[{"data":1,"prerenderedAt":397},["ShallowReactive",2],{"blog-aoi-inspection-pcba-en":3,"header-nav-en":69},{"title":4,"description":5,"date":6,"category":7,"image":8,"readingTime":9,"wordCount":10,"timeRequired":11,"htmlContent":12,"tags":13,"slug":19,"jsonld":20},"What AOI Inspection in PCBA Checks, Where It Fits, and What It Cannot Prove","A practical engineering guide to AOI inspection in PCBA, covering what AOI actually checks, where it fits relative to SPI, X-ray, ICT, and FCT, and how to review its limits before release.","2026-05-13","technology","/blog-cover/aoi-inspection-pcba.svg?title=What+AOI+Inspection+in+PCBA+Checks%2C+Where+It+Fits%2C+and+What+It+Cannot+Prove&category=technology",10,1937,"PT10M","\u003Cul>\n\u003Cli>AOI inspection in PCBA should be treated as a \u003Cstrong>visible-defect screening layer\u003C/strong>, not as a generic proof that the board is fully tested.\u003C/li>\n\u003Cli>The most useful boundary is simple: SPI checks solder paste before reflow, AOI checks visible assembly geometry and solder features, and X-ray or electrical test answer different questions later.\u003C/li>\n\u003Cli>A board can pass AOI and still fail X-ray, ICT, flying probe, or FCT because those methods cover hidden joints, electrical faults, or powered behavior that AOI does not own.\u003C/li>\n\u003Cli>The safest way to review AOI is to ask what visible defects it is supposed to catch, where it sits in the build flow, and what evidence still has to come after it.\u003C/li>\n\u003Cli>If the build includes dense hidden-joint packages, mixed-process routing, or unstable first-build inputs, AOI should be planned as one layer in a larger quality path instead of the whole quality story.\u003C/li>\n\u003C/ul>\n\u003Cblockquote>\n\u003Cp>\u003Cstrong>Quick Answer\u003C/strong>\nAOI inspection in PCBA is an optical inspection method for visible assembly defects such as placement, polarity, geometry, and solder-feature issues. It usually belongs around pre-reflow or post-reflow inspection, but it does not replace SPI, X-ray, ICT, flying probe, or functional test. The key decision is not whether AOI is useful, but which visible risks it owns and which risks still belong to later gates.\u003C/p>\n\u003C/blockquote>\n\u003Cp>For the broader quality-stack view that connects BOM control, inspection layers, electrical verification, and release gates, start with the \u003Ca href=\"/en/blog/pcba-assembly-test-quality-guide\">PCBA Assembly Test and Quality Guide\u003C/a>.\u003C/p>\n\u003Ch2 id=\"table-of-contents\" data-anchor-en=\"table-of-contents\">Table of Contents\u003C/h2>\n\u003Cul>\n\u003Cli>\u003Ca href=\"#first-review\">What should engineers look at first?\u003C/a>\u003C/li>\n\u003Cli>\u003Ca href=\"#what-it-means\">What does AOI inspection in PCBA actually mean?\u003C/a>\u003C/li>\n\u003Cli>\u003Ca href=\"#what-aoi-owns\">What defects does AOI really own?\u003C/a>\u003C/li>\n\u003Cli>\u003Ca href=\"#method-boundaries\">How does AOI differ from SPI, X-ray, and electrical test?\u003C/a>\u003C/li>\n\u003Cli>\u003Ca href=\"#when-it-matters-more\">When does AOI become more important in a build?\u003C/a>\u003C/li>\n\u003Cli>\u003Ca href=\"#freeze-before-release\">What should be frozen before relying on AOI results?