Why use lead-free soldering for SMT chip processing

When customers inquire about SMT chip processing, they often ask whether you are using lead-free soldering or leaded soldering. We will tell customers that both lead-free and leaded soldering are available, and the prices are different. What is the difference between leaded soldering and why should lead-free soldering be used for SMT chip processing? When you use a precise smt pick and place machine to complete the placement, but you don’t get a satisfactory product after soldering? The quality of welding directly affects the final quality of the product.We will introduce the difference between leaded and lead-free soldering.

First, the difference between leaded and lead-free soldering is generally said:

Lead-free solder paste or lead-free solder paste welding, lead-free solder paste is environmentally friendly, leaded solder paste is not environmentally friendly, so the difference between lead and lead-free SMT chip processing is environmental protection and non-environmental protection

Second, the difference between lead and lead-free

a. Different alloy compositions:

The composition of tin and lead commonly used in lead processing is 63/37

The composition of lead-free alloy is SAC305,

Namely Sn: 96.5%, Ag: 3% and Cu: 0.5%.

Lead-free processes cannot be absolutely lead-free, but only contain very low levels of lead

b. Different melting points:

The melting point of lead and tin is 180°-185°, and the working temperature is about 240°-250°.

The melting point of lead-free tin is 210°-235°, and the working temperature is 245°-280°.

c. Cost difference:

Tin is more expensive than lead, and when the equally important solder is changed to tin, the cost of the solder also increases. Therefore, the cost of lead-free processing is much higher than the cost of leaded processing.

Lead-free processing costs 2.7 times the cost of leaded processing for wave and hand soldering, and about 1.5 times the cost of reflow soldering paste.

Why use lead-free soldering for SMT chip processing?

Now is the time to sum up this issue. Lead-free soldering is mainly about environmental protection. It is healthier for users who use the product and has a much lower impact on the environment. However, the cost of lead-free soldering will be higher, so the unit price of SMD processing will also be higher. Will be high, customers need to use lead-free or lead welding, need to be considered according to the use environment of the product, product price and profit, rather than blindly pursuing lead-free welding.