Specifications for Soldering Iron Use]—— Specifications for Soldering Iron Use and Temperature Measurement
1. Fixed wattage soldering iron and non-adjustable temperature soldering iron
1. Mark 20 - 25 W, and the corresponding welding temperature is 200 - 250 degrees;
2. Mark 30 - 35 W, and the corresponding welding temperature is 250 - 300 degrees;
3. Mark 40 - 45 W, and the corresponding welding temperature is 280 - 350 degrees;
4. Marked 50 W, the corresponding welding temperature is 320 - 380 degrees;
5. Marked 60 W, the corresponding welding temperature is 320 - 400 degrees;
6. Mark 75 - 80 W, and the corresponding welding temperature is 350 - 400 degrees;
7. Mark 100 W, the corresponding welding temperature is 380 - 450 degrees;
2. Basic technical requirements
1. The electric soldering iron must have a good grounding device and a reliable grounding resistance.
2. Tin solder joints should be sufficiently wetted, smooth (lead-free will be slightly dark), free from defects such as short circuits, sharp edges, tin beads, pinholes, cold soldering, false soldering, and virtual soldering. Good electrical conductivity and certain Mechanical strength, the height of solder joints should meet the requirements.
3. Reasonable selection of solder, flux and tools. The basic material of the solder joint should be an alloy conductor produced by the fusion of eutectic solder.
Third, the selection method of electric soldering iron
1. Choose an electric soldering iron with a suitable wattage, and control the minimum temperature of the soldering iron tip, while the maximum temperature is determined by the material characteristics of the soldering iron tip and the nature of the flux.
2. The temperature of the electric soldering iron for soldering printed boards is different according to the size of the pad and the components (area, material), and the temperature of the soldering iron is implemented according to the following standards:
Lead soldering: the temperature is controlled at 250 degrees - 380 degrees;
Lead-free soldering: the temperature is controlled at 320 degrees - 450 degrees;
Not too high or too low.
3. The electric soldering iron (50 - 80W) is suitable for welding battery springs and large-area (grounded or above 5mm) solder joints, and the solder wire should be 1.2mm or above.
4. The electric soldering iron (20-45W) is used for wires (components) with a general pad diameter of 4mm or less, and the welding wire is 1.0mm or less.
5. The constant temperature soldering iron is suitable for repairing solder joints (holding tin) and IC welding, as well as workpieces, small components and temperature sensitive components that have strict requirements on the quality of solder joints. The solder wire is 1.0mm.
4. Operation method
1. The welding of solder joints adheres to the 5-step method: press 1 Cleaning - 2 Heating - 3 Adding solder - 4 Taking solder - 5 Quickly remove the soldering iron - Cooling and solidifying - Solder joints - Trimming and cleaning. The heating position should be accurate, quick and skilled.
2. Generally, the welding time is controlled within 2.5 seconds. For the welding time below 320 degrees, the welding time is controlled within 3 seconds. For the pad diameter above 4 mm, the welding time is controlled within 5 seconds. The welding of integrated circuits and heat-sensitive components should not exceed 2 seconds. seconds, and the number of repeated welding shall not exceed 3 times.
3. Put the solder (solder wire) on the solder joint, then melt the solder with a soldering iron, and transfer heat from the contact surface of the solder with the soldering iron to the welding surface to realize welding, which is the most effective way to heat the workpiece. Directly heating the workpiece with a soldering iron not only has poor thermal efficiency, but also accelerates the oxidation of the welding surface, which deteriorates the welding and causes more welding difficulties.
5. Matters needing attention in the use of soldering iron
1. The posture of holding the soldering iron during manual soldering: similar to the posture of holding a pen and writing.
2. Dirt and burnt flux on the contact surface of the soldering iron tip will hinder heat conduction, and should be wiped off with a damp sponge, and the contact surface should always be kept clean.
3. For the solder joints of SMD components and thin-foot components (such as wires, LEDs, etc.), the temperature of the soldering iron is generally implemented according to the following standards:
Lead soldering: the temperature is controlled at 250 degrees - 350 degrees;
Lead-free soldering: the temperature is controlled at 320 degrees - 400 degrees;
4. For solder joints with faster heat dissipation and more tin addition (such as battery positive and negative polarity sheets, etc.), the temperature of the soldering iron is generally implemented according to the following standards:
Lead soldering: the temperature is controlled at 280 degrees - 380 degrees;
Lead-free soldering: the temperature is controlled at 350 degrees - 420 degrees;
5. If the specified soldering iron tip cannot be erased, it can be removed with a file, and then immediately re-tinned with solder for protection. However, it is forbidden to use a file for the soldering iron tip with iron-clad contact surface, silver-plated or precious hard alloy contact surface.
6. It is not allowed to rub the welding surface with the tip of the soldering iron, and it is not allowed to press hard. When the contact surface of the soldering iron is too small to cover the existing soldering surface, the reciprocating friction of the welding surface can be used to assist the rapid expansion of the heating area and accelerate the flow of solder To ensure full solder joint profile.
7. When the new soldering iron is resting or not being used for welding temporarily, it is necessary to add tin to the soldering iron tip to protect the soldering iron tip; if you leave the station for more than 30 minutes, you must cut off the power supply of the soldering iron.
8. The working area should be kept clean, and the waste tin slag must be recycled into the soldering iron frame uniformly, and the broken tin cannot be knocked on the work surface, and it is strictly forbidden to directly hit the soldering iron to prevent damage or leakage;
9. For dense small solder joints (such as printed boards with dense patch components), use sharp-nosed soldering iron tips. For relatively sparse solder joints and thick-leg components, soldering and repair welding should use flat or knife-shaped soldering iron tips as much as possible.
6. Safety protection
1. The operating environment should have good ventilation or a local exhaust purification device for exhaust gas.
2. The shell of the electric soldering iron should be reliably grounded. Prevent the soldering iron from leaking electricity.
3. Before the welding operation of sensitive components, it is code-named electrostatic protection belt, and there should be reliable electrostatic protection measures during the transfer and transportation of products and devices.