\u003C/a>\u003C/li>\n\u003Cli>\u003Ca href=\"#next-steps\">Next steps with APTPCB\u003C/a>\u003C/li>\n\u003Cli>\u003Ca href=\"#faq\">FAQ\u003C/a>\u003C/li>\n\u003Cli>\u003Ca href=\"#references\">Public references\u003C/a>\u003C/li>\n\u003Cli>\u003Ca href=\"#author\">Author and review information\u003C/a>\u003C/li>\n\u003C/ul>\n\u003Ca id=\"first-review\">\u003C/a>\n\u003Ch2 id=\"what-should-engineers-look-at-first\" data-anchor-en=\"what-should-engineers-look-at-first\">What should engineers look at first?\u003C/h2>\n\u003Cp>Start with \u003Cstrong>inspection stage, visible-defect ownership, package visibility, and downstream test dependency\u003C/strong>.\u003C/p>\n\u003Cp>That order matters because AOI is often discussed too broadly. The better question is not \u003Ccode>Do we have AOI?\u003C/code> The better question is:\u003C/p>\n\u003Cp>\u003Cstrong>What visible defect classes should AOI catch before the board moves to hidden-joint inspection, electrical verification, or functional release?\u003C/strong>\u003C/p>\n\u003Cp>The first review questions should be:\u003C/p>\n\u003Col>\n\u003Cli>Is AOI being used before reflow, after reflow, or both?\u003C/li>\n\u003Cli>Which defects are actually visible on this assembly?\u003C/li>\n\u003Cli>Are there package types or regions that AOI cannot see well enough?\u003C/li>\n\u003Cli>What later test layer still has to confirm hidden joints, electrical faults, or powered behavior?\u003C/li>\n\u003C/ol>\n\u003Ctable>\n\u003Cthead>\n\u003Ctr>\n\u003Cth>Review axis\u003C/th>\n\u003Cth>What to check\u003C/th>\n\u003Cth>Why it matters\u003C/th>\n\u003Cth>What AOI alone does not prove\u003C/th>\n\u003C/tr>\n\u003C/thead>\n\u003Ctbody>\u003Ctr>\n\u003Ctd>Inspection stage\u003C/td>\n\u003Ctd>Whether AOI sits before reflow, after reflow, or in both positions\u003C/td>\n\u003Ctd>The stage changes what defects AOI can see\u003C/td>\n\u003Ctd>Full end-of-line quality\u003C/td>\n\u003C/tr>\n\u003Ctr>\n\u003Ctd>Visible-defect scope\u003C/td>\n\u003Ctd>Whether the program is using AOI for placement, polarity, geometry, or solder-feature review\u003C/td>\n\u003Ctd>AOI only helps if the defect is optically visible\u003C/td>\n\u003Ctd>Hidden-joint integrity\u003C/td>\n\u003C/tr>\n\u003Ctr>\n\u003Ctd>Package visibility\u003C/td>\n\u003Ctd>Whether tall parts, shadowing, bottom-terminated packages, or dense areas reduce optical confidence\u003C/td>\n\u003Ctd>Optical access limits inspection value early\u003C/td>\n\u003Ctd>That difficult areas are defect-free\u003C/td>\n\u003C/tr>\n\u003Ctr>\n\u003Ctd>Downstream dependency\u003C/td>\n\u003Ctd>Which later gates still own electrical or functional proof\u003C/td>\n\u003Ctd>AOI is part of a stack, not the whole stack\u003C/td>\n\u003Ctd>Powered behavior or release authority\u003C/td>\n\u003C/tr>\n\u003C/tbody>\u003C/table>\n\u003Ca id=\"what-it-means\">\u003C/a>\n\u003Ch2 id=\"what-does-aoi-inspection-in-pcba-actually-mean\" data-anchor-en=\"what-does-aoi-inspection-in-pcba-actually-mean\">What does AOI inspection in PCBA actually mean?\u003C/h2>\n\u003Cp>In this context, \u003Ccode>AOI inspection in PCBA\u003C/code> means \u003Cstrong>optical inspection of assembled-board features that are visible to the inspection system\u003C/strong>.