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Manassas Park, VA, United States

Schweigart H.,ZESTRON Europe | Tosun U.,ZESTRON America
SMT Surface Mount Technology Magazine | Year: 2011

Conformal coatings are applied to circuits boards used in high-reliability applications in the military, aerospace, communication, medical and automotive industries that demand a guaranteed, long-term product life. To guarantee the optimum adhesion of the protective coating and prevent formations of cracks or delamination, it is of utmost importance to ensure the highest cleanliness level of the assemblies prior to coating. While assessing the surface's cleanliness according to the J-STD 001E, a high ionic equivalent value indicates the existence of a large amount of hygroscopic impurities. In accordance with J-STD 001E, the presence of organic impurities can either be tested with infrared spectroscopy or detected with a quick and easy-to-use discoloration method such as the flux test. the integration of a cleaning process is usually required to be able to maintain all of the production thresholds set by J-STD 001E.


Tosun U.,ZESTRON America | Vargas A.,ZESTRON America | Kim B.,Pressure Products Company
IPC APEX EXPO 2014 | Year: 2014

Historically, the determination of the concentration of cleaning agent in high precision electronic cleaning baths has depended on any one of several possible measurable parameters. Refractive Index (RI) is by far the most common. RI methods are excellent tools for use in simple systems where a single solute dominates the signal. In these situations, it is possible to characterize and calibrate how that solute affects the signal. However, the introduction of flux residues during the wash bath lifetime complicates the bath chemistry/physics to such an extent that RI signals no longer provide the same insight. The introduction of flux residue has an enormous influence on the Refractive Index. Alternative means of measuring cleaning agent are necessary if cleaning agent concentration is to be known throughout the life of the bath. With a means to accurately measure bath cleaning agent, closed loop automated process control on the cleaning bath is possible; automating this labor intensive step in the production of electronic boards. We have found that acoustic measurements of cleaning bath solution are relatively independent of pH, conductivity, and dissolved solids in some of the most flux loaded baths. Utilizing acoustic sensing technology, field data was gathered from two beta site locations assessing the accuracy of the technology in fresh as well as contaminated wash baths.


Trademark
Zestron America | Date: 2006-04-25

Consumer car care products.


Wack H.,ZESTRON America | Becht J.,ZESTRON America | Tosun U.,ZESTRON America | Afshari S.,RMD Instruments
SMT Surface Mount Technology Magazine | Year: 2011

Can an existing chemistry-based cleaning process be used to clean eutectic and lead-free alloys in the same process? A study, detailed in the following article, was created to provide valid technical data to better assess the risk associated with using one cleaning machine for both eutectic and lead-free substrates.


Tosun U.,ZESTRON America | Parthasarathy R.,ZESTRON America | McCutchen M.,ZESTRON America
IPC APEX EXPO Conference and Exhibition 2013, APEX EXPO 2013 | Year: 2013

For mission critical electronics or Class III products, such as those used within the military, aerospace and medical industries, highest electronic reliability is a requirement as failure is not an option. Within the electronics industry, this means that residues, either ionic or non-ionic, must be fully removed. Partially removed or untouched residues can lead to component and product failures resulting from electrochemical migration, dendrite growth and electrical leakage currents. The goal of this study was to identify and qualify an aqueous cleaning process capable of removing combinations of no-clean flux residues for Class III electronic assemblies. Teamed with a global electronic manufacturing service (EMS) provider supplying electronics to the aerospace and medical industry, the Design of Experiment (DOE) developed was executed in two phases. Initial testing was completed utilizing EMS boards and final testing was validated using IPC test coupons and standards. The goals of each phase of the DOE were as follows: Phase 1: I. Determine optimum parameters to effectively clean flux residues from EMS board samples and verify cleanliness through visual inspection and ionic contamination analysis. Phase 2: I. Using the optimum parameters from Phase 1 above, clean additional EMS boards and verify cleanliness using Ion Chromatography (IC) and Solvent Extraction Conductivity (SEC) analyses. II. Conduct Surface Insulation Resistance (SIR) and Electrochemical Migration (ECM) analyses on IPC test coupons cleaned using parameters defined in Phase 1. III. Verify compatibility of all critical components and materials used on the boards with the selected cleaning agent. Through this DOE, the authors were able to identify and quantify the critical parameters impacting cleanliness for Class III electronic components as validated by numerous IPC assessment standards.

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