EIA-481-D is the specification that allows a tape made by one company to run on a placement machine made by another. It defines the mechanical interface \u2014 sprocket holes, pitch, pocket clearance and orientation \u2014 and it is the standard most carrier tape acceptance discussions eventually arrive at. This page summarises what the numbers mean in production terms.<\/p>\n\n\n\n
4.00 mm pitch.<\/strong> The distance between sprocket hole centres is fixed, because it defines one feeder index cycle.<\/p>\n\n\n\n 1.50 mm drive holes.<\/strong> Hole diameter is toleranced so that the feeder pin engages positively without binding.<\/p>\n\n\n\n \u00b10.2 mm cumulative error over ten holes.<\/strong> This is the critical one. Individual hole positions can be within tolerance and the tape can still fail, because the feeder accumulates error across ten indexes. Cumulative measurement, not single-hole measurement, is what determines whether a tape runs cleanly at speed.<\/p>\n\n\n\n Pocket clearance.<\/strong> The component must not protrude beyond either tape surface, must be removable vertically without mechanical restriction after cover tape removal, must not rotate more than 20\u00b0 inside the pocket, and must not move laterally more than 0.5 mm.<\/p>\n\n\n\n Cumulative pitch error is produced by three things: feed repeat accuracy, punching die rigidity, and tension variation between forming and punching. A machine with excellent single-shot accuracy but a flexing punching frame will still produce tape that fails the ten-hole test after a few thousand cycles. That is why our precision platforms use magnetic-levitation linear feeding for \u00b10.002 mm repeat positioning and guide-pin\/bushing location on the punching module \u2014 the two error sources are addressed separately.<\/p>\n\n\n\n IEC 60286-3 applies the same mechanical logic internationally, and individual customers frequently add their own acceptance criteria on top. When those criteria are known at the ordering stage, they can be designed into the tooling and written into the acceptance test; when they appear at the factory acceptance test, they usually cost a rework cycle. Our detailed EIA-481 article<\/a> covers the clauses in depth.<\/p>\n\n\n\n Verification needs measurement, not assurance. An AOI station<\/a> checks pocket and hole quality at production speed, and dimensional inspection records plus process capability documentation<\/a> support customer audits. Where a customer requires CPK data for critical characteristics, we run the study on their material.<\/p>\n\n\n\n If a tape specification is failing on the line, start from the defect diagnosis guide<\/a> or contact us<\/a> with the measurement data.<\/p>","protected":false},"excerpt":{"rendered":"Why cumulative tolerance is an equipment question<\/h2>\n\n\n\n
How to verify compliance<\/h2>\n\n\n\n
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Standards beyond EIA-481<\/h2>\n\n\n\n
Equipment that documents the result<\/h2>\n\n\n\n