Jimmy Lam Institute of Textiles & Clothing Jacquard Fabric on Circular Knitting machine Part 4: More Double Jersey Jacquard Fabrics Jimmy Lam Institute of Textiles & Clothing

Learning Objectives More unconventional double jersey jacquard fabric French Rib Blister Fabric Jacquard Backing

French Rib Similar to imitation lace fabric Two fabric tubes are linked together to form a unique fabric This method is to insert a fine yarn to tuck on the selected cylinder and dial needles at suitable interval. Normally, the finished commercial fabric looks different on two side. One appears on fine gauge, and the other appears in coarse gauge.

French Rib Fabric looks different on both side because one side uses coarse yarn, the other uses normal yarn.

Blister Fabric Two types: Single blister and double blister Blister fabric is well known for raised pattern effect on fabric surface. It is similar to rib jacquard except with knit and miss course. The structure is normally on fine gauge, 20-24 npi with polyester yarn for suiting fabrics.

Single Blister There are more courses knitted on face side (cylinder) than the back side (dial) of the fabric. The fabric shrinks and the single knit portion is raised up on the fabric surface, and the rib areas remain flat as the ground of the pattern.

Double Blister It takes 6 feeders for one structure If the ratio between the face courses and the back courses for single blister is 2:1, than the ratio for double blister is 3:1. It is obviously double blister will show more raised effect of pattern than single blister.

Blister Fabric cylinder and dial arrangement

Double Blister It takes three knitting course to make one course on the pattern for double blister. Therefore, an 8 course per repeat double blister will need 24 courses to produce. The characteristics of double blister is the raised effect, which are created by knitting a particular colour yarn in single knit (knit and miss format), while the other in double jersey format. As a result, the single jersey portion of the fabric will be raised up on the fabric surface.

8-course Double Blister Pattern Graph 24-course Motif 8-course design Knitting sequence : 2 courses in single knit (A) 1 course in double knit (B)

8-course double blister Knitting details Color A in double course, single knit Color B in double knit with birdeye’s backing

Jacquard Backing All jacquard patterns are developed on cylinder needles, the back of fabric is knitted by dial by varies backing technique. In dial needles, there are L (long) and S (short) needles and the possible selections are shown on the table.

Horizontal Backing On a rib jacquard fabric, when all dial needles are knitting on all feeders, the fabric will produce horizontal stripe and is known as horizontal backing horizontal stripe/backing is normally used for up to 4 colours. 2-colour, 3-color and 4-color, please refer to diagram The surface loop size is stretched proportional to the number of colours in the pattern. Eg. Two colours pattern, the course ratio between the surface and the back is 1:2; and for 3-color is 1:3 etc.

2-Color Horizontal Backing Technical Face Technical Back

4-Color Horizontal Backing Face Back The fabric composes of one blue and one white colour No float yarn at the back

Horizontal Backing Ratio between the face loop and the back loop

Disadvantages of horizontal backing Colour yarn at the back cannot be covered properly and show off between the surface loops. Result is poor resolution of colour pattern. Horizontal backing are unbalanced fabric. They will curl when cut and fabric setting is needed in after treatment.

Advantages of horizontal backing Produce the largest pattern size on fabric Lightest fabric weight when compare with other backing methods, therefore, coarse gauge jacquard double jersey always prefer horizontal backing. Horizontal backing is used on 12 gauge and below and especially on V-bed 5 to 12 gauge Circular machine with gauge of E16 or above seldom uses horizontal backing because of poor dimensional stability.

Birdeye’s backing To knit bird’s eye backing, the machine must be able to select one of the two dial needles to knit and miss on each feeder according to backing rule. 2-colour, 3-colour, 4-colour backing, please refer to diagram.

Birdeye’s backing Rule

2-colour Birdeye’s backing Face Back Honeycomb appears at the back

Effect of birdeye’s backing