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Soldering iron and tin in PCBA processing
26Oct
Andy 0 Comments

Soldering iron and tin in PCBA processing

The circuit board manufacturer will explain to you whether the soldering iron and tin in PCBA processing are poisonous

A netizen roast that he had been soldering with an electric soldering iron for a whole year in the PCBA factory, and he felt uncomfortable. His abdomen was a little swollen. Is soldering toxic? Is it lead poisoning.

In fact, it also depends on whether the lead solder wire used for soldering with electric soldering iron is lead-free or not, and the blood lead needs to be checked regularly. If it does not exceed the standard, there will be no problem at all. Is soldering tin toxic? Normally, if the protection and raw materials are purchased according to the national standards, the soldering tin will not cause serious damage. Now, lead-free products are basically used.

Lead is a toxic substance. Excessive absorption of lead by human body will cause lead poisoning. Low dose intake may affect human intelligence, nervous system and reproductive system. The alloy of tin and lead is commonly used soldering tin. It has good conductivity of metal and low melting point, so it has been used in welding process for a long time. Its toxicity mainly comes from lead. Lead smoke from soldering tin is easy to lead poisoning.

Lead metal may produce lead compounds, which are all classified as dangerous substances. In the human body, lead can affect the central nervous system and kidneys. The environmental toxicity of lead to some organisms has been generally confirmed. Blood lead concentration reaches 10 μ Above g/dl, it will produce sensitive biochemical effects. If long-term exposure causes the blood lead concentration to exceed 60~70 μ G/dl will cause clinical lead poisoning.

Lead must be toxic, let alone big or small. Even ordinary metals can be poisoned if they are too much. When soldering, there will be smoke, which contains an element harmful to the body. It is better to wear a mask when working, but it will have some impact more or less. Of course, if you can use lead-free solder wire, it will be safer than those with lead.

Is lead-free solder poisonous?

Solder wire is the material for soldering with electric soldering iron. Although its main component is tin, it also contains other metals. It is mainly divided into lead and lead-free (environmental protection type). With the introduction of the European Union ROHS standard, more and more PCB welding plants are choosing lead-free and environment-friendly, and lead solder wires are gradually being replaced. It is not impossible to export environmentally friendly solder wires. Lead free solder paste, lead free tin wire and lead free tin bar are the main products on the market at present.


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To put it simply: because the melting point of the harmful common solder is low, it contains about 60% lead and 40% tin, so the solder itself is toxic. Most soldering tin on the market is hollow and filled with rosin, so it is estimated that the gas you mentioned is volatilized from the melting of rosin in soldering tin. The gas volatilized from rosin is also slightly toxic, and this gas smells bad. The main hazard factor of soldering tin is lead smoke. Even lead-free soldering tin contains a certain amount of lead. The limit value of lead smoke in GBZ2-2002 is very low, and the toxicity is very high, so it needs to focus on protection. Due to the damage to human body and environment caused by welding process, in Europe, the protection of welding workers and environment has been enforced in the form of legislation. Welding is not allowed without protective measures. In the ISO14000 standard, there are clear provisions on the treatment and protection of pollution generated in the production process.

Tin contains lead. Soldering tin was classified as occupational hazard post (in the national occupational disease catalogue) when there was lead in the solder wire; Now our general enterprises use lead-free solder wire, the main component is tin, and the CDC measures tin dioxide; It is not included in the national occupational disease catalogue. Generally speaking, lead smoke in lead-free process will not exceed the standard, but soldering tin has other hazards, such as soldering flux (rosin) has certain hazards, which should be considered according to the specific situation. Employees can usually check the identification and category of tin allocated, so that they can find out the evidence and require the enterprise to rectify (they can give suggestions to the internal trade union of the factory). If the tin is made of lead, it must be harmful to your health. Over a long period of time, they accumulate in the body and cause great damage to the immune system of the nervous system.

The lead-free solder wire is environmentally friendly, but it is also harmful to human health. The low lead content of the lead-free solder wire does not mean that it does not contain lead. Compared with the lead containing solder wire, the lead-free solder wire has less pollution to the environment and human body than the lead containing solder wire. The gas generated during soldering is toxic, including rosin oil, zinc chloride and other gas vapors.

How to prevent toxic solder wire of electric soldering iron:

First of all, PCBA factory should use ROHS tin wire when soldering components with electric soldering iron, and should do a good job of prevention: for example, wear gloves, masks or gas masks, pay attention to ventilation in the workplace, good ventilation system, pay attention to cleaning after work, and drinking milk can also prevent lead toxicity in soldering tin.

1. You need to take a break. Generally, you need to take a rest of about 15 minutes to relieve fatigue, because the resistance is the worst when you are tired,

2. Smoking less and drinking more water can eliminate most of the harmful substances absorbed during the day,

3. Drinking mung bean soup or honey water before going to bed can reduce fire, which is helpful to your mood. Besides, mung beans and honey can eliminate a lot of lead and radiation absorbed!

4. It can avoid radiation. Try to avoid using more phones. PHS should use less mobile phones,

5. The soldering iron can be lightened by using the PPD welding head as much as possible, which can reduce the harm to the body by using less welding oil and rosin,

6. When the soldering oil and tin smoke, try to brush the sky with your head on the side. When the water comes, try to hold your breath,

7. Use less Tianna water and more alcohol, and the effect will be similar if you brush more alcohol for a while,

8. To wash your hands,

9. Take a bath before going to bed. Try to go to bed early and get up early to ensure adequate sleep. As long as you sleep well, impurities can basically be discharged with your body,

10. Work with a mask.

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