Why do I get cracks in my conformal coating during processing?

Conformal Coating cracking is a  failure mechanism in processing where the smooth surface fractures into sections with the cracks in the coating leaving the area below exposed to potential contaminants.

Causes of Cracking in Conformal Coating include:

  1. Cure temperature too high
  2. Conformal coating heat cured too quickly without allowing enough time for room temperature (RT) drying
  3. Film thickness too great causing coefficient of thermal expansion (CTE) mismatch and cracks occurring in the coating
  4. Operating temperature too high or too low causing the conformal coating to flex too much & crack.

To find out more click conformal coating cracking technical bulletin.


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About Dr Lee Hitchens

Dr Hitchens has been working in the electronics industry and the area of conformal coatings for over 25 years in various areas including sales and technical support. He has also been training people for almost the same amount of time in all areas of conformal coating whether that is materials & equipment selection, process development or troubleshooting to help them solve their particular problem. Recently, he decided that the industry needed a specific place where all of the useful knowledge on conformal coatings could be collated for users to find easily and use in their own production process. So, Nexus was born and he began the Nexus eBook project.

One response to “Why do I get cracks in my conformal coating during processing?”

  1. Karl Hardcastle says :

    With regard to item 2. Is this effectively trapping the solvent inside the coating which when heated up expands more than the coating creating the splits/ cracks?

    Karl Hardcastle Operations Manager

    SCH Technologies Newburgh Building McLintock Way Barnsley S70 6BF Tel: 01226 249019 Fax: 01226 770809 http://www.conformalcoating.co.uk

    Company Registration: 04043334 Registered office: SCH Services Limited Newburgh Building McLintock Way Barnsley South Yorkshire S70 6BF

    SCH Technologies is a Division of SCH Services Limited

    Office Number – +44 (0)1226 249019 http://www.conformalcoating.co.uk


    SCH Services Ltd offers a Technical Support Helpline to help address all issues relating to reliability. This includes contamination testing, cleanliness and cleaning issues, plus any coating related questions.

    Please contact us via email or telephone:

    help@schservices.com +44 (0)1226 249019 (office hours & answerphone) +44 (0)7862 253321 (out-of-hours emergency)

    The opinions expressed in this e-mail are strictly those of the sender and not of SCH Services Limited. This communication may contain information which is confidential and may also be privileged. It is for the exclusive use of the intended recipient(s). Unauthorised use, copying or disclosure of any of it may be unlawful. If you are not the intended recipient(s) please note that any distribution, copying or use of this communication or the information in it is strictly prohibited. If you have received this communication in error please notify us by e-mail or by telephone (+44 (0)1226 249019) and then delete the e-mail and any copies of it. Virus Warning – Although steps have been taken to ensure that all email and attachments are virus-free, we cannot guarantee nor be held liable.

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