{"id":31055,"date":"2026-07-28T14:09:39","date_gmt":"2026-07-28T12:09:39","guid":{"rendered":"https:\/\/www.lampert.info\/helium-leak-test-guide\/"},"modified":"2026-07-31T17:41:22","modified_gmt":"2026-07-31T15:41:22","slug":"helium-leak-test-guide","status":"publish","type":"post","link":"https:\/\/www.lampert.info\/en\/helium-leak-test-guide\/","title":{"rendered":"Helium leak test: a practical guide to hermetic welds"},"content":{"rendered":"\t\t<div data-elementor-type=\"wp-post\" data-elementor-id=\"31055\" class=\"elementor elementor-31055 elementor-30369\" data-elementor-post-type=\"post\">\n\t\t\t\t\t\t<section data-particle_enable=\"false\" data-particle-mobile-disabled=\"false\" class=\"elementor-section elementor-top-section elementor-element elementor-element-7e8c254 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"7e8c254\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-50 elementor-top-column elementor-element elementor-element-2a64fcc\" data-id=\"2a64fcc\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-170f30c elementor-widget elementor-widget-heading\" data-id=\"170f30c\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<h1 class=\"elementor-heading-title elementor-size-default\">Helium leak test: a practical guide to hermetic welds<\/h1>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-261b840 elementor-widget-divider--view-line elementor-widget elementor-widget-divider\" data-id=\"261b840\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"divider.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<div class=\"elementor-divider\">\n\t\t\t<span class=\"elementor-divider-separator\">\n\t\t\t\t\t\t<\/span>\n\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-fe66b21 elementor-widget elementor-widget-text-editor\" data-id=\"fe66b21\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p>The helium leak test (also known as a helium leak inspection) is the established validation method for hermetic welds on laboratory capsules, sensor housings, medical implants, and high-reliability electronic enclosures. Typical acceptance limits range from 10\u207b\u2075 mbar\u00b7l\/s for general industrial specifications to less than 10\u207b\u2079 mbar\u00b7l\/s for high vacuum and aerospace applications; the relevant standards are MIL-STD-883 (Test Method 1014) and DIN EN ISO 20485. Three factors determine whether a component passes the test: <strong>weld preparation<\/strong>, <strong>welding parameters<\/strong>, and <strong>test method<\/strong>. This guide explains what is tested, how it is tested, and how the welding process prepares the component for the test. <\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t<div class=\"elementor-column elementor-col-50 elementor-top-column elementor-element elementor-element-77c3c9e\" data-id=\"77c3c9e\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-8d7b75f elementor-widget elementor-widget-image\" data-id=\"8d7b75f\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"image.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t\t\t\t<figure class=\"wp-caption\">\n\t\t\t\t\t\t\t\t\t\t<img fetchpriority=\"high\" decoding=\"async\" width=\"800\" height=\"534\" src=\"https:\/\/www.lampert.info\/wp-content\/uploads\/2026\/06\/platinkapsel-gasdicht-verschweisst-lecktest-1024x683.jpg\" class=\"attachment-large size-large wp-image-30363\" alt=\"Gas-tight, welded platinum capsule, prepared for the helium leak test\" srcset=\"https:\/\/www.lampert.info\/wp-content\/uploads\/2026\/06\/platinkapsel-gasdicht-verschweisst-lecktest-1024x683.jpg 1024w, https:\/\/www.lampert.info\/wp-content\/uploads\/2026\/06\/platinkapsel-gasdicht-verschweisst-lecktest-300x200.jpg 300w, https:\/\/www.lampert.info\/wp-content\/uploads\/2026\/06\/platinkapsel-gasdicht-verschweisst-lecktest-768x512.jpg 768w, https:\/\/www.lampert.info\/wp-content\/uploads\/2026\/06\/platinkapsel-gasdicht-verschweisst-lecktest-1536x1024.jpg 1536w, https:\/\/www.lampert.info\/wp-content\/uploads\/2026\/06\/platinkapsel-gasdicht-verschweisst-lecktest-2048x1365.jpg 2048w\" sizes=\"(max-width: 800px) 100vw, 800px\" \/>\t\t\t\t\t\t\t\t\t\t\t<figcaption class=\"widget-image-caption wp-caption-text\">Platinum capsule hermetically sealed using micro-TIG welding, prepared for the helium leak test.<\/figcaption>\n\t\t\t\t\t\t\t\t\t\t<\/figure>\n\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section data-particle_enable=\"false\" data-particle-mobile-disabled=\"false\" class=\"elementor-section elementor-top-section elementor-element elementor-element-cc41514 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"cc41514\" data-element_type=\"section\" data-e-type=\"section\" data-settings=\"{&quot;background_background&quot;:&quot;classic&quot;}\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-833aec5\" data-id=\"833aec5\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-cab859b elementor-widget elementor-widget-heading\" data-id=\"cab859b\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<h2 class=\"elementor-heading-title elementor-size-default\">Why is the helium leak test so important?<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-80bc69d elementor-widget-divider--view-line elementor-widget elementor-widget-divider\" data-id=\"80bc69d\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"divider.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<div class=\"elementor-divider\">\n\t\t\t<span class=\"elementor-divider-separator\">\n\t\t\t\t\t\t<\/span>\n\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-5201b76 elementor-widget elementor-widget-text-editor\" data-id=\"5201b76\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p>A hermetic weld is only as good as the test that verifies it. This applies to laboratory capsules containing radioactive seeds, biological samples, or air-sensitive substances; to medical implants in body tissue; and to sensor housings in the deep sea or in the vacuum of space. <\/p><p>The helium leak test is the industry standard because:<\/p><ul><li><strong>Helium<\/strong> has <strong>the smallest kinetic diameter<\/strong> of all practically usable tracer gases. It penetrates weld defects that other test gases do not detect. <\/li><li><strong>the background concentration of helium in the atmosphere is low<\/strong> (about 5 ppm), resulting in a high signal-to-noise ratio.