Not all electronics assemblies require cleaning – many of them cannot depend on “no-clean” flux without critical cleaning. Barbara and Ed Kanegsberg have the experience and expertise in cleaning electronics assemblies to work with complex builds as well as legacy systems.
The need for cleaning is increasing. Densely-populated assemblies, assemblies with low standoff, and assemblies with high-value, critical end-use requirements require defluxing and removal of other contaminants. “No clean” (low residue) fluxes and OA fluxes must be removed to assure continuous performance in high-reliability products. The higher reflow temperatures associated with lead-free fluxes makes defluxing even more challenging. Electronics assemblies that are incorporated into high-value products, including those for medical, military, and aeronautics applications require higher standards for defluxing, contamination control, and materials compatibility.
What happens after defluxing?
Electronics assembly is not an end in itself. Electronics assemblies are often incorporated into high-value products. At BFK Solutions, we work with all parts of the supply chain, including components manufacturers, electronics assemblers, and final product assemblers, to assure that post-defluxing and final product assembly are conducted successfully. We determine appropriate monitoring and cleanliness testing for our clients to assure that quality and performance standards are met or surpassed. This includes testing for ionic and, increasingly, for non-ionic residue.
The coating on electronics components appeared to survive the defluxing process only to dissolve during subsequent assembly steps. BFK Solutions helped the final assembler to resolve the problem.
New solvent blends
As part of a SERDP program, BFK Solutions and Sam Houston State University are developing and testing the cleaning/defluxing effectiveness of azeotropic solvent blends. Aspects involve reviewing cleaning agents properties (including flashpoint determination), selecting challenging no-clean and RMA fluxes, designing realistic test coupons, setting up reflow and defluxing protocols, and assessing cleanliness. Results will be published.
The client had an opportunity to expand electronics assembly using RMA fluxes. BFK Solutions assessed the current cleaning capabilities and costs of newer systems. The information allowed the client to make an informed decision regarding bid/no bid on the aerospace contract.
Conformal Coatings – Outgassing and Particles
Electronics assemblies were incorporated into sealed final assemblies. The client was concerned with Electro-Magnetic Interference (EMI) shielding, low outgassing of conformal coating, and minimization of particles. BFK Solutions provided cleaning processes as well as cleanroom and pre-cleanroom processes to minimize particle generation. We also found vendor options to meet their shielding and coating specifications.
Professional activities, electronics assemblies
BFK Solutions has been actively involved in the recent revision of the IPC defluxing handbook. We are frequent presenters at IPC and SMTA programs. The second edition of “Handbook for Critical Cleaning” includes defluxing approaches and with performance issues associated with excess residue on electronics assemblies.