![]() ![]() This should bedone with customer approval.Understanding wire gauge (thickness) is important when buying craft wire or beading wire, or items made from wire such as jump rings, head pins, earring hooks, and other findings. Before making such a modificationon many assemblies, I would qualify the pad/jumper on one or two testassemblies and validate it thoroughly through qualification. However, you need toconsult with the design engineer before attempting such a modification becausethe pad width is critical to other electrical functions such as impedancecontrol, EMF, crosstalk, Hall effect (skin effect in very high frequency circuits),and minimum conductor spacing, for example. The goal here is to provide the same cross-sectional areabetween the original pad/trace and the wire, so a rule of thumb ofapproximately 2X to 3x the wire diameter is probably going to work. ![]() ![]() Inyour case I believe you need to determine the optimum pad size for a given wirespecification such as the connector lead, for this you can use the table in IPC7711/7721 in reverse. To determine the correct WIRE size for a modification or repair(such as a jumper), IPC 7711/7721 Repair Method #4.2.5 provides a table (Table1) to determine appropriate jumper wire size to use based on the existingtrace or pad, in order to (again) provide ample current-carrying capacity. This is determined by thedesign engineer if the pads and wires are going to be designed-in, and thesecurrent-carrying capacities are spelled out in IPC 2152 of the designstandards. The pad, trace, and the wire size are determined by thecurrent-carrying capacity required of the circuit. ![]() Is there a rule of thumb for pad size such as 2x the bare wire diameter? Is there an applicableIPC guide or specification? I am looking for therecommended pad size for any given wire diameter. We are lap soldering connector wiresfrom a multipin connector to the surface of a board. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |