PCBA Tech - SMT for electronic products and lead-free soldering

SMT is a series of PCB-based processing processes,

SMT is the abbreviation of English Surface Mount Technology, Chinese means surface mount welding (mounting) technology, the technology of welding electronic parts to the surface of the circuit board

Extended reading: What is SMT? What does smt do and what does smt patch mean?

What are the advantages of SMT chip processing technology for the development of modern electronic products, let me explain to you below.

What are the advantages of SMT chip processing?

1. Electronic products are small in size and high in assembly density

Nowadays, the volume of electronic products is getting smaller and smaller, the motherboard is smaller, and the electronic parts are getting smaller and smaller. The traditional manual patch can no longer meet the needs of modern electronic products, from 0804 to the current 0201. The application and development of electronic components require fully automated surface mount technology machinery to replace labor. At present, more than 90% of electronic products use SMT processing technology.

2. High reliability and strong anti-vibration ability

The chip components used in SMT chip processing have high reliability, small size and light weight, and strong anti-vibration ability. It adopts SMT automatic production, fast mounting, high productivity, strong reliability, and the defective products are basically one in ten thousand, ensuring In order to improve the reliability and quality of the product, the defect rate is reduced and the production efficiency is improved.

3. High productivity and automated production

SMT chip processing equipment can basically be produced by on-line fully automated equipment, including board loading machine, printing machine, SPI, placement machine, reflow soldering, AOI, board loading machine, and the entire line of equipment can achieve automated production. Improve production efficiency, save time and labor costs, and ensure that product quality is significantly improved

4. Reduce expenses and reduce costs

5. Reduce costs and reduce expenses

The number of drilling holes is reduced, which saves repair costs; the frequency characteristics are improved, which reduces the circuit debugging costs; the chip components are small in size and light in weight, which reduces the packaging, transportation and storage costs;

The use of SMT patch processing technology can save materials, energy, equipment, manpower, time, etc., and can reduce costs by more than 50%.

Why use lead-free soldering for SMT chip processing

When customers inquire about SMT chip processing, they often ask whether they use lead-free soldering or lead soldering. We will tell customers that both lead-free and lead-free soldering are available. The price is different, so lead-free and lead-free soldering. What is the difference between lead soldering and why should lead-free soldering be used for SMT chip processing? Let me introduce the difference between lead and lead-free soldering.

1. The difference between leaded and lead-free soldering in general:

Soldering with lead solder paste or lead-free solder paste, lead-free solder paste is environmentally friendly, and lead-free solder paste is not environmentally friendly, so the difference between lead and lead-free in SMT chip processing is environmental protection and non-environmental protection

2. The difference between leaded and lead-free

1. Different alloy compositions:

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

The composition of the lead-free alloy is SAC305,

That is, Sn: 96.5%, Ag: 3%, and Cu: 0.5%.

The lead-free process cannot be absolutely lead-free, but can only contain very low lead content 2. Different melting points:

The melting point of lead-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°.

3. Cost difference:

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

The cost of lead-free processing is 2.7 times the cost of leaded processing for wave soldering and manual soldering, and the cost of solder paste for reflow soldering is about 1.5 times.

Why use lead-free soldering for SMT chip processing?

Now is the time to summarize this issue. Lead-free soldering is mainly about environmental protection. It will be healthier for users who use the product, and the impact on the environment will be reduced. 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-free soldering, it needs to be considered based on the use environment of the product, product price and profit, rather than blindly pursuing lead-free soldering.