\u003C/p>\n\u003Cp>That usually includes:\u003C/p>\n\u003Cul>\n\u003Cli>component presence\u003C/li>\n\u003Cli>orientation and polarity\u003C/li>\n\u003Cli>placement shift or skew\u003C/li>\n\u003Cli>visible solder-geometry issues\u003C/li>\n\u003Cli>bridging or insufficient visible solder features\u003C/li>\n\u003Cli>some contamination or visible surface anomalies\u003C/li>\n\u003C/ul>\n\u003Cp>It does not mean:\u003C/p>\n\u003Cul>\n\u003Cli>hidden-joint inspection under every package\u003C/li>\n\u003Cli>fixture-based electrical verification\u003C/li>\n\u003Cli>powered functional behavior\u003C/li>\n\u003Cli>final shipment release by itself\u003C/li>\n\u003C/ul>\n\u003Cp>That boundary is important because many weak AOI articles quietly turn AOI into a synonym for \u003Ccode>quality control\u003C/code>. It is not.\u003C/p>\n\u003Cp>AOI is strongest when the build risk is still visible on the surface of the assembly. Once the question becomes hidden-joint integrity, node-level electrical fault detection, or powered function, other methods have to take over.\u003C/p>\n\u003Ca id=\"what-aoi-owns\">\u003C/a>\n\u003Ch2 id=\"what-defects-does-aoi-really-own\" data-anchor-en=\"what-defects-does-aoi-really-own\">What defects does AOI really own?\u003C/h2>\n\u003Cp>AOI owns the defects that can be inspected as visible geometry and visible solder features.\u003C/p>\n\u003Ctable>\n\u003Cthead>\n\u003Ctr>\n\u003Cth>Defect class\u003C/th>\n\u003Cth>Why AOI is useful\u003C/th>\n\u003Cth>What still may be needed later\u003C/th>\n\u003C/tr>\n\u003C/thead>\n\u003Ctbody>\u003Ctr>\n\u003Ctd>Missing or misplaced components\u003C/td>\n\u003Ctd>Optical presence and location are visible\u003C/td>\n\u003Ctd>Electrical test to confirm the board still behaves correctly\u003C/td>\n\u003C/tr>\n\u003Ctr>\n\u003Ctd>Polarity or orientation issues\u003C/td>\n\u003Ctd>Surface markings and placement direction can often be reviewed optically\u003C/td>\n\u003Ctd>Functional proof if the part orientation changes behavior in-system\u003C/td>\n\u003C/tr>\n\u003Ctr>\n\u003Ctd>Skew, shift, or tombstoning\u003C/td>\n\u003Ctd>Assembly geometry is visible after placement or reflow\u003C/td>\n\u003Ctd>Process feedback to determine why the defect happened\u003C/td>\n\u003C/tr>\n\u003Ctr>\n\u003Ctd>Visible solder bridging or insufficient visible wetting\u003C/td>\n\u003Ctd>Optical inspection can flag visible solder-shape anomalies\u003C/td>\n\u003Ctd>X-ray if the concern moves under hidden-joint packages\u003C/td>\n\u003C/tr>\n\u003Ctr>\n\u003Ctd>Surface contamination or obvious visual anomalies\u003C/td>\n\u003Ctd>AOI can contribute where the issue is visually exposed\u003C/td>\n\u003Ctd>Separate cleanliness or release review when the risk goes beyond visible appearance\u003C/td>\n\u003C/tr>\n\u003C/tbody>\u003C/table>\n\u003Cp>This is why AOI is often valuable as both:\u003C/p>\n\u003Cul>\n\u003Cli>a defect-screening layer\u003C/li>\n\u003Cli>a process-feedback layer for the assembly line\u003C/li>\n\u003C/ul>\n\u003Cp>But the language still needs discipline:\u003C/p>\n\u003Cp>\u003Cstrong>AOI can show that the visible assembly looks wrong, or appears acceptable within the optical view. It cannot prove every important defect is visible.\u003C/strong>\u003C/p>\n\u003Ca id=\"method-boundaries\">\u003C/a>\n\u003Ch2 id=\"how-does-aoi-differ-from-spi-x-ray-and-electrical-test\" data-anchor-en=\"how-does-aoi-differ-from-spi-x-ray-and-electrical-test\">How does AOI differ from SPI, X-ray, and electrical test?\u003C/h2>\n\u003Cp>AOI becomes easier to explain when it stays in its own lane.