Most tip styles can be used for a variety of different applications. Use the following chart to select appropriate tips for the feature type (pad, via, etc.) you are testing. Several tips styles will probably work for a given application, so experiment with several tips until you find one that provides the best performance. For testing loaded boards, tip selection factors to consider are lead length (bent or straight), surface cleanliness and pad size. In general, tips with sharp points and internal cutting edges with trap leads (such as the Trident or crown tip) are excellent cutting edges (such as fluted and pyramid tips) are usually best for penetrating through contamination, but these may leave marks on the contact surface. For applications where marking is undesirable, bullet nose or conical tips may be used on clean boards.
The tip selection is a crucial topic when selecting a probe, so please feel free to contact your nearest ECT facility, we are more than happy to assist you with your tip selection.
Some applications require a none aggressive tip like the D, J or F type tip. These tips leave no marks or footprint on the test pads. Other applications may need to break through oxide layers, OSP or other contaminations. For these test points the B, E, I, L, T and U Tip with their medium to very aggressive geometry penetrate through the contaminations and offer best first pass contact.
Solder Pads, Solder Balls
Over time solder build up oxide layers, therefore medium to very aggressive tip geometries are used. H-INS or HM-INS Tip – The tip geometry is designed with a pin present detection. If a component lead is not soldered correctly and fully into the PCB boards, the insulating ring around the H tip will act as a collar, preventing the conductive probe tip from making contact with the faulty test point.
Typical tips are used that center themself into the via hole. ECT offers a variety of different I tip angles, which are used to accommodate through-hole vias as well as solder filled hole. Other tips like the G or V tip are suited to contact only the outer ring of the vias on the board surface.
Post, Pins and Screws
For other applications like posts, pins or screws are more unpredictable and therefore more challenging to select the best tip style. Posts and pins are captured with tips like the A, H or L tip. Other applications depending on material, size, shape, access or clearance, contamination and so on may require other tips.