{"id":7241,"date":"2026-09-10T05:13:00","date_gmt":"2026-09-09T21:13:00","guid":{"rendered":"https:\/\/mellumeeyewear.com\/?p=7241"},"modified":"2026-09-03T14:26:24","modified_gmt":"2026-09-03T06:26:24","slug":"how-to-qc-titanium-frames-weld-inspection-bend-testing-and-surface-standards","status":"publish","type":"post","link":"https:\/\/mellumeeyewear.com\/pt\/how-to-qc-titanium-frames-weld-inspection-bend-testing-and-surface-standards\/","title":{"rendered":"How to QC Titanium Frames: Weld Inspection, Bend Testing, and Surface Standards"},"content":{"rendered":"<p class=\"wp-block-paragraph\"><a href=\"https:\/\/mellumeeyewear.com\/pt\/categoria-produto\/custom-titanium-optical-glasses\/\" style=\"color:#0073aa; text-decoration:underline; font-weight:500;\">Tit\u00e2nio<\/a> frame QC is a different discipline from <a href=\"https:\/\/mellumeeyewear.com\/pt\/categoria-produto\/custom-acetate-sunglasses\/\" style=\"color:#0073aa; text-decoration:underline; font-weight:500;\">acetate<\/a> or steel QC. The critical checks are weld integrity, bend resistance, surface finish, and dimensional tolerance \u2014 and each requires specific tools and procedures. A titanium frame that passes visual inspection can still fail catastrophically at the weld or crack invisibly under flexing.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">This guide covers what a proper titanium QC process looks like, so you can verify your factory&#8217;s process \u2014 or run your own incoming inspection.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">Why Titanium QC Is Different<\/h3>\n\n\n\n<figure class=\"wp-block-table\"><table><thead><tr><th>Material<\/th><th>Primary QC Focus<\/th><th>Failure Mode<\/th><\/tr><\/thead><tbody><tr><td>Acabamento e<\/td><td>Surface finish, color, symmetry<\/td><td>Scratches, color mismatch, warping<\/td><\/tr><tr><td>Steel<\/td><td>Cosmetic finish, hinge alignment<\/td><td>Corrosion, cosmetic defects<\/td><\/tr><tr><td>Tit\u00e2nio<\/td><td><strong>Weld integrity, bend resistance<\/strong><\/td><td><strong>Hidden cracks, weld failure, work-hardening cracks<\/strong><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">The difference: acetate and steel failures are visible. Titanium failures are often internal \u2014 a cracked weld looks fine until the frame snaps. This is why titanium QC must include destructive and semi-destructive testing, not just visual inspection.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">QC Check 1: Weld Integrity Inspection<\/h3>\n\n\n\n<h4 class=\"wp-block-heading\">Visual inspection (first pass)<\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">Under 3-5x magnification, check every weld joint for:<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table><thead><tr><th>Defect<\/th><th>What It Looks Like<\/th><th>Severity<\/th><\/tr><\/thead><tbody><tr><td>Porosity<\/td><td>Tiny pits or bubbles on weld surface<\/td><td>Critical \u2014 weakens joint<\/td><\/tr><tr><td>Cracking<\/td><td>Fine lines at weld edge or center<\/td><td>Critical \u2014 will propagate<\/td><\/tr><tr><td>Incomplete fusion<\/td><td>Gap or discontinuity at joint<\/td><td>Critical \u2014 joint not bonded<\/td><\/tr><tr><td>Discoloration<\/td><td>Blue\/purple\/grey tint around weld<\/td><td>High \u2014 oxygen contamination<\/td><\/tr><tr><td>Undercut<\/td><td>Groove at weld toe<\/td><td>High \u2014 stress concentration<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Important:<\/strong>&nbsp;Slight heat tint at the weld is not automatically a reject. A faint straw-gold tint is often acceptable (slight oxidation); blue-grey tint indicates contamination and should be rejected.