Reliability generally refers to the probability that a product will perform a specified task under specified conditions within a specified time. It is related to the corresponding load, usage environment, and application cycle. It is usually evaluated by using a temperature cycling method.
The reliability of lead-free interconnects is a very complex issue, and simply depends on the “acceleration factor” of the test.
In most applications, the product is in the environment of 0-100 ° C, the load is relatively low, lead-free is more reliable than lead ; but for automotive electronics, military products, the operating temperature is often below 50–150 ° C. The solder joints are subjected to a large load, and the lead solder joints are often more reliable than the lead-free solder joints.
The lead-free craft and ROHS are two concepts. The lead-free craft refers to the usage of lead-free solder. It is a crafts technology that realizes interconnecting PCB and SMD that meet ROHS requirements.
The lead-free craft has the following characteristics compared to the lead craft:
1.Increased solder melting point
3.The fluidity is deteriorated, and the fluidity of the lead-free solder is deteriorated due to the relative shortage of the superheating temperature, and the melting of the copper at a high temperature causes the fluidity to be worse, and in general, the weldability is deteriorated.
① Prepare a actual product surface soldered pcb assembly board . Because printed solder paste and the PCB assembly board without soldering cannot fix the test end of the thermocouple, it is necessary to use the soldered actual product for testing. In addition, the test sample cannot be used repea...
Most military industrial enterprises in China use epoxy insulation varnish as a three-anticoating material, using traditional immersion, brushing and spraying processes. Because the output of military products is relatively small, many companies use manual operations. The main disadvantage of man...
Pcb prototypes samples need to be aged prior to solderability testing. Because the solderable surface of the component or PCB circuit board that has just been produced is generally not problematic, it will deteriorate due to oxidation after being stored for a period of time. The test must conside...