\u003C/p>\n\u003Ctable>\n\u003Cthead>\n\u003Ctr>\n\u003Cth>Method\u003C/th>\n\u003Cth>What it mainly answers\u003C/th>\n\u003Cth>What it does not replace\u003C/th>\n\u003C/tr>\n\u003C/thead>\n\u003Ctbody>\u003Ctr>\n\u003Ctd>SPI\u003C/td>\n\u003Ctd>Whether solder paste deposition is in control before placement and reflow\u003C/td>\n\u003Ctd>Post-reflow optical inspection or assembled-board electrical verification\u003C/td>\n\u003C/tr>\n\u003Ctr>\n\u003Ctd>AOI\u003C/td>\n\u003Ctd>Whether visible placement, polarity, geometry, and solder features look acceptable\u003C/td>\n\u003Ctd>Hidden-joint inspection, electrical defect screening, or functional behavior proof\u003C/td>\n\u003C/tr>\n\u003Ctr>\n\u003Ctd>X-ray\u003C/td>\n\u003Ctd>Whether hidden joints and concealed solder areas need inspection evidence\u003C/td>\n\u003Ctd>Surface optical review or end-use functional testing\u003C/td>\n\u003C/tr>\n\u003Ctr>\n\u003Ctd>ICT or flying probe\u003C/td>\n\u003Ctd>Whether the assembled board has electrical faults such as opens, shorts, or component issues\u003C/td>\n\u003Ctd>Visible-geometry inspection or powered behavior validation\u003C/td>\n\u003C/tr>\n\u003Ctr>\n\u003Ctd>FCT\u003C/td>\n\u003Ctd>Whether the assembled board works in its intended powered context\u003C/td>\n\u003Ctd>Upstream defect localization or visual inspection\u003C/td>\n\u003C/tr>\n\u003C/tbody>\u003C/table>\n\u003Cp>That table matters because several common misreadings happen over and over:\u003C/p>\n\u003Cul>\n\u003Cli>AOI is treated as if it makes X-ray unnecessary\u003C/li>\n\u003Cli>AOI is treated as if it proves the board is electrically correct\u003C/li>\n\u003Cli>AOI is treated as if it can replace functional test\u003C/li>\n\u003Cli>SPI and AOI are described as interchangeable because both are inspection tools\u003C/li>\n\u003C/ul>\n\u003Cp>Those claims are weak because they collapse different gates into one word: \u003Ccode>inspection\u003C/code>.\u003C/p>\n\u003Cp>Related reading:\u003C/p>\n\u003Cul>\n\u003Cli>\u003Ca href=\"/en/pcba/aoi-inspection\">AOI Inspection\u003C/a>\u003C/li>\n\u003Cli>\u003Ca href=\"/en/pcba/spi-inspection\">SPI Inspection\u003C/a>\u003C/li>\n\u003Cli>\u003Ca href=\"/en/pcba/xray-inspection\">X-Ray Inspection\u003C/a>\u003C/li>\n\u003Cli>\u003Ca href=\"/en/pcba/testing-quality\">Testing & Quality\u003C/a>\u003C/li>\n\u003Cli>\u003Ca href=\"/en/blog/spi-vs-aoi-when-to-run-each-in-pcba\">SPI vs AOI: When to Run Each in PCBA\u003C/a>\u003C/li>\n\u003C/ul>\n\u003Ca id=\"when-it-matters-more\">\u003C/a>\n\u003Ch2 id=\"when-does-aoi-become-more-important-in-a-build\" data-anchor-en=\"when-does-aoi-become-more-important-in-a-build\">When does AOI become more important in a build?\u003C/h2>\n\u003Cp>AOI matters more when \u003Cstrong>visible assembly discipline is a major early risk\u003C/strong>.\u003C/p>\n\u003Cp>That usually includes:\u003C/p>\n\u003Cul>\n\u003Cli>builds with dense SMT placement\u003C/li>\n\u003Cli>boards where polarity and orientation mistakes are expensive to catch later\u003C/li>\n\u003Cli>assemblies where visible solder geometry is an early process signal\u003C/li>\n\u003Cli>programs where first-build learning still depends on strong process feedback\u003C/li>\n\u003Cli>repeat builds where optical screening helps stop visible defects before later gates waste time\u003C/li>\n\u003C/ul>\n\u003Cp>AOI also becomes more important when the team wants faster feedback between print, placement, and reflow behavior. In that role, AOI is not just a pass-fail checkpoint. It becomes part of process governance.