What is red glue? Red glue is a polydilute compound, which is different from solder paste in that it solidifies when heated. Its freezing point temperature is 150 ℃, at which point red glue begins to transform directly from a paste like substance into a solid.
The properties of red gum: Red gum has viscosity, fluidity, temperature characteristics, wetting properties, etc. Based on this characteristic of red glue, the purpose of using red glue in production is to firmly adhere the parts to the surface of the PCB and prevent them from falling off.
What is solder paste? Solder paste is a new type of welding material that emerged with SMT mounting. It is a paste like mixture formed by mixing solder powder, flux, other surfactants, thixotropic agents, etc.
Solder paste is mainly used for the soldering of electronic components such as surface resistors, capacitors, and ICs on PCBs in the SMT industry. Its main feature is the role of conductive soldering.
The difference between solder paste and red glue
1. Red glue has a fixing effect and does not conduct electricity, while solder paste also has a fixing effect but does conduct electricity;
2. Red glue needs to undergo wave soldering before welding can be carried out;
3. The temperature of red glue during wave soldering is lower than that of solder paste during wave soldering;
4. Red glue is generally used as an auxiliary material for fixation, as solder paste can conduct electricity, it is often used during welding.
Selection criteria for red glue process and pure solder paste process in SMT process
In general, if there are no traditional plug-in components on the product, a solder paste process (including single-sided, double-sided, or multi-layer boards) will be used. For single panels with traditional components, the soldering surface will be made using the red glue process. A double-sided board with traditional components on one side, a solder paste process on the other side, and a red adhesive process on the other solder surface.
The red glue process needs to go through a wave soldering process to complete the welding of parts and PCBs. The process is slightly longer, which increases labor and manufacturing costs. The solder paste process can be soldered through reflow soldering, which is relatively short, saves manpower and costs, and has a short production cycle, improving market competitiveness.
The difference between solder paste steel mesh and red glue steel mesh
Firstly, depending on the location of the opening, the solder paste steel mesh can be directly opened in a 1:1 ratio according to the position of the SMT pad, making it easier for the solder paste to leak directly onto the PCB pad and facilitate welding! And the red glue steel mesh is special in that its function is to brush glue and paste components for easy welding, so the opening is located between the solder pads of the components. So, if the steel mesh is used incorrectly, it cannot be reworked and can only be scrapped.
Secondly, solder paste steel mesh and red adhesive steel mesh are determined based on different PCB device SMT processing techniques! In general, when PCBs are on the same side and there are fewer SMT devices and more plug-in devices, the use of red adhesive steel mesh technology will increase.
