RoHS & REACH Compliant PCB Assembly

  • One-Stop Solution for PCBs, Components & Assembly
  • SMT assembly + PTH assembly + Manual assembly
  • RoHS/REACH Compliant Lead-Free PCB Assembly
  • ISO9001:2015 Certified & UL Listed
  • IPC A-610 Class 2 standards
  • 100% E-test, AOI, ICT, FCT

Introduction of Lead-Free PCB Assembly

We all know PCB assembly means soldering components on a printed circuit board, whether by SMT reflow soldering, by waving soldering, or by manually soldering. So it is obvious that lead-free PCB assembly means the solder used in PCB assembly does not contain lead (Pb) which is not RoHS compliant. so we all call it RoHS-compliant PCB assembly. To understand lead-free PCB assembly, or lead-free printed circuit board assembly, we had to know what is leaded solder and lead-free solder first.

Leaded solder is commonly used in the electronic PCB assembly industry for many years widely. Because it has very good solderability and is also cost-effective. The composition of tin and lead commonly used in leaded PCB assembly processing is Tin: 63%, Lead: 37%, or around Tin: 60, Lead: 40%.

Lead-free solder is more and more commonly used nowadays. The reason is lead (PB) is harmful to the human body and also not environmentally friendly. The typical type of lead-free solder is SAC305 usually, which contains: Tin: 96.5%, Silver: 3%, and Copper: 0.5%. Of course, there is a very minor percentage of other elements.

A practical standard lead-free solder (Tin) used in the PCB assembly process includes:

In Viasion, all our PCBs assembled are lead-free now. So all our PCBs are RoHS and REACH compliant.

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    Viasion’s Advantages as the One-Stop Lead-Free PCB Assembly Manufacturer

    16+ years of experience

    Our 16 years of experience and accumulation, professionalism and continuous innovation, integrity, and high-quality service, have been recognized and praised by customers and won the goodwill of Viasion.

    Professional production team

    Viasion has a skilled production team. We use lead-free technology to carry out the manufacturing. Our RoHS PCB board meet the requirements of environmental protection.

    Great customer service

    Our sales personnel will provide customers with standardized, professional, personalized fast service in the pre-sales, while-sales, and after-sales processes.

    Competitive pricing

    We will meet the needs of customers with the most favorable price, the best quality, and the fastest speed. Viasion has been highly regarded by customers in the aspects of the quality of products, price, sales service, and reputation.

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    Usage of Lead-Free PCB Assembly?

    Lead-free PCB assembly is used in RoHS-compliant electronic products. Lead-free PCB assembly has become an irreversible trend in the PCB assembly industry. With the gradual improvement of international environmental protection requirements, the lead-free process has become an inevitable process in the development and production of the electronics industry.

    Although the lead-free process has been implemented for so many years, there are still some companies using the leaded process due to its excellent solderability, but the lead-free process will be more and more used worldwide because it is environment friendly.

    So generally speaking, lead-free PCB assembly is used in most of electronic products and will be more and more commonly used.

    When Should You Use Lead-free PCB Assembly?

    PCBA Manufacturers are subject to RoHS standards. Manufacturing RoHs-compliant PCB assembly means replacing traditional lead-based solders with lead-free alternatives.

    If you encounter the following situations, you may benefit from using lead-free PCB assembly.

    Differences between Leaded and Lead-Free PCB Assembly

    Please refer to the following main difference between leaded PCB assembly and lead-free PCB assembly (also RoHS PCB assembly): 

    Environmental protection or not

    The most important difference between leaded soldering and lead-free soldering is environmental protection for not. Lead solder paste is not environmental protection because there is lead(Pb) in it, and lead(Pb) is very toxic to the human body.

    Different percentages of metal elements in the solder

    The metal element in the leaded tin is Tin: 61.9%, lead: 38.1%, more generally speaking: Tin: 60%, Lead: 40%. The most widely used lead-free solder is SAC30. SAC305 means 96.5%, Ag: 3%, and Cu: 0.5%. But we need to know that lead-free processes cannot be 100% lead-free, but the lead element should be less than 1000ppm(<0.1%), which meets the acceptable of RoHS and REACH.

