Interlock How It Changes with Construction and Elastane Content
Interlock does not stay constant when construction changes. Understanding the direction of change helps during development.
Effect of knit structure
Loop length and density move results first, usually before any yarn change is made. Working figures for Interlock normally sit around 200-280 GSM in mainstream production. Note interlock machine on the tech pack so nobody tests against an older revision.
Effect of elastane content
More elastane raises recovery but changes the value measured by interlock machine, so retest after any blending change. Record elastane content alongside Interlock, because blends shift the measured value. A result outside 200-280 GSM usually points to process drift rather than to the fibre itself.

Effect of finishing
Heat setting and softeners shift results, which explains differences between a hand sample and bulk. Keeping reference values for Interlock lets suppliers quote without extra sampling rounds. Ask for conditioning details together with interlock machine, since both affect the reading.
Typical range
Working values stay around 200-280 GSM for mainstream activewear. Working figures for Interlock normally sit around 200-280 GSM in mainstream production. Note interlock machine on the tech pack so nobody tests against an older revision.
Development advice
Change one variable at a time, then verify against interlock machine before moving to the next sample round. Record elastane content alongside Interlock, because blends shift the measured value. A result outside 200-280 GSM usually points to process drift rather than to the fibre itself.