Textile Network

## Explain why weave design with more than 10 picks repeat is not possible to be woven by a tappet loom ?DUET-2014 Ans : all aspects apparel Suppose, we need to make a sateen weave which will require 12 tappets. So counter rotate once in every 12 picks occupies one-twelve of a revolution. i.e 30 degree the dwell period is 1/3 of pick. i.e 10 degree .The shaft will rise while the tappet turns 20 degree, will dwell during next 10 degree and will fall the next 20 degree. For this purpose, are should use larger tappet. For most looms, the lift required at the heald shaft will be between 12.5 cm to 20 cm. To use the tappet contains 10 picks, the outer diameter of the would be larger than 30 cm which is probably too large to accommodate inside the loom from.So more than 10 picks repeat is not possible by a tappet loom.

## Discuss the history of weft insertion systems.DUET-2013 Ans : Projectile weaving machine was invented in 1924 by an engineer named Rossmann became commercial in 1953. The first patent for the raper weaving machine was granted in 1898, then followed the Gabler system in 1925 and the Dewas system in 1930.Production of rapier weaving machine started in 1972. The first air-jet system was invented in 1914 but it became important commercially after 1980's. Continuous weft insertion on a circular weaving machine(multi phase) was proposed before the end of the 19th century. After mid 90's multi phase weaving machine has showed new developments.

Size of Jacquard: Design capacity of the jacquard for the control of the ends Number of independent end lifts that can obtained Virtually unlimited for the no. of picks in the weave repeat. ## What is meant by "600 needle jacquard (12*50). DUET-2010 Ans : 12 is known as short row, 50 is known as long row. It has twelve horizontal rows of needles placed one above the other with 50 needles in each row, plus a few extra needles. Instead of no. of needles, the no. of hooks can given to define size of jacquard,say, 600-hook jacquard. Hook is the main lifting element of the jacquard shedding.

## Is it possible to produce cross-border fabric by using an ordinary dobby ? If so,how ?DUET-2010 Ans: Normally it is not possible but in particular way it can be possible. To produce cross-border fabric by using an ordinary dobby, it may change of some mechanical construction. These are : Change lag chain Change peg plan

## What type of cross timing is suitable for dense fabric weaving and why ?        DUET-2013 Ans: For compact fabric early shedding is used because here Shed is formed  270 degree Shed is closed at 270-360 degree Beat up is occurred at 0/360 That means after heald shaft crossing beating is occurred.As a result ( pick can not springing back ) No bumping action and reed does not touch the felted yarn.

## Why 7 wheel take up is best ? DUET-2011 Ans : It can give larger ppi in cloth from a small stock of wheels by changing two wheels in the train. It can control even friction of a pick/inch The calculations to find out the no of picks/quarter inch in cloth and number of teeth in change wheel have been made simplified.

## Why shorter back shed suitable for cotton weaving ? DUET-2012 Ans: Shed angle more. Less extension of yarn than silk or filament. Less yarn breakage. Yarn hairiness less. Shuttle easy move from one side to another side. Easily separation of the upper & lower sheets.

## What are the technical problems of shuttle weaving ? DUET-2013 Ans : Shuttles causes abrasion on the warp yarn. Some times causes warp breaks. Function slowly. Shuttle looms are noisy. The movement of shuttle will be more difficult to control and there will be a greater possibility of its ejection from the loom.

** Define inching motion & reversing motion.Also mention their utilities in weaving.    DUET-2014                                                                       Inching motion :The forward slow movement of loom is known as inching motion. Utilities: When slow speed is required, then it is used for slight rotation Loom will run until the switch off To repair any fault To adjust the position of the stopped loom. Reversing motion : The backward slow movement of loom is known as reversing motion. Utilities: If pick insertion is done wrongly this motion used to take out the pick. Used to move the loom parts in the opposite direction. Using for conventional weaving machines.

Why more than two tappets are impractical to use in bottom shaft of a loom ? DUET-2014                    Ans:Bottom shaft contains two picking tappet i.e one revolution of bottom shaft, two times picking is done, so it is needed to do two times shedding for one revolution of bottom shaft. So,If shedding tappet is placed on bottom shaft.It is impossible to use more than two. If bottom shaft contains 3 tappets produce 3 times beating and 3 times picking which is not real i.e picking mechanism is always mounted on the bottom shaft and picking takes place alternatively from the opposite side for each revolution of bottom shaft.