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">Weld cross-section test (sampling)<\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">For each production batch, cut one sacrificial frame through the weld and inspect under 10x magnification:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Good weld:<\/strong>\u00a0Continuous, dense, no porosity, full penetration<\/li>\n\n\n\n<li><strong>Bad weld:<\/strong>\u00a0Porous, discontinuous, shallow penetration, inclusions<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">This destructive test is the only way to verify actual weld quality. A factory that refuses to do it is hiding something.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">QC Check 2: Bend Testing<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Titanium&#8217;s advantage is flexibility \u2014 but only if the frame can actually flex without cracking.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">The manual bend test<\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">For finished frames, trained QC staff perform a controlled bend test:<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li>Hold the frame front firmly<\/li>\n\n\n\n<li>Bend each temple outward to a defined angle (typically 20-30 degrees beyond normal)<\/li>\n\n\n\n<li>Release and check for:\n<ul class=\"wp-block-list\">\n<li><strong>Cracking sound<\/strong>\u00a0\u2014 immediate reject<\/li>\n\n\n\n<li><strong>Crack lines at the hinge or weld<\/strong>\u00a0\u2014 reject<\/li>\n\n\n\n<li><strong>Permanent deformation<\/strong>\u00a0(doesn&#8217;t return to shape) \u2014 check against spec<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li>Repeat 3-5 times per frame on sampling basis<\/li>\n<\/ol>\n\n\n\n<h4 class=\"wp-block-heading\">The fatigue test (for sport\/active collections)<\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">For frames marketed as flexible or sport-grade, use a mechanical fatigue tester:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Bend temple to 45 degrees, release, repeat 10,000-50,000 cycles<\/li>\n\n\n\n<li>Pass criteria: no cracking, no visible deformation, hinge still functions<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Most standard fashion frames do not need this test. But if your brand claims &#8220;flexible titanium,&#8221; your factory should be able to produce fatigue test data.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">QC Check 3: Surface Finish Standards<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Titanium&#8217;s surface finish determines both aesthetics and feel.<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table><thead><tr><th>Finish Type<\/th><th>Inspection Method<\/th><th>Pass Criteria<\/th><\/tr><\/thead><tbody><tr><td>Polished (mirror)<\/td><td>Reflectivity check under light<\/td><td>Uniform reflection, no swirl marks<\/td><\/tr><tr><td>Brushed \/ satin<\/td><td>Grain direction under raking light<\/td><td>Consistent grain, no cross-grain scratches<\/td><\/tr><tr><td>Matte<\/td><td>Tactile + visual<\/td><td>Even matte, no glossy patches<\/td><\/tr><tr><td>PVD coated<\/td><td>Adhesion + color check<\/td><td>No peeling, uniform color<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<h4 class=\"wp-block-heading\">PVD coating adhesion test<\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">If the frame has PVD (physical vapor deposition) coating:<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Tape test:<\/strong>\u00a0Apply adhesive tape to coated surface, pull firmly. Coating should not peel<\/li>\n\n\n\n<li><strong>Scratch test:<\/strong>\u00a0Light scratch with a calibrated tool. Coating should not flake<\/li>\n\n\n\n<li><strong>Salt spray test<\/strong>\u00a0(for high-end): 24-48 hours in salt spray chamber. Coating should show minimal corrosion<\/li>\n<\/ol>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">QC Check 4: Dimensional Tolerance<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Titanium frames require tighter tolerances than acetate:<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>Dimension<\/th><th>Standard Tolerance<\/th><\/tr><\/thead><tbody><tr><td>Hinge screw hole position<\/td><td>\u00b10.05mm<\/td><\/tr><tr><td>Frame front width<\/td><td>\u00b10.3mm<\/td><\/tr><tr><td>Temple