Thursday, June 28, 2018

Difference Between Tappet, Dobby and Jacquard Shedding in Textile

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Different Types of Shed in Weaving Technology:

There are three types of shed or shedding mechanism in the textile industry. Those are listed in the below:
  1. Tappet shedding mechanism,
  2. Dobby shedding mechanism,
  3. Jacquard shedding mechanism.

Tappet shed or shedding is classified into two types where one is positive shedding tappet and the other one is negative shedding tappet. Dobby shedding has mainly two types i.e. negative dobby shedding and positive dobby shedding.
Comparison between tappet, jacquard and dobby shedding
Fig: Comparison between tappet, jacquard and dobby shedding

What is Tappet Shedding in Textile?

An important type of cam to which a rotary motion is provided for the object of producing reciprocating motion in levers and rods by sliding contact. When the rod is to receive a series of lifts, with intervals of rest and in this way forming a shed which is known as tapped shedding. Tappet shedding has simplest design capacity than others shedding. It is one of the most costly weaving looms in textile. Loom speed of tappet shedding is comparatively very high than others. The tappet is normally placed below the weaving loom during the weaving process. A maximum number of heald shafts in tappet shedding is fourteen. Tappet shedding has comparatively higher production than dobby shedding and jacquard shedding. Here, production cost also very low. 

What is Dobby Shedding in Textile?

In order to produce figure patterns by using a large number of heald shafts than the capacity of a tappet, a shedding device named dobby is placed on the top of a weaving loom. Dobby shedding has medium or complex design capacity. The cost of dobby shedding loom is less than tappet shedding. In weaving loom, dobby is placed normally above the loom. Here, loom speed is lower than tappet shedding but higher than jacquard shedding. It should be noted here that, dobby shedding has less production than tappet and cost of production is also low. 

What is Jacquard Shedding in Textile?

To produce large figure patterns by using a very large no. of warp yarn separately by means of hooks, harness cords and needles without any heald shaft, jacquard shedding device is placed on the top of the loom. Its design capacity is very complex. This type of loom cost is very low and loom speed is also lower than another shedding. During weaving, jacquard shedding device is placed generally above the weaving loom. It has comparatively less production than tappet shedding and dobby shedding. Cost of jacquard shedding production is low. 

Difference Between Tappet Shedding, Dobby Shedding, and Jacquard Shedding:

SL No.
Tappet Shedding
Dobby Shedding
Jacquard Shedding
01
Simplest design capacity.
Medium i.e. complex design capacity.
Elaborate i.e. very complex design capacity.
02
Most costly weaving loom.
Less costly weaving loom.
Very less costly loom.
03
Loom speed is very high.
Loom speed is medium to high.
Loom speed is slow.
04
Max. No. of heald shafts is 14.
Theoretically it can control max. 48 heald frames. In case of wool, particularly 36 heald and in cotton-24
Theoretically it can control any no. of warp thread individually.
05
Tappet is placed generally below the loom.
Dobby is placed generally above the loom.
Jacquard is placed normally above the loom.
06
Lowest cost of production.
Cost of production is low.
07
Different tappets are fitted to bottom shaft for different designs.
For different designs, different designs of pegging legs are placed on pattern drum or cylinder.
Different designed pinches cards are placed on cylinder for different designs.
08
Production is more than dobby.
Less production.
Less production.
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