Lead free PCB assembly is used for electronic products that comply with RoHS standards. Lead free PCB assembly has become an irreversible trend in the PCB assembly industry. With the gradual improvement of international environmental requirements, lead-free PCB assembly technology has become an inevitable trend in the development and production of the electronics industry. So generally speaking, lead-free PCB assembly is used for most electronic products and will become increasingly common. Lead free PCB assembly manufacturers are subject to RoHS standards. Manufacturing PCB assemblies that comply with RoHS standards means replacing traditional lead based solder with lead-free alternatives.

Although lead-free PCB assembly processes have been implemented for many years, there are still some companies that use lead based processes because of their excellent solderability. However, lead-free PCB assembly processes will be increasingly used globally because they are environmentally friendly. So, should we use lead or lead-free PCB assembly in the equipment? If you encounter the following situations, using lead-free PCB assembly may be helpful for you.

Your product may be sold in countries/regions with regulatory requirements, such as the European Union.

Your state or local government requires the use of lead-free manufacturing processes, such as in California, USA.

You are concerned that using lead containing products may pose health risks.

You are concerned about the potential liability risks associated with lead containing products.

You recognize the trend of green manufacturing and do not want to lose customers due to environmentally unfriendly production.

You can rest assured to provide lead-free PCB assembly services without any quality issues during mass production.

Please refer to the following main differences between lead PCB assembly and lead-free PCB assembly (also known as RoHS PCB assembly):

For lead-free PCB assembly, the most important difference between lead soldering and lead-free soldering is environmental friendliness. Lead containing solder paste is not environmentally friendly because it contains lead (Pb), which is highly toxic to the human body.

The metal elements in lead containing tin are tin: 61.9%, lead: 38.1%, more generally speaking: tin: 60%, lead: 40%. The most widely used lead-free solder for lead-free PCB assembly is SAC30. SAC305 represents 96.5%, silver: 3%, copper: 0.5%. But what we need to know is that the lead-free PCB assembly process cannot be 100% lead-free, but the lead element should be less than 1000ppm (<0.1%), which meets the acceptable standards of RoHS and REACH

The melting point of lead tin is 180-190 degrees Celsius, and the working temperature is about 240-260 degrees Celsius. The melting point of lead-free tin used for lead-free PCB assembly is 210-230 degrees Celsius, and the working temperature is 250-280 degrees Celsius. But now solder suppliers have also developed low-temperature solder that can melt below 200 degrees Celsius.

The price of lead-free solder is relatively expensive because the substrate in lead-free solder is relatively expensive.

How do we determine if a printed circuit board is lead-free when we receive it? Due to the fact that many customers require PCB assembly that complies with RoHS standards. We will discuss this issue from the following aspects.

For experienced workers, it is easy to distinguish between PCBs soldered with lead-free solder or leaded solder. Because the colors of solder joints are different: lead containing solder appears bright white, while lead-free solder appears darker and slightly yellow.

Lead containing solder typically contains 70% tin and 30% lead. Lead free solder typically contains 96% tin, 3% silver, 0.5% copper, and small amounts of other elements.

Lead containing solder is only used for products that allow lead content. But lead-free solder can be used for lead-free PCB assembly and can be used for most electronic products. Lead free solder complies with RoHS and REACH regulations and can be exported to Europe and the United States.

By introducing the above aspects, when you receive a PCB, you can quickly identify whether it is a lead-free PCB.

Currently, lead-free PCB assembly is becoming increasingly common. How can we produce qualified lead-free PCBs? The following are the things we need to pay close attention to:

For PTH assembly, the welding time should be controlled as accurately as possible. Generally speaking, the process from heating the solder joint to melting and filling the solder joint should be completed within a few seconds. If the time is too long, the flux on the solder joint will completely evaporate and eventually lose its soldering effect, or if the temperature of the solder joint cannot reach the soldering temperature due to too short a time, the solder cannot be fully melted, and there is only a small amount of soldering on the solder joint, causing poor contact, this is called virtual soldering phenomenon.

In addition, attention should be paid to the amount of solder and flux used, as too much or too little can affect the quality of the soldering. In addition, during the welding process, be careful not to touch the solder joints, especially when the solder on the solder joints has not completely solidified. Do not move the welding equipment and wire on the solder joints, otherwise the solder joints will deform and virtual welding will occur. Only by understanding its welding procedures can it fully exert its best effect.

For manual soldering, the temperature of the soldering iron tip is very important because different soldering iron tips placed on rosin blocks/flux at different temperatures will produce different phenomena. Therefore, it is necessary to keep it at the appropriate temperature, usually the temperature at which rosin/flux melts quickly and does not smoke is the most suitable.

