IE math question: Stitch length 38 inches, SPI 9, Machine RPM 3400 and production per hour 80 pcs then calculate NDT?

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Solution:

NDT mean needle down time also called needle up & down going time or needle running time.

Total stitch= SPI x Seam length

      = 9 x 38

                 =342 stitch

 Produce stitch= 342 x 80

                        =27360 stitch

  Machine time= RPM x 60

                       =3400 x 60

                       =204000

                 Produce stitch

NDT=……………………….. x100

                 Machine time

  

                  27360

       =…………………… x100

                 204000

 

                2736000

       =……………………

                204000

 

       = 13.41%  (Answer)