Reasons for SMT red glue drawing process

Reasons for SMT red glue drawing process
The function of the patch red glue is to make the parts firmly adhere to the PCB surface to prevent them from falling However, when wire drawing occurs during use, the glue will randomly fall on other parts and components of the PCB Obviously, it will affect the appearance of PCB and seriously affect the use of electronic products Wire drawing is caused by many factors, including process, cloth, glue, environment, etc Now, I will share with you some patch red glue factors and solutions for wire drawing
1. Fast dispensing speed
A suitable SMT patch adhesive has its fixed performance indicators, such as viscosity and thixotropy index, to meet the needs of fixed production process, but some users do not understand the effectiveness of glue,

In order to improve the production efficiency, the glue speed is accelerated, but it ignores the efficiency of the product itself and cannot meet the needs of the new process When the dispensing speed increases suddenly and thixotropy cannot keep up, glue and wire drawing are easy to occur The solution is to accelerate productivity and change processes Before consulting the manufacturer, determine whether the current product performance can meet the new technology. If not, you can ask the manufacturer to provide solutions to prevent abnormal conditions
What is the reason for the drawing process? What is the SMT patch red glue? How to solve it?
2. Uneven mixing before use
We all know that patch red glue is a kind of material with high thixotropy. The purpose is to solve the wire drawing phenomenon in production. However, the reactive thixotropy index is the thixotropy index. The thixotropy index is related to viscosity. When random or probabilistic wire drawing occurs during printing or distribution, it can be considered that the local viscosity of glue is uneven, resulting in local thixotropy difference. At this time, the red glue can be punched out, stirred evenly and used continuously.
Third, printing network problems
The use process of patch red glue is generally printing and removing Now we will discuss the problem of printing screen First of all, we must understand the information of the printing screen, such as metal, plastic, etc Metal printing screen is generally steel screen or copper screen If the printing hole is not smooth and polished, it will produce wire drawing during printing When choosing to use the plastic printing screen, it is necessary to choose the appropriate patch red glue, because some formula red glue is not suitable for use on plastic materials One reason is that the cleanliness of the printing screen is mentioned Therefore, understanding the requirements of printing screen can also avoid wire drawing in production
Fourth, the glue itself
The problem with the glue itself mentioned here is mainly due to the changes in the efficiency and quality of the red glue for the patch due to some reasons during storage. For example, the storage environment does not match. The general storage requirement is low temperature storage. Under high temperature, the glue thickens for a long time, which is easy to use. Wire drawing occurs; The high humidity and poor air tightness of the storage environment lead to moisture absorption or the rapid moisture absorption of the glue itself, leading to the collapse of the red glue, and also lead to wire drawing during use. In this case, the storage environment of red glue should be kept low temperature and dry to prevent glue. The quality of glue varies due to external influences.

The above is the explanation given by the editor of pcb circuit board company.
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