TYPPES OF SHEDDING MECHANISM (JACQUARD):-

Types of shedding mechanism (jacquard):-

Ealier i have given a dtailed description ans type of dobby which are used in textile industry. Now here some jacquard shedfing mechanism, it's type and differnt working are going to be discussed in future articals and blogs. 

3) Jacquard shedding mechanism:-

To provide with limited design width jacquard in needed. This shedding motion has no shafts instead a harness consisting of as many as cords as there are ends in the warp sheet connects each end individually to the jacquard machine. Each warp could weave independently of all others. Complex and most versatile shedding motion . Biggest weave is possible with jacquard shedding as each warp yarn may be individually controlled.

Image of jacquard loom with punchcard.

Scope of Jacquard Shedding:-

1.  No heald frame is used.

2. Harness is used to lift and lower the warp thread.

3. One warp thread for each harness.

4. Most complex design is produced.

5. Maximum number of warp yarn it can control.

Working principle of jacquard shedding:-

A Jacquard attachment has blades, hooks, needle, a griffe, griffe hooks and a perforated cylinder.

The warp strands, drawn through the heddle eyes and tied to the loom by harness cords which are threaded through a comber board for even distribution over the width of the loom . The blades are set in a blade frame, moves up and down. The hooks are near the blades are engaged by them and lifted up and the warp strands are also lifted by the griffe hook and harness cords to form the upper part of shed ( the warp yarn in the fabric) . Hooks that are out of reach of the blade drop, together with the griffe. The hook and the warp strand of warp drops, because they are attached to weight. The lower strands of the warp yarn from the lower part of the shed (the warp yarn in the fabric). The coming from the area of the blade action are drawn out by needles activated by the cylinder, which in turn has a rocking and rotating motin. A piece of cardboard consist of individual paper cards is placed on the cylinder. The cards have perforations and when a needle comes to a perforation it enters the cylinder and the hook stays near the blade , but when a needle doesn’t meet a perforation, it is pushed back and the hook kept away from the knife. By combining perforated and unperforated place of the card , it is possible to exercise complete control over the raising and lowering of warp strands and to form a design on the fabrics.

Fig of a Jacquard Shedding.

Advantages of Jacquard shedding:-

1. Jacquard shedding mechanism are capable of producing large and intricate weave designs that are beyond the scope of dobby shedding mechanism..

2. In jacquard weaving it is possible to control every warp yarn individually.

3. Many specialized types of jacquard machine have been developed for weaving particular kinds of fabrics, such as Terry towels, damask, butta, design and carpet.

4. Most of the rest are general purpose types are comparatively easy to classify.

SUGGETION:-

Jacquard shedding mechanism is a very useful for producing designed fabrics. Some of the disadvantages hampered the shedding. We have to ensure the fault free shedding process in jacquard shedding mechanism.

CONCLUSION:-

The shedding process is done by some special device. Each device is maintaining the separate mechanism to produce shed.

Difference between, Tappet shedding, dobby shedding and jacquard shedding mechanism:-

As given below there are many differences that can be observed in all three shedding mechanism. They can be described as,

1. IN TAPPET SHEDDING:-

1.A simple design can be weaved.

2. Maximum 14 heald shafts can be used to weave a fabric. Theoretically it can control 6 - 10 heald shafts.

3. Speed of loom is very high.

4. Heald shaft motion is driven from the below of the loom.

5. For different design different tappets are fitted to the bottom shaft.

6. Fabric cost is low.

7. Production is more than the dobby loom.

2) In Dobby shedding:-

1. Medium design i.e.complex structure can be weaved.

2. Theoretically it can control maximum 48 ,but practically for wool number of heald shafts 36 and for cotton 24 heald shafts is able to use.

3. Loom speed is high.

4. The motion for shedding is given from above of the loom and in some loom from side of the loom.

5. For different designs, different design pegging legs are placed on cylinder.

6. It is expensive in costing.

7. Production is less.

3) In Jacquard shedding:

1. It is used to produce elaborate design i.e. very complex structure.

2. Theoretically it can control any number of warp threads individually.

3. Speed of the machine is low.

4. Motion is given from the above of the loom.

5.  For different designs, different punched cards are placed on cylinder.

6. It is highly expensive.

7. It’s production is less.

Ref:-https://textilelearner.net