Skip to main content



8 Chapters
8 Chapters

Which class of board to choose? IPC class 2 or IPC class 3 standard? Does it really make any difference? Are manufacturers solely responsible for the board quality? Do designers play any role in it? If you have all these questions on your mind then this design guide will help you clear up that ambiguity.

This design guide helps you design and build PCBs for precision and reliability:

  • IPC guidelines for manufacturing defects
  • IPC standards for assembly processes
  • Common differences between the classes
  • IPC documents to set the level of acceptance criteria




When we talk about IPC classes, we are speaking about the level of inspection that defines the manufactured board’s precision and reliability. The three classes are categorized based on the criticality of the application, the tolerances to the harsh environment, and so on. In short, the three classes determine the quality of the board. With IPC class 3 being the highest in quality and class 1 being the lowest. The other important thing that we would like to state here is that we cannot solely explain  IPC class 3 without also understanding the other two classes. Hence, in this design guide, we mention class 1 and class 2 for your better understanding.

Sierra Circuits offers internal quality review systems that guarantee zero-defect boards. We also provide engineering support to verify if your design is IPC class 3/A or mil-spec compliant.




  • IPC standards for the assembly process
  • How to design and build annular rings
  • PCB failure: Analysis & testing
Design Guide Form Header Image

Sierra Circuits PCB Certifications & Registrations

Sierra Circuits holds IPC-6012, IPC-6013, IPC-6015, IPC-6018, and IPC-A-600 PCB certifications
Sierra Circuits is ISO 9001:2015 certified for Military and Aerospace PCBs
Sierra Circuits is ISO 13485:2016 certified for Medical Device PCBs
Sierra Circuits is ITAR Registered
Sierra Circuits holds MIL-PRF-55110 & MIL-PRF-31032 PCB certifications
Sierra Circuits is certified by the National Institute of Standards and Technology
Sierra Circuits is REACH Compliant for PCB certifications
Sierra Circuits is RoHS Compliant for PCB certifications
Sierra Circuits holds PCB certifications for Flex, Rigid-Flex, and Rigid PCBs by the Underwriters Laboratory



Sierra Circuits has been trusted by innovators as a go to resource for best in class circuit boards since 1986.

Certification Logo
Certification Logo
Certification Logo
Certification Logo
Certification Logo
Certification Logo
Certification Logo
Certification Logo


Since 1986, Sierra Circuits has faithfully served more than 20,000 PCB designers and engineers with PCB design, manufacturing and assembly and High-Density Interconnect technology.

Sierra Circuits handles all aspects of PCB production. From PCB layout and design, to assembly and manufacturing—we provide our customers with unprecedented quality, reliability, and a single point of support.

Advanced PCBs
PCBs manufactured and assembled in the United States



Start a Secure Quote


24 hours a day, 7 days a week.

Call us: +1 (800) 763-7503
Email us: through our Customer Care form

SG赛车一期计划 秒速赛车开奖app 澳洲幸运5最快开奖结果