<\/li><li><strong>Helium-calibrated mass spectrometers<\/strong> are commercially available and can achieve sensitivities below 10\u207b\u00b9\u00b2 mbar\u00b7l\/s in the laboratory.<br><br><\/li><\/ul><p>To clarify the terminology: \u201cLeak test\u201d is the standard generic term for the pass\/fail verification, while \u201cleak detection\u201d refers to the process of locating the leak. \u201cHelium leak test\u201d and \u201chelium leak inspection,\u201d on the other hand, are used interchangeably in the market. <\/p><p>In most hermetic applications, the question is not, \u201cCan the weld pass any leak test?\u201d but rather, \u201cCan it meet the leak rate required by the application?\u201d Therefore, the target leak rate is determined first, and then the weld and test method are designed to meet that target. <\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section data-particle_enable=\"false\" data-particle-mobile-disabled=\"false\" class=\"elementor-section elementor-top-section elementor-element elementor-element-bf77ae6 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"bf77ae6\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-2b7b4e6\" data-id=\"2b7b4e6\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-20369df elementor-widget elementor-widget-heading\" data-id=\"20369df\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<h2 class=\"elementor-heading-title elementor-size-default\">Acceptable leak rates by application<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-59c379b elementor-widget-divider--view-line elementor-widget elementor-widget-divider\" data-id=\"59c379b\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"divider.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<div class=\"elementor-divider\">\n\t\t\t<span class=\"elementor-divider-separator\">\n\t\t\t\t\t\t<\/span>\n\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-00f6f3b elementor-widget elementor-widget-text-editor\" data-id=\"00f6f3b\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p>The leak rate is measured in mbar\u00b7l\/s (millibars \u00d7 liters per second), which is the volume of gas that escapes per unit of time under standard conditions. Applications tolerate a wide range of values: <\/p><table><thead><tr><th>Application<\/th><th>Typical acceptance leak rate<\/th><th>Test Method<\/th><\/tr><\/thead><tbody><tr><td><strong>General-purpose industrial hermetic<\/strong> (connectors, sensor housings)<\/td><td>10\u207b\u2074 to 10\u207b\u2075 mbar\u00b7l\/s<\/td><td>Sniffer probe, pressure drop<\/td><\/tr><tr><td><strong>Brachytherapy seeds<\/strong> (radioisotope capsules)<\/td><td>10\u207b\u2076 to 10\u207b\u2078 mbar\u00b7l\/s, application-specific<\/td><td>Vacuum chamber + bombing<\/td><\/tr><tr><td><strong>High-reliability electronics<\/strong> (aviation, medical implants, military)<\/td><td>Volume-dependent: <span style=\"font-size: 14.4px;\">5\u00d710\u207b\u2078<\/span> to <span style=\"font-size: 14.4px;\">1\u00d710\u207b\u2076<\/span> mbar\u00b7l\/s (air equivalent), space\/Class K up to 10\u207b\u2079<\/td><td>Vacuum chamber in accordance with MIL-STD-883, Test Method 1014<\/td><\/tr><tr><td><strong>Glass-to-metal feedthroughs<\/strong> (hermetic enclosures)<\/td><td>10\u207b\u2078 mbar\u00b7l\/s (typical)<\/td><td>Vacuum chamber bombing<\/td><\/tr><tr><td><strong>Vacuum-tight components<\/strong> (UHV, particle physics)<\/td><td>10\u207b\u2079 to 10\u207b\u00b9\u00b2 mbar\u00b7l\/s<\/td><td>Vacuum chamber, calibrated mass spectrometer<\/td><\/tr><tr><td><strong>Implantable cardiac and neurological devices<\/strong><\/td><td>10\u207b\u2078 to 10\u207b\u2079 mbar\u00b7l\/s<\/td><td>FDA\/ISO-specific protocols<\/td><\/tr><tr><td><strong>Laboratory capsules for high-pressure research<\/strong> (diamond-piston cells, platinum)<\/td><td>10\u207b\u2076 to 10\u207b\u2078 mbar\u00b7l\/s<\/td><td>Vacuum chamber bombing<\/td><\/tr><tr><td><strong>Lithium-ion cell sealing<\/strong> (series)<\/td><td>\u2264 10\u207b\u2076 mbar\u00b7l\/s, trend toward stricter limits<\/td><td>Sniffing + production scaling<\/td><\/tr><\/tbody><\/table><p><strong>Note on MIL limits:<\/strong> MIL-STD-883, Test Method 1014, grades the rejection limits based on the internal volume of the enclosure: up to 0.05 cm\u00b3, the limit is 5\u00d710\u207b\u2078; from 0.05 to 0.4 cm\u00b3, it is 1\u00d710\u207b\u2077; and above 0.4 cm\u00b3, it is 1\u00d710\u207b\u2076 mbar\u00b7l\/s, in each case expressed as an air equivalent. For space hybrids (Class K), the limits are one decade stricter in each case. General values such as \u201c10\u207b\u2078 to 10\u207b\u2079\u201d describe the strictest end of this scale. <\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section data-particle_enable=\"false\" data-particle-mobile-disabled=\"false\" class=\"elementor-section elementor-top-section elementor-element elementor-element-41733a1 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"41733a1\" data-element_type=\"section\" data-e-type=\"section\" data-settings=\"{&quot;background_background&quot;:&quot;classic&quot;}\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-67025b7\" data-id=\"67025b7\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-03c45de elementor-widget elementor-widget-heading\" data-id=\"03c45de\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<h2 class=\"elementor-heading-title elementor-size-default\">Overview of testing methods<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-49be6ae elementor-widget-divider--view-line elementor-widget elementor-widget-divider\" data-id=\"49be6ae\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"divider.