Non-woven, Braiding, Weaving, Knitting and Laminating Principles may form the 3D Fabric. Out of these, the Woven 3D fabrics are formed by two methods.


The first method of 3D woven fabric denotes 3 Dimensional fabrics, that is length, width and breadth. In 3 Dimensional fabrics, the thickness is an important criterion. Ordinary fabrics also have length, width and breadth, but in the 3 Dimensional fabrics, the thickness is much more than ordinary fabric. The thickness is achieved by forming multiplayer using multi series of warp and multi series of weft, which are intersecting at regular 90o angle as in usual cloth weaving principle.


The other method of 3D woven fabric denotes 3 Directional thread fabric, that is x, y, z. In 3 directional thread fabric, thickness is not an important criteria but there are three series of threads run in 3 directions viz. x, y & z intersecting each other at 60o angle. Two series of threads form the warp and one series of thread form the weft.


Hence to have clear understanding of 3D woven fabrics, the three-directional fabric (x, y, z) can be denoted by "3 Dr" and three-dimensional fabric (I, w, b) can be denoted by "3Dm".


Special looms are required to operate the warp threads in 60o angle for weaving 3Dr-3 Directional fabrics. But the 3 Dimensional -3Dm- fabric can be woven by using ordinary loom with usual weaving principle-shedding, picking, beating - by having multi layers of warp and multi layers of weft. Even though the treble cloth with 3 series of warp and weft could be called 3Dm fabrics, in general, minimum 4 series of warp and weft are used in weaving to form several layers, one above the other to get the sufficient thickness resulting into 3 Dimensional fabric.


The length way and width way cross section of "3 weft layer 3Dm" fabric woven by using 4 series of warp and 3 series of weft is shown below: -


By looking into the cross section, any "Fabric Structure Designer" can very well say that 3Dm fabric is a "Simple weft Tapestry" fabric.


As per the principle of weft Tapestry fabric, to weave 3Dm fabrics, it is required to use one series of stitching warp and multi series of separating warp as per the number of layers to be formed.


As seen from the cross section, the stitching warp passes from top to bottom and bottom to top but all the separating warp lies almost straight and hence the stitching warp takes up more length than the separating warp.


Therefore, the stitching warp is brought from a loose tension beam and the entire separating warp is brought from another normal tension beam.


The following points are to be understood from both the cross sections: -


The first layer weft (Face) - shown as "a" - lies between the stitching warp (shown as 1) and first separating warp series (shown as 3).


The second layer of weft (Middle) - shown as "b"- lies between the first and second separating warp series (shown as 3 and 4).


 

The third layer of weft (Middle) lies between the second and third separating warps series and so on.


The last layer of weft (Bottom) has shown as "c" Iies between last separating warp series and stitching warp (shown as 4 and 2).


No. of healds required to weave the 3Dm fabric can be calculated as below:-


Stitching ends are always taken in two healds to operate these ends from top to bottom and from bottom to top simultaneously.


No. of healds required for separating warp, depends upon number of layers of weft to be laid. To lay 3 layers of weft, 2 separating warp series drawn in 2 healds are required. To lay 4 layers of weft, 3 separating warp series drawn in 3 healds are required and for 5 layers it is 4 healds and so on. Therefore No. of series of separating warp = no. of healds = one less than the no. of weft layers to be laid. Put together,


3-layered 3Dm fabric is woven by using 4 healds (2 stitching warp healds + 2 separating warp healds)


4-layered 3 Dm fabrics are woven by using 5 healds (2 stitching warp healds + 3 separating warp healds).


The operation of healds to produce 3 weft layered 3Dm fabric is as follows:-


Total number of healds = 4

Stitching warp healds (St.H.) = 2 (No.1 & 2)

Separating warp healds (Se. H.) = 2 (No.3 & 4)

The three weft layers are denoted as:

Face pick (a), Centre Pick (b), Back pick (c)


A report is completed by putting 6 picks (3 + 3)


Weft Introduced


Stitching Healds

Operation

St. H - 1,2

Stitching Healds

Operation

Se. H.-3,4

Face pick (a)

Centre pick (b)

Back pick (c)

St. H -1 Up

St. H -1 Up

St. H -1 Up

All down

Se H - 3 Up

All Up

Face pick (a)

Centre pick (b)

Back pick (c)

St. H -2 Up

St. H -2 Up

St. H -2 Up

All down

Se H - 3 Up

All Up


The length way and width way cross sections of 5 weft layer 3 m fabric are shown below.




 

The operation of healds to produce 5 - layered 3Dm fabrics are as follows.


Total number of healds = 6

Stitching warp Healds (St. H.) = 2 (No.1, 2)

Separating warp Healds (Se. H) = 4 (No. 3, 4, 5, 6)

The five weft layers are denoted as:-

Face weft - Layer 1 (a)

Middle weft-Layer 2 (b)

Middle weft-Layer 3 (c)

Middle weft- Layer 4 (d)

Back weft - Layer 5 (e)


A Report is completed by putting 10 picks (5 + 5)


Weft Introduced


Stitching Healds

Operation

St.H - 1,2

Stitching Healds

Operation

Se. H.-3,4

Face weft layer-1 (a)

Middle weft layer-2 (b)

Middle weft layer-3 (c)

Middle weft layer-4 (d)

Back weft layer-5 (e)

St. H -1 Up

St. H -1 Up

St. H -1 Up

St. H -1 Up

St. H -1 Up

All down

Se H - 3 Up

Se H 3,4 Up

Se H 3, 4, 5 Up

All Up

Face weft layer-1 (a)

Middle weft layer-2 (b)

Middle weft layer-3 (c)

Middle weft layer-4 (d)

Back weft layer-5 (e)

St. H -2 Up

St. H -2 Up

St. H -2 Up

St. H -2 Up

St. H -2 Up

All down

Se H - 3 Up

Se H 3,4 Up

Se H 3, 4, 5 Up

All Up


The thickness and weight of the 3Dm fabrics is directly proportional to the number of weft layers used, and thickness of the weft.

                       

For example the thickness of the 3Dm mat of 13"x19" size woven on 5 layer principle using 6 healds (2St.H+ 4 Se. H) shown in the figure is of one inch in thickness and weighs nearly 1000 grams which is equal to 5.25 kg. per sq. yard. The thickness of weft used is 0.2", which resulted 1" thickness by 5 layers (5 layers x 0.2"= 1")


To quote another example, a 3 layered 3Dm mat of 15"x 20" size is " in thickness, weigh 500 grams which is equal to 2.16 kg/ sq yard.


The 3Dm fabrics are used for reinforcing of different material in one fabric. Cotton used in top and bottom layer with jute used in the middle layers, gives the fabric very good softness on the face and backside because of cotton and at the same time gives required strength and hardness in the center because of Jute.


The thickness of the fabric is useful for many industrial purposes such as heavy load bearing and hammering.


It is concluded by stating that Handlooms with multi healds and treadles can be easily used to weave 3Dm fabric to meet the increasing demand of these fabrics in the recent past both in local and export market.


Hence, Weavers' Service Centre, Ahmedabad has already undertaken the development of different varieties of 3Dm Fabrics to give guidance about the technique of manufacturing of these fabrics to the Handloom weavers who are already in the production of Floor carpets in and around Ahmedabad.


About the Author:


The author is presently serving as Deputy Director (Weaving) at Weaver's Service Centre, Bangalore.