{"id":3414,"date":"2024-01-02T14:01:09","date_gmt":"2024-01-02T06:01:09","guid":{"rendered":"https:\/\/www.jingpengpcb.com\/?p=3414"},"modified":"2026-10-02T19:31:20","modified_gmt":"2026-10-02T11:31:20","slug":"smt-grape-ball-phenomenon","status":"publish","type":"post","link":"https:\/\/www.jingpengpcb.com\/en\/blog\/smt-grape-ball-phenomenon\/","title":{"rendered":"Causes and Solutions for the SMT \"Staphylococcus\" Phenomenon"},"content":{"rendered":"

The \"grape phenomenon\" typically refers to a situation where solder paste does not fully melt during the reflow soldering process, but instead solidifies into individual solder beads that stack on top of one another, forming a cluster resembling a bunch of grapes.<\/p>\n

\"Causes<\/p>\n

Causes of the SMT \"Staphylococcus\" Phenomenon<\/h3>\n

1. Solder paste has absorbed moisture and oxidized<\/h4>\n

One of the main causes of the \"grape phenomenon\" is the oxidation of solder paste. This oxidation can result from a variety of factors, including operator negligence, the use of expired solder paste or improper storage, as well as the reheating or improper mixing of solder paste.<\/p>\n

Moisture absorption by the solder paste is a possible cause of its oxidation; sometimes, the steel plate or stencil is not completely dry after solvent cleaning.<\/p>\n

2. Solvent evaporation from solder paste and flux<\/h4>\n

The flux in solder paste is a key factor affecting its melting. The role of the flux is to remove oxides from the metal surface, thereby reducing oxidation of the solder metal surface.<\/p>\n

Another function is to protect the tin powder from coming into contact with the air. If the flux evaporates too early, it will be unable to effectively remove oxides from the metal surface, resulting in a decline in the quality of the solder paste.<\/p>\n

3. Insufficient return temperature<\/h4>\n

If the temperature of the reflow oven is not high enough to completely melt the solder paste, this can also lead to the \"grape\" phenomenon. This is especially true when there is a small amount of solder on the printed circuit board (PCB), as oxidation of the solder paste and volatilization of the flux are more likely to occur.<\/p>\n

This is because the solder paste is exposed to air for a longer period of time, which increases the likelihood of the \"staphy\" phenomenon.<\/p>\n

Solutions for Mitigating the \"SMT Grape\" Phenomenon<\/h3>\n

1. Use solder paste with higher activity<\/h4>\n

When selecting solder paste, using a more active type can reduce the occurrence of the \"grape\" phenomenon. This type of solder paste offers better oxidation resistance.<\/p>\n

2. Increase the amount of solder paste applied<\/h4>\n

Increasing the amount of solder paste dispensed helps reduce the time the solder paste is exposed to air, thereby lowering the risk of the \"staphylococcus\" effect.<\/p>\n

3. Increase the width or thickness of the opening in the steel plate<\/h4>\n

By increasing the width or thickness of the openings in the steel plate, the amount of solder paste deposited can be increased, further improving oxidation resistance.<\/p>\n

4. Reduce the preheating time for reflow soldering<\/h4>\n

Reducing the preheating time in the reflow soldering process and increasing the heating rate can minimize flux volatilization, thereby reducing the likelihood of the \"staphylo\" phenomenon.<\/p>\n

5. Use nitrogen<\/h4>\n

By introducing nitrogen, the oxidation rate of the solder paste is reduced, further minimizing the occurrence of the \"grape\" effect.<\/p>\n

The Operating Process of a Surface Mount Placement Machine<\/h2>\n

Now, let\u2019s take a look at how a placement machine works\u2014a crucial part of SMT technology. The placement machine is primarily responsible for precisely placing components onto printed circuit boards.<\/p>\n

1. Submitting a Board<\/h3>\n

First, the PCB to be assembled enters the placement machine's work area and is secured in the designated position.<\/p>\n

2. Choosing a Nozzle<\/h3>\n

The placement machine will select the appropriate nozzle based on the position set in the program.<\/p>\n

3. Selection of a Board Feeder<\/h3>\n

The board feeder transfers components from the feeder to the placement machine's work area.<\/p>\n

4. Component Picking<\/h3>\n

The SMT pick-and-place head uses a vacuum to pick up components, ensuring precise placement.<\/p>\n

5. Component Inspection<\/h3>\n

The placement machine uses a vision system to inspect components, including their features, positions, and angles.<\/p>\n

6. Displacement-Based Positioning<\/h3>\n

The placement machine accurately positions components on the pads of the PCB.<\/p>\n

7. Component Placement<\/h3>\n

Next, the pick-and-place head precisely places the components onto the corresponding pads on the PCB.<\/p>\n

8. Plate Out Placement<\/h3>\n

Once the components have been mounted on the PCB, the placement machine returns the nozzle to its home position, and the PCB continues on to the next SMT process.<\/p>\n

The above provides a detailed overview of the SMT Staph placement machine\u2019s workflow and operating process.<\/p>\n

These key steps ensure the smooth operation of the production line, reduce component loss, and improve production efficiency, ultimately leading to better product quality.<\/p>\n

If you have any further questions about PCBA or would like more information, please visit our company's website.<\/p>","protected":false},"excerpt":{"rendered":"

\u8461\u8404\u7403\u73b0\u8c61\u901a\u5e38\u6307\u7684\u662f\u9521\u818f\u5728\u56de\u6d41\u710a\u8fc7\u7a0b\u4e2d\u6ca1\u6709\u5b8c\u5168\u7194\u5316\uff0c\u800c\u662f\u51dd\u7ed3\u6210\u5355\u4e2a\u9521\u73e0\u5e76\u5806\u53e0\u5728\u4e00\u8d77\uff0c\u5f62\u6210\u4e00\u4e32\u8461\u8404\u72b6\u7684\u73b0\u8c61\u3002 \u9020 […]<\/p>\n","protected":false},"author":1,"featured_media":8898,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"slim_seo":{"title":"Causes and Solutions for the SMT \"Staphylococcus\" Phenomenon","description":"How can the \"SMT grape phenomenon\" be resolved? Explain the relationship between causes such as moisture absorption and oxidation of solder paste and the reflow soldering temperature profile, and provide solutions. Also, describe the process from board feeding to placement on the SMT placement machine."},"_slim_seo_primary_term_category":0,"_slim_seo_primary_term_post_tag":0,"footnotes":""},"categories":[26],"tags":[34,262],"class_list":["post-3414","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-blog","tag-smt","tag-262"],"_links":{"self":[{"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/posts\/3414","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=3414"}],"version-history":[{"count":1,"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/posts\/3414\/revisions"}],"predecessor-version":[{"id":19377,"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/posts\/3414\/revisions\/19377"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/media\/8898"}],"wp:attachment":[{"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/media?parent=3414"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/categories?post=3414"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/tags?post=3414"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}