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<div class=\"elementor-divider\">\n\t\t\t<span class=\"elementor-divider-separator\">\n\t\t\t\t\t\t<\/span>\n\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-152d214 elementor-widget elementor-widget-text-editor\" data-id=\"152d214\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<h3>Vacuum chamber (highest accuracy)<\/h3><p>The component is placed in a vacuum chamber connected to a helium mass spectrometer. If the component has been previously loaded with helium (through helium bombing or filling during sealing), helium diffuses outward through any leaks and is detected. Highest sensitivity: up to 10\u207b\u00b9\u00b2 mbar\u00b7l\/s in an optimized laboratory setup; typical detection limit in practice at service providers is around 10\u207b\u2079 mbar\u00b7l\/s. Considered the standard for medical applications, aviation, and brachytherapy seeds. However, the process is slower per component due to the required chamber pumping time. <\/p><h3>Sniff probe<\/h3><p>The component is filled with helium, and a handheld probe scans the seam to detect helium escaping into the ambient air. This method is ideal for production line testing, as it can be performed quickly and without the need for a chamber. Sensitivity typically ranges from 10\u207b\u2075 to 10\u207b\u2077 mbar\u00b7l\/s. The method is portable and can pinpoint leak locations, which is an advantage for repair workflows. <\/p><h3>Pressure bombing (helium precharge)<\/h3><p>A sealed component is placed in a pressure vessel filled with helium for a specified duration, and helium diffuses through any leaks into the interior. The helium content is then tested in the vacuum chamber. This enables post-seal testing of components that were not filled with helium during welding. The measurement must be performed within one hour after the bombing process, but may be extended to up to four hours using a qualified procedure. The fixed conditions cover internal volumes of up to only 20 cm\u00b3, which in practice means that larger housings are filled directly with helium during sealing (e.g., in a glove box) rather than being bombed afterward. <\/p><h3>Pressure drop and mass flow methods<\/h3><p>For larger volumes where helium tracer tests are impractical, the pressure drop test (sealed component under pressure, with pressure drop measured over time) provides a coarser leak measurement. This method is less sensitive than helium tracer methods, but it is acceptable for general industrial hermetic specifications and is independent of the tracer gas. <\/p><h3>Fine leak and gross leak: the test sequence matters<\/h3><p>Paradoxically, a large leak may appear \u201ctight\u201d in a fine-leak test because the tracer gas has already escaped through the large leak before the measurement is taken, causing the mass spectrometer to detect no helium particles. MIL-STD-883, Test Method 1014, therefore combines the fine-leak and gross-leak tests in a defined sequence with tight time windows following the bombing. The simple bubble test in a water bath is suitable here as a quick preliminary check in the workshop, but it is unsuitable for detecting small leaks. <\/p><p><strong>Interpreting false readings:<\/strong> not every signal on the leak detector indicates a weld defect. <strong>Permeation<\/strong> is the passage of gas through the material itself, which is particularly relevant for polymer seals and glass. In this case, the solution lies in the choice of material, not in weld correction. <strong>Virtual leaks<\/strong> are trapped volumes of gas within the component (cavities, gaps behind the weld, blind holes); during a vacuum test, they outgas like a real leak, but no leak point can be detected from the outside. Therefore, gap geometries behind the weld should be avoided in the design. <\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section data-particle_enable=\"false\" data-particle-mobile-disabled=\"false\" class=\"elementor-section elementor-top-section elementor-element elementor-element-2e07896 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"2e07896\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-aacc299\" data-id=\"aacc299\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-ab43a26 elementor-widget elementor-widget-heading\" data-id=\"ab43a26\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<h2 class=\"elementor-heading-title elementor-size-default\">Units and conversion<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-af285f6 elementor-widget-divider--view-line elementor-widget elementor-widget-divider\" data-id=\"af285f6\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"divider.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<div class=\"elementor-divider\">\n\t\t\t<span class=\"elementor-divider-separator\">\n\t\t\t\t\t\t<\/span>\n\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-5214f29 elementor-widget elementor-widget-text-editor\" data-id=\"5214f29\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p>Three units dominate this field. Rule of thumb: 1 mbar\u00b7l\/s = 0.1 Pa\u00b7m\u00b3\/s. <\/p><table><thead><tr><th>Unit<\/th><th>Conversion<\/th><th>Typical context<\/th><\/tr><\/thead><tbody><tr><td><strong>mbar\u00b7l\/s<\/strong><\/td><td>Unit of reference in this guide<\/td><td>European practice, leak detector displays<\/td><\/tr><tr><td><strong>Pa\u00b7m\u00b3\/s<\/strong><\/td><td>1 Pa\u00b7m\u00b3\/s = 10 mbar\u00b7l\/s<\/td><td>SI unit; ISO standards, ASTM scope specifications<\/td><\/tr><tr><td><strong>atm\u00b7cm\u00b3\/s<\/strong><\/td><td>1 atm\u00b7cm\u00b3\/s \u2248 1.013 mbar\u00b7l\/s<\/td><td>MIL-STD-883, U.S. specifications<\/td><\/tr><\/tbody><\/table><p>Two pitfalls in U.S. specifications: MIL-STD-883 specifies leak rates in atm\u00b7cm\u00b3\/s; these values are practically identical to mbar\u00b7l\/s. Furthermore, the rejection limits are based on <strong>air equivalents<\/strong>; measured helium rates must be converted, using a factor of 0.37 for fixed conditions and the howl-mann equation for flexible conditions. <\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section data-particle_enable=\"false\" data-particle-mobile-disabled=\"false\" class=\"elementor-section elementor-top-section elementor-element elementor-element-0250331 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"0250331\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-c2dd0c4\" data-id=\"c2dd0c4\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-e9ca997 elementor-widget elementor-widget-heading\" data-id=\"e9ca997\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<h2 class=\"elementor-heading-title elementor-size-default\">Standards and regulations<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-b5d8a48 elementor-widget-divider--view-line elementor-widget elementor-widget-divider\" data-id=\"b5d8a48\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"divider.