\u003C/p>\n\u003Cp>At the same time, AOI becomes less complete when:\u003C/p>\n\u003Cul>\n\u003Cli>hidden-joint packages dominate the risk\u003C/li>\n\u003Cli>tall parts or shadowing reduce visibility\u003C/li>\n\u003Cli>the main failure concern is electrical rather than optical\u003C/li>\n\u003Cli>the board still lacks a stable assembly package and later defects are more likely to be input-driven\u003C/li>\n\u003C/ul>\n\u003Cp>The governing rule is:\u003C/p>\n\u003Cp>\u003Cstrong>use AOI to own visible defects early, but do not ask it to certify risks that sit outside optical visibility.\u003C/strong>\u003C/p>\n\u003Ca id=\"freeze-before-release\">\u003C/a>\n\u003Ch2 id=\"what-should-be-frozen-before-relying-on-aoi-results\" data-anchor-en=\"what-should-be-frozen-before-relying-on-aoi-results\">What should be frozen before relying on AOI results?\u003C/h2>\n\u003Cp>Before AOI results are used as real release evidence, freeze:\u003C/p>\n\u003Col>\n\u003Cli>the assembly package, including placement and polarity intent\u003C/li>\n\u003Cli>the inspection stage, including whether AOI is pre-reflow, post-reflow, or both\u003C/li>\n\u003Cli>the package-visibility assumptions, especially where hidden joints or shadowing matter\u003C/li>\n\u003Cli>the downstream gate plan for X-ray, electrical test, or functional validation where required\u003C/li>\n\u003Cli>the release boundary between visible-defect screening and final shipment confidence\u003C/li>\n\u003C/ol>\n\u003Cp>If those items are still moving, AOI can still provide useful process feedback, but it should not be overstated as complete product proof.\u003C/p>\n\u003Ca id=\"next-steps\">\u003C/a>\n\u003Ch2 id=\"next-steps-with-aptpcb\" data-anchor-en=\"next-steps-with-aptpcb\">Next steps with APTPCB\u003C/h2>\n\u003Cp>If your build is being slowed by unclear AOI coverage, confusion between SPI and AOI, hidden-joint package risk, or uncertainty about what optical inspection should catch before ICT, flying probe, or functional test, send the BOM, assembly drawing, package list, and test expectations to \u003Ca href=\"mailto:sales@aptpcb.com\">sales@aptpcb.com\u003C/a> or upload the files through the \u003Ca href=\"/en/quote\">quote page\u003C/a>. APTPCB's engineering team can return DFM feedback within 24 hours and point out whether the main gap sits in assembly definition, optical visibility, hidden-joint planning, or later electrical-test ownership.\u003C/p>\n\u003Cp>If you need deeper context before release, review:\u003C/p>\n\u003Cul>\n\u003Cli>\u003Ca href=\"/en/blog/pcba-assembly-test-quality-guide\">PCBA Assembly Test and Quality Guide\u003C/a>\u003C/li>\n\u003Cli>\u003Ca href=\"/en/pcba/aoi-inspection\">AOI Inspection\u003C/a>\u003C/li>\n\u003Cli>\u003Ca href=\"/en/pcba/spi-inspection\">SPI Inspection\u003C/a>\u003C/li>\n\u003Cli>\u003Ca href=\"/en/pcba/xray-inspection\">X-Ray Inspection\u003C/a>\u003C/li>\n\u003Cli>\u003Ca href=\"/en/pcba/testing-quality\">Testing & Quality\u003C/a>\u003C/li>\n\u003C/ul>\n\u003Cdiv data-component=\"BlogQuickQuoteInline\">\u003C/div>\n\n\u003Ca id=\"faq\">\u003C/a>\n\u003Ch2 id=\"faq\" data-anchor-en=\"faq\">FAQ\u003C/h2>\n\u003C!-- faq:start -->\n\n\u003Ch3 id=\"can-aoi-inspection-prove-a-pcba-is-fully-tested\" data-anchor-en=\"can-aoi-inspection-prove-a-pcba-is-fully-tested\">Can AOI inspection prove a PCBA is fully tested?\u003C/h3>\n\u003Cp>No. AOI proves only what the optical inspection layer is responsible for. Hidden-joint, electrical, and functional questions still belong to other gates.\u003C/p>\n\u003Ch3 id=\"is-aoi-the-same-as-spi\" data-anchor-en=\"is-aoi-the-same-as-spi\">Is AOI the same as SPI?