{"id":47758,"date":"2024-04-23T01:38:40","date_gmt":"2024-04-23T01:38:40","guid":{"rendered":"https:\/\/silmantech.com\/?p=47758"},"modified":"2024-04-20T01:41:45","modified_gmt":"2024-04-20T01:41:45","slug":"how-to-design-smt-solder-paste-stencils","status":"publish","type":"post","link":"https:\/\/silmantech.com\/ar\/how-to-design-smt-solder-paste-stencils\/","title":{"rendered":"How to Design SMT solder paste stencils"},"content":{"rendered":"
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  1. Ensure precise positioning and specification adherence. Strictly follow the specified method for opening to achieve high opening accuracy.<\/li>\n\n\n\n
  2. Independent opening specifications should not be too large, and the total width should not exceed 2mm. For solder pad specifications exceeding 2mm, a 0.4mm bridge should be added in the middle to prevent affecting the strength of the stencil.<\/li>\n\n\n\n
  3. Strictly control the tensioning process, ensuring that the opening range is horizontally centered.<\/li>\n\n\n\n
  4. The openings on the underside of the stencil should be 0.01mm to 0.02mm wider than those on the upper side, forming a tapered shape to facilitate effective release of solder paste and reduce the frequency of stencil cleaning<\/a>.<\/li>\n\n\n\n
  5. Ensure smooth walls of the stencil openings, especially for QFP and CSP components with spacing less than 0.5mm, requiring the supplier to perform electro-polishing treatment.<\/li>\n\n\n\n
  6. In general, the opening specifications and shapes of SMT components should match those of the solder pads in a 1:1 ratio.<\/li>\n<\/ol>\n\n\n\n

    Special Opening Design Principles:<\/p>\n\n\n\n

      \n
    1. For 0805 components, it is recommended to open as follows: Each solder pad is cut inward by 1.0mm, then an inner concave circle is made with B = 2\/5Y; A = 0.25mm or A = 2\/5*L to prevent solder balls.<\/li>\n\n\n\n
    2. For 1206 and above chip components: After each solder pad is moved outward by 0.1mm, an inner concave circle is made with B = 2\/5Y; a = 2\/5*L to prevent solder balls.<\/li>\n\n\n\n
    3. For circuit boards with BGA, the opening ratio of the steel mesh is 1:1 for ball pitch above 1.0mm and 1:0.95 for ball pitch below 0.5mm.<\/li>\n\n\n\n
    4. For all QFP and SOP components with 0.5mm pitch, the opening ratio in the total width direction is 1:0.8.<\/li>\n\n\n\n
    5. For QFP components with 0.4mm pitch, the opening ratio in the total width direction is 1:0.8, and in the length direction is 1:1.1, with rounded corners on the outer side. The opening width for 0.65mm pitch SOP components is reduced by 10%.<\/li>\n\n\n\n
    6. For PLCC32 and PLCC44, the opening ratio in the total width direction is 1:1, and in the length direction is 1:1.1.<\/li>\n\n\n\n
    7. For general SOT packaged devices, the opening ratio at the large solder pad end is 1:1.1, and at the small solder pad end, the total width direction is 1:1.<\/li>\n<\/ol>","protected":false},"excerpt":{"rendered":"

      Special Opening Design Principles:<\/p>","protected":false},"author":3,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_stopmodifiedupdate":false,"_modified_date":"","footnotes":""},"categories":[88,1],"tags":[],"class_list":["post-47758","post","type-post","status-publish","format-standard","hentry","category-cleaning-machine","category-news","category-88","category-1","description-off"],"_links":{"self":[{"href":"https:\/\/silmantech.com\/ar\/wp-json\/wp\/v2\/posts\/47758","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/silmantech.com\/ar\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/silmantech.com\/ar\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/silmantech.com\/ar\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/silmantech.com\/ar\/wp-json\/wp\/v2\/comments?post=47758"}],"version-history":[{"count":0,"href":"https:\/\/silmantech.com\/ar\/wp-json\/wp\/v2\/posts\/47758\/revisions"}],"wp:attachment":[{"href":"https:\/\/silmantech.com\/ar\/wp-json\/wp\/v2\/media?parent=47758"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/silmantech.com\/ar\/wp-json\/wp\/v2\/categories?post=47758"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/silmantech.com\/ar\/wp-json\/wp\/v2\/tags?post=47758"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}