PCBA Tech - Why preheat before PCBA processing

In the mass-produced PCB processing and welding environment, the importance of the temperature profile has been widely understood. Slow heating and preheating stages help to activate the flux, prevent thermal shock and improve the quality of solder joints during smt placement. However, when it comes to rework, prototyping, or PCBA first-piece proofing projects, it is easy to forget the importance of the warm-up phase, which may cause the equipment to be compromised even if it is not damaged. So, for such an important step, why is it often forgotten in the actual operation of the smt processing plant? What are the consequences of omitting this stage?

Reflow soldering preheating zone

What is the preheating before PCBA soldering?

When technicians and practitioners hear the words temperature curve or temperature curve, they think of smt reflow soldering. The four main temperature control zones can be easily seen along the huge length of the welding zone, which will eventually produce perfect welding joints, hope so. Each stage is carefully controlled and improved through the experience of technicians and trial and error. Each stage plays a role in promoting solder joint quality and reducing defects. But other industrial soldering machines may not have such fine temperature control. But what they have in common is the warm-up phase.

Flux combustion in selective wave soldering

The function of the preheating stage is to steadily increase the temperature of the entire component from room temperature to a holding temperature lower than the melting point of the solder paste, which is about 150 degree Celsius. Adjust the temperature change to maintain a constant slope of a few degrees per second. The preheating stage is directly followed by the soaking stage, which will maintain the temperature for a period of time to ensure that the board is heated evenly. Then there is the reflow stage, and the solder joint formation is started. During the preheating and soaking stages, the volatile solvent in the solder paste is burned off and the flux is activated.

Medical electronics PCBA electronics manufacturing capabilities

The medical electronic equipment manufacturing industry is facing fierce competition at all levels of the market. The industry is responding with a high degree of innovation in product layout/manufacturing and is taking healthcare to a new level through technological advancement.

The following project experience:

1. Manufacturing of PCB circuit boards for medical diagnostic equipment;

2. Production of interconnection between flexible circuit boards (Flex) and rigid-flex boards (Rigid Flex);

3. Manufacturing of medical electronic equipment circuit boards for imaging systems and imaging electronic equipment;

4. PCBA assembly for the circuit board of the medical motion control system;

5. PCB processing of high-tech temperature measurement equipment used for security inspection and epidemic prevention;

6. Used for smt processing of control circuit boards of medical optical instruments;

7. Processing of medical power control board for small dental equipment;

8. 3D high-resolution scanner hardware manufacturing;

9. Printed circuit board packaging materials for digital X-rays;

Extensive PCBA assembly/package manufacturing capabilities, and use the latest technology. The PCBA project provides personalized services. You can go to the site to directly communicate with the engineering team in depth, and ensure that the communication between the manufacturer and the engineer is improved.