Technical
What are the advantages and applications of flexible microcircuits?
FPC Reinforcement Types
Criteria for Classification of electronic Component Classes
Four softwares suitable for beginners to draw PCB circuit boards
What information is needed for SMT processing?
What are the advantages of small and medium batch SMT processing?
PCB related knowledge- The purpose of each layer of the PCB
How to do heat resistance testing for PCB board
Detailed explanation of rigid-flex board and IC carrier board
PCBA prototype procedure
Defects which can be detected by the SPI
What are the spacing requirements for designing PCB circuit boards?
What are the classification and advantages of PCB metal substrates?
Difference between the processing technology of 1Layer AL PCB and 2Layer AL PCB
Introduction of FPC Cable and its usage
advantages of Shenzhen SMT assembly factory
inspection items before PCB ordering
usages of ceramic substrates
main applications of PCB boards
Cost-effective PCB product services
How to check short circuit of a circuit board during manual soldering
Identify the polarity of electronic components during PCBA processing
Means Which Can Prevent Component Shifting in SMT Processing
Skills of PCB prototype manual soldering
Reasons for the shift of Components in the SMT Process
Seven Types of PCB Probes
What Should Be Paid Attention to in Layout of High-frequency PCB
Precautions for PCB CCL Selection
Advantages of LED Plant growth light
Advantages of using LED grow lights to grow industrial hemp
Detailed explanation of PCB manufacturing process and precautions
Detailed explanation of PCB manufacturing process and precautions
How to draw multilayer PCB on Altium Designer
Three basic elements of interference and how to suppression them.
Decrease interference between digital circuit and analog circuit
SMT Component Placement Process Of Parts : Manual Placement
SMT factory incoming PCB material inspection
Basic concepts commonly used in PCB design
Ideas and principles of High speed PCB layout
Component layout rules and safety distance considerations
SMT assembly process quality specification
5 points in PCB layout
Professional interpretation of SMT
Advantages and disadvantages of different PCB surface treatment
Special process in PCB prototype
Why the via hole become open after component assembly
Keep the cost of the PCB as low as possible
what are the causes of PCB board heating radiation problem
Pad size and via diameter dimensions consideration in PCB prototyping
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

What Is the Printing Process of SMT Solder Paste?

In order to standardize the solder paste printing process in the SMT workshop and ensure the quality of solder paste printing, the following process guidelines for solder paste printing in the SMT workshop have been formulated. Today, Shenzhen PCB Assembly factory SYS Tech brought you SMT solder paste printing steps, let's take a look!

I. Tools and accessories used in SMT solder paste printing process:

1. Printing machine
2. PCB board
3. Stencil
4. Solder paste
5. Solder paste mixing knife

PCB solder paste printing


II. SMT solder paste printing steps

1. Check before printing

1.1 Check the correctness of the PCB board to be printed;
1.2 Check whether the surface of the PCB to be printed is intact and free of defects and dirt;
1.3 Check whether the stencil is consistent with the PCB and whether its tension meets the printing requirements;
1.4 Check whether the stencil is blocked. If there is a blocking phenomenon, wipe the stencil with a dust-free paper moistened with alcohol, and dry it with an air pressure gun. When using the air pressure gun, keep a distance of 3~5 cm from the stencil;

1.5 Check whether the solder paste used is correct, whether it is used according to the "Storage and Use of Solder Paste", whether it remarks: pay attention to the temperature recovery time, mixing time, lead-free and leaded distinction, etc.


2. SMT solder paste printing

2.1 Fix the correct stencil to the printing machine and adjust it OK;

2.2 Assemble a clean and good squeegee to the printing machine;

2.3 Use the solder paste mixing knife to add the solder paste to the stencil. For the first time to add solder paste, the height of the solder paste is about 1 CM, and the width is 1.5~2 CM. The length depends on the length of the PCB. Both sides should be about 3 CM longer than the printed area. It should not be too long or too short. After that, add solder paste every two hours, and the amount of tin is about 100 G;

2.4 Put in the PCB board for printing, the first 5PCS board printed requires full inspection. After the printing quality is passed, notify the IPQC for the first inspection. After confirming that the printing quality is normal, notify the production line operator to start production;

2.5 During the normal printing process, the operator needs to check the printing effect every half an hour to see if there are any undesirable phenomena such as poor solder, solder bridge, solder projections, offset, and missing printing. Focus on checking the printing effect of components with too dense pins such as "BGA, QFP, SOP, power strip", etc;                                                                                                 

2.6 The stencil needs to be cleaned once every time 5PCS is printed. If there are components with too dense pins on the PCB board such as "BGA, QFP, SOP, FPC connector", the cleaning frequency should be increased and cleaned every 3PCS;

2.7 During the production process, if continuous 3PCS printing is found to be bad, you should notify the technician should to adjust; clean the badly printed PCB board. When cleaning poorly printed PCB, do not directly scratch the surface of the PCB with hard objects to prevent scratches on the surface wiring of the PCB. If dealing with PCBs with gold fingers, you should avoid the gold fingers. After repeated wiping with dust-free paper moistened with a little alcohol, use an air pressure gun to blow dry, and check under a magnifying glass. If there is no residue solder paste, then it’s OK;

2.8 During the normal printing process, check whether the solder paste has overflowed regularly, and collect the overflowed solder paste;

2.9 After the production is finished, the auxiliary materials and tools such as solder paste, squeegee, and stencil should be recycled, and the frocks and fixtures should be cleaned;

3. Solder paste printing process requirements

3.1 The main defects of printing are: poor solder, continuous solder, solder projections, offset, missing printing, excess solder, scooped solder, dirty board, etc;

3.2 The printing thickness of the solder paste is the thickness of the stencil -0.02mm~+0.04mm;

3.3 Ensure that after reflow soldering effect is free of defects.