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How do you finish a PCB?
HASL is the predominant surface finish used in the industry. The process consists of immersing circuit boards in a molten pot of a tin/lead alloy and then removing the excess solder by using ‘air knives’, which blow hot air across the surface of the board.
What is the difference between Enig and HASL?
HASL is generally preferred for hand-soldering due to the easy joint formed. However, HASL leaves an uneven surface despite the leveling process. ENIG, on the other hand, provides for a very flat surface making ENIG preferable for fine pitch and high pin count components especially ball-grid array (BGA) devices.
What is Smobc in PCB?
The surface finish has two essential functions: – To protect the exposed copper circuitry. – To provide a solderable surface when assembling (soldering) the components to. the PCB. Most surface finishes are considered SMOBC (Solder Mask Over Bare Copper).
What is HASL in PCB?
HASL or HAL (for hot air (solder) leveling) is a type of finish used on printed circuit boards (PCBs). The PCB is typically dipped into a bath of molten solder so that all exposed copper surfaces are covered by solder. Excess solder is removed by passing the PCB between hot air knives.
Why do printed circuit boards have copper finishes?
Anyone involved within the printed circuit board (PCB) industry understand that PCBs have copper finishes on their surface. If they are left unprotected then the copper will oxidize and deteriorate, making the circuit board unusable. The surface finish forms a critical interface between the component and the PCB.
What’s the purpose of a PCB surface finish?
A printed circuit board (PCB) surface finish has two main functions: To prevent the copper from oxidizing and to provide a solderable surface. Some PCB surface finishes, however, are more popular and versatile than others.
How is molten solder used to finish PCB?
The application process involves dipping the PCB in a solution of molten solder and then blowing off the residue using a hot air knife. The solution of molten solder is made of lead and tin alloys. The greatest advantage of HASL surface finishing is that it is economical.
What are the disadvantages of printed circuit board?
Disadvantages: 1 Easy to Cause Handling Damage 2 Process Uses a Carcinogen (Thiourea) 3 Exposed Tin on Final Assembly can Corrode 4 Tin Whiskers 5 Not Good for Multiple Reflow/Assembly Processes 6 Difficult to Measure Thickness