PCB Circuit Board Preheating Case Studies

PCB Circuit Board Preheating (SMT & Maintenance)

Widely used in SMT production and circuit board maintenance for PCB preheating, BGA chip desoldering preheating and multi-layer board dehumidification drying. It effectively prevents PCB bulging, copper foil warping and potting bubbles, ensuring welding and packaging quality of circuit boards.

Case 1: Preheating for BGA Motherboard Desoldering

Application Scenario:

Direct high-temperature desoldering of Northbridge, Southbridge, CPU base and BGA chips on computer and industrial motherboards at room temperature easily causes PCB bulging, copper foil warping and board delamination.

Practical Solution:

Preheat the bottom of the PCB motherboard at 120℃ to raise the overall board temperature evenly and release board stress. Then disassemble chips locally with a hot air gun, effectively preventing PCB bulging, copper foil falling off and circuit delamination to protect motherboard integrity.

Case 2: Dehumidification Preheating for Multi-Layer PCB Potting

Application Scenario:

Multi-layer industrial control PCBs retain internal moisture after storage in humid environments. Direct epoxy potting causes pinholes and bubbles, reducing insulation and waterproof performance.

Practical Solution:

Bake the PCB at a constant 60℃ for 30 minutes to completely volatilize internal moisture. Subsequent epoxy potting achieves tight lamination without pinholes or bubbles, greatly improving the insulation, moistureproof and waterproof performance of circuit boards.