Difference between warp knitting & weft knitting

 

Difference between warp knitting & weft knitting

Warp knitting	Weft knitting
The loops are produced to the length of fabric.	The loops are produced to the width of the fabric.
The Yarns run in the vertical direction.	The Yarns run in the horizontal direction.
Each loop in the horizontal direction is made from a different Yarn.	A horizontal row of loops can be made by using on Yarn.
It is elastic to the length.	It is elastic to the width.
Its elasticity is less.	Higher elasticity.
Yarns are supplied from beam.	Yarns are supplied from cone.
At least one yarn is needed for each needle.	Any number of needle are required for one yarn.
Less shrinkage.	Higher shrinkage.

Differences Between Double Lift Dobby & Single Lift Dobby

 

Differences Between Double Lift Dobby & Single Lift Dobby 

Double lift dobby	Single lift dobby
1. It forms a open shed.	1. It forms a bottom closed shed.
2. Produce corrugated fabrics, since the beat up is done in crossed shed	2. Produce intimates the appearance of hand loom fabrics, since the beat up is done on closed shed.
3. Double hooks in this dobby control a single heald.	3. Each hook of this dobby controls a single heald.
4. It is driven from the bottom shaft of the loom.	4. It is driven from the crank shaft of the loom.
5. Less time is required.	5. More time is required to produce a shed.
6. Speed of loom is high.	6. Speed of loom is low.
7. Less strain is put on warp line.	7. More strain is put on warp line.
8. Less wear & tear.	8. Heavy wear & tear.

Difference between knit and woven fabric

 

Difference between knit and woven fabric

Woven Fabric	Knit Fabric
Woven fabrics are warp and weft yarn interlacement.	Here, a single yarn is interloop.
Woven fabric have selvage.	Knit fabric have no selvage.
Warp and weft used to make the fabric.	Single yarn used, this method were avoided the warp and weft.
Produce by loom.	Produce by knitting machine.
Sizing Required	Sizing is not required
Low elastic fabric.	Highly elastic fabric.

Study on Raschel Warp knitting machine.

 Experiment Name: - Study on Raschel Warp knitting machine.

Introduction:

The warp knitting machine is a knitting m/c where the loops are formed in course wise direction and the fabric produced is in open width form. In Tricot warp knitting m/c compound needles are used. The warp yarns are feed to the needles through guide bars using shogging and swinging motion.

Objectives:

*      To identify with Raschel Warp knitting machine.
*      To know the machine specification.
*      To learn the feature of this machine.
*      To know the different parts of this machine.
*      To know the machine mechanism.
*      To learn the knitting actions of this machine.


Main parts:

*      Guide
*      Needle bar
*      Sinker
*      Front of machine
*      Trick  plate
*      Fabric


Machine description:

Their chain links are usually numbered in even numbers, 0, 2, 4, 6 etc., generally with two links per course. Raschel sinkers perform only the function of holding down the loops whilst the needles rise. They are not joined together by a lead across their ends nearest to the needle bar so they can move away clear of the needles, towards the back of the machine, for the rest of the knitting cycle. The needle trick plate verge acts as a fabric support ledge and knock-over surface.
The fabric is drawn downwards from the needles, almost parallel to the needle bar, at an angle of 120–160 degrees, by a series of take-down rollers. This creates a high take-up tension, particularly suitable for open fabric structures such as laces and nets.

Fig 1:  Knitting elements of a latch needle raschel machine

Fig 2 : Cross-section of a latch needle raschel machine.

The warp beams are arranged above the needle bar, centered over the rocker shaft, so that warp sheets pass down to the guide bars on either side of it. The beams are placed above the machine so that it is accessible at the front for fabric inspection and at the back for mechanical attention to the knitting elements. The guide bars are threaded, commencing with the middle bars and working outwards from either side of the rocker-shaft. They are numbered from the front of the machine.

With the raschel arrangement, there is accommodation for at least four 32-inch diameter beams or large numbers of small diameter pattern bars. The accessibility of the raschel machine, it’s simple knitting action, and its strong and efficient take-down tension make it particularly suitable for the production of coarse gauge open-work structures employing pillar stitch, inlay lapping variations and partly threaded guide bars. These are difficult to knit and hold down with the tricot arrangement of sinkers. Additional warp threads may be supplied at the selvedges to ensure that these needles knit fabric overlaps, otherwise a progressive press-off of loops may occur.