    Different melting points in the soldering process

    The melting point of leaded tin is 180 to 190 Celsius degree and the operating temperature is about 240 to 260 Celsius degree. The melting point of lead-free tin is 210 to 230 Celsius degree, and the operating temperature is 250 to 280 Celsius degree. But now the solder suppliers have also developed low-temperature solder which can be melted at less than 200 Celsius degrees.

    Cost difference

    The price of lead-free solder is more expensive. The reason is the base material in the lead-free solder is more expensive.

    How to Distinguish Lead-Free PCB Assembly and Leaded PCB Assembly?

    How to judge whether a print circuit board is lead-free or not when we get a PCB? Since lots of customers need RoHS-compliant PCB assembly. Concerning this question, let’s discuss it from the following several aspects.

    For experienced workers, it is easy to distinguish the PCBs soldered by lead-free solder or leaded solder. Because the color of the solder joint is different: the color of the leaded solder appears bright white, but the color of the lead-free solder looks darker and a little yellow.

    Leaded solder contains 70% of tin and 30% of lead normally. But lead-free solder normally contains 96% of tin, 3% of silver, 0.5% of copper, and a little very low percentage of other elements. 

    Leaded solder is only used in the products allowed lead exists. But lead-free solder can be used in most electronic products. Lead-free solder is RoHS and REACH compliant, and can be exported to Europe and the United States.

    With the introduction of the above aspects, you will quickly identify whether it is a lead-free PCB or not when you get a PCB.

    6 Important Factors in Lead-Free PCB Assembly

    Lead-free PCBA is more and more common by far. What should we do to produce qualified lead-free PCB? The following points are the things we need to pay close attention to: 

    Why Does Leaded PCB Assembly Still Exist in the Industry?

    We all know leaded printed circuit board assembly is not good for the human body, and also not good for the environment. But why does leaded custom PCB assembly still exist by far? The main reasons are as below. But in Viasion, we only produce lead free PCB assembly which is RoHS and REACH compliant.

    Special requirements of the products

    Some products need very special soldering standards which can not be done with lead-free assembly, or some components cannot withstand a higher temperature of lead-free soldering, so the customer had to choose leaded soldering.

    The products need very low cost

    Because the production cost of lead-free PCBA is higher than that of leaded circuit board assembly, which will lead to many manufacturers more or less continue to use the lead process. Especially for the customers who produce big quantities and cheap electronic products.

    The country/place does not need RoHS/REACH

    By far, there are still many countries or places that do not apply for RoHS/REACH policy. So leaded electronic PCB assembly is still popular. But of cause leaded soldering is not good for environmental protection.

    What Should Consider If We Choose Lead-Free PCB Assembly?

    For some customers, lead-free PCBA is not a must. So they may be confused about whether they should use lead-free assembly or leaded assembly on their products when they need custom PCB assembly services. The following introductions may be helpful to the customer to choose the right method.

    First of all, lead-free custom PCB assembly is mainly about environmental protection, which is healthier for users and has a much lower impact on the environment. So if the products need to meet RoHS and REACH, the customer must choose lead-free electronic PCB Assembly. But since lead-free solder is more expensive, the assembly cost for lead-free assembly is a little higher than leaded assembly. So for customers, it is better to consider the use environment of the product need to used, the price, and the profit of the product, rather than blindly pursuing lead-free welding.

    The welding temperature without lead is around 35 Celsius degree higher than that of with lead. In the SMT assembly process, the welding temperature is also higher than the Tg of the PCB substrate, and the lead-free welding temperature is higher than the lead welding temperature, which will cause the PCB easily thermal deformation and components damage when cooling if the TG of the PCB material is too low. So the PCB materials with higher Tg should be appropriately selected.

    The lead-free welding process requires PCB with good heat resistance, high glass transition temperature Tg, low thermal expansion coefficient, and low cost. So the influence of high temperature on component packaging should be considered. Since the packaging material of traditional surface mounting components can meet the welding temperature of lead solder as long as it can withstand 240Celsius degrees, and the welding temperature of complex products can reach 260 Celsius degree in lead-free welding, whether the packaging of components can withstand high temperature is a problem that must be considered.

