Qu'est-ce que la soudure au plomb en électronique ?

Solder may be a metal alloy that’s melted with a hot iron. It is composed of tin and lead. Various metals can be joined together utilizing the soldering materials. The iron is warmed to temperatures above 600 degrees Fahrenheit to create a solid electrical connection. At that point, it is cooled. 

The heat from an iron joined to a temperature controller is used to liquefy solder. Around 600 degrees Fahrenheit is utilized to warm it to a temperature over its melting point, at which point it dissolves and cools to create the soldered joint.

Employing a desoldering apparatus, pâte à souder can be removed in expansion to make solid electrical joints. Patch may be a metal combination that’s utilized to create copper joints in circuit sheets and solid, long-lasting bonds in copper channels. Also, it can be provided in two distinctive sorts and breadths (lead and lead-free), with a run of.032″ to 062″.

Filler metals used in soldering were traditionally lead-based (lead solder). However, due to stringent environmental regulations, lead-based solders are being phased out and replaced with lead-free alternatives. These new solders, which may contain antimony, bismuth, brass, copper, indium, tin, or silver, are crucial in reducing the environmental impact of waste recycling and electronics manufacturing.

What is Lead and Lead-Free Soldering?

Lead Soldering

Lead-based solder

It is a metal alloy. SNPB solder is another term for it. It is made up of 60:40 tin-to-lead ratios. It is used for soldering activities. It is the finest choice for fastening electrical connections. It dissolves at 180 to 190°C. Lead and tin are the primary components of lead solder. 

The melting point of the lead alloy is 183°C. It’s easier to heat it up to operational temperature. It is resilient to shocks. The internal faults of the structure decrease as it cools.

Lead-free solder

It’s employed to use less hazardous materials. These are often made of metals with higher melting temperatures and connected with soldered wire. Tin, copper, bismuth, silver, brass, indium, and antimony are the materials that it is used with. It has a variety of metals in it. 

Lead-free solder may contain components such as zinc, nickel, copper, silver, and tin. The melting point of tin-copper is 217°C, so it is the most often used lead-free combination.

It has a more excellent melting point, which makes handling it more challenging. The main reason for moving to lead-free solder is to eliminate lead from the processes used in waste recycling and electronics manufacturing.

What is Lead-Free Solder Used for?

It finds extensive application in the assembly of composants électroniques, consumer goods, automotive circuits, aircraft systems, medical devices, telecommunications equipment, industrial gear, and renewable energy technologies. 

It provides a safer and greener substitute for conventional lead-based solder. Also, it ensures product safety and reliability. It is compatible with modern technology and suited for advancing various industries while minimizing environmental impact.

Types of Lead-Free Solder

Tin and Antimony Solder: It has 5% antimony and 95% tin. Water supply lines can safely use this lead-free solder type. These solders are employed in environments with frequent, severe fluctuations in temperature and vibrations. It melts at 450°F and 464°F. Its shelf life is infinite.

Copper and Tin Solder: It has 3% copper and 97% tin in it. Water supply lines can be safely used. It is intended for plumbing couplings made of brass and copper that sweat. It melts between 440°F and 572°F. Its shelf life is infinite.

Silver and Bearing solder: It contains silver, copper, bismuth, and tin. It is ideal for low-lead brass applications. It has a wide melting range (420°F to 460°F). It enables more time for soldering joints.

Lead Solder vs. Lead-Free Solder

Lear vs Lead free soldering

Lead Solder

Lead solder is a metal alloy with a base component of tin (Sn) and lead (Pb). It has the following characteristics:

Cooling: It has a slower cooling rate as compared to other metal options, reducing the possibility of joint cracking.

Wet joints: This type of solder is effective for wetting joints. It provides an effective electrical connection for both leads and PCB pads.

Melting point: Lead solder melts at a certain temperature. This simplifies automated Assemblage de PCB. Reduced melting point makes it easier to attain temperature and less likely to damage electronics. 

Lead-Free Solder

Antimony, Bismuth, Copper, Nickel, Silver, Tin, and Zinc are common metals in lead-free solder. Among them, tin and copper are the most often utilized lead-free combinations. The melting point of lead-free solder is higher than that of lead mixed. This method of soldering produces harder and stronger junctions than lead soldering. 

The necessity of avoiding lead-containing products has had a great impact on almost every part of our lives. It is not the best option for sensitive aerospace or medical equipment applications. Surface tension is necessary for soldered junctions free of lead to withstand external forces. 

This is not much of an issue for printed circuit board applications because most circuits are not meant to operate in high-stress situations.

When comparing the solderability and quality of solder joints to lead solder joints, lead solder creates a smooth, glossy junction that gives the impression of greater quality.

Lead-Free Soldering Process

To guarantee the formation of trustworthy solder junctions, the lead-free soldering procedure entails several crucial procedures. 

First, components must be cleaned and aligned correctly. Next, according to the application’s specifications, an appropriate lead-free solder alloy must be chosen. Flux spraying helps remove oxides and promote solder wetting. 

Also, preheating the components helps to minimize thermal shock. Correct solder application and joint formation are ensured using appropriate soldering techniques, such as hand or reflow. Following cooling, a post-solder inspection and testing are carried out. 

This confirms assembly quality and standard compliance, and a visual inspection for flaws and, if required, cleaning to remove flux residues is carried out. 

Manufacturers can meet environmental laws and obtain dependable solder junctions and high-quality assemblies by carefully following these processes.

Soldering Process

Challenges of Lead-Free Soldering

High melting point: Soldering lead-free solder usually needs higher temperatures, which might put more heat strain on circuit boards and component parts.

Lead-free soldering presents unique challenges. It has a reduced process window, meaning it is less forgiving of fluctuations in soldering methods and environments. This necessitates precise control over variables such as flux application, temperature, and time. 

The higher melting point of lead-free solder also poses a challenge, as it requires higher temperatures that can potentially strain circuit boards and component parts.

Ensuring wetting and flow: Ensuring the wetting and flow of lead-free solder is difficult. Therefore, careful attention is needed to ensure good connection formation during soldering processes.

Distinct mechanical characteristics: Lead-free solder might be harder than lead-based solder, which could affect the assembly’s overall quality and the reliability of solder junctions.

Transition considerations: To ensure a successful implementation, careful consideration must be made when making alterations to soldering processes and procedures.

Conclusion

Since lead has an impact on both the environment and human health, it is essential to understand the difference between lead and lead-free solders. Compared to lead-based solders, which are toxic and can cause a variety of health problems, lead-free solders are safer and better for the environment. The use of lead-based solders is currently prohibited in many countries due to lead toxicity. In the electronic industry, as well as plumbing and electrical work, lead-free solders are now often utilized. It’s crucial to take into account the solder’s performance requirements, cost, and potential effects on human health and the environment.

It is simpler to use leaded solder. Its melting point is lower. It is reasonably costly. Compared to lead-free solders, this results in fewer solder joint quality issues. Because of its unique qualities and advantages, lead solder is typically more cost-effective and efficient.

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