      Fig 3 : Raschel warp knitting machine

Features of raschel machine:

1.    Raschel machines originally had a gauge expressed in needles per 2 inches (5 cm), so that, for example a 36-gauge raschel would have eighteen needles per inch. Now, the standard E gauge (needles per inch) is generally used.
2.    There is a wide gauge range, from E1 to E32.
3.    Their chain links are usually numbered in even numbers, 0, 2, 4, 6….etc.
4.    Generally with two links per coarse.
5.    Raschel sinkers are performing only the function of holding down the loops whilst the needles rise.
6.    Sinkers are not joined together by a lead across their ends nearest to the needle bar so they can move away clear of the needles, towards the back of the machine, for the rest of the knitting cycle.
7.    The needle trick plate verge acts as a fabric support ledge and knock over surface.
8.    The fabric is drawn downwards from the needles, almost parallel to the needle bar, at an angle of 120-160 degrees, by a series of takedown rollers. This creates s high take-up tension, particularly suitable for open fabric structure such as laces and nets.
9.    The warp beam is arranged above the needle bar, centered over the rocker shaft, so that warp sheet pass down to the guide bar on either side of it.
10. The beam is placed above the machines so that it is accessible at the front for fabric inspection and at the back for mechanical attention to the knitting elements.
11. The guide bars are threaded, commencing with the middle bars and working outwards from either side of the rocker shaft. They are numbered from the front of the machine.
12. With the raschel arrangement, there is accommodation for at least four 32-inch diameter beams or large numbers of small diameter pattern bars.
13. The accessibility of this machine, it’s simple knitting action, and its strong and efficient take-down tension make it particularly suitable for the production of coarse gauge open work structures employing pillar stitch , inlay lapping Variations and partly threaded guide bars, these are difficult to knit and hold down with the tricot arrangement of sinkers.
14. Additional warp threads may be supplied at the selvedges to ensure that these needles knit fabric overlaps, otherwise, a progressive press off of loops may occur.

Study on the Crochet warp knitting machine.

 Experiment Name: - Study on the Crochet warp knitting machine.

Introduction:

The warp knitting machine is a knitting m/c where the loops are formed in course wise direction and the fabric produced is in open width form. In Tricot warp knitting m/c compound needles are used. The warp yarns are feed to the needles through guide bars using shogging and swinging motion.

Objectives:

*      To get clear concept about the driving mechanism of crotchet knitting machine.
*      To know the functions of different parts of the machine.
*      To know about the different motions of the machine.
*      To know different parts of the machine.
*      To improve our technical knowledge.

Specification of the machine:

Ø  Company: DAH HEER Industrial Co. LTD.
Ø  Brand: DAHU.
Ø  Origin: Taiwan.
Ø  Model No: L
Ø  Size: 15 G

Main parts:

Motor
Main shaft
Size lever
Shogging motion lever
Weft yarn guide bar
Warp yarn guide bar
Needle bar
Needle
Pressure roller
Take up roller
Ratchet wheel

Machine description:

The machine is driven by an electric motor. Motion is transferred to the machine parts by gear and toothed belt. Here weft yarn guide bar gives to and fro motion and shogging motion. Shogging motion lever give motion to the weft yarn guide bar. Shogging motion is driven from motor by main shaft. Needle bar and warp yarn guide bar also give to and fro and shogging motion by the same mechanism. Take up roller has ratchet wheel, by which take up roller gets motion from the motor by pushing pawl and some mechanism.

    Fig: Crochet warp knitting machine.

