The two critical areas of design for conformal coating
Authors and contributors
- Dr Lee Hitchens, Nexus
- Karl Hardcastle, SCH Technologies
When we discuss conformal coating and the issue of design, then we are really talking about two areas of design. These are design for reliability and design for processing.
Defining both design criteria can be critical to the success of the product and the circuit board.
Get the conformal coating design for reliability wrong and the product may fail in the long term before the expected lifetime is reached.
Fail to design for the conformal coating process correctly and the product may not even reach the field due to excessive costs.
Both types of design are assessed separately by Nexus but both should be considered together to give the best results for the product.
A summary of each design type is given below and a deeper study is continued on other pages.
Designing for conformal coating reliability
Understanding the design requirements of the circuit board to be protected by the conformal coating is one of the most fundamental questions that can be asked.
After all, the purpose of the conformal coating is to protect the electronics, by extending and preserving the life of the product.
When designing for reliability then there are several important areas to consider for the product.
These include:
- Reliability Requirements
- Life Cycle
- Environment
- Materials and Parts selection
- Electrical Effects
Considering each area separately can be crucial for the reliability of the product.
Click to find out more about Design for reliability of the product
Design for conformal coating process
Once the product reliability requirements have been defined as part of the conformal coating design procedure then the resulting information needs to be combined with the data from the holistic approach.
The holistic approach examines many factors that when combined with the product reliability requirements give us exact information for designing for process.
The conformal coating process defined
Combining reliability requirements and holistic information gives us the following information:
- Conformal coating material to be used
- Application method that is suitable for the material and circuit board
- Masking requirements if necessary
- Production line stages required
- Process parameters to be met
- Inspection criteria to be used
This data is then combined into a set of conformal coating instructions that can be used to implement the conformal coating process.
Click to find out more about designing for conformal coating process.
Design Rules
Designing a circuit board for conformal coating processing and production can be straightforward.
However, there are some basic rules and guidelines that can make life easier.
Follow some of them and you could save money and time in your conformal coating application process.
Nexus have examined the design rules for integrating conformal coating into production into various sections including:
Understanding these design rules and their relationship with the material, conformal coating process and the circuit board is a fundamental step.
However, if certain rules are not followed, and the design of the circuit is incompatible with the conformal coating process, then the resultant circuit board design can challenge even the most sophisticated conformal coating system and its operator to achieve the finish desired.
Click to find out more about design rules for manufacture and process.