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<div class=\"elementor-divider\">\n\t\t\t<span class=\"elementor-divider-separator\">\n\t\t\t\t\t\t<\/span>\n\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-a92e637 elementor-widget elementor-widget-text-editor\" data-id=\"a92e637\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<table><thead><tr><th>Rules<\/th><th>Content and relevance<\/th><\/tr><\/thead><tbody><tr><td><strong>MIL-STD-883, Test Method 1014 \u201cSeal\u201d<\/strong><\/td><td>U.S. benchmark for microelectronics packages: fine\/gross leak test conditions, bombing parameters, volume-dependent reject limits. Base document currently at Revision L with change 1 dated June 27, 2025; most recent documented method revision 1014.17. <\/td><\/tr><tr><td><strong>DIN EN ISO 20485:2018<\/strong> (ISO 20485:2017)<\/td><td>Key civil standard for leak testing using tracer gas.<\/td><\/tr><tr><td><strong>DIN EN 1779:1999-10<\/strong><\/td><td>Criteria for the selection of test methods and test procedures; draft standard 2024-12 in progress.<\/td><\/tr><tr><td><strong>ASTM E493\/E493M-11 (2022)<\/strong><\/td><td>Inside-out test mode for pre-sealed components (semiconductors, hermetic relays); fits directly onto welded capsules and housings.<\/td><\/tr><tr><td><strong>ASTM E498\/E498M-11 (2022)<\/strong><\/td><td>Tracer probe mode: test specimen evacuated, tracer gas external; scope starting at 1\u00d710\u207b\u2078 Pa\u00b7m\u00b3\/s.<\/td><\/tr><tr><td><strong>ASTM E499\/E499M-11 (2017)<\/strong><\/td><td>Detector-probe mode (sniffing); scope starting at 1\u00d710\u207b\u2077 Pa\u00b7m\u00b3\/s.<\/td><\/tr><tr><td><strong>ASTM F2391-22<\/strong><\/td><td>Helium leak test for implant and medical device packaging; classifies leaks from large (10\u207b\u00b2 to 10\u207b\u2075 Pa\u00b7m\u00b3\/s) to ultra-fine (10\u207b\u2079 to 10\u207b\u00b9\u00b9 Pa\u00b7m\u00b3\/s).<\/td><\/tr><\/tbody><\/table><p>The terminology standard DIN EN ISO 20484 (which replaces DIN EN 1330-8) defines the relevant terminology.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section data-particle_enable=\"false\" data-particle-mobile-disabled=\"false\" class=\"elementor-section elementor-top-section elementor-element elementor-element-3a79a12 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"3a79a12\" data-element_type=\"section\" data-e-type=\"section\" data-settings=\"{&quot;background_background&quot;:&quot;classic&quot;}\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-50 elementor-top-column elementor-element elementor-element-030ea27\" data-id=\"030ea27\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-a6a7824 elementor-widget elementor-widget-heading\" data-id=\"a6a7824\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<h2 class=\"elementor-heading-title elementor-size-default\">How weld preparation affects test results<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-ddd3be9 elementor-widget-divider--view-line elementor-widget elementor-widget-divider\" data-id=\"ddd3be9\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"divider.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<div class=\"elementor-divider\">\n\t\t\t<span class=\"elementor-divider-separator\">\n\t\t\t\t\t\t<\/span>\n\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-0b1dfe7 elementor-widget elementor-widget-text-editor\" data-id=\"0b1dfe7\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p>A leak test cannot save a poorly prepared weld. The factors that determine whether the test is passed occur before the welding step: <\/p>\n<ol>\n<li><strong>Cleanliness of the joint surfaces.<\/strong> Contaminants in pores, recesses, or crevices burn off during welding and cause porosity in the weld. Ultrasonic cleaning is the standard practice in the laboratory; for deep recesses or threads, a stiff brush and abrasive cleaner should also be used. <\/li>\n<li><strong>Joint geometry.<\/strong> A weld can only seal surfaces that are geometrically in contact with each other. A 0.1-mm gap can typically be bridged, whereas a 0.5-mm gap typically no longer meets the hermetic specifications. <\/li>\n<li><strong>Material compatibility.<\/strong> Proven for hermetic micro-TIG welding: 316L stainless steel (DIN 1.4404), titanium grades 2 and 5, platinum and platinum-rhodium alloys, Kovar, nickel-based superalloys, gold, and gold-palladium alloys. Tantalum, niobium, and zirconium typically require preliminary test welds. <\/li>\n<li><strong>Pulse parameters matching the wall thickness.<\/strong> For thin capsule walls (0.1\u20130.3 mm), low energy and short pulse durations (15\u201325% energy, 1.0\u20133.5 ms) prevent burn-through and porosity. For thicker specimens, longer pulses with deeper penetration ensure complete fusion of the seam. <\/li>\n<li><strong>Inert gas integrity.<\/strong> Argon \u2265 99.9% (argon 4.6) at approximately 2 l\/min with automatic pre- and post-flow protects the weld pool from atmospheric contamination. Insufficient inert gas causes oxide inclusions, which act as leak paths. <\/li>\n<li><strong>First-article validation.