If your application advantages from an RoHS exemption allowing you to hold on using lead, you'll be able to hold the tin-lead used as an engraving masks when the PCB was manufactured; After re-melting, SnPb is an effective finish. This board also does a great job of illustrating the use of NSMD (Non Solder Mask Defined) pads. This allows the BGA ball to sag down a little more and grip on the side of the pad too. It additionally illustrates the proper approach to mask the trace between the pad and the via.
The deposit is uniform and has good wettability, a number of re-melts are also attainable; the end is ideal for press-fit connections and again panel boards. The solderability and wettability are good and the production costs are low.
1.
OSP PCB shall be packed in vacuum with a desiccant and humidity show card connected. Transport and storage of PCB with OSP shall be made utilizing isolation paper to prevent friction from damaging the OSP floor. You can depend on Camptech II Circuits to manufacture your PCBs and assemble them with consistently high quality.
The tip kinds selected for the INGUN E-TYPE® FUSION series are characterised by aggressive edges and wonderful edge-retention properties. Especially the newly-developed tip style 70 guarantees reliable contacting of OSP-coated test points with out solder due to a particularly sharp-edged cutting geometry. Disadvantages – Thickness can't be measured precisely, not an excellent possibility for plated through gap, brief shelf life, requires comparatively aggressive flux at assembly, tough to examine, and delicate to dealing with. Advantages – Cost effective and easy course of, nicely suited to tight-pitch pads, good solder mask integrity, doesn’t affect last gap dimension. Advantages – Good for PTH (Plated Through Holes), consistent thickness, solders simply, good contact resistance, flat and planar surface.
The draw back is OSP is not as robust and it may be sensitive to dealing with, so multiple soldering can destroy the film. If naked board exceeds the storage life, can be returned to OSP producer to remodel.
Advantages – months shelf life, excellent solderability, quick and straightforward course of cycle, inexpensive, and can be reapplied and reworked easily. There was no particular floor finish with considerably less voiding. The solder paste used was no-clean lead-free Sn3Ag0.5Cu (SAC 305) and the board was reflowed in convection oven with air environment utilizing a typical lead-free reflow profile. To discover out extra, you possibly can read the IPC-2221B “Generic commonplace on Printed Board Design” and IPC-6012 “Performance Specification for Rigid Printed Boards” requirements. The thickness is tough to manage; tin oxidises very easily and can develop “whiskers”, which are tiny filaments that may be the cause of quick circuits; storage is proscribed to six months.
In apply, OSP degradation is typically already witnessed after 4 hours. Despite its limitations in planarity, the HAL finish has succeeded to keep up a reasonably broad acceptance on most markets. Also NiAu has established itself as a dependable end, though Au air pollution within the solder bath or solder joint could be of concern to some. Where I-Sn seems to be extra popular in Europe, I-Ag appears to have the choice within the Americas. The OSP- finish is being used rather a lot in Asia however has much less acceptance in the remainder of the world.
Each has their benefits and drawbacks to contemplate, let’s consider the top three at your disposal. After reading every little thing above, you could be considering that solving a tin whisker problem is close to inconceivable, nevertheless it’s not.
That mask will keep the solder balls from being sucked off of the BGA. 4.In the storage course of, OSP floor can't be exposed to acidic substances, the temperature cannot be too excessive, otherwise OSP will evaporate. Your final and last line of defense against tin whiskers is to think about using a plating finish on your PCB that isn’t pure tin.
The palladium-nickel plating developed by INGUN ensures the hardness required to reliably penetrate powerful coatings and contamination. The plunger tips specifically withstand contamination properly, and are extremely durable and immune to wear.