To obtain lead-free PCB assembly services, we must ensure that all materials are lead-free, including all electronic components and PCBs. When purchasing components, you need to request suppliers to provide parts that comply with RoHS standards. In addition, it is necessary to order lead-free PCBs.

Additionally, personnel must be stable. Try to stabilize frontline employees, technicians, and process engineers as much as possible. The positions of several key personnel must be stable, and negotiations with clients should be done after discussion. Efforts should be made to operate according to the contract in order to achieve long-term cooperation.

Each factory has its own strengths and weaknesses, so focusing on areas of advantage is key. Then provide high-quality products at competitive prices. At Haibo, we always focus on small batch lead-free PCB assembly services and electronic manufacturing services. We always focus on establishing high-quality long-term partnerships with our customers.

We all know that assembling lead containing printed circuit boards is harmful to the human body and not good for the environment. But why is the assembly of lead containing printed circuit boards harmful to the human body? Does custom PCB assembly still exist? The main reasons are as follows. But at Haibo, we only produce lead-free PCB components that comply with RoHS and REACH standards.

Some products require very special soldering standards that cannot be achieved through lead-free assembly, or some components cannot withstand the high temperature of lead-free soldering, so customers must choose lead soldering.

Due to the higher production cost of lead-free PCB assembly compared to lead based circuit board assembly, many manufacturers will continue to use lead based processes to varying degrees. Especially for customers who produce large quantities and inexpensive electronic products.

Currently, there are still many countries or regions that have not implemented RoHS/REACH policies. Therefore, lead containing electronic PCB assembly remains popular. But of course, lead welding is not conducive to environmental protection.

For some customers, lead-free PCB assembly is not necessary. Therefore, when they need customized PCB assembly services, they may be confused about whether lead-free PCB assembly or lead assembly should be used on their products. The following introduction may help customers choose the right method.

Firstly, customized lead-free PCB assembly is mainly environmentally friendly, healthier for users, and has much less impact on the environment. So if the product needs to meet RoHS and REACH requirements, customers must choose lead-free PCB assembly. However, due to the higher price of lead-free solder, the assembly cost of lead-free PCB assembly is slightly higher than that of lead assembly. So for customers, it's better to consider environmental policies, prices, and product profits rather than blindly pursuing lead-free soldering.

The lead-free soldering temperature is about 35 degrees higher than the lead soldering temperature. During SMT assembly, the soldering temperature is also higher than the Tg of the PCB substrate, and the lead-free soldering temperature is higher than the lead soldering temperature. If the TG of the PCB material is too low, it is easy to cause PCB thermal deformation and component damage during cooling. Therefore, PCB materials with higher Tg should be selected appropriately.

The lead-free soldering process requires PCBs to have good heat resistance, high glass transition temperature Tg, low thermal expansion coefficient, and low cost. Therefore, it is necessary to consider the impact of high temperature on component packaging. Due to the fact that the packaging material of traditional surface mount components can meet the soldering temperature of lead solder as long as it can withstand 240 degrees Celsius, while the soldering temperature of complex products during lead-free soldering can reach 260 degrees Celsius, it is necessary to consider whether the packaging of components can withstand high temperatures.

In addition, the impact of high temperature on the internal connections of the device should also be considered. The internal connection methods of ICs include gold wire ball welding, ultrasonic pressure welding, and reverse welding, especially for new electronic components such as BGA, CSP, composite components, modules, etc. The materials used for internal connections are the same as the solder used for surface assembly, and they also use reflow soldering technology.

From a cost perspective, the cost of lead-free solder currently developed is higher than that of tin lead alloys. Many people may think that the cost of solder material accounts for a high proportion. However, according to some statistical data, PCB manufacturers generally control the cost of solder within 10% of the total cost, especially for technical electronics/PCB, so it will not have a significant impact on the overall cost of the final product. Therefore, most customers choose lead-free PCB assembly in their RoHS compliant PCBs.

Nowadays, solder manufacturers are still researching and finding the most suitable metal to replace lead. To achieve two simple goals: good weldability and low cost. The following are the characteristics to consider when choosing lead alternatives.

This metal/alloy must be available worldwide, easily obtainable in most countries, and its quantity must be large enough to meet global demand.

Alternative alloys should also have recyclability. Therefore, it is best not to add too much metal to the formula, otherwise the recycling process will be too complicated and the recycling cost will be too high.

The problem with lead is that it is toxic and harmful to the environment. Therefore, when we try to find alternatives, we need to find something non-toxic.

