy to use and require no skill or specialized installation tools. They mainly mount flexible PCBs, which may not allow mechanical fasteners.

How to Mount a Circuit Board

Let’s now see how to mount a PCB assembly, starting with gathering the necessary materials and tools. The materials include (but are not limited to) the following:

Mounting Hardware (Core Materials):

• The PCBs (finished boards with pre-installed components)
• Hardware like stand-offs and screws or brackets

Auxiliary Tools:

• Screwdrivers
• hexagonal wrenches

Soldering Tools：

• Soldering wires or Suckers
• soldering irons, etc.

General Purpose tools:

• Wire strippers, wire cutters, anti-static bracelet, etc.
• Digital Multimeter

Step 1: Prepare Mounting Space

• Determine the installation position and space
  
• Clean it to remove any dirt or other material
  

Step 2: Select Mounting Hardware

• Determine Requirements: Evaluate the PCB design and application, considering vibration, thermal management, and future maintenance needs.
• Material Selection: For instance, use nylon for electrical insulation and brass for enhanced durability.
• Hardware Preparation: Gather all required hardware and keep it within easy reach.
  

Step 3: Modify PCB（Optional Step）

• Perform any required modifications to the board
  
• These may include drilling holes or cutting parts
  

Step 4: Assemble and Secure PCB

• Install the stand-offs where you’ll place the board
  
• Tighten them by hand or with the help of a tool like a wrench
  
• Place the PCB on the stand-offs, aligning it with the mounting holes
  
• Carefully insert the nuts or screws, tightening them by hand
  
• Finally, use a wrench to tighten them
  
• Avoid over-tightening or under-tightening the screws
  
• Attach cables, connectors, and other accessories
  

Step 5: Testing and Troubleshooting

• Power the board and device or electrical system to ensure they function correctly
  
• Using the multimeter, perform various tests on the assembly
  
• Test it for opens and short circuits or other defect
  
• Measure its voltage and current levels
  
• Ensure every electrical parameter matches those specified for the application
  

Key Considerations When Mounting Circuit Boards

Printed circuit board mounting has specific needs. These differ across PCB types and usage conditions. With that in mind, the following are things to take into account when mounting one:

Mechanical Stability

Ensure the installation is mechanically sound to withstand application conditions. For instance, an automotive board must endure vibrations. This need requires you to choose and size your installation hardware correctly.

Proper Alignment

Improper alignment is one of the most common problems. To avoid that, precisely position mounting holes and slots. Correctly mill or drill them, too, using precision equipment and tools. Make exact measurements and use appropriate hardware.

Thermal Management

Your installation may overheat if it lacks adequate cooling. In high-power applications, thermal strategies like heat sinks and fans are necessary. Alternatively, use on-board dissipation methods like thermal paste or grease.

Electrical Isolation and Grounding

Electrical isolation and grounding make the installation safe to use. It also prevents electrical noise, improving signal quality. Determine the strategies to use beforehand. Doing so ensures your installation will perform as intended.

Circuit Board Mounting Best Practices

The process has a few rules to observe when installing the board. The following tips summarize them. They should help you ensure product or system performance and reliability.

1. Always assess the application environment and use components that can withstand heat, humidity, vibrations, etc.

2. Use proper torque when fastening components like screws. Under-tightening could cause the board to move about, while over-tightening could lead to damage.

3. Use adhesive for a board you cannot drill holes into or if you intend to install it on a flat surface. They are easy to use and less intrusive than other hardware types.

4. Some circuits have strict signal protection requirements, requiring shielding. Secure yours using appropriate methods, such as sheathed cables or EMI cans.

5. Excessive vibrations can damage your board by breaking the solder joints. In such cases, mitigation strategies like rubber mounts and spacers can help.

6. Install high-flexural strength materials like FR4 with snap-in fitters and fragile paper-based boards with push spacers.

Conclusion

PCBs must reliably operate in their end-use products. Their appropriate installation is, therefore, essential to avoid performance problems. A well-installed board also lasts longer since it has lower chances of getting damaged. That, in turn, depends on how well you understand the mounting steps.