SMT007 Magazine

SMT007-Nov2021

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44 SMT007 MAGAZINE I NOVEMBER 2021 vironments like automotive, LED, military, aerospace, medical, mobile, and more applica- tions. But what if the coating is too thin or de- fective? Failure may result. Here are some common failure modes de- tectable by the inspection machine: • When entrapped air or solvents skin over—oen caused during the drying pro- cess or multilayer coating application— bubbles become entrapped before settling out. e inspection machine can detect bubbles measuring length or percentage of the affected area. • Cracks leave an area exposed and less protected from moisture and dust. is usually happens when the curing temp- erature is too high or when curing occurs too quickly. If combined with a thick coating application, it causes fracturing of the coating into sections. If a crack turns in a bigger affected area, it can become a delamination problem, which can also be created by a circuit board cleanliness issue. • Conformal coating thickness can present two problems, one related to a too-thick coating, and the other related to a thin coating layer. For these scenarios, measuring thickness—which is one of the main advantages of using LIFT technology—this system can find common defects caused by an incorrect coating thickness. ese include capillary flow, de-wetting, and uneven coating—a challenging defect to detect with traditional, oen destructive, measuring technologies. Inspection Solutions Traditional laser-confocal or electron microscopes only measure three-dimensional shapes and can- not inspect transparent materials. The microscope penetration depth is too shallow, and the process- ing time is quite lengthy, so measuring transparent materials is a significant challenge due to the laser's shallow penetration depth and elapsed time. UV- based systems also gauge material thickness in a particular spot, which does not deliver the accuracy and repeatability needed. Neptune T This system uses non- destructive 3D inspec- tion technology to ex- amine the thickness of transparent and semi- transparent materials like coatings, underfill, and epoxy used on a PCB. This ensures the confor- mal coating used to pro- tect the delicate circuitry is applied correctly and will ensure the device oper- ates as it should. Expanding on its capabilities, the system has advanced with the next phase in its de- velopment. This is to inspect batch and inline con- formal coating inspection systems using data ag- gregation and data-driven process. Neptune C+ Neptune C+ allows manu- facturers to identify defects with 2D, 3D, and cross-sec- tion views. The system mea- sures materials for coverage, thickness, and consisten- cy with user-defined thresh- old settings. Instead of mea- suring IC leads with a point method, which can yield un- reliable results, the Neptune Series measures the actual coating thickness to sat- isfy demanding quality standards. LIFT (Laser Interferometry for Fluid Tomography) With the help of laser interferometry for fluid to- mography (LIFT), the layer thickness of transparent media is determined within seconds. This tech-

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