Clear product design is the important to building assemblies of all complexities correctly the first time.
Since cables, harnesses, and electromechanical assemblies are combinations of both electrical and mechanical designs this can be tricky. Here are some key points to help with product designs.
- Right angles are easiest to interpret but not always necessary.
- It should be clear where to measure dimensions from, like end of connector or back of connector.
- Dimensions should be from places which can be measured on a completed assembly (wire cut lengths are not very useful). We will 100% check these in final inspection.
- Length tolerances should be wide enough to be easy to manufacture+/-5% is great. (use a -0 tolerance if nominal length is the shortest acceptable)
- Labels and heatshrink should appear on the drawing with dimensions and tolerances (or specified as “about” or “TYP”)
- Specifying the pinout of the connector, especially with colors, is very helpful. Best practice is 3rd angle projection of the connector face.
Bill Of Materials
- Manufacturer part numbers for all components is ideal for all parts except where we stock generics like UL wire and heatshrink
- Best practice is to callout items numbers on the physical layout, usually with a circled BOM item#.
Pinout Tables are very helpful
- Pinout tables are easier to interpret than schematics, especially for larger harnesses
- This is a great place to indicate different wire sizes, colors, types, and terminal types if that’s not obvious somewhere else on the print
- Including cut lengths on this table is not necessary