length<\/td><td>\u00b10.5mm<\/td><\/tr><tr><td>Temple bend angle<\/td><td>\u00b10.5 degrees<\/td><\/tr><tr><td>Weld joint thickness<\/td><td>\u00b10.1mm<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<h4 class=\"wp-block-heading\">Tools required:<\/h4>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Digital caliper<\/strong>\u00a0\u2014 for linear dimensions<\/li>\n\n\n\n<li><strong>CMM (coordinate measuring machine)<\/strong>\u00a0\u2014 for critical positions (hinge holes, angles)<\/li>\n\n\n\n<li><strong>Feeler gauges<\/strong>\u00a0\u2014 for gap measurements<\/li>\n\n\n\n<li><strong>Angle gauge<\/strong>\u00a0\u2014 for temple bend angles<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">A factory that only uses calipers cannot verify hinge hole positions to 0.05mm. Ask what measuring equipment they use.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">QC Check 5: The Final Wear Test<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Before packing, QC staff should wear-test a sampling of frames:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Put the frame on for 10 seconds \u2014 check for pressure points, slippage, temple tension<\/li>\n\n\n\n<li>Open and close hinges 20 times \u2014 smoothness, resistance, any clicking<\/li>\n\n\n\n<li>Squeeze the frame gently \u2014 no cracking sound, returns to shape<\/li>\n\n\n\n<li>Check temple tips against skin \u2014 smooth, no sharp edges<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">This is the same test a customer will do at retail \u2014 it should happen at the factory first.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">What to Ask Your Factory<\/h3>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>Question<\/th><th>Good Answer<\/th><th>Red Flag<\/th><\/tr><\/thead><tbody><tr><td>&#8220;Do you do weld cross-section testing?&#8221;<\/td><td>&#8220;Yes, one per batch&#8221;<\/td><td>&#8220;We don&#8217;t cut good frames&#8221;<\/td><\/tr><tr><td>&#8220;What&#8217;s your bend test procedure?&#8221;<\/td><td>Specific angles and cycle counts<\/td><td>&#8220;We bend-check by hand&#8221;<\/td><\/tr><tr><td>&#8220;What measuring equipment do you use?&#8221;<\/td><td>&#8220;CMM for hinge positions&#8221;<\/td><td>&#8220;Calipers&#8221;<\/td><\/tr><tr><td>&#8220;Can I see a fatigue test report?&#8221;<\/td><td>&#8220;Here&#8217;s one from last batch&#8221;<\/td><td>&#8220;We don&#8217;t do that&#8221;<\/td><\/tr><tr><td>&#8220;What&#8217;s your titanium reject rate?&#8221;<\/td><td>Honest number (5-15% is realistic)<\/td><td>&#8220;Almost zero&#8221; (unlikely)<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">Frequently Asked Questions<\/h3>\n\n\n\n<h4 class=\"wp-block-heading\">What&#8217;s a realistic titanium frame reject rate?<\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">5-15% at final QC is normal. Zero rejects is suspicious \u2014 it usually means QC is not rigorous enough to find defects.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">Can I inspect titanium frames myself without equipment?<\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">Basic checks yes (bend test, visual weld check, hinge function). Precision checks need tools. For significant orders, third-party inspection with proper equipment is worth the cost.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">How do I know if a weld is actually titanium and not glued?<\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">Weld cross-section inspection. A glued joint shows a glue line; a welded joint shows continuous <a href=\"https:\/\/mellumeeyewear.com\/pt\/categoria-produto\/custom-metal-sunglasses\/\" style=\"color:#0073aa; text-decoration:underline; font-weight:500;\">metal<\/a>. Also, glued frames fail the bend test \u2014 the joint separates.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">Is every titanium frame PVD coated?