There was a time, in the not too distant past, when working in a factory was based primarily on physicality. Plant productivity was mostly determined by how many containers an employee could fill in an hour or how fast a pallet could be stacked. Fortunately, for factory employees, those days have all but disappeared. Today, factories rely on automated equipment that is controlled by software, robotics for moving and placing parts and materials, and WiFi and IoT for communicating information and data internally and externally. Of course, these advanced industrial production processes require skilled personnel for management and to ensure operations run efficiently.
Factory worker programming production equipment
In order for personnel to ensure products are made that meet performance (operation and reliability) demands, factory equipment relies upon industrial PCB manufacturing. Some may think building circuit boards is building circuit boards and there is no appreciable difference in the process regardless of the application or environment in which the boards will operate. They would be wrong! Just as there are differences in the quality expectations for PCBAs based upon where and/or how they will be utilized, so there is variation in the manufacturing process that creates them. Let’s explore the specialty required for the industrial PCB manufacturing process and what you can do during design to aid its facilitation.
Industrial versus Commercial PCB Manufacturing
The manufacturing process of PCB contract manufacturers (CMs) is guided by the following industry standards:
This standard sets forth and defines three performance classes for finished PCBs.
Class 1 - General Electronic Products. Lifecycle expectation of 1-2 years or less.
Class 2 - Dedicated Service Electronic Products. Lifecycle expectation of 3-5 years.
Class 3 - High-Reliability Electronic Products. Lifecycle expectation of 15 years.
These specifications apply to the quality of manufacturing by the CM.
This standard establishes specifications for rigid PCBs based upon their classification level as set forth in IPC 6011.
This standard is the counterpart to IPC 6012D for flex and rigid-flex boards.
The standards above apply to all circuit board manufacturing processes, although additional regulations and guidelines are placed upon the process for certain PCBA applications. This includes critical industries; such as aerospace and medical devices. It is typical for commercial PCB manufacturing to fall under the least restricted categorization of class 1. By contrast, industrial production environments are more likely to require better-built boards that would likely require class 2 manufacturing process adherence. This distinction and others are listed in the comparison table below.
Comparison of Industrial and Commercial PCB Manufacturing Processes
|Industrial PCB Manufacturing Requirements||ATTRIBUTES||Commercial PCB Manufacturing Requirements|
|Typically, class 2 or 3||IPC 6011 CLASSIFICATION||Typically, class 1 or 2|
|Typically, high Tg||MATERIAL QUALITY||Standard FR4|
|May require balancing between heavy and normal copper weights||COPPER CONSISTENCY||Typically, not an issue|
|Constructing the board towards symmetry (including copper geometric area) around the center axis in the z direction.||STACKUP BALANCE||Typically, not an issue|
|Consistent temperature distribution is necessary for even flow of solder during PCBA.||THERMAL CONSISTENCY||Typically, not an issue|
|Typically, needed||MOISTURE PROTECTION||Typically, not needed|
The table above is not meant to be applicable to every industrial and/or commercial PCB manufacturing process as the specific design in question will define the significance of the attributes listed. However, the table can be taken as representative of the most common situations for industrial and/or commercial board builds. Now, let’s see what you can do to aid your CM in manufacturing your industrial boards.
Designing for Industrial PCB Manufacturing Process Optimization
As shown above, there are distinct differences in the significance of select aspects of PCB manufacturing for industrial and commercial boards. Generally, commercial board requirements are satisfied by most basic PCB manufacturing processes. Industrial boards; however, require that you and your CM employ more stringent control over materials and the fabrication and assembly stages. You can aid your CM by applying the following design tips for industrial PCB manufacturing.
Industrial PCB Manufacturing Process Design Tips
- Choose the appropriate standard classification
The best rule of thumb is to specify the lowest IPC classification for PCB manufacturing that meets your performance objectives. For example, in many cases, class 2 boards are acceptable rather than the more restrictive class 3.
- Choose the best materials for your board’s application
When selecting your boards you should incorporate the environment as well as the application to help you make the best decision. For industrial boards, this is likely to mean that high voltage PCB materials will be needed.
- Ensure your board’s copper weight is consistent across the board
Copper imbalance can be an issue for both fabrication (e.g. during hot air solder leveling or HASL surface finishing) and assembly (e.g. during reflow). High current PCB design is prevalent for industrial applications; therefore, you should design to minimize large discrepancies in copper weights, as much as possible.
- Design your stackup for symmetric construction
Balancing the copper of your stackup geometrically is important for signal integrity as variances impact trace parameters; such as impedance.
- Employ thermal balance techniques
One of the most significant factors that impact PCB assembly (PCBA) is thermal balance or even thermal distribution of heat. Avoiding solder defects necessitates that your board is designed for good thermal distribution.
- Ensure that board protection techniques are applied
Factory environments can present many environmental hazards for circuit boards. These include circumstances; such as large temperature differentiation, that can introduce moisture to your board. Moreover, contamination can occur during manufacturing; therefore, applying good protection methods is a requirement.
With the advent of Industry 4.0 and ever advanced industrial production facilities, the gap between PCB manufacturing for industrial and commercial boards will continue to widen. Therefore, you need to partner with a CM that embraces these changes and has the capabilities and expertise to ensure your industrial PCBs meet the demands.
|Tempo's Industry 4.0 Custom PCB Manufacturing Services
At Tempo Automation, we not only build high-quality boards for industrial applications the fastest in the industry but also employ advanced manufacturing techniques in our own smart factory.
And to help you get started on the best path for your industrial boards, we furnish information for your DFM checks and enable you to easily view and download DRC files. If you’re an Altium Designer or Cadence Allegro user, you can simply add these files to your PCB design software. For Mentor Pads or other design packages, we furnish DRC information in other CAD formats and Excel.