Wales per Inch (WPI) Setting It Correctly on a Tech Pack
Wales per Inch (WPI) should be written into the tech pack with a value, a tolerance and a method. This removes ambiguity from quotations.
Definition to agree
number of vertical stitch columns per inch. Working figures for Wales per Inch (WPI) normally sit around 20-40 depending on gauge in mainstream production. Note knitting machine setting on the tech pack so nobody tests against an older revision.
Target value
Open the specification at 20-40 depending on gauge, adjusted to the end use. Record elastane content alongside Wales per Inch (WPI), because blends shift the measured value. A result outside 20-40 depending on gauge usually points to process drift rather than to the fibre itself.
Method line
Always pair the target with knitting machine setting so the mill and the laboratory test the same way. Keeping reference values for Wales per Inch (WPI) lets suppliers quote without extra sampling rounds. Ask for conditioning details together with knitting machine setting, since both affect the reading.
Tolerance line
State plus or minus limits to keep production realistic while protecting the requirement. Working figures for Wales per Inch (WPI) normally sit around 20-40 depending on gauge in mainstream production. Note knitting machine setting on the tech pack so nobody tests against an older revision.
Approval step
Approve the result on pre-production bulk rather than on development fabric only. Record elastane content alongside Wales per Inch (WPI), because blends shift the measured value. A result outside 20-40 depending on gauge usually points to process drift rather than to the fibre itself.