<\/strong> For new geometries or materials, cut a sample weld cross-sectionally before starting series production. Full penetration depth and oxide-free weld metal in the cross-section are the most reliable indicators that the helium leak test will be successful. <\/li>\n<\/ol>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t<div class=\"elementor-column elementor-col-50 elementor-top-column elementor-element elementor-element-a3a5399\" data-id=\"a3a5399\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-de1dcc2 elementor-widget elementor-widget-image\" data-id=\"de1dcc2\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"image.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t\t\t\t<figure class=\"wp-caption\">\n\t\t\t\t\t\t\t\t\t\t<img decoding=\"async\" width=\"800\" height=\"534\" src=\"https:\/\/www.lampert.info\/wp-content\/uploads\/2026\/06\/goldkapsel-gecrimpt-vor-dem-verschweissen-1024x683.jpg\" class=\"attachment-large size-large wp-image-30366\" alt=\"Crimped gold capsule before hermetic sealing\" srcset=\"https:\/\/www.lampert.info\/wp-content\/uploads\/2026\/06\/goldkapsel-gecrimpt-vor-dem-verschweissen-1024x683.jpg 1024w, https:\/\/www.lampert.info\/wp-content\/uploads\/2026\/06\/goldkapsel-gecrimpt-vor-dem-verschweissen-300x200.jpg 300w, https:\/\/www.lampert.info\/wp-content\/uploads\/2026\/06\/goldkapsel-gecrimpt-vor-dem-verschweissen-768x512.jpg 768w, https:\/\/www.lampert.info\/wp-content\/uploads\/2026\/06\/goldkapsel-gecrimpt-vor-dem-verschweissen-1536x1024.jpg 1536w, https:\/\/www.lampert.info\/wp-content\/uploads\/2026\/06\/goldkapsel-gecrimpt-vor-dem-verschweissen-2048x1365.jpg 2048w\" sizes=\"(max-width: 800px) 100vw, 800px\" \/>\t\t\t\t\t\t\t\t\t\t\t<figcaption class=\"widget-image-caption wp-caption-text\">Crimped gold capsule before hermetic sealing; the initial state before sealing.<\/figcaption>\n\t\t\t\t\t\t\t\t\t\t<\/figure>\n\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section data-particle_enable=\"false\" data-particle-mobile-disabled=\"false\" class=\"elementor-section elementor-top-section elementor-element elementor-element-dc1234f elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"dc1234f\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-30a7c36\" data-id=\"30a7c36\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-c77b693 elementor-widget elementor-widget-heading\" data-id=\"c77b693\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<h2 class=\"elementor-heading-title elementor-size-default\">Common errors and how to correct them<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-4c967a3 elementor-widget-divider--view-line elementor-widget elementor-widget-divider\" data-id=\"4c967a3\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"divider.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<div class=\"elementor-divider\">\n\t\t\t<span class=\"elementor-divider-separator\">\n\t\t\t\t\t\t<\/span>\n\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-56b93ed elementor-widget elementor-widget-text-editor\" data-id=\"56b93ed\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<table><thead><tr><th>Symptoms<\/th><th>Common cause<\/th><th>Correction<\/th><\/tr><\/thead><tbody><tr><td><strong>Local porosity<\/strong><\/td><td>Surface contamination caused by burning<\/td><td>Ultrasonic cleaning, brushing, repeat preparation<\/td><\/tr><tr><td><strong>Insufficient penetration depth<\/strong><\/td><td>Pulse duration too short for wall thickness<\/td><td>Increase pulse duration in 0.5-ms increments; perform a cross-section cut for verification<\/td><\/tr><tr><td><strong>Oxide inclusions<\/strong><\/td><td>Insufficient argon pre-flow<\/td><td>Check that the argon flow is \u2265 2 l\/min and that the pre-flow is active<\/td><\/tr><tr><td><strong>Leak at a seam corner \/ edge<\/strong><\/td><td>Gap geometry or fixture offset<\/td><td>Improve the fixture; place tack welds before the through-weld<\/td><\/tr><tr><td><strong>Weld cracks<\/strong><\/td><td>Excessive heat input with crack-prone alloys<\/td><td>Reduce energy, shorten the pulse, or change the material program if necessary<\/td><\/tr><tr><td><strong>Fluctuating leak rate from batch to batch<\/strong><\/td><td>Operator parameter drift or electrode wear<\/td><td>Use the program memory and electrode counter (the MAW provides both via Modbus)<\/td><\/tr><\/tbody><\/table>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section data-particle_enable=\"false\" data-particle-mobile-disabled=\"false\" class=\"elementor-section elementor-top-section elementor-element elementor-element-87ba2a3 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"87ba2a3\" data-element_type=\"section\" data-e-type=\"section\" data-settings=\"{&quot;background_background&quot;:&quot;classic&quot;}\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-fa58a87\" data-id=\"fa58a87\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-b622762 elementor-widget elementor-widget-heading\" data-id=\"b622762\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<h2 class=\"elementor-heading-title elementor-size-default\">How the Lampert Micro Arc Welder prepares parts for leak tests<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-0e7de26 elementor-widget-divider--view-line elementor-widget elementor-widget-divider\" data-id=\"0e7de26\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"divider.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<div class=\"elementor-divider\">\n\t\t\t<span class=\"elementor-divider-separator\">\n\t\t\t\t\t\t<\/span>\n\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-207466d elementor-widget elementor-widget-text-editor\" data-id=\"207466d\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p>The <a href=\"https:\/\/www.lampert.info\/en\/products\/industry\/microarcwelder\/\">Lampert Micro Arc Welder (MAW)<\/a> is designed to produce reproducible, leak-test-compatible hermetic welds:<\/p><ul><li><strong>5\u20131,200 a peak current and 0.1\u201334 ms pulse duration.<\/strong> The energy sector ranges from thin laboratory capsules to rugged industrial sensor housings.<\/li><li><strong>12 preinstalled material programs<\/strong> for stainless steel, titanium, platinum, copper, aluminum, and more. No more guesswork with parameters during initial sample qualification. <\/li><li><strong>Patented process monitoring.