Computer Aided Design (CAD) is a software program on the computer that helps designers to create whole garments, design printed patterns for textiles and create specific weave and knit patterns. CAD systems have opened lots of new possibilities to designers and development departments, from higher creativity, possibility of fast incorporation of novelties and improvements into their work and higher flexbility for adaptation to constantly and quickly changing fashion trends and market demands, up to more rational and sensible use of time and materials. CAD is used in Jacquard design, editing, creating loom control files, and punching of textile designs. The jacquard design is a unique combination of artwork, weave, and yarn specifications. In this article I will discuss about application of computer-aided designing (CAD) in jacquard design.
Figure 1: CAD in jacquard designing
Application of CAD in Jacquard Design:
Jacquard designing is for those patterns having repeat on ends greater than 32 frames. A jacquard loom is the weaving technology to use when wishing to produce greater complexity in the interlocking of warp and weft directional yarns, in terms of: weave architecture combinations; single layer fabrics; multilayer multilevel wovens (shapes and solid woven fabrications). Contrary to the tappet and dobby shedding, the jacquard system has harness or hook responsible for the shedding. Hooks are used to raise/lower the individual yarns. Therefore, designs having unlimited repeat pattern like flowers, logos, text, etc. can be produced using jacquard.
There are no heddle frames used on jacquard, but ends are raised or lowered individually as per requirement in each repeat. Jacquard machine is used to produce fancy fabrics like damask, leno, or brocades fabrics. There are two main types of jacquard as already discussed in jacquard shedding portion. These are mechanical jacquard and electronic jacquard.
How to feed design on mechanical jacquard: To make design using mechanical jacquard, pattern cards that are punched and laced together according to repeat are used. Circular holes are punched in the card corresponding to needles. A hole in card is responsible to raise warp end and make top shed line, and blank is responsible to lower the warp end and make bottom shed line. Pattern card has design holes for needles and peg holes to fix card in exact position and lace holes for joining cards together as you can see fully punched card in Figure 2.
Figure 2: Fully punched pattern card
One card is used for one pick only, so there are as many cards as many picks in the repeat of design. Comber board made of close-grained wood is a long perforated board extending the width of loom, and the objective of comber board is to spread harness cords uniformly, which determines the warp density in the cloth. The reed number must correspond to the number of holes per unit length in the comber board. The number of holes in width of comber board is equal to the number of needles in the short row of jacquard. The number of holes in lengthwise direction of comber board depends on the warp density of cloth being made.
For example, if jacquard machine contains eight needles in the short row, there will be eight holes in the short row of comber board. While if reed contains 96 ends/inch, there will be 12 holes in each inch of long row, thus giving in total 96 holes/inch in the comber board lengthwise. Once a comber board is threaded and drilled, the width of fabric and the width of repeat are calculated. The thread per unit width could be decreased but never increased.
In tappet and dobby shedding, the number of ends per centimeter can vary. With jacquard shedding, the number of ends per centimeter is determined by harness cords. There is no possibility of weaving a fabric with more ends per centimeter than the harness has. However, it is possible to weave design with a less number of ends per centimeter by using casting out.
Casting out:
Casting out means to leave selected hooks and harness cords so that they become idle. For example, the maximum hooks are 400 and the maximum warp density is 32 ends/cm. So, the size of 400 thread repeats will be 400/32 equals to 12.5 cm. If we want to produce 24 ends/cm, the maximum required hooks will be 24 × 12.5 equals to 300 hooks. We have to leave 100 hooks idle, so each fourth row will be idle or we can make every fourth hook idle.
How to feed design on electronic jacquard loom:
For making fabric on electronic jacquard machine, different designing software are used like Scot weave (for fabric) and Eat software (for terry towel) on which from image processing, resolution setting, ends and picks calculation, and weave assigning method to cast out all process are done, and then this information is transferred to floppy disk or USB and fed on loom.
For computer-aided designing of jacquard, certain kinds of computer software are used, for example, Scot weave. For jacquard production, in scot weave image (design) is first converted to loom readable form. For that purpose, certain steps are carried out as follows:
Artworks
Jacquard designer
Jacquard loom
Artwork:
Artwork is the initial step of jacquard process. In artwork, image is imported. Every image has too many colors (dominant and not readable). For jacquard image, colors are reduced to two colors. Reducing image color is also known as color compression. Artwork is also responsible for adjusting the size of the design or image in terms of ends/inch and picks/picks. Design tracing can also be done in artwork. Moreover, editing of design, copy paste of design, and mirroring of design are done in artwork.
Jacquard designer:
After working on design in artwork, it is imported to jacquard designer. In jacquard designer, different weaves are applied to different colors. In other words, for each different color, a different weave is applied. Scot weave has a treasure of different kinds of built-in weaves and counts of yarns. After applying weaves, yarns of required count are applied in warp and weft to see the design whether it is correct or not.
Jacquard looms:
After applying weave and yarns to the design, then it is checked. If the design is correct, then it is imported to jacquard window in Scot weave. Here, harnesses (hooks) are applied to each yarn. Jacquard loom window is also responsible for adjusting the selvedge of the fabric to be produced and also specific yarn to be run for the specific weave in weft. After that, design is saved in a floppy disk and transferred from computer software to jacquard loom.
References:
Structural Textile Design: Interlacing and Interlooping by Yasir Nawab, Syed Talha Ali Hamdani, & Khubab Shaker
Fibres to Smart Textiles: Advances in Manufacturing, Technologies, and Applications Edited by Asis Patnaik and Sweta Patnaik
Textile and Clothing Design Technology Edited by Tom Cassidy and Parikshit Goswami
Founder & Editor of Textile Learner. He is a Textile Consultant, Blogger & Entrepreneur. He is working as a textile consultant in several local and international companies. He is also a contributor of Wikipedia.
