Technical
How to Judge the Acceptance of PCB Quality
Which Color Circuit Board Sells the Most Expensive
Method to Solve the Noise Interference of Power Supply on High-frequency PCB Board
Disassembly Skills of Chip Components on PCB
What Factors Should Be Considered in the Selection of High-frequency PCB CCL
How to Place Special Components during PCB Layout
What Are the Functions of Capacitors in Circuits?
Testing Techniques for Common Electronics Components
What to do if There is a Short Circuit on the PCB
Desoldering Principles and knowhow during PCBA Processing
Black Oxidation of the Inner Layer of the Multilayer PCB
How to Ensure the High-performance Design of PCB
What Is the Printing Process of SMT Solder Paste?
PCB without fiducial mark, Is There Any Way to do SMT for It
What Are the Benefits of Reserving Break-up Tab for PCB Production
How Does SMT Affect PCB Production Time and Speed It Up
Classification of PCBs from three aspects
Common Problems and Solutions for Dry Film pasting during PCB Manufacturing process
Several Elements to Inspect after PCB Design
What is a halogen-free circuit board?
What Do Capacitive Coupling and Decoupling Mean?
What Are the Differences Between PCB Paste Mask and Solder Mask?
How PCBA Is Packaged and Shipped
How long can PCBA finished products be stored?
What Are the Differences and Relations Between PCB, PCBA, and SMT?
PCB Baking Specifications
PCB "Solder Mask Tenting" and "Solder Mask Opening"
Five reasons for PCB deformation and six solutions
Importance of first article inspection of PCBA board
Temperature zone standard for SMT reflow soldering
Small and medium volume PCB manufacturers in China
The main reason for PCBA cleaning
For power filter, the more capacitors, the better?
What does PCBA programming mean?
Content of PCB incoming testing
What conditions must be met for PCB circuit board soldering?
What is Blind via and Buried via
PCBA Manufacturers Temperature and Humidity Sensitive Components Management
Why choose Shenzhen SMT processing factory?
How long does it take to calculate the quotation for PCBA manufacturing?
Introduction of PCB design clearance requirements
Explanation of BOM, DIP, SMT, SMD
Introduction of the process of PCBA prototype
How to prevent pseudo soldering or cold soldering defects in PCBA manufacturing?
Factors that affect the Price of FPCB
What information is required for SMT processing at PCBA factory?
Skills of using 0ohm resistor in PCB design
How to select a PCBA manufacturer
SMT processing solder joint quality inspection
Characteristics difference between immersion gold PCB and gold plating PCB
Common malfunctions of Circuit Board Caused by Moisture
A Few Rules about PCB Panelization
Compare of multi-layer PCB with single/double layer PCB
Why do we need to introduce so many subdivided GND
Difference between immersion gold boards and gold plating boards
Aluminum PCB structure
Classification of different GND in circuit
Why PCB baking is necessary during manufacturing process
The handle and precautions of OSP board in SMT process
How to choose capacitors for filter decoupling
How to choose filter capacitor for switching power supply
5 database need for SMT process
Function of three-terminal capacitor
Introduction of PCB OSP surface treatment
Method of inspecting the quality of SMT by step
How to find the short point between VCC and GND
Difference between 850nm and 940nm infrared LED
Component layout of PCB SMT DFM
Pad shape influence on the strength and reliability of the soldering joints
The difference between high temperature solder paste and low temperature solder paste
Introduction to manual welding processing
Manual visual inspection in PCBA processing
Characteristics of the conformal coating process
Difference between hardware engineers and software engineers
PCBA processing operation rules
China PCB upstream materials has continued to soar
Difference between serial buses and parallel buses
The key points of quality control in PCBA processing
Common causes of solder beading during SMT process
Analysis of the advantages and disadvantages of HASL PCB surface
Requirements for layout of components during SMT assembly
Selection of electronic components and CCL for PCBA
Performance and appearance quality inspection of components.
Quality and Reliability of SMT Chip Processing and Production
Coupling and decoupling function of capacitor
Two methods to connect digital ground and analog ground
Common sense in SMT process

Common causes of solder beading during SMT process

Sometimes there will be some quality problems in PCBA processing. These problems that affect the quality of PCBA processing need to be avoided. The solder beading appearing in SMD processing is such a situation. Next, Shenzhen PCBA manufacturer SYS Technology will briefly introduce some common causes of solder beading.

1. Solder beading mainly appear on sides of chip resistor and capacitor, and in some cases they also appear around the pins of chip ICs. Tin beads not only affect the appearance of PCBA board products, but more importantly, due to the dense components on the printed board, there is a risk of short circuits in the application process, which in turn harms the quality of electronic products. There are many reasons for solder beading, and they are often caused by one or more factors. Therefore, prevention and improvement must be done one by one so that they can be better controlled.

2. Solder beading refers to some large solder balls occur after reflow soldering. When printing solder paste, the solder paste may be out of the printed pad due to various reasons such as collapse and squeeze. During reflow soldering, this solder paste that exceeds the pad cannot be melted together with the solder paste on the pad, and Solder beading is formed under the component or the periphery of the pad.

3. However, in PCBA processing, most of the solder beading are produced on both sides of the chip components. Take the chip components with the pad design in square shape for example. After the solder paste printed, if the solder paste exceeds, it will be very easy to cause tin beads. Melting with the solder paste on the pad will not produce solder beading.

However, when the amount of solder is large, the component placement pressure will squeeze the solder paste under the component (insulator), and it will melt during reflow soldering. Due to the surface tension, the melted solder paste gathers into a large ball, which tends to raise the components, but this force is very small, they are squeezed to both sides of the components by the gravity of the components, separated from the pads, and tin beads are produced when they are cooled. If the gravity of the component is large and the solder paste is squeezed out, multiple solder balls may even be produced.

4. According to the causes of tin beads, the main factors that form tin beads in the SMT processing are:
a. Graphic design of stencil openings and pads.
b. Stencil cleaning.
c. The accuracy of SMT placement machine.
d. Temperature Profile of reflow oven.
e. Placement pressure of SMT machine.
f. The amount of solder paste outside the pad.