How much do you know about PCB surface mount technology(SMT) process assembly?


April 4, 2024

PCB surface mount technology (SMT) is a vital part of modern electronics manufacturing. This guide will provide you with a comprehensive understanding of this critical area by providing an in-depth look at the process, key steps, common issues, solutions, and best practices of PCB SMT assembly.

Details in PCB SMT assembly

1 PCB Design Preparation:

Ensure that the PCB design meets surface mount technology(SMT) process assembly requirements, including component layout, pad design, etc.

2 Component sourcing:

Source the required SMD components to ensure the quality and reliability of the components.
Verify the compatibility of components with PCB designs.

3 Printing Solder Paste:

Print solder paste on the PCB to ensure the accuracy and uniformity of the solder paste.
Solder paste printing using a printing press or similar equipment.

4 Component Placement:

Use automated equipment, such as placement machines, to precisely place SMD components on the PCB.
Ensure the correct position and orientation of the components for subsequent soldering.

5 Reflow Soldering:

Components are soldered to the PCB by hot air or reflow oven to form a reliable solder connection.
Control the reflow temperature and time to ensure the quality of the weld.
It’s a key part of the surface mount technology process.

6 Inspection:

Perform welding quality inspections, including visual inspections, X-ray inspections, etc.
Make sure the soldered connections are intact and there are no issues such as short circuits or open circuits.

7 Cleaning & Testing and Packing & Shipping:

Clean the PCB to remove residual solder paste, dirt, and other impurities.
Ensure that the cleanliness meets the requirements to improve the reliability of the board.
Perform functional tests or electrical tests to ensure that the assembled PCB is working properly.
Testing can be performed using automated test equipment or manual test methods.

8 Packing & Shipping:

The finished PCB is packaged to protect it from damage in transit and storage.
Prepare the product and ship it as planned.

The above is the main process of PCB surface mount technology assembly, and each step is crucial, affecting the quality and performance of the final product. By tightly controlling every step and following best practices, high-quality PCB SMT assembly can be ensured.

Advantages of surface mount technology (SMT) chip processing:

  • The assembly density is high, and the electronics are small in size and light in weight.
  • High reliability and strong seismic resistance with low solder joint defect rate.
  • Good high-frequency characteristics. Reduced electromagnetic and radio frequency interference.
  • Easy to automate and increase productivity. Reduce the cost by half. Save energy, materials, equipment, time, etc.

surface mount technology processCommon problems and solutions

  1. Poor soldering: It may be caused by the quality of the solder paste, insufficient reflow temperature, etc. Adjusting the welding parameters can solve this problem.
  2. Component Offset: This can be caused by inaccurate component placement or PCB design issues. This problem can be avoided by optimizing the component placement process.
  3. Soldering Short Circuit: It can be caused by too much solder paste or inaccurate component position. Controlling the amount of solder paste and improving placement accuracy can solve this problem.

LHD Advantage

  • There are 6 SMT lines, which do not stop 24 hours a day, working in two shifts. The high-speed machine can assemble 3000 points in one hour. We will maintain the equipment regularly to ensure that the work can be completed normally and efficiently.
  • We have a corresponding person to strictly control each surface mount technology process, and reduce the defective rate to infinitely close to 0.
  • We have electronic warehouses, temperature control rooms, ovens to store components with different temperature requirements, and also safes to store valuable components. Hope we can be your best choice, we will not let you down.


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