1、 Overview
Tin stripping solutionST-511#It is a single liquid nitric acid specially prepared for stripping tin and lead tin electroplating layers of printed circuit boardsIt can quickly peel the tin and lead tin electroplating layers on the surface of copper at one time. It has no peroxide and stable performanceFixed; Large amount of dissolved tin; It can be prepared on site (it can be prepared at any time according to the needs at the factory site, and the operation is simple;No smoke and high temperature during preparation); It does not contain complexing agent and fluoride, and the waste liquid is easy to treat; OnlineRecycling (professional equipment is required) to achieve zero emission of pollutants.Tin stripping solutionST-511#It is best to use spray operation mode, which is also suitable for soaking operation mode. Operate in immersion modeDo not soak for a long time when working, otherwise the through hole and line may be corroded.

2、 Technical indicators
1. Appearance: light yellow transparent liquid.
2. Density: ≈ 1.25 ± 0.05
3. Acidity: 5.5 ± 0.5N
4. Tin stripping speed: 10-25 µ M / min
5. Copper corrosion rate: 0.5 ± 0.2 µ M / min
6. Tin dissolution: 130-150g / L (about 2.5m2 / L)
7. Packing: 30kg (25lt), 200lt, or according to customer requirements.

3、 Operating conditions
ST-511#Stock solution useTemperature 25-35 ℃ (not higher than 40 ℃)timeabout30-60 seconds (spraying operation)Cooling needs

4、 Process control
1. Cylinder opening: it is recommended to use 20% - 30% old liquid to combine the cylinder opening to ensure a stable tin removal rate.
2. The counter flow mode is adopted to ensure the full spillage effect and good working effect.
3. Control the solution temperature between 20-40 ℃, preferably 25-35 ℃. If the temperature exceeds 40 ℃, cold water must be usedThe system may be shut down or suspended to ensure proper operating temperature.
4. Adjust the over speed of the circuit board according to the thickness of the tin layer, the new and old degree of the lead tin solution and the cleanliness of the surface of the boardDegrees.
5、退锡time达到 90 秒仍退不净时，倒出至少 30%-40%旧液，添加 ST-511#Type lead removalTin liquid to normal level.
6. When the fourth step still fails to achieve the desired effect, or the specific gravity of tin stripping solution is 1.36-1.38, reopen the cylinder.
7. St-511 is used in an automatic addition system with feedback and emission#Better results.

5、 Product characteristics
While stripping tin and lead, an organic protective film is formed on the copper surface, which makes the attack of nitric acid on copper very smallThe surface has specular luster.High efficiency tin removal, no precipitation and no trouble of blocking the nozzle.Environment friendly fluorine-free formula, smokeless and basically tasteless. The waste liquid can be recycled by the tin stripping solution after high-tech treatmentDirect reuse.Liquid medicine analysis is not required during use. When the stripping speed of liquid medicine fails to meet the process requirements, part of the liquid medicine can be usedAdd or replace all.

6、 Precautions
This product contains strong oxidant and strong acid. It shall not be in direct contact with human body. The operator shall wear goggles and acid resistant glovesAnd protective equipment such as aprons and rain boots. In case of splashing on the skin accidentally, please wash it with plenty of water and send it to the hospital if necessaryGovernance.The used old working solution can still peel off the tin coating, but the side corrosion and copper corrosion are increased compared with the new solution, which should be used as the first layerUse of working fluid.This product should be stored separately in a cool place to avoid high temperature and sunlight. The barrel cover should not be completely sealed. During storageVolatile components such as nitric acid will escape, which will reduce the efficiency of liquid medicine. Long term storage should be avoided.

Shelf life: three months.