<\/strong> Real-time defect detection (contact, pressure, electrode wear, temperature, \u201celectrode sticking\u201d). Defective welds are flagged before they reach the leak tester. <\/li><li><strong>Modbus TCP\/IP<\/strong> with 21 documented registers for production integration, parameter logging, electrode wear tracking, and weld spot counting. Parameter logging supports traceability requirements for typical medical and aerospace applications. <\/li><li><strong>Automatic argon pre- and post-flow.<\/strong> Consistent inert gas integrity at approximately 2 l\/min of argon \u2265 99.9%.<\/li><li><strong>Glove-box compatible.<\/strong> For air- or moisture-sensitive encapsulation and for enclosures whose internal volume exceeds the practical bombing limit: if you fill the enclosure directly with helium during sealing, you won&#8217;t need to perform bombing afterward.<\/li><\/ul><p>The article <a href=\"https:\/\/www.lampert.info\/en\/hermetic-sealing-micro-pulse-welding\/\">\u201cHermetic Sealing with micro-TIG welding<\/a>\u201d provides an overview of applications, including materials and recommended parameters; the <a href=\"https:\/\/www.lampert.info\/en\/welding-principle\/\">Lampert welding principle<\/a> explains how the welding pulse is generated.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section data-particle_enable=\"false\" data-particle-mobile-disabled=\"false\" class=\"elementor-section elementor-top-section elementor-element elementor-element-2773263 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"2773263\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-3a0b10e\" data-id=\"3a0b10e\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-7fb5e54 elementor-widget elementor-widget-heading\" data-id=\"7fb5e54\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<h2 class=\"elementor-heading-title elementor-size-default\">Device recommendation: the Lampert Micro Arc Welder<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-5540e04 elementor-widget-divider--view-line elementor-widget elementor-widget-divider\" data-id=\"5540e04\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"divider.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<div class=\"elementor-divider\">\n\t\t\t<span class=\"elementor-divider-separator\">\n\t\t\t\t\t\t<\/span>\n\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-a7cd71d elementor-widget elementor-widget-text-editor\" data-id=\"a7cd71d\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<table><thead><tr><th>Specification<\/th><th>Value<\/th><\/tr><\/thead><tbody><tr><td>Peak current (TIG)<\/td><td>5 to 1,200 a<\/td><\/tr><tr><td>Pulse duration<\/td><td>0.1 to 34 ms<\/td><\/tr><tr><td>Minimum workpiece thickness<\/td><td>0.1 mm<\/td><\/tr><tr><td>Weld spot diameter<\/td><td>0.2 to 4.0 mm; for depths over 1 mm, use a 1.3 mm electrode<\/td><\/tr><tr><td>Material sets (default)<\/td><td>12 (universal, gold, silver, platinum, palladium, bronze, stainless steel, titanium, aluminum, tin, brass, copper)<\/td><\/tr><tr><td>Aluminum mode<\/td><td>Specially optimized (HF-superimposed welding curve)<\/td><\/tr><tr><td>Industry 4.0 interface<\/td><td>Modbus TCP\/IP via LAN (21 documented registers)<\/td><\/tr><tr><td>Patented welding process control<\/td><td>Yes (real-time error detection)<\/td><\/tr><tr><td>inert gas<\/td><td>Argon \u2265 99.9%, approx. 2 L\/min<\/td><\/tr><tr><td>Weight<\/td><td>10.9 kg<\/td><\/tr><tr><td>Certification<\/td><td>EN 60974-6, EN 61000-6-2\/-6-4, RoHS 2011\/65\/EU; UKCA-compliant<\/td><\/tr><tr><td>Warranty<\/td><td>1 year; developed and manufactured in Germany<\/td><\/tr><tr><td>Investment (full starter package)<\/td><td>Starting at approximately 7,000 EUR net<\/td><\/tr><\/tbody><\/table>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section data-particle_enable=\"false\" data-particle-mobile-disabled=\"false\" class=\"elementor-section elementor-top-section elementor-element elementor-element-b5ad88f elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"b5ad88f\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-5f3b091\" data-id=\"5f3b091\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-4e3f4bd elementor-widget elementor-widget-heading\" data-id=\"4e3f4bd\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<h2 class=\"elementor-heading-title elementor-size-default\">Frequently asked questions about the helium leak test<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-82bb71b elementor-widget-divider--view-line elementor-widget elementor-widget-divider\" data-id=\"82bb71b\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"divider.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<div class=\"elementor-divider\">\n\t\t\t<span class=\"elementor-divider-separator\">\n\t\t\t\t\t\t<\/span>\n\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-e767fa1 elementor-widget elementor-widget-eael-adv-accordion\" data-id=\"e767fa1\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"eael-adv-accordion.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t            <div class=\"eael-adv-accordion\" id=\"eael-adv-accordion-e767fa1\" data-scroll-on-click=\"no\" data-scroll-speed=\"300\" data-accordion-id=\"e767fa1\" data-accordion-type=\"accordion\" data-toogle-speed=\"300\">\n            <div class=\"eael-accordion-list\">\n\t\t\t\t\t<div id=\"what-leak-rate-is-considered-hermetic\" class=\"elementor-tab-title eael-accordion-header\" tabindex=\"0\" data-tab=\"1\" aria-controls=\"elementor-tab-content-2421\"><span class=\"eael-accordion-tab-title\">What leak rate is considered \u201chermetic\u201d?