<\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">No. PVD is an option, not a standard. Many premium titanium frames are uncoated \u2014 the bare titanium finish is part of the aesthetic.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<p class=\"wp-block-paragraph\"><a href=\"https:\/\/mellumeeyewear.com\/pt\/contact\/\"><strong>Get our titanium QC documentation \u2192<\/strong><\/a><\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><\/p>","protected":false},"excerpt":{"rendered":"<p>Titanium frame QC is a different discipline from acetate or steel QC. The critical checks are weld integrity, bend resistance, [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":7244,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_uag_custom_page_level_css":"","site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"set","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[74],"tags":[],"class_list":["post-7241","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-industry-news"],"mb":[],"uagb_featured_image_src":{"full":["https:\/\/mellumeeyewear.com\/wp-content\/uploads\/2026\/09\/How-to-QC-Titanium-Frames-1.png",1200,675,false],"thumbnail":["https:\/\/mellumeeyewear.com\/wp-content\/uploads\/2026\/09\/How-to-QC-Titanium-Frames-1-150x150.png",150,150,true],"medium":["https:\/\/mellumeeyewear.com\/wp-content\/uploads\/2026\/09\/How-to-QC-Titanium-Frames-1-300x169.png",300,169,true],"medium_large":["https:\/\/mellumeeyewear.com\/wp-content\/uploads\/2026\/09\/How-to-QC-Titanium-Frames-1-768x432.png",768,432,true],"large":["https:\/\/mellumeeyewear.com\/wp-content\/uploads\/2026\/09\/How-to-QC-Titanium-Frames-1-1024x576.png",1024,576,true],"1536x1536":["https:\/\/mellumeeyewear.com\/wp-content\/uploads\/2026\/09\/How-to-QC-Titanium-Frames-1.png",1200,675,false],"2048x2048":["https:\/\/mellumeeyewear.com\/wp-content\/uploads\/2026\/09\/How-to-QC-Titanium-Frames-1.png",1200,675,false],"trp-custom-language-flag":["https:\/\/mellumeeyewear.com\/wp-content\/uploads\/2026\/09\/How-to-QC-Titanium-Frames-1.png",18,10,false],"woocommerce_thumbnail":["https:\/\/mellumeeyewear.com\/wp-content\/uploads\/2026\/09\/How-to-QC-Titanium-Frames-1-500x500.png",500,500,true],"woocommerce_single":["https:\/\/mellumeeyewear.com\/wp-content\/uploads\/2026\/09\/How-to-QC-Titanium-Frames-1-1000x563.png",1000,563,true],"woocommerce_gallery_thumbnail":["https:\/\/mellumeeyewear.com\/wp-content\/uploads\/2026\/09\/How-to-QC-Titanium-Frames-1-100x100.png",100,100,true]},"uagb_author_info":{"display_name":"Mellume","author_link":"https:\/\/mellumeeyewear.com\/pt\/author\/peterdu8170gmail-com\/"},"uagb_comment_info":0,"uagb_excerpt":"Titanium frame QC is a different discipline from acetate or steel QC. The critical checks are weld integrity, bend resistance, [&hellip;]","mfb_rest_fields":["title","uagb_featured_image_src","uagb_author_info","uagb_comment_info","uagb_excerpt"],"_links":{"self":[{"href":"https:\/\/mellumeeyewear.com\/pt\/wp-json\/wp\/v2\/posts\/7241","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/mellumeeyewear.com\/pt\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mellumeeyewear.com\/pt\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mellumeeyewear.com\/pt\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/mellumeeyewear.com\/pt\/wp-json\/wp\/v2\/comments?post=7241"}],"version-history":[{"count":1,"href":"https:\/\/mellumeeyewear.com\/pt\/wp-json\/wp\/v2\/posts\/7241\/revisions"}],"predecessor-version":[{"id":7243,"href":"https:\/\/mellumeeyewear.com\/pt\/wp-json\/wp\/v2\/posts\/7241\/revisions\/7243"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/mellumeeyewear.com\/pt\/wp-json\/wp\/v2\/media\/7244"}],"wp:attachment":[{"href":"https:\/\/mellumeeyewear.com\/pt\/wp-json\/wp\/v2\/media?parent=7241"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mellumeeyewear.com\/pt\/wp-json\/wp\/v2\/categories?post=7241"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mellumeeyewear.com\/pt\/wp-json\/wp\/v2\/tags?post=7241"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}