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IEC 60294: Cylindrical Component Measurement — GO/NO-GO Gauging for Axial Resistors and Capacitors
A Lead Span Deviation Exceeding ±1 mm Will Jam the Automatic Insertion Machine
IEC 60294:2012 specifies dimension measurement methods for cylindrical electronic components. For axial insertion machines, the lead span S is the most critical dimension — deviation exceeding ±1 mm can cause insertion failure.
| Dimension | Symbol | Typical Tolerance | Inspection Method |
|---|---|---|---|
| Body Length | L | ±0.5 mm | GO/NO-GO gauge, optical projection |
| Body Diameter | D | ±0.3 mm | GO/NO-GO gauge, micrometer |
| Lead Diameter | d | ±0.05 mm | Micrometer |
| Lead Span | S | ±1.0 mm | GO/NO-GO gauge (most critical) |
| Lead-End to Body | F | ±0.5 mm | Caliper |
Axial component feeder compatibility checklist:
1. Lead span S = PCB hole spacing ±0.5 mm
2. Lead diameter d = hole diameter - (0.2–0.3 mm) clearance
3. Body length L + 2×F < adjacent component spacing
→ All three satisfied → trouble-free auto-insertionTN Lab — One component dimensional tolerance determines an entire SMT line efficiency.