<\/span><i aria-hidden=\"true\" class=\"fa-toggle fas fa-plus\"><\/i><\/div><div id=\"elementor-tab-content-2421\" class=\"eael-accordion-content clearfix\" data-tab=\"1\" aria-labelledby=\"what-leak-rate-is-considered-hermetic\"><p>There is no single, universally accepted definition. \u201cHermetic\u201d is application-specific: medical implant standards typically require 10\u207b\u2078 to 10\u207b\u2079 mbar\u00b7l\/s; general industrial hermetic standards accept 10\u207b\u2074 to 10\u207b\u2075; and high-vacuum and aerospace applications require values below 10\u207b\u2079. For context: \u201cbacteria-tight\u201d corresponds to approximately 10\u207b\u2074 mbar\u00b7l\/s, while \u201cvirus-tight\u201d ranges from 10\u207b\u2076 to 10\u207b\u2078 mbar\u00b7l\/s, depending on the source. Define the target value before designing the weld. <\/p>\n<\/div>\n\t\t\t\t\t<\/div><div class=\"eael-accordion-list\">\n\t\t\t\t\t<div id=\"can-the-helium-leak-test-be-performed-without-a-vacuum-chamber\" class=\"elementor-tab-title eael-accordion-header\" tabindex=\"0\" data-tab=\"2\" aria-controls=\"elementor-tab-content-2422\"><span class=\"eael-accordion-tab-title\">Can the helium leak test be performed without a vacuum chamber?<\/span><i aria-hidden=\"true\" class=\"fa-toggle fas fa-plus\"><\/i><\/div><div id=\"elementor-tab-content-2422\" class=\"eael-accordion-content clearfix\" data-tab=\"2\" aria-labelledby=\"can-the-helium-leak-test-be-performed-without-a-vacuum-chamber\"><p>Yes. The sniffer probe achieves a sensitivity of 10\u207b\u2075 to 10\u207b\u2077 mbar\u00b7l\/s and is suitable for production line and field testing. For higher sensitivity (10\u207b\u2078 and better), the vacuum chamber is the industry standard. <\/p>\n<\/div>\n\t\t\t\t\t<\/div><div class=\"eael-accordion-list\">\n\t\t\t\t\t<div id=\"do-i-need-helium-when-welding-so-i-can-perform-a-helium-leak-test-later\" class=\"elementor-tab-title eael-accordion-header\" tabindex=\"0\" data-tab=\"3\" aria-controls=\"elementor-tab-content-2423\"><span class=\"eael-accordion-tab-title\">Do I need helium when welding so I can perform a helium leak test later?<\/span><i aria-hidden=\"true\" class=\"fa-toggle fas fa-plus\"><\/i><\/div><div id=\"elementor-tab-content-2423\" class=\"eael-accordion-content clearfix\" data-tab=\"3\" aria-labelledby=\"do-i-need-helium-when-welding-so-i-can-perform-a-helium-leak-test-later\"><p>No. Pressure bombing after welding fills the sealed component with helium and allows for leak testing even on components that were sealed in argon or air. Bombing pressure (30 to 75 psia) and dwell time are defined in MIL-STD-883, Test Method 1014, based on volume; the measurement must be performed within 1 hour after bombing, or up to 4 hours using a qualified procedure. <\/p>\n<\/div>\n\t\t\t\t\t<\/div><div class=\"eael-accordion-list\">\n\t\t\t\t\t<div id=\"my-case-has-a-larger-internal-volume-will-bombing-still-work-\" class=\"elementor-tab-title eael-accordion-header\" tabindex=\"0\" data-tab=\"4\" aria-controls=\"elementor-tab-content-2424\"><span class=\"eael-accordion-tab-title\">My case has a larger internal volume. Will bombing still work? <\/span><i aria-hidden=\"true\" class=\"fa-toggle fas fa-plus\"><\/i><\/div><div id=\"elementor-tab-content-2424\" class=\"eael-accordion-content clearfix\" data-tab=\"4\" aria-labelledby=\"my-case-has-a-larger-internal-volume-will-bombing-still-work-\"><p>Only to a limited extent. The fixed conditions of Test Method 1014 cover internal volumes up to 20 cm\u00b3; above that, either the bombing times increase significantly (up to 190 hours are listed for Class K hybrids) or the detection sensitivity decreases. Practical recommendation: when sealing larger enclosures, fill them directly with helium, for example, when welding in a glove box. <\/p>\n<\/div>\n\t\t\t\t\t<\/div><div class=\"eael-accordion-list\">\n\t\t\t\t\t<div id=\"can-the-lampert-maw-reliably-generate-medical-grade-leak-rates-10-mbarls\" class=\"elementor-tab-title eael-accordion-header\" tabindex=\"0\" data-tab=\"5\" aria-controls=\"elementor-tab-content-2425\"><span class=\"eael-accordion-tab-title\">Can the Lampert MAW reliably generate medical-grade leak rates (10\u207b\u2078 mbar\u00b7l\/s)?<\/span><i aria-hidden=\"true\" class=\"fa-toggle fas fa-plus\"><\/i><\/div><div id=\"elementor-tab-content-2425\" class=\"eael-accordion-content clearfix\" data-tab=\"5\" aria-labelledby=\"can-the-lampert-maw-reliably-generate-medical-grade-leak-rates-10-mbarls\"><p>Yes, with proper preparation, the right range of materials, validated pulse parameters, and inert gas integrity. Micro-TIG welds reliably meet typical medical and electronic hermetic specifications using validated parameters. For high-vacuum or research specifications (below 10\u207b\u2079), validate sample welds in advance. <\/p>\n<\/div>\n\t\t\t\t\t<\/div><div class=\"eael-accordion-list\">\n\t\t\t\t\t<div id=\"which-materials-can-be-hermetically-sealed-most-reliably\" class=\"elementor-tab-title eael-accordion-header\" tabindex=\"0\" data-tab=\"6\" aria-controls=\"elementor-tab-content-2426\"><span class=\"eael-accordion-tab-title\">Which materials can be hermetically sealed most reliably?<\/span><i aria-hidden=\"true\" class=\"fa-toggle fas fa-plus\"><\/i><\/div><div id=\"elementor-tab-content-2426\" class=\"eael-accordion-content clearfix\" data-tab=\"6\" aria-labelledby=\"which-materials-can-be-hermetically-sealed-most-reliably\"><p>316L stainless steel (DIN 1.4404), Grade 2 and 5 titanium, platinum and platinum-rhodium alloys, Kovar, and nickel-based superalloys are the established standards. Tantalum, niobium, and zirconium are suitable under certain conditions; request a test weld. <\/p>\n<\/div>\n\t\t\t\t\t<\/div><div class=\"eael-accordion-list\">\n\t\t\t\t\t<div id=\"is-hermetic-sealing-possible-in-the-glove-box\" class=\"elementor-tab-title eael-accordion-header\" tabindex=\"0\" data-tab=\"7\" aria-controls=\"elementor-tab-content-2427\"><span class=\"eael-accordion-tab-title\">Is hermetic sealing possible in the glove box?<\/span><i aria-hidden=\"true\" class=\"fa-toggle fas fa-plus\"><\/i><\/div><div id=\"elementor-tab-content-2427\" class=\"eael-accordion-content clearfix\" data-tab=\"7\" aria-labelledby=\"is-hermetic-sealing-possible-in-the-glove-box\"><p>Yes. With the proper preparation, the Lampert MAW can operate in inert gas environments. This is important for encapsulations that are sensitive to air or moisture, and for components whose internal volume makes subsequent gas flushing impractical. <\/p>\n<\/div>\n\t\t\t\t\t<\/div><div class=\"eael-accordion-list\">\n\t\t\t\t\t<div id=\"does-the-leak-test-work-with-hydrogen-instead-of-helium\" class=\"elementor-tab-title eael-accordion-header\" tabindex=\"0\" data-tab=\"8\" aria-controls=\"elementor-tab-content-2428\"><span class=\"eael-accordion-tab-title\">Does the leak test work with hydrogen instead of helium?