{"id":6091,"date":"2024-08-28T17:00:52","date_gmt":"2024-08-28T09:00:52","guid":{"rendered":"https:\/\/www.qhsmt.com\/?p=6091"},"modified":"2024-09-05T16:07:10","modified_gmt":"2024-09-05T08:07:10","slug":"how-to-locally-increase-the-amount-of-solder-paste-or-solder-in-the-smt-process","status":"publish","type":"post","link":"https:\/\/www.qhsmt.com\/zh\/2024\/08\/28\/how-to-locally-increase-the-amount-of-solder-paste-or-solder-in-the-smt-process\/","title":{"rendered":"How to locally increase the amount of solder paste or solder in the SMT process"},"content":{"rendered":"
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Author: Zhou<\/p>\n\n\n\n

With the miniaturization and precision of electronic products, surface mount technology (SMT) is becoming more and more widely used in the electronics manufacturing industry. In the SMT process, the amount of solder paste directly affects the quality and reliability of the solder joints. In some specific cases, in order to meet specific soldering requirements, we need to increase the amount of solder paste or solder in the local area.<\/p>\n<\/blockquote>\n\n\n\n

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The necessity of increasing the amount of solder paste or solder locally.<\/strong><\/h2>\n\n\n\n

In some cases, a local increase in solder paste or solder amount is necessary, and here are some common reasons: Heat dissipation: For components that generate a lot of heat, increasing the amount of solder can help improve heat conduction efficiency. Mechanical strength: Increasing the amount of solder in areas subjected to mechanical stress can result in stronger solder joints. Compensate for dimensional deviations: Due to deviations in component pin and PCB pad dimensions, more solder may be required to ensure a reliable connection.<\/p>\n\n\n\n

A method for increasing the amount of solder paste or solder locally<\/strong><\/h2>\n\n\n\n

Here are some ways to increase the amount of solder paste or solder locally in the SMT process:<\/p>\n\n\n\n

1.Adjust the size of the stencil opening<\/mark><\/strong><\/p>\n\n\n\n

By adjusting the size of the openings in the stencil, the amount of solder paste deposited can be directly controlled.<\/p>\n\n\n\n

    <\/ol>\n\n\n\n

    Enlarge the opening: Enlarge the size of the stencil opening corresponding to the pad that requires more solder, thereby increasing the amount of solder paste deposited.<\/p>\n\n\n\n

    Use of special shaped openings: Trapezoidal or runway-shaped openings allow more solder paste to be deposited at the edge of the pad.<\/p>\n\n\n\n

    Advantages:<\/strong> <\/em><\/mark>Simplicity, low cost, no need to change existing processes. Disadvantages:<\/strong> <\/mark> <\/em>If the operation is improper, it may affect the printing quality; Limited by the minimum feature size of the stencil.<\/p>\n\n\n\n

    2.Multiple printing<\/mark><\/strong><\/p>\n\n\n\n

    Print the same PCB multiple times to increase the amount of solder paste deposited.<\/p>\n\n\n\n

    Advantages: <\/strong><\/em>the amount of additional solder can be precisely controlled; Suitable for specific areas where more solder is needed. Disadvantages: <\/strong><\/em>increased production time and cost; Inaccurate alignment can lead to printing problems.<\/p>\n\n\n\n

    3.Use solder preforms<\/mark><\/strong><\/p>\n\n\n\n

    Before reflow soldering, place the solder preform on the PCB pad.<\/p>\n\n\n\n

    Advantages:<\/em><\/strong> the amount of solder can be precisely controlled; Suitable for applications that require large quantities of solder. Disadvantages: <\/em><\/strong>Manual placement is costly and time-consuming; Automated placement may require additional process steps.<\/p>\n\n\n\n

    4.Solder impregnation or wave soldering<\/mark><\/strong><\/p>\n\n\n\n

    For through-hole components or specific pads, solder dipping or wave soldering can be used to increase the amount of solder.<\/p>\n\n\n\n

    Advantages:<\/em><\/strong> Quickly and efficiently add a large amount of solder; Suitable for adjustments after reflow soldering. Disadvantages: <\/em><\/strong>Not suitable for all SMT applications; If not properly controlled, it can lead to solder bridging.<\/p>\n\n\n\n

    5.Adjust the metal content and rheological properties of solder paste<\/mark><\/strong><\/p>\n\n\n\n

    Higher solder amounts can be achieved after reflow by using solder pastes with higher metal content or different rheological properties.<\/p>\n\n\n\n

    Advantages: <\/em><\/strong>Can be applied to the whole board or selective area; There is no need to change the stencil design. Disadvantages: <\/em><\/strong>May affect the reflow curve and the overall process; Special solder paste is required, which increases the cost.<\/p>\n\n\n\n

    The decision to locally increase the amount of solder paste or solder in the SMT process should be carefully considered to balance its advantages with potential pitfalls. Each approach has its use case, and often requires a combination of approaches to achieve the goal. Engineers need to evaluate the specific requirements of the assembly process, the characteristics of the components, and the impact of productivity and cost.<\/p>\n\n\n\n