Wednesday, 14 July 2010

Warp Knitting | Calculation of Yarn run-in (mm/rack)

The relationships between fabric parameters and yarn run-in (yarn consumption) is an extremely important factor for production planning.This data allows the knitter to estimate his yarn requirements,predict  his production rate.
The values needed to determine the yarn run-in :
Lapping,Gauge  E (needles/inch) ,course per cm (CPC),needle thickness  (d).
Calculation :

  • Head of the loop = πd /2.2
d = needle thickness
  • Legs of the loop = 2 x S
S = 10 mm : course per cm (cpc)

image
  • a =  number of needle loops
  • b =  number of needle gaps crossed by the sinker loop
  • c =  number of sinker loops in the same wale
T = 25,4 mm : E (gauge)

image 

Yarn run-in (mm/rack) *= 480 [a ( πd /2.2  + 2S) +bT + cT ]
notice : * The calculated values are as approximate values
Example 1 :
closed 1x1
  • E = 28
  • CPC = 20
  • d = 0,5 mm
  • Lapping =  1 0 / 1 2 //   | a = 1 | b = 1 | c = 0 (per course).
Yarn run-in (mm/rack) = 480 ( 0,7 mm + 1 mm +0,9 mm) = 1250 mm/rack

Example 2 :
open pillar

  • Yarn run-in (mm/rack) = 480 ( πd /2.2  + 3 S )  notice : * The calculated values are as approximate values
  • Yarn run-in (mm/rack) = 480 (0,7 mm + 1,5 mm)
  • Yarn run-in (mm/rack) = 1056 mm
Example 3 :koper 2n overlap_pilar_closemod 
  • Yarn run-in (mm/rack) = 480 [2 ( πd /2.2  + 2S) +bT + cT ]  notice : * The calculated values are as approximate values
  • Yarn run-in (mm/rack) = 480 [2 (1,7 mm + 0,9 mm + 0,45 mm) ]
  • Yarn run-in (mm/rack) = 480 [ 2 (3,05 mm) ]
  • Yarn run-in (mm/rack) = 2928 mm

7 comments:

Anonymous said...

Thank you, this very good site. also I want to know calculation of yarn run in for tulle and marquisette (also marquisette 2 bar?). Any help for these ?

deepak said...

Dear sir
please tel me about the run-in calculation for the in-lay stitch also.is am i right if while calculating in-lay if i count only one leg and half of the loop head?

Warp Knitting said...

@ anonymous : if you know the chain notation for tulle and marquisette and than you can calculate the run-in accordingly.

@deepak : run-in for inlay :
mm/rack = 480(bT+cT).

deepak said...

hello sir,
how are you? thanks for this knowledge sharing site.
i wanted to know how to calculate the yarn run in for the lycra(Stretch Yarns).since i was observing some samples and i found very less run in for lycra,also i request you to please explain the relation of pre stretch of the stretch yarn and run in for the same,and also if possible then explain about how to decide the pre stretch of the lycra while warping them.

Warp Knitting said...

@ Deepak,
The run-in for Lycra or others elastic yarn depend of the fabric construction,whether this fabric need high stretch with low run-in or less stretch mean more run-in and also the composition between Nylon and elastic may vary.

Usually the pre-stretch and final stretch during warping process will recommend from yarn manufacture.More big yarn count the final stretch for warping will less than smaller yarn count,the pre-stretch may vary according the condition and yarn properties.

vanko said...

Hello Sir,
First I'd like to say thanks for your great contribution. I'm newbie in this industry and self studying. Could you pls tell me how to determine or calculate the lycra and nylon composition in powernet fabric when run-in values are known.

Warp Knitting said...

Hello Vanko,thanks for visiting,I will describe your request in next post.

Heksatex