An industrial PCB must remain stable under harsh conditions. Therefore, it has features that are rugged enough to withstand extreme environments. This article will help you understand how it differs from conventional circuit boards, its manufacturing requirements, and example applications in the real world.

What is an industrial printed circuit board?
An industrial PCB is a circuit board designed specifically for industrial applications. It can be a PCB for a power supply system or a high-voltage motor controller. Another example is a PCB for a building’s lighting system or control electronics for automated manufacturing equipment.

These boards support the entire electrical system and must continue to operate under harsh conditions. For example, they cannot fail when the temperature varies greatly or when humidity rises sharply.

These boards must meet other environmental conditions, including mechanical shock, vibration, or high voltage. Therefore, they are very useful in the following fields: energy industry, industrial automation, defense electronics, avionics, etc.

How are industrial PCBs different?
Industrial circuit boards differ from ordinary circuit boards in many ways, including operating temperature and voltage range, vibration and shock resistance, moisture resistance, and expected service life.

Operating Temperature
Industrial-grade PCBs can operate reliably over a wide temperature range, from as low as -65°C to about 150°C. This means it can be a board that works in cold environments or maintain its performance in hot environments, depending on the desired application characteristics.

Vibration and Shock Resistance
Industrial circuits are characterized by excessive vibration and mechanical shock. Therefore, their PCBs must be designed to adequately resist damage. Sometimes, the substrate is flexible to absorb vibrations, or made of a rigid backing material such as metal.

Moisture and Corrosion Resistance
Industrial PCBs have a higher resistance to moisture damage or corrosion. Typically, this protection includes coating them with thicker, higher-quality solder mask. Other measures include using moisture-resistant materials to make the board.

Operating Voltage and Power Requirements
Industrial circuits are typically high-voltage circuits. Their PCBs often use large-gauge power lines to handle higher currents. Other measures include extensive heat sinking and materials that can withstand higher heat, such as metals and ceramics.

Lifespan
An important difference between industrial circuit boards and commercial or consumer-grade boards is their longer lifespan. They can usually last 5 to 10 years, and some can even last more than 10 years.

Industrial PCB Types and Design Standards
Industrial circuit boards are mainly classified by their material type and structure or stacking method. They can be flexible or rigid, and single-layer or multi-layer. Each board type has its own applications. They also meet IPC Class 3 standard requirements.

Types of Industrial Circuit Boards
Rigid boards are made of rigid substrates such as FR4 or metal, while flexible boards are made of polyimide or polytetrafluoroethylene (PTFE). Some combine flexible and rigid materials.

Rigid boards are suitable for situations where space is sufficient and structural integrity is critical. On the other hand, flexible boards are suitable for situations where space is limited or the PCB must bend permanently or during use.

Single-layer boards are the most basic type. It is suitable for simple applications such as LED lighting. Multi-layer boards have more than two copper layers and provide more routing options. The number of layers can be as high as 16 or more.

Industrial PCB Design Standards
Industrial circuit boards meet IPC Class 3 standards. They meet the high-performance requirements for harsh environments as specified by the IPC 6012E standard. The standard covers military, medical, and automotive PCBs.

Several appendices in the standard identify requirements for specific applications. They are IPC 6012 ES for military and aerospace electronics, IPC 6012 EM for medical devices, and IPC 6012 EA for automotive boards.

Circuits that meet IPC Level 3 standards can withstand higher temperatures, mechanical shock and vibration, humidity, and other environmental stresses. Their materials typically have the following key properties.

Tg values ​​above 170 degrees Celsius to withstand high temperatures

Thermal conductivity above 0.4 W/mK for proper heat dissipation.

Dielectric constant less than 4 to prevent signal degradation

Thick copper to withstand high power levels

Industrial PCB Manufacturing Process
Industrial PCB manufacturing processes are slightly different from standard circuit boards. Design engineers must consider special board characteristics and select the right material for the substrate. In addition, special wiring and layout requirements or testing standards must be met.

Material Selection
Since industrial PCBs need to operate in harsh conditions, their materials must be able to withstand a variety of extreme conditions, including heat, vibration, and shock. Depending on the application environment, different materials are used.

FR4 – A glass fiber epoxy substrate suitable for milder applications with moderate requirements. For more demanding applications, high Tg FR4 provides better performance.
Polyimide – Used to make flexible circuit boards. In addition to bending, it can withstand higher environmental stresses such as vibration and temperature than FR4.
Ceramic – Supports high-temperature applications and high-frequency circuits. Mainly produces RF or microwave boards.
Metal core – Metal core can quickly dissipate heat and can withstand higher mechanical shock and vibration levels. Mainly used in power electronic boards and LED PCBs.
Design and Layout
Industrial PCB design takes into account the more demanding application environment. Proper routing is also necessary, otherwise the board may have performance issues due to incorrect component placement and thermal management issues. The following are the characteristics of the design and layout process:

Use thicker copper to meet high power requirements
Ensure controlled impedance or impedance matching
Use ground planes to shield signal layers and reduce signal loss
Use blind or buried vias
Incorporate backup traces to prevent system failures
Integrate thermal management features such as graphite layers to dissipate heat and heat shields near hot components
Prototyping and Manufacturing
Industrial PCBs require prototyping before going into full production. Prototypes go through a testing process to identify errors. This production phase saves you the potential loss of a defective final product.

During the manufacturing process, manufacturers ensure that the correct manufacturing techniques are employed. They also follow various production standards to provide products that meet customer needs and industry standards. Some standards, such as thicker coatings, protect the board from moisture damage.

Testing
Industrial boards undergo rigorous testing using manual/visual and automated methods such as AOI and X-ray. These methods help find defects before the board leaves the factory and is integrated into the end-use system.

Other tests include ICT (In-Circuit Test), Flying Probe Test, and Burn-in Test. These tests ensure high-quality boards that meet various standards such as UL and IPC Class 3.

What are Industrial Printed Circuit Boards used for?

The industrial applications for printed circuit boards are wide-ranging and varied. They range from PCB integration into electrical devices such as motors to control electronics for automation systems. Here is a summary of some of these uses.

Industrial Motor Drives and Controllers
Power Systems
Automotive Electronics
Industrial Systems Controller Circuits
Telecommunication Equipment and Systems
Energy Production Systems
Health Care Equipment and Systems
Aerospace Systems Avionics
Military and Defense Electronics

The aerospace and satellite industries are seeing an increasing demand for high-performance printed circuit boards (PCBs). The industry is always at the crossroads of innovation, with an increasing focus on customer safety and travel experience. Over the years, KKPCB has invested in technology and resources that allow us to manufacture and assemble the high-performance, precise, high-tolerance, and reliable PCBs required by these industries.