Features of crochet machine:

1.    On crochet machines, the warp chains are separate from the weft inlay and it is the latter threads that join the chaining Wales to each other.
2.    A single horizontal needle bar whose simple reciprocating action can be used to operate individually- tricked latch, carbine or embroidery needles.
3.    The patent or carbine bearded needle is used for fine structures and has a sideways crimped beard placed in a permanently- pressed position.
4.    No sinker, instead a fixed hold back bar is fitted in front of the knock over verge to prevent the fabric moving out with the needles.
5.    Closed lap pillar stitches and inlay threads controlled and supplied as separate warp and weft respectively.
6.    Each needle is lapped from below by its own warp guide, which is clipped to a bar, whose automatic one needle overlap and return and under lap and shog is fixed and is controlled from an electric cam whilst it’s upwards and downwards swing is derived from a rocker shaft. The warp yarn is often placed low at the front of the machine.
7.    The weft yarn often placed above and towards the back of the machine, supplying the carrier tubes, which are clipped to the spring-loaded inlay bars.
8.    There are usually up to two warp guide bars and up to 16 weft inlay bars, which may be electronically controlled.
9.    The weft inlay bars may rather be electronically-driven or mechanically controlled in the traditional manner by chain links or levers. The choice is governed by the requirements either of long complex pattern repeats and quick pattern changes as in sampling, or for simple structures and long production runs.
10. The knitting widths of crochet machine may vary between 16 and 122 inches (400 and 3100 mm).
11. Gauge, often expressed in needles per centimeter, are between 2 and 10 (E5 to E24).
12. Machines run at speeds between 200 and 350 courses per minute.
13. Crochet machines can process a range of filament yarns from 20 dtex to 1000 dtex.
14. The warp yarn is often placed low at the front of the machine.
15. Special attachments are available for producing fancy effects such as cut or uncut fring edges, pile, braiding and snail shell designs.
16. Crochet machines, with their simple construction, ease of pattern and width changing, and use of individual yarn packages or beams provide the opportunity for short runs on coarse, or fine-gauge fancy and open-work structures and edgings, as well as the specialist production of wide fancy fabrics or narrow elastic laces.

Different Mechanism of a plain loom

 

The process of producing a fabric by interlacing warp and weft threads is known as weaving. The machine used for weaving is known as weaving machine or loom. Weaving is a skill that has been practiced for thousands of years. The initial application of weaving dates back to the Egyptian civilization. Over the years, both the process as well as the machine has undergone phenomenal changes. As of today, there is a wide range of looms being used, right from the simplest hand loom to the most sophisticated loom.

In this rang, the most widely prevalent loom, especially with reference to India, is the ubiquitous “plain power loom”. In this and in the chapters that follow, the various mechanisms associated with the plain power loom are discussed in elaborate detail.

Different mechanisms of a Plain Power Loom

In order to interlace wrap and weft threads to produce a fabric, the following mechanisms are necessary on any type of loom. There are three mechanisms involve they are

1. Primary mechanisms

2. Secondary mechanisms

3. Auxiliary mechanisms

1.    Primary Mechanisms

These are primary or essential mechanisms. Without these mechanisms, it is practically impossible to produce a fabric. It is for this reason that these mechanisms are called ‘primary’ mechanisms. The primary mechanisms are three in number.

a. Shedding mechanism

b. Picking mechanism

c. Beat-up mechanism

a.    Shedding mechanism

The shedding mechanism separates the warp threads into two or more layers according to design or divisions to form a tunnel known as ‘shed’

b. Picking mechanism

The picking mechanism passes weft thread from one selvedge of the fabric to the other through the shed by means of a shuttle, a projectile, a rapier, a needle, an air-jet or a water-jet. The inserted weft thread is known as “pick”.

c. Beat-up mechanism

The beat-up mechanism beats or pushes the newly inserted length of weft thread (pick) into the already woven fabric at a point known as “fell of the cloth”. These three mechanisms namely shedding, picking and then beat-up are done in sequence.

2.     Secondary Mechanisms

These mechanisms are next in significance to the primary mechanisms. If weaving is to be continuous, these mechanisms are essential. So they are called the ‘secondary’ mechanisms. They are:

a)    Take-up motion

b)    Let-off motion.

a)    Take-up motion

The take-up motion withdraws the cloth from the weaving area at a constant rate so as to give the required pick-spacing (in picks/inch or picks/cm) and then winds it on to a cloth roller.

b)   Let-off motion

The let-off motion delivers the warp to the weaving area at the required rate and at constant tension by unwinding it from the weaver’s beam. The secondary motions are carried out simultaneously.