Solder is widely used in the electronic and circuit board assembly industry. For example, SMT assembly, PTH assembly, manual soldering, and maintenance. Therefore, alternative alloys must be able to meet the needs of all these fields.

In order to protect our environment, countries around the world advocate for green products, so more and more PCB factories will produce more PCB products with lead-free hot air soldering layer surface treatment. The SMT factory will choose PCBs with lead-free hot air solder layers to supply RoHS circuit boards.

From a technical perspective, many countries attach great importance to lead-free technology. Many countries have specialized institutions for the research and development of lead-free solder, which collaborate with solder manufacturers to develop various lead-free solder materials, and a considerable number of them have been experimentally proven to replace tin lead solder products. The focus of lead-free solder research is:

Some people have concerns about whether factories will add new toxic and harmful substances to lead-free solder to remove lead. I understand this concern. We should recognize that such an approach is absurd, unacceptable, and goes against environmental requirements. Some people have the view that "although we should pay attention to whether it meets environmental requirements, can we underestimate its weldability and post weld reliability?" The answer is of course "NO. Moreover, some people are concerned about the cost-effectiveness of lead-free solder. From the above discussion, we can know what kind of lead-free solder will be more popular.

In terms of equipment, lead-free solder factories also have wave soldering and reflow soldering equipment, but many lead-free solder research and development institutions and manufacturers are still striving to improve the quality parameters of lead-free solder itself to adapt to customers' existing equipment.

The newly developed lead-free solder should be as compatible as possible with various fluxes, and the compatibility should be as strong as possible. It should not only work with the support of active rosin resin flux (RA), but also be used for mild, weak active rosin flux (RMA) or resin free cleaning flux, which is the future development trend.

Firstly, the workshop must be lead-free, therefore lead containing tin cannot be used. We need to ensure that the workshop only conducts PCB assembly that complies with RoHS standards.

Static electricity needs to be done well, the workshop needs to be dust-proof, and there are also requirements for temperature and humidity. The temperature should be 24 ± 2 ℃, the humidity should be 60 ± 10% RH, and the placement should be neat.

The passages in the workshop should be kept unobstructed; The ground is free of dust, water seepage, water accumulation, slipping, cigarette butts, paper scraps, and other debris.

Maintain sufficient air conditioning, ventilation, and lighting in the workshop; Electrical power, machine layout, and circuit layout should comply with safety standards, fire exits should be unobstructed, and fire equipment should be complete.

Determine whether to set up changing rooms or lockers according to the needs of the work environment, meet production requirements, and maintain the cleanliness of the changing rooms and lockers.

The tools, vehicles, raw materials, semi-finished products, etc. used in the product manufacturing process should follow the principles of cleanliness and easy access, and be classified and placed in designated locations;

After work, each team must clean up debris and garbage from the warehouse or place them in designated areas, and tidy up and clean the ground; Production personnel are required to thoroughly clean the workshop once a month and may increase the frequency of cleaning if necessary. The workshop floor cleaning work should be carried out at least twice a day, and the workshop garbage should be disposed of in a timely manner. During the cleaning process, attention should be paid to the cleanliness of the surrounding dead corners.

Each workshop manager should provide workshop level safety and environmental education, as well as team level safety and environmental education and training, to new employees (including trainees and substitute personnel); Regularly educate employees on safety and environmental awareness, knowledge, and skills.

Organize and carry out various safety and environmental activities, inspect, supervise, and guide each team to carry out safety and environmental activities. Regularly hold safety and environmental meetings, promptly address safety and environmental issues, handle various employee opinions, establish and improve workshop safety and environmental data and files.

If pursuing cost-effective FPC manufacturing services, choosing a Chinese manufacturer is the best choice. As a manufacturing powerhouse, China has abundant resources, cheap labor, and a large number of technical personnel. We recommend Haibo, a Chinese FPC assembly service provider with over 10 years of experience, who has performed outstandingly in various aspects

Efficient and reasonable quotation:There is an efficient quotation process to assist you in making decisions, providing reasonable prices and highly competitive quotes in China.
High quality and reliable products:Produce high standard printed circuit boards, manufacture and test according to specifications, international standards, and internal controls, and conduct pre production inspections to ensure robust processes.
Quick and on-time delivery:The assembly equipment is in good condition, with high productivity, minimal downtime, short delivery time, and also provides urgent services.
Timely and effective response:Always respond to customer needs, provide accurate information, answer questions through multiple channels, and offer one-stop services.
Strong technical strength:China's FPC manufacturing technology is leading, and Haibo has a complete SMT solution that covers assembly, inspection, and other capabilities. It also provides prototype production and customization services.