Knitwear Technology Part Two : Multi-jack, jacquard steel selection

1. Knitwear TechnologyPart Two : Multi-jack, jacquard steel selection Jimmy Lam Institute of Textiles & Clothing

2. Learning Objectives • Multi-step jack selection • Pattern drum selection • Jacquard steel selection

3. Multi-step jacks selection • The earlier selection based on simple needle and jack (high/low butt) principle can only produce a very small pattern size. • To expand pattern, we have to put more jacks under needles. • Multi-step jacks selection (with 6 to 8 jacks) is an example. (Universal MC-410)

4. Multi-step jacks selection More jacks are put under the needles to increase the pattern size

5. Example of multi-step jack pattern

6. Knitting Sequence

7. Summary of pattern • No pattern costs, pattern jacks are set manually • Pattern jack setout cannot be saved, re-arrangement is needed for new pattern • Pattern time is jack set out time • Pattern width is narrow; • Pattern height depends on number of control card used.

8. Pattern Drum Selection

9. So far, we have discussed pattern (jacquard) selection by: • Hi/lo butt needles; • Hi/lo butt jacks and needles; and • Multi-step jack selection • To increase pattern size, we can use • Pattern drum ;and • Pattern steel selection

10. Pattern Drum and Jacks • Universal MC-M is the only machine offers pattern drum selection • The machine has two pattern drums, each drum has 72 pattern keys and each key has 36 tooth • The pattern height is 144 (2X72) courses and the pattern width is 36 wales (jacks are in diagional set out)

11. Principle • The drum will be lift up and give forward and backward racking for new selection when the carriage reaches the right or left end of the needle bed • If “teeth” remains in the pattern key, it will push the pattern jack to “sunk” below the needle bed, results in miss loop. • Only when jack in upward position, the jack butt can select by needle bed for knitting action.

12. Techno-economics of pattern drum selection • We concern with pattern preparation time and pattern cost • Pattern Drum Selection • Pattern size 144 courses X 36 wales • Cost of 144 courses gives 144 pattern keys • If each key is @5.00, total cost is 144X5=$720 • Pattern time • One pattern key takes 25 seconds • 144 pattern keys take 25 sec X 144 = 1 hour

13. If produce by jacquard steel selection • Pattern cost is equal to labour cost • Pattern time • One jacquard steel takes 20 min, a 144 jacquard steels take 48 hours • About 6 days wages, roughly $1500-2000 • Therefore, for small pattern, pattern drum uses one hour and half the money on jacquard steel. In addition, storage of pattern drum/keys are lot easy

14. Jacquard Steel Selection

15. Jacquard Steel Selection • It is the only mechanical jacquard selection allows unlimited or freehand design. • Pattern width = needle bed width (roughly 80 inches) • Pattern height = No. of jacquard steels

16. Jacquard Steel SelectionSingle system

17. Jacquard Steel selectionDouble systems

18. Patterning on Jacquard Steel

19. Example : Four colour pattern on jacquard steel

20. Jacquard Steel (single system) • Hole in the steel = needle miss • No hole/bolcked= needle selected • For a 3 colour rib jacquard pattern with 30 surface courses on single jersey, it will take 90 jacquard steels

21. Jacquard Steel (Double System) • Requirement : Two rows of holes on jacquard steel, one for each knitting system; • Three cam tracks for each knitting system, one for the needle, and two for the jacks • The jacquard steel selection is done when the cam carriage is away from the needle bed. • The time available is only a fraction of second, therefore, vibration from the heavily jacquard roller and steel could cause a wrong pattern on fabric.

22. Discussion • Discuss the advantages of pattern drum selection • Discuss the advantages and limitation of jacquard steel selection