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What is the difference between solder paste and SMT red glue?


As products in the electronic industry become more and more sophisticated, components become smaller in size, and PCB boards and products are diversified, some electronic accessories have emerged on the "stage" of the electronic industry, among which solder paste and SMT red Glue is an indispensable material in the electronics industry. What is the difference between these two products?

Solder paste is a new type of soldering material that came into being with SMT. It is a paste-like mixture formed by mixing solder powder, flux and other surfactants, thixotropic agents, etc. It is mainly used for the welding of electronic components such as PCB surface resistance, capacitors and ICs in the SMT industry.

SMT red glue is a stable single-component epoxy resin glue used in the SMT field. It is mainly used to fix components on the printed board. It is generally distributed by dispensing or stencil printing. After the device is placed in an oven or reflow soldering machine, it is heated and hardened.

SMT red glue is different from solder paste:

1. The color of solder paste and SMT red glue are different in appearance. The solder paste is gray paste; SMT red glue is red paste.

2. In terms of performance: once the SMT red glue is heated and hardened, it will not melt when heated, which means that the thermal hardening process of the SMT red glue is irreversible, which is the curing phenomenon in the SMT red glue. The solder paste does not solidify after soldering, and the formed solder joint can be melted into tin water again at high temperature.

3. From a process point of view: red glue generally adopts a dispensing process, which is suitable for circuit boards with a small number of points; while solder paste generally adopts a reflow oven printing process, which can print a large number of circuit boards at one time.

4. From the point of view of quality, compared with solder paste, red glue is more affected by the climate and environment, and has a high defect rate after welding, which is more likely to cause dropped parts and missing soldering. The solder paste has strong solderability, and the soldering firmness is relatively high.

5. Different options in terms of manufacturing cost:

1) When there are many SMT components and relatively few plug-in components, many companies generally use the solder paste process, and the plug-in components are welded by post-processing.

2) When there are many plug-in components and there are relatively few SMT components, the red glue process is generally used, and the plug-in components are welded by post-processing. Regardless of which process is used, the purpose is to increase yield and quality.

6. In terms of use: red glue generally plays a fixed and auxiliary role. Solder paste is the real soldering effect.

7. In terms of electrical conductivity: red glue is not conductive, and solder paste is conductive.

8. In terms of furnace temperature: the temperature of the red glue is lower when it passes through the reflow soldering machine. After the red glue passes through the reflow soldering, it needs wave soldering to be soldered. The temperature of the solder paste in the reflow soldering machine is relatively high.

Here we give a warm reminder: the red glue process and the solder paste process must follow some fixed operating requirements when bonding SMD components, so that the entire SMT production process can be completed correctly. The use effect of SMT red glue will vary due to different thermal curing conditions, connected objects, equipment used, and operating environment. When using, SMT red glue should be selected according to the production process.