<\/span><i aria-hidden=\"true\" class=\"fa-toggle fas fa-plus\"><\/i><\/div><div id=\"elementor-tab-content-2428\" class=\"eael-accordion-content clearfix\" data-tab=\"8\" aria-labelledby=\"does-the-leak-test-work-with-hydrogen-instead-of-helium\"><p>Yes. The standard carrier gas is a mixture of 5% H\u2082 in 95% N\u2082 (non-flammable), which is less expensive than helium. Helium costs can also be reduced through recovery or by using lower concentrations. For maximum sensitivity, helium remains the standard. <\/p>\n<\/div>\n\t\t\t\t\t<\/div><div class=\"eael-accordion-list\">\n\t\t\t\t\t<div id=\"what-welding-parameters-are-suitable-for-thin-laboratory-capsules\" class=\"elementor-tab-title eael-accordion-header\" tabindex=\"0\" data-tab=\"9\" aria-controls=\"elementor-tab-content-2429\"><span class=\"eael-accordion-tab-title\">What welding parameters are suitable for thin laboratory capsules?<\/span><i aria-hidden=\"true\" class=\"fa-toggle fas fa-plus\"><\/i><\/div><div id=\"elementor-tab-content-2429\" class=\"eael-accordion-content clearfix\" data-tab=\"9\" aria-labelledby=\"what-welding-parameters-are-suitable-for-thin-laboratory-capsules\"><p>For wall thicknesses of 0.1 to 0.3 mm: 15 to 25% energy, 0.5 to 1.5 ms pulse duration, tapered tungsten electrode, argon at approximately 2 l\/min. Validate the initial sample using a cross-section. <\/p>\n<\/div>\n\t\t\t\t\t<\/div><div class=\"eael-accordion-list\">\n\t\t\t\t\t<div id=\"where-can-i-get-advice-on-my-specific-helium-leak-test-application\" class=\"elementor-tab-title eael-accordion-header\" tabindex=\"0\" data-tab=\"10\" aria-controls=\"elementor-tab-content-24210\"><span class=\"eael-accordion-tab-title\">Where can I get advice on my specific helium leak test application?<\/span><i aria-hidden=\"true\" class=\"fa-toggle fas fa-plus\"><\/i><\/div><div id=\"elementor-tab-content-24210\" class=\"eael-accordion-content clearfix\" data-tab=\"10\" aria-labelledby=\"where-can-i-get-advice-on-my-specific-helium-leak-test-application\"><p>Contact Lampert application engineering at <a href=\"mailto:mail@lampert.info\">mail@lampert.info<\/a>. Upon request, we provide free sample welds with a written welding report, particularly useful when the target leak rate, geometry, or material differ from the standard. <\/p>\n<\/div>\n\t\t\t\t\t<\/div><\/div>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section data-particle_enable=\"false\" data-particle-mobile-disabled=\"false\" class=\"elementor-section elementor-top-section elementor-element elementor-element-ecf9daf elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"ecf9daf\" data-element_type=\"section\" data-e-type=\"section\" data-settings=\"{&quot;background_background&quot;:&quot;classic&quot;}\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-f18056b\" data-id=\"f18056b\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-37e45a3 elementor-widget elementor-widget-heading\" data-id=\"37e45a3\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<h2 class=\"elementor-heading-title elementor-size-default\">Conclusion: first the target leakage rate, then the weld seam<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-d0cf84f elementor-widget-divider--view-line elementor-widget elementor-widget-divider\" data-id=\"d0cf84f\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"divider.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<div class=\"elementor-divider\">\n\t\t\t<span class=\"elementor-divider-separator\">\n\t\t\t\t\t\t<\/span>\n\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-9faea5b elementor-widget elementor-widget-text-editor\" data-id=\"9faea5b\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p>The helium leak test is the gold standard for hermetic welds, ranging from general industrial specifications at 10\u207b\u2075 mbar\u00b7l\/s to aerospace and medical implant standards below 10\u207b\u2079. Manufacturers of hermetic components first define the target leak rate, then select the test method (vacuum chamber for maximum sensitivity, sniffer probe for production lines, bombing for post-seal testing), and consistently tailor the welding preparation to these requirements. Clean joint surfaces, controlled gap dimensions, appropriate pulse parameters, and intact inert gas coverage determine the test result long before the component even enters the leak tester. <\/p><p>The <a href=\"https:\/\/www.lampert.info\/en\/products\/industry\/microarcwelder\/\">Lampert Micro Arc Welder<\/a> provides the tools for this: 12 material programs, patented process monitoring, automatic argon management, and Modbus logging for traceability. With proper preparation, MAW welds reliably meet typical industrial hermetic specifications. <\/p><p>Free sample welds with a written welding report included: for questions regarding specific applications, please contact Lampert application engineering at <a href=\"mailto:mail@lampert.info\">mail@lampert.info<\/a>.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<\/div>\n\t\t","protected":false},"excerpt":{"rendered":"<p>The helium leak test is the established validation method for hermetic welds on laboratory capsules, sensor housings, medical implants, and electronic enclosures. Leak rates by application, test methods ranging from vacuum chambers to bombing, and weld preparation, which determines the result. <\/p>\n","protected":false},"author":13,"featured_media":30363,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"_yoast_wpseo_focuskw":"Helium Leak Test","_yoast_wpseo_title":"Helium leak test: guide to hermetic welds","_yoast_wpseo_metadesc":"Helium leak testing for hermetic welds: leak rates by application, test methods ranging from vacuum chambers to bombing, plus practical weld 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