![\"Best](\"https:\/\/www.jingpengpcb.com\/wp-content\/uploads\/2023\/08\/the-best-welding-method-for-circuit-boards.jpg\")
<\/p>\nThis article will take an in-depth look at a key step in the welding process\u2014metal wetting. We will explore the meaning of wetting, the role of surface tension, the formation of metal alloy eutectics, and the importance of the wetting angle.<\/p>\n
During the soldering process, when hot, molten solder dissolves and penetrates the surface of the metal being soldered, this is referred to as the metal being tinned. This process involves the mixing of solder and copper to form a new alloy consisting partly of copper and partly of solder.<\/p>\n
This solvent action is called tin wetting, which forms intermolecular bonds between the various components, resulting in the formation of metal alloys. The formation of strong intermolecular bonds is central to the soldering process; it determines the strength and quality of the solder joint.<\/p>\n
Tin plating can only be performed if the surface of the copper on the printed circuit board is free of contamination and does not have an oxide layer, and if the solder and the work surface have reached the appropriate temperature.<\/p>\n
We are all familiar with the surface tension of water, which causes cold water droplets to remain spherical on a greasy metal printed circuit board. This is because, in this situation, the adhesive force that causes a liquid on a solid surface to spread is less than its cohesive force. Washing with warm water and detergent reduces the surface tension of water, allowing it to wet the greasy metal board and form a thin layer.<\/p>\n
This occurs because the intermolecular forces of adhesion are greater than the cohesive forces. Unlike water, the cohesive force of tin-lead solder is even greater than that of water, causing the solder to form a sphere to minimize its surface area (for a given volume, a sphere has the smallest surface area compared to other geometric shapes, satisfying the requirement for the lowest energy state).<\/p>\n
The role of flux is similar to that of a cleaning agent on a greasy metal plate. Furthermore, surface tension is highly dependent on the cleanliness of the surface and temperature. Ideal tin wetting can only be achieved when the adhesion energy is significantly greater than the surface energy (cohesive force).<\/p>\n
During soldering, intermetallic bonds between copper and tin form grains, the shape and size of which depend on the duration and intensity of the soldering temperature. Less heat results in a fine-grained structure, producing a high-quality solder joint with optimal strength.<\/p>\n
However, if the reaction time is too long\u2014whether due to excessive welding time, excessive temperature, or both\u2014it will result in a coarse crystalline structure that is gritty and brittle, with low shear strength.<\/p>\n
When copper is used as the metal substrate and a tin-lead solder alloy is used, lead does not form metallic alloys with copper. However, tin can diffuse into the copper to form copper-tin alloys such as Cu\u2083Sn and Cu\u2086Sn\u2085.<\/p>\n
The wetting angle is an important concept that relates to the eutectic temperature of solder and its interaction with metal surfaces. When the eutectic temperature of solder is approximately 35\u00b0C higher than the surface temperature, a meniscus forms when a drop of solder is placed on a hot, flux-coated surface. To some extent, the wettability of a metal surface can be assessed by the shape of the meniscus. If the solder meniscus has a distinct undercut edge\u2014similar to a water droplet on a greasy metal plate\u2014or is even spherical, the metal surface may be unsuitable for soldering. Good solderability is indicated only when the angle of the meniscus is less than 30 degrees.<\/p>\n
By gaining a deeper understanding of the tinning process for metals, we can better comprehend the key steps in the soldering process, thereby improving soldering quality and efficiency.<\/p>\n
Tinning is a critical step in the soldering process; it determines the strength and quality of the solder joint. Understanding the role of tinning, the effects of surface tension, and the formation of metal alloys is essential for successful soldering. Additionally, understanding the concept of the tinning angle can help assess the feasibility of soldering.<\/p>\n
By continually deepening our understanding of welding processes, we can achieve higher-quality welded joints.<\/p>\n
<\/p>\n
Frequently Asked Questions:<\/strong><\/p>\n No. Tinning is primarily used for soldering copper to tin. Other metals may require different soldering methods.<\/p>\n The wetting angle refers to the angle formed between the solder and the metal surface. When the angle is less than 30 degrees, the solder exhibits good wettability.<\/p>\n The size of the tinning angle affects the quality and feasibility of soldering. An appropriate tinning angle ensures the strength and stability of the solder joint.<\/p>\n Yes, flux can help improve solder wetting, especially when the metal surface isn't clean enough.<\/p>\n Selecting the appropriate welding materials depends on the type of metal to be welded and the application requirements. It is recommended to make this selection under the guidance of a professional.<\/p>","protected":false},"excerpt":{"rendered":" \u6587\u5c06\u6df1\u5165\u8ba8\u8bba\u710a\u63a5\u8fc7\u7a0b\u4e2d\u7684\u4e00\u4e2a\u5173\u952e\u6b65\u9aa4\u2014\u2014\u91d1\u5c5e\u7684\u6cbe\u9521\u3002\u6211\u4eec\u5c06\u4e86\u89e3\u6cbe\u9521\u7684\u542b\u4e49\u3001\u8868\u9762\u5f20\u529b\u7684\u4f5c\u7528\u4ee5\u53ca\u91d1\u5c5e\u5408\u91d1\u5171\u5316\u7269\u7684\u4ea7 […]<\/p>\n","protected":false},"author":1,"featured_media":8859,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"slim_seo":{"title":"Best Soldering Methods for Printed Circuit Boards","description":"What is the best method for soldering PCBs? This article explains the principles of soldering\u2014from tin wetting, surface tension, and metal alloys to the wetting angle\u2014and covers the selection of solder and temperature profiles."},"_slim_seo_primary_term_category":0,"_slim_seo_primary_term_post_tag":0,"footnotes":""},"categories":[26],"tags":[252],"class_list":["post-2492","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-blog","tag-252"],"_links":{"self":[{"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/posts\/2492","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/comments?post=2492"}],"version-history":[{"count":1,"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/posts\/2492\/revisions"}],"predecessor-version":[{"id":19259,"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/posts\/2492\/revisions\/19259"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/media\/8859"}],"wp:attachment":[{"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/media?parent=2492"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/categories?post=2492"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/tags?post=2492"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}1. Is tin plating suitable for all metals?<\/h3>\n
2. What is the solder wetting angle?<\/h3>\n
3. Why is the solder angle important?<\/h3>\n
4. Can flux be used to improve solder wetting?<\/h3>\n
5. How do you choose the right welding materials?<\/h3>\n