How to Make Designs for Warp Knitting Jacquard Shoes?

In modern footwear manufacturing, double-needle bar Raschel Piezo-Jacquard warp knitting machines—such as the RDJ5/1, RDJ6/1, RDJ7/1 (single piezo) and RDJ4/2, RDJ6/2 (double piezo)—are widely recognized as premier seamless warp knitting platforms.

The A-ZEN RDJ6/2 machine features two independent Jacquard bars and four ground bars, specifically engineered for high-volume production of intricate Jacquard shoe upper fabrics. This guide provides a detailed technical overview of double-jacquard pattern design logic, machine specifications, and fabric finishing know-how.

1. RDJ6/2(EL) Machine Specifications

Double-needle bar machines equipped with Piezo-Jacquard technology allow two separate fabric surfaces to be connected with custom three-dimensional patterns (also categorized as 3D spacer mesh fabrics). All ground and Jacquard guide bars are controlled via high-precision Electronic Guide Bar Drives (EL System), supported by Electronic Beam Control (EBC System) for optimal yarn let-off stability.

Technical Parameters:

• Working Widths: 90" (228 cm), 138" (350 cm)

• Machine Gauges: E22, E24, E28

• Pattern & Let-off Control: EL Drive & EBC Electronic Let-Off

• Knock-over Comb Distance: Adjustable from 1.0 mm to 7.0 mm

• Knitting Elements: 2 individual latch needle bars, 2 knock-over comb bars, 2 stitch comb bars

• Needle Specification: Groz-Beckert 35.60G04 latch needles (RDJ6/2)

• Recommended Knock-over Distance: 1.2 mm – 4.5 mm (prevents loop accumulation while maintaining smooth high-speed operation)

• Recommended Yarn Linear Density: 15.6 tex (140D) and above

  
  

Guide Bar Configuration:

• GB1 & GB4 (Ground Bars): GB1 forms stitches on the front needle bed; GB4 forms stitches on the back needle bed.

• JB2 & JB3 (Piezo-Jacquard Bars): Independent Jacquard bars capable of stitch-forming across both front and back needle beds to generate 3D patterns and shoelace holes.

 

"1": GB1; "2、3": JB2(JB2.1, JB2.2);  "4、5": JB3 (JB3.1, JB3.2); "6":GB4; "7": Front knock-over comb bar;

"8": Back knock-over comb bar;  "9、10": Latch Needle Beds; "11、12": Sinker Beds.

GB1 stitch-forming on the front needle bed, GB4 stitch-forming on the back needle bed; JB2 and JB3 can make stitch-forming on both beds. No.9 and No.10 are latch needle beds, and the latch needle of RDJ6/2 is a 50.60G02 spec needle; the needle brand is Groz-Beckert. 

The yarn spec suggested using above 15.6tex (140D). If the knock-over comb bar distance is too narrow, the yarn is easy to accumulate, so it can not form new loops. If the knock-over distance is too wide, the machine would be difficult to run. We suggest the knock-over comb bar distance be set between 1.2 and 1.5 mm.

II Basic Structure of Double Needle Jacquard Designs (RDJ4/2)

The Basic Logic of Piezo Jacquard Structure 

As we are clear that GB1 and GB4 make pillar stitch structures, and JB2 mostly forms stitches on the front bed and JB3 on the back one. The notation of each ground bar is:

GB1: 1-0-1-1/0-1-1-1//;

JB2: 1-0-1-1/1-2-1-1//;

JB3: 1-1-1-2/1-1-1-0//;

GB4: 1-1-0-1/1-1-1-0//.

Warp-knitted shoe upper patterns are mainly formed by JB2 and JB3 guide needles movements. When the piezo jacquard needles do not move on both odd and even courses, under this condition, the light structure forms. When the piezo jacquard guide needles move on odd courses, the net structure forms, and when they move on even courses, the heavy structure forms.

This is the basic fabric-forming structure logic of the piezo jacquard needles' movements.