3.     Auxiliary Mechanisms

To get high productivity and good quality of fabric, additional mechanisms, called auxiliary mechanisms, are added to a plain power loom. The auxiliary mechanisms are useful but not absolutely essential. This is why they are called the ‘auxiliary’ mechanisms. These are listed below.

a. Warp protector mechanism

b. Weft stop motion

c. Temples

d. Brake

e. Warp stop motion (Predominantly found in automatic looms)

a. Warp protector mechanism

The warp protector mechanism will stop the loom if the shuttle gets trapped between the top and bottom layers of the shed. It thus prevents excessive damage to the warp threads, reed wires and shuttle.

b. Weft stop motion

The object of the weft stop motion is to stop the loom when a weft thread breaks or gets exhausted. This motion helps to avoid cracks in a fabric.

c. Temples

The function of the temples is to grip the cloth and hold it at the same width as the warp in the reed, before it is taken up.

d. Brake

The brake stops the loom immediately whenever required. The weaver uses it to stop the loom to repair broken ends and picks.

e. Warp stop motion

The object of the warp stop motion is to stop the loom immediately when a warp thread breaks during the weaving process.

Sizing

 

Sizing

Size is a gelatinous film forming substance in solution or dispersion form, applied normally to warp yarns. It can sometimes be applied to weft yarns. Sizing is the process of applying the size material on yarn. A generic term for compounds that are applied to warp yarn to bind the fiber together and stiffen the yarn to provide abrasion resistance during weaving. Starch, gelatin, oil, wax, and manufactured polymers such as polyvinyl alcohol, polystyrene, poly acrylic acid, and poly acetates are employed.

Objects of Sizing:

• ·        To protect the yarn from abrasion.
• ·        To improve the breaking strength of the yarn.
• ·        To increase smoothness of yarn.
• ·        To increase yarn elasticity.
• ·        To decrease hairiness.
• ·        To decrease the generation of static electricity.

Types of Sizing:

Pure sizing: when the size pick up % is about 3 – 10 % it is called pure sizing.

Light sizing: when the size pick up % is about 11 -16% it is called light sizing.

Medium sizing: when the size pick up % is about 17 – 40 % it is called medium sizing.

Heavy sizing: when the size pick up % is above 40 % then it is called heavy sizing.

Disadvantages of Sizing:

• Cost of land and machine is high.
• Requires lot of labours.
• Requires utility like gas, electricity etc and their cost is high.
• Cost of ingredients.
• The process is long and it takes time.
• There is a risk of degradation of yarn.
• The yarn diameter is increased.
• Requires robust loom.
• It increases yarn stiffness.
• The fabric needs to be desized before use.
• Need knowledge and information about the size ingredients.
• There is a risk of pollution.
• Sizing changes the shade of colored yarn.
• 100% size material cannot be removed.
• Size material presence leads to uneven dying.

Different Parts of a Loom

 

Main parts of a loom is given below:

1. Heald Shaft

This part is related to the shedding mechanism. The heald shaft is made of wood or metal such as aluminium. It carries a number of heald wires through which the ends of the warp sheet pass. The heald shafts are also known as ‘heald frames’ or ‘heald staves’. The number of heald shafts depends on the warp repeat of the weave. It is decided by the drafting plan of a weave.

The main function of the heald shaft is as follows:

It helps in shed formation

It is useful in identifying broken warp threads

It maintains the order or sequence of the warp threads

It determines the order of lifting or lowering the required number of healds for a pick. In other words it helps in forming the design or pattern in a fabric.

It determines the warp thread density in a fabric, i.e. the numbers of heald wires per inch determine the warp thread density per inch.

2. Sley or lay

It is made of wood and consists of the sley race or race board, reed cap and metal swords carried at either ends. The sley mechanism swings to and fro. It is responsible for pushing the last pick of weft to the fell of the cloth by means of the beat up motion. The sley moves faster when moving towards the fell of the cloth and moves slower when moving backwards. This unequal movement is known as ‘eccentricity of the sley’. It is needed in order to perform the beat up and also to give sufficient time for passage of shuttle to pass through the warp shed. The beat up of the lastly laid pick of weft is accomplished through a metal reed attached to the sley.

3. Shuttle

It is basically a weft carrier and helps in interlacement of the weft with the warp threads to form cloth. The shuttle which is made of wood passes from one end of the loom to the other. It travels along the wooden sley race and passes between the top and bottom layers of the warp sheet. The shuttle enters a shuttle box fitted at either ends of the loom, after passing through the warp shed. A shuttle normally weighs about 0.45 kgs.

