SMD Soldering | Surface Mount Soldering Guide
Learn How to Solder SMD in this Detailed Surface Mount Soldering Guide.
SMD Soldering and Desoldering is little different from thru-hole Soldering and Desoldering Process.
SMD Desoldering is generally done using a Hot Air Blower while Soldering can be done using a soldering iron and solder wire or using solder paste or solder balls (BGA) and SMD Hot Air Blower / rework station.
There are many process for surface mount soldering for SMD Components but none is perfect for all applications.
Table of Contents:
Types of SMD Soldering Process
All SMD soldering processes have technical concerns and there are ways to resolve those concerns. Because it offers higher yield and lower operation cost, convection dominant IR soldering has evolved as the preferred process for reflow soldering.
Vapor phase soldering will not disappear but will continue to be used in niche applications. For some specialized jobs, other reflow soldering processes such as laser and hot bar resistance soldering are also used.
These soldering processes are intended not to replace either vapor phase or IR but to complement them. The process ultimately used should be selected on the basis of the specific requirements of the intended application, the solder defect results, and the overall cost.
SMD Soldering Process for Mass Production
For Mass Production in Factories, SMD Soldering is Done using SMT Machine. The Main such Machine is the Reflow Oven.
The most widely used reflow soldering processes in electronics are:
- Vapor Phase; and
- Infrared.
Read:
Video: Selective Soldering Process
Manual SMD Soldering Process
Manual SMD Soldering is Done using a Soldering Iron or Soldering Station, Hot Air SMD Rework Station, Solder Wire and Solder Paste. This process is used mainly for Repairing / Rework.
Read: SMT Soldering and PCB Assembly
Video: SMD Soldering Guide – How to Solder SMD Components
Selection of Soldering Process
Since the electronics industry will remain in a mixed pcb assembly mode, use of SMD Electronic Components and Through-Hole Electronic Components to assemble Different Types of PCB, the use of through-hole components will continue for the foreseeable future. There is no process more cost effective than wave soldering for through-hole active and passive electronic components. The use of reflow with solder paste will also be preferred for some application.
Because of the widespread use of low solids or no-clean solder flux, the use of nitrogen has become common for both wave soldering and reflow soldering processes. However, one should not expect nitrogen to be a panacea for solder defects. It will help only to the extent of its influence on soldering yield. Nitrogen is not going to solve issues related to other parameters such as design, flux activity, solder paste, print quality, and solder profile etc.
The selection of a soldering process depends on the mix of electronic components to be soldered. Various soldering processes will complement each other instead of replacing them. Even hand soldering is not going to disappear entirely.
SMT PCB Assembly Process
PCB Assembly Process Flow Chart (PCBA Process)
FAQs: Surface Mount Soldering
What tools do I need for SMD soldering?
Automated SMD Soldering is done using Surface Mount Technology (SMT. Reflow Oven and Pick-and-Place Machine are two major machines needed in the process.
For manual SMD soldering, you will need a soldering iron with a fine tip (25-30W), fine soldering wire (0.5mm or smaller), flux (liquid or paste), tweezers, a magnifying glass or microscope, and a clean, well-lit workspace.
How do I prevent solder bridges during SMD soldering?
Solder bridges occur when solder unintentionally connects adjacent pads. To prevent this, use a minimal amount of solder, apply flux to the pads, and use solder wick or a desoldering pump to remove excess solder. Fine-tipped tweezers can help position components accurately.
What is the difference between reflow and hand soldering for SMD components?
Reflow soldering involves placing components on a PCB, then heating the entire assembly to melt solder and create connections. Hand soldering requires manually placing components, applying solder, and heating each joint. Reflow is more suitable for mass production, while hand soldering is common for prototypes or low-volume work and rework.
How can I ensure good SMD soldering results?
Practice is the key. Ensure your soldering iron is at the right temperature (not too hot), use the right amount of flux, and avoid excessive heat exposure to prevent damage. Clean the soldering tip regularly, and practice component placement and soldering on scrap PCBs before working on critical projects.
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