\u003C/h3>\n\u003Cp>No. SPI checks solder paste before reflow. AOI checks visible assembly features around placement or after reflow.\u003C/p>\n\u003Ch3 id=\"if-a-board-passes-aoi-do-i-still-need-x-ray\" data-anchor-en=\"if-a-board-passes-aoi-do-i-still-need-x-ray\">If a board passes AOI, do I still need X-ray?\u003C/h3>\n\u003Cp>Sometimes yes. If the risk sits under BGA, QFN, LGA, or other hidden-joint structures, AOI does not replace X-ray.\u003C/p>\n\u003Ch3 id=\"can-aoi-replace-ict-or-flying-probe\" data-anchor-en=\"can-aoi-replace-ict-or-flying-probe\">Can AOI replace ICT or flying probe?\u003C/h3>\n\u003Cp>No. AOI is an optical method. ICT and flying probe are electrical-verification methods for different defect classes.\u003C/p>\n\u003Ch3 id=\"what-is-the-most-common-mistake-in-aoi-planning\" data-anchor-en=\"what-is-the-most-common-mistake-in-aoi-planning\">What is the most common mistake in AOI planning?\u003C/h3>\n\u003Cp>Treating AOI as the whole quality plan instead of one visible-defect layer inside a larger inspection and test stack.\u003C/p>\n\u003C!-- faq:end -->\n\n\u003Ca id=\"references\">\u003C/a>\n\u003Ch2 id=\"public-references\" data-anchor-en=\"public-references\">Public references\u003C/h2>\n\u003Col>\n\u003Cli>\u003Cp>\u003Ca href=\"/en/pcba/aoi-inspection\">APTPCB AOI Inspection\u003C/a>\nSupports AOI as an optical inspection layer for visible PCB and PCBA defect classes.\u003C/p>\n\u003C/li>\n\u003Cli>\u003Cp>\u003Ca href=\"/en/pcba/spi-inspection\">APTPCB SPI Inspection\u003C/a>\nSupports the upstream role of SPI before placement and reflow.\u003C/p>\n\u003C/li>\n\u003Cli>\u003Cp>\u003Ca href=\"/en/pcba/xray-inspection\">APTPCB X-Ray Inspection\u003C/a>\nSupports the hidden-joint inspection boundary that AOI does not replace.\u003C/p>\n\u003C/li>\n\u003Cli>\u003Cp>\u003Ca href=\"/en/pcba/quality-system\">APTPCB Quality System\u003C/a>\nSupports the broader layered quality flow around SPI, AOI, X-ray, ICT, and FCT.\u003C/p>\n\u003C/li>\n\u003Cli>\u003Cp>\u003Ca href=\"https://kohyoung.com/en/automated-optical-inspection-technology\">Koh Young: Automated Optical Inspection Technology\u003C/a>\nSupports AOI as an optical inspection method for components, solder joints, patterns, and foreign material.\u003C/p>\n\u003C/li>\n\u003Cli>\u003Cp>\u003Ca href=\"https://kohyoung.com/en/solder-paste-inspection-technology\">Koh Young: Solder Paste Inspection Technology\u003C/a>\nSupports the stage boundary between SPI paste measurement and later AOI inspection.\u003C/p>\n\u003C/li>\n\u003Cli>\u003Cp>\u003Ca href=\"https://www.keysight.com/us/en/products/in-circuit-test-for-manufacturing/in-circuit-test-systems.html\">Keysight: In-Circuit Test Systems\u003C/a>\nSupports ICT as a separate electrical-verification layer rather than an optical-inspection function.\u003C/p>\n\u003C/li>\n\u003C/ol>\n\u003Ca id=\"author\">\u003C/a>\n\u003Ch2 id=\"author-and-review-information\" data-anchor-en=\"author-and-review-information\">Author and review information\u003C/h2>\n\u003Cul>\n\u003Cli>Author: APTPCB PCBA inspection and process content team\u003C/li>\n\u003Cli>Technical review: AOI, SPI, X-ray, and electrical-test planning engineering team\u003C/li>\n\u003Cli>Last updated: 2026-05-13\u003C/li>\n\u003C/ul>\n\n\u003Csection class=\"related-links\" aria-label=\"Related\">\u003Ch3>Related links\u003C/h3>\u003Cul>\u003Cli>\u003Ca href=\"/en/blog/pcba-assembly-test-quality-guide\">PCBA