Chapter 16Automatic Optical Inspection of SolderingMihály Janóczki, Ákos Becker, László Jakab,Richárd Gróf and Tibor TakácsAdditional information is a
In consequence, this is the most important part of the AOI inspection process. Most scientificpapers are preoccupied with this subject [95]-[123]. The
Figure 6. Reflection pattern on meniscus model with RGB ring illuminationUsing reflection patterns is the basis of all papers that have been published
Manufacturer TRI InnovationModelTR7530 S3016 S3054QCField of view (orthogonal camera) [pixel]1024 x 768 2752 x 2048 @ 55 x 43 mm 672 x 512Pixel size (
SPI API PSI API PSIpre r ef low pre wave post wavecomponent in past e component in adhesivemissing past ewhet her it is not covered by component
ManufacturerModelCamera movementBoard movementComponent inspectionPrinting/paste inspectionDistinction principlesDistinction parametersCamera typeCame
ManufacturerModelMinimum inspection component sizePosition accuracyBoard clearance top [mm]Board clearance bottom [mm]Board size max. [mm x mm]Board s
ManufacturerModelPre-reflow inspectionPost-reflow inspectionCamera typeOrthogonal camera field of view [mm]Orthogonal camera resolution [µm]Number of
ManufacturerModelInspection capacity typicalBoard size max. [mm x mm]Board size min. [mm x mm]Board warp [mm]Board clearance top [mm]Board clearance b
then the appropriate parts would seem to be defective. These are the pseudo-failures whichcan reduce productivity so their number should as clos
lead-based solder alloys – which are much more even and mirror-like – they reflect lightdifferently, so different procedures may be used to veri
failure can be detected, the smaller the likelihood of refuse device manufacturing. Because ofcomponent down-scaling and increasing in density, optica
achieved, when it cools and solidifies. As a result of this, the microstructure that is created hasa greater surface roughness than in the previous ca
Figure 10. SEM image of the surface of a lead-based solder meniscusFigure 9. Electron microscope image of the surface of a tin-lead solder meniscusAut
An important question is precisely what the roughness of the pattern formed on the surfaceof lead-free solder alloys depends on, and how “reli
Figure 12. SEM image of a cross-section of a lead-based solder meniscusFigure 13. SEM image of a cross-section of a lead-based solder meniscusAutomati
alloys is even more visible. In the following SEM images the rough surface typical of lead-freesolder alloys can be observed.Figure 14. SEM image of a
Type of measurement result Lead-based solder paste Lead-free solder pasteMeasured surface roughness (RMS) 0.03092 0.0986Distribution of measured RMS v
Evolver software uses finite element analysis to calculate the surface profile at certain pointson the surface. In areas with a greater radius of curv
results in a darker image and in the case of observation along the z axis (from above), as istypical of microscopes, only the surfaces that are parall
Figure 19. Photograph and graphic representation of SMT joint made with lead-free solder Figure 20. Photograph and graphic representation of empty so
Figure 21. Photograph and graphic representation of empty solder pad covered in lead-based solder (DF imaging) Figure 22. Photographs (above: BF, bel
inspections, parametric test procedures can be used to evaluate the digital image and on thebasis of this they classify the inspected PWB, component o
Figure 23. Photograph and graphic representation of SMT joint made with lead-free (left) and lead-based (right) sol‐der8. Detailed analysis of AOI sy
In case of larger inspection areas, the systems are mounted with special drives which can movethe camera system or the inspected part. The movements o
Ring illumination around 4 cameras Grey-level distribution of 1 section Ring illumination around 1 camera Grey-level distribution of 1 camera 23
processes can only be used to a limited degree because of the high-complex manufacturingprocess and the equally complex and highly varied appearance o
In addition, AOI engineers need to cope with several other difficulties a major one of which isthat the production process changes continuously e.g. t
can be significantly improved with the help of macro optimization. In the first task, the pseudorate was reduced while slip-throughs remains zero (Tab
Secondly parallel pseudo and slip-through reduction were carried out (Table IX, Fig. 11, Fig.12).Real failures (Quasi-tombstone) [pieces]Pseudo fai
Figure 28. Pseudo and slip-through reductionAutomatic Optical Inspection of Solderinghttp://dx.doi.org/10.5772/51699423
If we suppose that the optimal size of image base is determined (and which cannot be exceeded)and relevant images are collected resulting in a reasona
Certainly the automatic optimization methods also need to collect the relevant imagesautonomously to create the reference image base.
