Printed Circuit Boards


Kingral is a printed circuit board manufacturer.We can offers the highest quality printed circuit boards(PCB) at the most competitive pricing. Whether you need a few quick turn PCB prototypes or mass production, our world class manufacturing can meet your specialized pcb needs.
Combining years of experience with the latest in high-tech manufacturing efficiencies allow our pricing to be among the most completive. Our boards are manufactured based on IPC guidelines and comply with ISO-9001-2000, UL, and RoHS standards. We will give more good idear for(printed circuits,printed board,electronics pcb,fast pcb)


PCB Surface Finished

All Printed Circuit Boards(PCB's) have copper finishes on their surface. If they are left unprotected then the copper will oxidise and deteriorate, there are various protective finishes available, namely:

Hot air solder levelling (HASL)
Organic Solder Preservative (OSP)
Electroless-Nickel Immersion Gold (ENIG)
Immersion Silver and Immersion Tin

Hot air solder levelling (HASL)

HASL is the predominant surface finish used in the industry. The process consists of immersing circuit boards in a tin/lead alloy and the excess solder is then removed by 'air knives', which blow hot air across the surface of the board. For the circuit board manufacturer, the HASL process is expensive and maintenance intensive. Not to mention the increased health and safety hazards. For the printed circuit assembly (PCA) process, HASL has many advantages. It is the cheapest PCB available and the surface finish remains solder able through multiple reflow, wash and storage cycles.
HASL has been working well for many years but with the advent of 'greener', more environmentally friendly processes, it's days are numbered. In addition to the lead free movement, the increased complexity of boards and finer pitches has exposed many limitations with the HASL finish.
 
Organic Solder Preservative (OSP)

OSP is designed to produce a thin, uniform, protective layer on the copper surface of the PCB's. This coating protects the circuitry from oxidisation during storage and assembly operations. It has been around for quite a while but is only recently gaining popularity with the search for lead free techniques and fine pitch solutions. For PCB manufacturers it's very simple and easy to control. For PCA assembly, it has superior capabilities over traditional HASL with regard to coplanarity, solderability but requires significant process changes with the type of flux and number of heat cycles. Careful handling is needed as acidic fingerprints degrade the OSP and leave the copper susceptible to oxidisation. Assemblers prefer to work with metal finishes that are more flexible and endure more heat cycles. It also causes major problems at ICT with the bed of nails fixture contact. More aggressive probing is required to break through the OSP layer which could potentially even lead to damage and piercing of the PCA test via's or testpoints.

Electroless-Nickel Immersion Gold (ENIG)

These coatings have been used with great success on many boards despite the high per unit cost. It has a flat surface and excellent solderability. The main drawback is that the electroless nickel layer is brittle and has been found to break up during mechanical stress. This effect is known in the industry as 'black pad' or 'mudflat cracking'. This has lead to bad press for ENIG, if these problems could be overcome this finish would be the ideal coating - apart from the incremental cost.
 
Immersion Silver

Immersion silver is a relatively recent addition to the PCB finish. It's main use has been in Asia and is gaining popularity in North America. Europe now has emerging market. During the soldering process the silver layer gets dissolved into the solder joint leaving a tin/lead/silver alloy on the copper which provides very reliable solder joints for BGA packages. The contrasting colour makes it easy to inspect, as opposed to OSP. It's also a drop in replacement for HASL for soldering operations. There is although an underlying question mark over silver 'migration', but newer finishes have anti-migration agents added to minimise the effect. Immersion Silver is a very promising finish but end users are very conservative. Many customers place this finish as 'under investigation', but it may well emerge as the best finish. There have been some initial studies into reliability at ICT and it has emerged that etch time (surface rough/shiny) and thickness of finish are important considerations regarding repeatability. There are no suggestions that there will be any negative effects seen at in circuit test stage.

Immersion Tin

Immersion tin is a newer alternative surface finish, with many similar characteristics to it's silver counterpart. However, there are major health and safety issues to consider. It is mainly used in Europe and Asia whilst it's use in the US is restricted due to the concern over the thiourea used in tin solution (a suspected carcinogen).
8 Layers PCB
名称:8 Layers PCB
8 Layers PCB
名称:8 Layers PCB
6 Layers PCB
名称:6 Layers PCB
4 Layers PCB
名称:4 Layers PCB
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