Why is PCB surface finishes important?

PCBsupplierChina talk the PCB surface finishes are an important interface between the component and the PCB. The finish’s two primary functions are to shield the exposed copper wiring and to offer a solderable surface for joining (soldering) the components to the printed circuit board.

What is pcb surface finishes?

The process of applying a PCB surface layer to the PCB is known as PCB surface finishes.The objective of PCB surface finishes are to guarantee that the PCB has good solderability and electrical properties.There are numerous varieties of printed circuit board surface treatments available.PCB Surface treatment is a multistage process that includes the following steps:

· Chemical treatment of chemical etching or electropolishing

· Organic coating followed by baking at high temperature

· Cationic electroless nickel plating and chemical conversion to Ni/Sn surface alloy

· Anodic aluminium oxide (Al-oxide) coating

· Organic coating followed by baking at high temperature as in step C.

What is OSP?

PCBmanufacturer talk Copper is continuously oxidized by the air, which leaves it discoloured and brittle.Anti-oxidation preserves the pcb surface finishes from corrosion by forming a very thin protective layer of material over the exposed copper, usually on a conveyorized system.

It’s made of a water-based organic compound that binds to copper and creates an organometallic layer that protects the copper before soldering.It is also far more environmentally friendly than standard lead-free finishes, which are either more hazardous or require considerably more energy use.

Advantages and Disadvantages of OSP

Lead-free

OCB is a lead-free process so it is more environmentally friendly than the traditional HASL.

Cost

OSP can treat pcb surface finishes at a much lower cost.This is because it requires less material to soak and rinse when the pcb surface finishes.This also reduces waste disposal costs.If you are already using a lead-free solder paste (which has a lower volume than standard solder pastes)

Flat pcb surface finishes

OSP has a very flat pcb surface finishes, which can be beneficial when working with components that have tight tolerances.The smoothness of the HASL finish may cause issues in this case because it is more likely to pick up debris from the air and trap solder paste.

Simple process

OSP offers a simple PCB Surface Finishes process, which makes it much easier to maintain and control each board’s quality.This is an advantage if you need large quantities or have very tight tolerances.OSP handles PCB Surface Finishes as minor inconsistencies in solder masks can cause problems.

Repairable

The OSP process is repairable, which means that if you damage the finish on the board.Or if you need to remove it to fix a soldering problem.There is a way to remove it and replace it without having to throw away the whole PCB.

Disadvantages

Limited to RoHS compliance

OSP is only compliant for materials that are free from lead, cadmium and mercury.This means it cannot be used with any non-RoHS components or boards made of other types of metals.For this reason, OSP can’t replace both HASL and ENIG in all situations.

Environmental impact

Although OSP is a lead-free process, it requires the use of solvents that have their own environmental impacts which need to be taken into consideration.The cleaning steps also produce wastewater.So there may still be concerns about its effect on the environment if large volumes are required.

Sensitive

OSP is sensitive to the effects of heat over time.  This means that it may need a rework process if boards are located in areas with higher temperatures.This can mean additional costs and resources for your business.

Short shelf life

OSP is a water-based finish, which means it has a limited shelf life.It’s typically only good for around two months if left in an open container and can be ruined by exposure to humidity or moisture over time.

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