    In addition, the influence of high temperature on the internal connection of the device should be considered. IC internal connection method has gold wire ball welding, ultrasonic pressure welding, and reverse welding methods, especially BGA, CSP, and composite components, modules, and other new components, their internal connection with the material is the same as the surface assembly of the solder, is also the use of reflow welding process.

    From the point of view of cost, currently developed lead-free solder cost is higher than tin-lead alloy. Many people may think that the proportion of the cost of solder is very high. However, according to some statistics, PCB manufacturers generally control the cost of the solder to 0.1% of the total cost, especially for the high technology electronics/PCBs, so it will not have too much impact on the overall cost of the final product. So most customers choose lead free PCB assembly in their RoHS compliant PCB. 

    Characteristics of the Material Used to Replace Lead in Solder Alloy

    Today, solder producers are still researching to find the most suitable metal to replace lead. To meet the 2 simple goals: the solderability is good and the cost is low. The following are the characteristics that need to be considered in choosing a substitution for lead.

    Available worldwide

    The metal/alloy must be available worldwide, easy to get in most countries, and also the amount needs to be big enough to meet the demands of the whole world.


    Alternative alloys should also be recyclable. So it is better not to add too many metals in the formula, or the recycling process would be too complicated and the cost of recycling would be too high.


    The problem with lead is: lead is toxic and not good for the environment. So when we are trying to find something as a substitution, we need to find something non-toxic.

    Compatible with the electronic industry

    We should remember solder is widely used in the electronics and circuit board assembly industry. Such as SMT assembly, PTH assembly, manual hand soldering, BGA soldering, wire bonding, repairing, and wire and cable assembly. So the alternative alloys must be capable of all these areas.

    Key Points in Lead-Free Solder Research

    To protect our environment, all countries in the world call for green products, so more and more PCB factories are going to produce more PCB products with lead-free hot air solder level surface finish treatment. And SMT factories will choose the PCB with a lead-free hot air solder level to supply RoHS circuit board. 

    From a technical point of view, many and many countries pay attention to being lead-free. Many countries have lead-free solder research and development specialized institutions, these research and development institutions and solder manufacturers, have developed a variety of lead-free solder, and a considerable part of the experiment has been proven to be a substitute for tin-lead solder products. Key points in lead-free solder research are:

    Production Environment of a Lead-Free PCB Assembly Workshop

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    Frequently Asked Questions

    Lead-free PCB assembly refers to the PCB assembly manufactured by a lead-free process. All materials, such as printed circuit board, components and solder, must be lead-free.

    Lead-free PCB assembly is rapidly becoming the standard for PCBA manufacturing due to regulatory requirements, environmental concerns, and other reasons.

    The following is a brief introduction to some processing points of the lead-free process.

    1) The inspection of solder paste and PCBs:
    The lead-free process requires inspection of the PCB and solder paste parameters to ensure that the lead-free materials are used. 

    2) Components:
    Check the bill of materials first to ensure that the components are made of lead-free materials.

    3) Solder paste printing:
    In the step of printing solder paste, the lead-free stencil of the forming stage is placed on the circuit board and then printed with lead-free solder paste.

    4) Pick and place components:
    This is a pick-and-place operation, but the components used need to be identified and marked during the BOM verification phase. The machine or operator selects a labeled component and places it in a specified location.

    5) Testing and packaging:
    Test the solder joints in this step. Visual inspection is followed by AOI and X-ray inspection. Physical and functional tests are performed before packaging.


    Both terms say the same thing: it means the assembled PCB boards are environmental friendly.

    Lead free PCBA is short fro lead free printed circuit board assembly. It means PCB assembly without lead.

    Improve environmental protection and ensure the sustainable development of the industry.

    Significantly reduce or avoid health damage caused by using products containing lead.

    Seen from the perspective of PCBA manufacturing, the main problem with lead-free PCB assembly is the effect on the circuit board caused by temperature rise. Rework of lead free PCB assembly is also more difficult.

    We think the following factors are the more important ones in lead free board assembly: printed circuit board is lead free, solder bar or solder paste used in SMT assembly or PTH assembly is lead free, the whole lead free PCBA line is only prepared for lead free PCB assembly, then no lead remains in any tools or equipment.

    Yes, we only supply lead-free PCB assembly because of environmental protection.