Various Warp-knitted Structures 

When the ground bars GB1 and JB2 form a stitch only on the front bed and JB3 and GB4 form a stitch only on the back bed, the separate net effect appears. As image 2b shows clearly, when the net of the front bed and the net of the back bed move at the same needle position, the shoe textile will show empty holes, which could be used for shoelace holes.

And as image 2c notes, when JB3 forms a stitch on the front bed with colored or different-spec yarn from JB2 and GB1, the two separate surfaces would be joined together to become a complete textile unit. Lastly, in image 2d, when JB2 forms stitches on both the front and back beds, while JB3 only does so on the back bed, the separate surfaces are also joined, and the front surface only shows yarns from GB1 and JB2.

To sum up, the different uses of jacquard bars would lead to a total of different shoe upper structures.

The Example of How to Make Warp-knitted Double Jacquard Shoe Upper Fabrics

1. Calculate the Size of the Shoe Sample:

Before starting design development, we shall learn how to change the shoe size in design courses.

T means the total number of columns of shoes, and V means the total number of courses of shoes. W stands for size on the horizontal side(cm), and H means size on the vertical side(cm).

The calculation is as follows:

T=W*WPC;

V=H*CPC.

2. Software Jacquard Color Matrix

In the warp knitting design software, “H” stands for Piezo Jacquard needles non-movement, and “T” means Piezo Jacquard needles movement.

There are many colors in the warp knitting design software, and different colors stand for different mesh structures. Here, here we give you a brief example:

4# and 8# colors stand for Light Structure, 1# means Heavy Structure, 12# represents Net Structure, and 26# is a symbol of Middle Structure between Light Structure. 25# and 18# mean Link Structure between Net Structure and Heavy Structure, respectively.

The different combinations of these colors make various mesh effects on warp-knitted shoe uppers. 

Yarn Spec. Used on Shoe Uppers:

GB1: 15.6 tex/48F (140D/48F) semi-bright nylon FDY;

JB2: 23.3 tex/72F (210D/72F) semi bright nylon DTY;

JB3: 22.2 tex/96F (200D/96F) semi bright polyester DTY;

GB4: 16.7/48F (150D/48F) semi-bright polyester DTY.

Warp Knitting Machine Type & Technique Parameters:

RDJ4/2, Gauge E24, and the working width is 138”;

Knock-over comb bar distance: 0.65-1.0 mm (knock-over comb bar adjusted by stitch comb swiveling device);

CPC on machine: 16 c/cm;

Finished weight: 478.5g/m2;

Running Speed: 450 r/min;

Yarn Let-off (EBC):

·GB1: 1,700 mm/rack;

·JB2: 2,380 mm/rack;

·JB3: 2,500 mm/rack;

·GB4: 1,750 mm/rack;

Jacquard Design Matrix

JB2 includes 1#, 4#, and 12# colors, and JB3 includes 1#, 4#, 12#, 18#, 25#, and 26# colors. JB3 forms stitches on both the front and back beds. Because of this, GB4 and JB3 run more yarn than GB1 and JB2 do.

Finished Sample:

III Some Tips on the Shoe Uppers Finishing Process

It is noted that setting and finishing are vital to the shoe upper fabric process; here we share one practical experience with you.

Firstly, we need to measure the size of shoe upper samples carefully and match them with a transparent cardboard tool (note that shoe fabric is 3 cm bigger than standard cardboard).

After pre-setting, the fabric size is shall be 0.5 cm bigger than standard cardboard. 

The following steps are dyeing and setting. To make sure the shoe upper size is generally correct, the tolerance scope shall be within -2~2 mm.

Above mentioned tips are experienced skills from the production, of course, making a high-end shoe upper fabric is not an easy job; however, we commit ourselves to making a contribution to the continuous development of warp knitting technology. 

 

RDJ4/2 Machine Link: RDJ4/2, RDJ6/2 Catalog

Related Resource: How to produce superior warp-knitted shoe upper fabric?

IV A-ZEN RDJ6/2 Double-needle Bar Machine Working Video

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We believe that the shared knowledge will extend our passion to explore warp knitting technology.