Technical Library | 2010-06-10 21:01:48.0
This paper researches the effectiveness of the R.O.S.E. cleanliness testing process for dissolving and measuring ionic contaminants from boards soldered with no-clean and lead-free flux technologies.
Technical Library | 2015-07-16 17:24:23.0
Qualification of electronic hardware from a corrosion resistance standpoint has traditionally relied on stressing the hardware in a variety of environments. Before the development of tests based on mixed flowing gas (MFG), hardware was typically exposed to temperature-humidity cycling. In the pre-1980s era, component feature sizes were relatively large. Corrosion, while it did occur, did not in general degrade reliability. There were rare instances of the data center environments releasing corrosive gases and corroding hardware. One that got a lot of publicity was the corrosion by sulfur-bearing gases given off by data center carpeting. More often, corrosion was due to corrosive flux residues left on as-manufactured printed circuit boards (PCBs) that led to ion migration induced electrical shorting. Ion migration induced failures also occurred inside the PCBs due to poor laminate quality and moisture trapped in the laminate layers.
Technical Library | 2019-03-13 15:19:55.0
It is well documented that Nano coatings on SMT stencils offer many benefits to those assembling PWBs. With reduced standard deviation and improved transfer efficiency nano coatings can provide, there is also a cost. As PWB assemblers work to justify the return on investment, one key question continues to arise. What is the durability or life of these coatings and what can be done in the print process to maximize the life of the coatings?This paper addresses durability of the coatings in relation to the number of print cycles and underside wipe cycles applied as well as materials used on the underside wipe process. Different parameters will be applied and data will be collected. The results of this study will be summarized to help those using or considering the use of these nano coatings to improve their print process and suggestions will be given to maximize the life of the coatings.
Technical Library | 2008-04-29 15:50:45.0
The electronics industry is undergoing a materials evolution due to the pending Restriction of Hazardous Substances (RoHS) European Directive. Printed wiring board laminate suppliers, component fabricators, and printed wiring assembly operations are engaged in a multitude of investigations to determine what leadfree (Pbfree) material choices best fit their needs. The size and complexity of Pbfree implementation insures a transition period in which Pbfree and tin/lead solder finishes will be present on printed wiring assemblies
Technical Library | 2013-04-18 16:46:42.0
Conformal coatings are considered a method of providing corrosion protection to electrical assemblies used in high-humidity or harsh environments. They are applied to PCBs for various reasons: to protect from moisture and contamination, to minimize dendritic growth, to provide stress relief, and for insulation resistance. These contribute to more durable handling, enhanced device reliability, and reduced warranty costs. Increased miniaturization of new circuit board designs requires flexible, low stress coating material to protect delicate components and fine-pitch leads. Silicone conformal coatings offer many advantages that address the general trend of ongoing PCBs designs, such as: high flexibility and low modulus to reduce stress on delicate or small components... First published in the 2012 IPC APEX EXPO technical conference proceedings.
Technical Library | 2017-03-22 20:58:08.0
Water soluble lead-free solder paste is widely used in today’s SMT processes, but the industry is slowly moving away from water soluble solder pastes in favor of no-clean solder pastes. This shift in usage of solder paste is driven by an effort to eliminate the water wash process. Some components cannot tolerate water wash and elimination of water washing streamlines the SMT process. Despite this shift, certain applications lend themselves to the use of water soluble solder paste.This paper details the research and development of a new water soluble lead-free solder paste which improves on the performance characteristics of existing technologies.