Assembly Test and Quality Guide\u003C/a>\u003C/li>\u003Cli>\u003Ca href=\"/en/pcba/aoi-inspection\">AOI Inspection\u003C/a>\u003C/li>\u003Cli>\u003Ca href=\"/en/pcba/spi-inspection\">SPI Inspection\u003C/a>\u003C/li>\u003Cli>\u003Ca href=\"/en/pcba/xray-inspection\">X-Ray Inspection\u003C/a>\u003C/li>\u003Cli>\u003Ca href=\"/en/pcba/testing-quality\">Testing & Quality\u003C/a>\u003C/li>\u003Cli>\u003Ca href=\"/en/blog/spi-vs-aoi-when-to-run-each-in-pcba\">SPI vs AOI: When to Run Each in PCBA\u003C/a>\u003C/li>\u003Cli>\u003Ca href=\"/en/quote\">quote page\u003C/a>\u003C/li>\u003C/ul>\u003C/section>",[14,15,16,17,18],"aoi inspection pcba","aoi inspection","pcba inspection","spi vs aoi","xray inspection","aoi-inspection-pcba",{"blog":21,"breadcrumb":30,"faq":44},{"@context":22,"@type":23,"headline":4,"description":5,"image":8,"url":24,"datePublished":6,"dateModified":6,"timeRequired":11,"keywords":25,"articleSection":7,"author":26,"publisher":29},"https://schema.org","BlogPosting","https://aptpcb.com/en/blog/aoi-inspection-pcba","aoi inspection pcba, aoi inspection, pcba inspection, spi vs aoi, xray inspection",{"@type":27,"name":28},"Organization","APTPCB",{"@type":27,"name":28},{"@context":22,"@type":31,"itemListElement":32},"BreadcrumbList",[33,38,42],{"@type":34,"position":35,"name":36,"item":37},"ListItem",1,"Home","https://aptpcb.com/",{"@type":34,"position":39,"name":40,"item":41},2,"Blog","https://aptpcb.com/en/blog",{"@type":34,"position":43,"name":19,"item":24},3,{"@context":22,"@type":45,"mainEntity":46},"FAQPage",[47,53,57,61,65],{"@type":48,"name":49,"acceptedAnswer":50},"Question","Can AOI inspection prove a PCBA is fully tested?",{"@type":51,"text":52},"Answer","No. AOI proves only what the optical inspection layer is responsible for. Hidden-joint, electrical, and functional questions still belong to other gates.",{"@type":48,"name":54,"acceptedAnswer":55},"Is AOI the same as SPI?",{"@type":51,"text":56},"No. SPI checks solder paste before reflow. AOI checks visible assembly features around placement or after reflow.",{"@type":48,"name":58,"acceptedAnswer":59},"If a board passes AOI, do I still need X-ray?",{"@type":51,"text":60},"Sometimes yes. If the risk sits under BGA, QFN, LGA, or other hidden-joint structures, AOI does not replace X-ray.",{"@type":48,"name":62,"acceptedAnswer":63},"Can AOI replace ICT or flying probe?",{"@type":51,"text":64},"No. AOI is an optical method. ICT and flying probe are electrical-verification methods for different defect classes.",{"@type":48,"name":66,"acceptedAnswer":67},"What is the most common mistake in AOI planning?",{"@type":51,"text":68},"Treating AOI as the whole quality plan instead of one visible-defect layer inside a larger inspection and test stack.",{"pcbManufacturingColumns":70,"capabilityColumns":195,"resourceColumns":226,"pcbaColumns":266},[71,119,148,177],{"heading":72,"links":73},"PCB Product Families",[74,77,80,83,86,89,92,95,98,101,104,107,110,113,116],{"label":75,"path":76},"FR-4 PCB","/pcb/fr4-pcb",{"label":78,"path":79},"High-Speed PCB","/pcb/high-speed-pcb",{"label":81,"path":82},"Multilayer PCB","/pcb/multilayer-pcb",{"label":84,"path":85},"HDI PCB","/pcb/hdi-pcb",{"label":87,"path":88},"Flexible PCB","/pcb/flex-pcb",{"label":90,"path":91},"Rigid Flex PCB","/pcb/rigid-flex-pcb",{"label":93,"path":94},"Ceramic PCB","/pcb/ceramic-pcb",{"label":96,"path":97},"Heavy Copper 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