5. Inspection of bare PWBsThere are several possibilities, appliances and algorithms when inspecting bare PWBsoptically. These are able t
The same is true for inspecting component presence, but for solder-joint detection thesetechnologies are in their infancy at present. The
meniscus. The meniscus forms from the liquid alloy during the soldering process. Aftercooling, the meniscus becomes solid and reflects ill
[3] Sheng-Lin Lu, Xian-Min Zhang, Yong-Cong Kuang, Optimized Design of an AOI Il‐luminator, Proceedings of the 2007 International Conference on
[19] Keith Fairchild, Evaluating ROI of AXI vs. AOI, Circuits Assembly, October 2006, pp.20-25[20] “Realising Expectations of AOI http://www.dataw
[33] Stuart A. Taylor, CCD and CMOS Imaging Array Technologies: Technology Review,Technical Report EPC-1998-106, Xerox Research Centre Europe h
[46] Ji-joong Hong, Kyung-ja Park, Kyung-gu Kim, Parallel Processing Machine VisionSystem for Bare PCB Inspection, IEEE, 1998, pp. 1346-1350[
[61] S. C. Richard, The Complete Solder Paste Printing Processes, Surface Mount Technol‐ogy, Vol. 13, 1999, pp. 6-8[62] Peter Krippner, Detlef Beer, A
Neural Network, IEEE International Conference on Systems, Man and Cybernetics,Vol. 3, 2004, pp. 3051-3056[76] Feng Zhang, AEWMA Control Chart for
IEEE International Symposium on Intelligent Control Part of IEEE Multi-conferenceon Systems and Control Singapore, 1-3 October 2007, pp. 375-378[93] B
[106] Fan-Hui Kong, A New Method for Locating Solder Joint Based On Rough Set, Pro‐ceedings of the Sixth International Conference on Machine Learning
6. Inspections following SMT sequencesIn the SMT assembling process there are three main phases where AOI plays an importantrole; after-paste printing
[118] Andy Yates, Steven Brown, Jim Hauss, Paul Hudec, Inspection Strategies for 0201Components, CyberOptics Corporation 2002, First Publ
[131] D.W. Capson, S.K. Eng, A Tiered-Color Illumination Approach for Machine Inspec‐tion of Solder Joints, IEEE Transactions on Pattern Analysis and
[147] Agilent Medalist SJ50 Series 3, Automated Optical Inspection (AOI) and Measure‐ment, Data Sheet, Printed in the USA September, 2006, Upd
[165] Egidijus Paliulis, Raimondas Zemblys, Gintautas Daunys, Image Analysis Problemsin AOI Systems, Information Technology and Control, Vol.
[180] Dr. Kwangli Koh (Koh-Young), Eliminating False Calls With 3D AOI Technology,EPP Europe, Issue 4, 2009, pp. 40-43[181] Wei-Hung Su, K
[193] Akira Kusano, Takashi Watanabe, Takuma Funahashi, Takayuki Fujiwara, HiroyasuKoshimizu, 3D Inspection of Electronic Devices by Means of Stereo M
6.1. Solder paste inspectionAccording to PWB assemblers, it is very important that the quality of the print solder paste isinspected because it heavil
ManufacturerModelBoard size max. [mm x mm]Board size min. [mm x mm]Maximum board weight [kg]Maximum inspection area [mm]Maximum pad size in field of v
ManufacturerModelConveyor speed [mm/sec]Conveyor height [mm]Board warpVolume repeatability on a certification targetVolume repeatability on a circuit
6.2 Automatic placement inspectionInspection of the PWB after component placement is the next possibility. With this methodpossible placement failures
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