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PCB Surface

PCB Surface

pcb finish

PCB surface finish include: PCB surface finish is a coating between a component and a bare board PCB. It is applied for two basic reasons: to ensure solderability, and to protect exposed copper circuitry. As there are many types of surface finishes, selecting the right one is no easy task, especially as surface mounts have become more complex and regulations such as RoHS and WEEE have changed industry standards.

Recently, the common PCB surface treatment technologies which GreensTone may use when manufacturing PCBs are HASL(hot air solder leveling), organic coating (OSP), electroless nickel/gold, immersion silver, immersion gold, etc.

The solder mask is mainly Liquid UV Photo-imageable Ink with green, red, black, yellow, white, matt black/green, bule, gray, etc. green should be the most commonly used one.  The suggested soldermask clearance in GERBER is 2-4 mils.

The silkscreen layer is the top layer of the PCB and serves as a reference indicator for placing components on the PCB. The graphics and text on PCB, a circuit board is usually printed with a permanent non-conductive epoxy ink. The color is typically white. Screen printing is used to specify useful information on the PCB board, which can help users during the assembly. It is used to mark component values, part numbers, test points, polarity, etc.

PCB Surface Features

PCB surface finish Comparison of cost and solderability

Actual solderability: Electroplating nickel gold> HASL > OSP > ENIG >Immersion silver >Immersion tin

Cost: Electroplating nickel gold > ENIG > Immersion silver> Immersion tin > HASL > OSP.

The functions of the solder mask layer on the PCB board

Preventing short circuit from bridge connection in the soldering process

  • Preventing the physical breakage of a conductor circuit

  • Prevent short circuit between conductive lines and solder joints when proceeding reflow soldering, wave soldering, and manual welding

  • Preventing the copper layer from oxidation

  • Its high Insulating brings the possibility to the high density of PCB boards

Here are three main ways to add silkscreen coating on a PCB

Manual screen-printing: This is a process that can be used when line widths are greater than 7 mm and the registration tolerance is 5 mm.

Liquid Photo Imaging (LPI): This process provides more accuracy and legibility over manual screening and is used when line widths are greater than 4 mm

Direct Legend Printing (DLP): This is the most accurate way of adding a silkscreen, however,  it is very expensive.

PCB Surface Manufacturing Introduction

HASL (hot air solder leveling)/HASL lead Free

HASL/HASL lead free is the process of coating tin-lead/ tin-lead free solder on the surface of PCB so that it forms a layer of both anti-copper oxidation and good weld ability of the coating.


Organic Coating (OSP)

OSP is a chemical process to build a layer of organic skin film on the clean bare copper surface, it helps anti-oxidation,and moisture resistance, to protect the copper surface from vulcanization or oxidation, etc. In simply words,OSP acts as a barrier between copper and air.


ENIG (Electroless Nickel/Immersion Gold)

ENIG is a thick nickel gold alloy with good electrical properties on the copper surface,acts as a rust barrier to protect PCB for a long time, which can be useful and achieve excellent electrical performance in the long term use of PCB.


Immersion Silver

Silver impregnation does not put heavy coat on PCB, which provides good electrical properties and maintains good solder ability when exposed to humidity ,heat,and pollution,


Immersion Tin

With adding organic additives to the tin layer, the tin layer structure is granular, which overcomes the tin whisker problems and has excellent thermal stability and solder ability.

PCB Assembly Cases in GreensTone

smt pcb
smt manufacturer
smt in pcb
smt electronics manufacturing
smt control board
smt circuit board
smt circuit
smt board assembly
smt assembly supplier
smt assembly service
smt assembly manufacturer
smt assembler
smt  pth assembly
smd pcb manufacturer
pcb smt assembly
pick and place pcb assembly
prototype smt assembly
prototype smt pcb assembly
smd board assembly
smd pcb assembly
pcb pick and place service
pcb and smt
double sided smt assembly
assembled pcb smt

Yes, thanks for your update on the projects status,it’s good for me to make our order plan.

—— Pablo from Spain June 20th, 2019.

Your engineer check the files very carefully,thank you for it, it helps me a lot.

—— Mark from a leading LED strips supplier in Australia Match,8th 2018.

The goods arrived very well, the packing is good, thank you.

—— Antonio from Valladolid, Spain May 25th, 2017.

We've been worked with GreensTone for many years, there is no failure.

—— Wally Nunn from Australia---a leading Pool products manufacturer July13th, 2016.

I reached out to GreensTone Electronics to manufacture the circuit boards. After a few discussions, Rebecca could see the community focus of the project and went above and beyond to reduce costs, ensure delivery and filmed elements of the production for educational purposes. Manufacturing offshore isn't as easy as it appears on the surface so it was invaluable to have Rebecca believe in the cause and be an ally in the production working toward the same goal.

—— Mic. from Australia Feb. 10th, 2015, written on his Facebook.

Yes, thank you we received the 34x LC VMS TILE 1C REV A earlier this week. The assembly quality is very good.

—— Ruth from Australia April 9th, 2014.

Thank you for taking time to check it,you are very efficient.

—— Peter Astrom from Sweden Sep 8th, 2013.

Your engineer is very clever,thanks for the help to check the file's problem.

—— Tony from Australia July 21st, 2012.
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4F B5 XuJingChang Industry Zone HaoYe Rd. No.39, XinHe Street, FuYong District, Shenzhen, China