1. Mainly clean the copper surface by micro-etching to a depth of 0.75-1.0 microns, removing attached organic pollutants to ensure a clean copper surface for effective contact with molten tin and quick IMC generation. Uniform micro-etching results in good solderability, with the board washed with water and quickly dried by hot air.
2. The preheating zone typically utilizes a 1.2 meter (4 feet) infrared heating tube. Board transmission speed depends on board size, thickness, and complexity. For a 60mil (1.5mm) board, the speed is generally 4.6-9.0m/min. Surface temperature reaching 130-160 degrees allows for flux coating, and preheating before coating with hydrochloric acid prevents rust or burning of metal parts.
3. The tin melting tank contains approximately 430 kg of solder alloy composed of 63/37 eutectic, maintained at around 260 degrees. Ethylene glycol oil is intentionally floated on the tin-melting noodles, compatible with the flux. Board transfer speed through the tin furnace area is approximately 9.1m/min. Upper and lower rollers provide a dwell time of about 2 seconds, with a 6-inch span between front and rear roller groups.
4. Board thickness, pad spacing, pad shape, and tin thickness contribute to potential unevenness of the tin surface on the pads. Cold air is first blown from bottom to top on the approximately 1.8-meter air bed, followed by cooling the lower surface and further cold air blowing from top to bottom in the 1.2-meter runner bearing area. This cleaning process effectively removes flux residue without causing excessive thermal shock.
2. The preheating zone typically utilizes a 1.2 meter (4 feet) infrared heating tube. Board transmission speed depends on board size, thickness, and complexity. For a 60mil (1.5mm) board, the speed is generally 4.6-9.0m/min. Surface temperature reaching 130-160 degrees allows for flux coating, and preheating before coating with hydrochloric acid prevents rust or burning of metal parts.
3. The tin melting tank contains approximately 430 kg of solder alloy composed of 63/37 eutectic, maintained at around 260 degrees. Ethylene glycol oil is intentionally floated on the tin-melting noodles, compatible with the flux. Board transfer speed through the tin furnace area is approximately 9.1m/min. Upper and lower rollers provide a dwell time of about 2 seconds, with a 6-inch span between front and rear roller groups.
4. Board thickness, pad spacing, pad shape, and tin thickness contribute to potential unevenness of the tin surface on the pads. Cold air is first blown from bottom to top on the approximately 1.8-meter air bed, followed by cooling the lower surface and further cold air blowing from top to bottom in the 1.2-meter runner bearing area. This cleaning process effectively removes flux residue without causing excessive thermal shock.