4. Shuttle Box

It is the housing for the shuttle and is made of wood. It has a spindle and a picker. It may also accommodate the picker without spindle. The top and side of the box towards the sley race are open. The shuttle dwells inside the box for the intermediate period between two successive picks.

5. Picker

The picker is a piece made either of leather or synthetic material. It may be placed on a spindle or grooves in the shuttle box. It is used to drive the shuttle from one box to another. It also sustains the force of the shuttle while entering the box.

6. Reed

It is a metallic comb that is fixed to the sley with a reed cap. The reed is made of a number of wires and the gap between wires is known as dents. Each dent can accommodate one, two or more warp ends. The count of the reed is decided by the number of dents in two inches. The reed performs a number of functions which are enumerated as follows:

It pushes the lastly laid pick of weft to the cloth fell

It helps to maintain the position of the warp threads

It acts as a guide to the shuttle which passes from one end of the loom to the other.

It determines the fineness of the cloth in conjunction with the healds.

It determines the openness or closeness of the fabric.

There are various types of reed such as ordinary reed, gauze reed, expanding reed, V reed etc.

7. Warp Beam

This is also known as the weaver’s beam. It is fixed at the back of the loom. The warp sheet is wound on to this beam. The length of warp in the beam may be more than a thousand metres.

8. Back Beam

This is also known as the back rest. It is placed above the weaver’s beam. It may be of the fixed or floating type. In the first case the back rest merely acts as a guide to the warp sheet coming from the weaver’s beam. In the second case it acts both as a guide and as a sensor for sensing the warp tension.

9. Breast Beam

It is also known as the front rest. It is placed above the cloth roller at the front of the loom and acts as a guide for the cloth being wound on to the cloth roller. The front rest together with the back rest helps to keep the warp yarn and cloth in horizontal position and also maintain proper tension to facilitate weaving.

10. Cloth Beam

It is also known as the cloth roller. The woven cloth is wound on to this roller. This roller is placed below the front rest. It is also known as the cloth roller. The woven cloth is wound on to this roller. This roller is placed below the front rest.

Study on tappet shedding mechanism.

 

Experiment Name : Study on tappet shedding mechanism.

Introduction: Tappets are generally used for heald shedding. Tappet is a type of cam to which a rotary motion is given for the purpose of producing reciprocating motion in rods and levers by sliding contact. When the rod is to receive a series of lifts, with intervals of rest and thus forms a shed called tappet.

Objective:

1) To learn about shedding mechanism of tappet loom.

2) To learn about different parts related to this mechanism.

Figure:

Related Machine parts:

• Tappets.
• bottom Shaft
• Treadle levers
• Fulcrum
• Heald Shaft
• Heald Eye
• Top Reversing Roller

Construction of the mechanism:

1) Tappet achieve motion from bottom shaft.

2) The bowls are placed on the surface off treadle lever.

3) Both treadle lever are connected to lever.

4) Lamb rods, Heald Shaft, Leather Straps are connected to front side of treadle lever.

Working Principle:

1) Tappets are receive motion from bottom shaft.

2) When tappets rotate the nose of tappet strike on the bowls of treadle lever which move down with every strike.

3) The treadle lever pull the lamb rod when tappet strike on it. Due to the pulling operation the heald shaft also move downward.

4) There is returning spring set up to the top  of the loom frame to send back the heald frame to previous position.

Study on seven wheel take up mechanism.

 

Experiment Name: Study on seven wheel take up mechanism.

Theory: The function of the take up the motion is to draw a fabric to the cloth roller regularly as it is woven. Texture of a fabric largely depends upon the number of ends and picks per inch, that contribution to the uniform texture of the fabric.

Objective:

I) To learn about the take up mechanism.

II) To learn about gearing of that mechanism and calculate PPI.

Figure:

Related Machine Parts:

• Sley Sword.
• Finger
• Take up lever
• Pawl
• Returning Clutch
• Ratchet Wheel
• Standard Pinion
• Change Wheel
• Change Pinion
• Compound Wheel
• Compound Pinion
• Take Up Wheel
• Take Up Roller

Construction of the mechanism:

A) In this mechanism take up lever connect both sley sword ad ratchet wheel . For beat up the ratchet wheel move due to push by the pawl

B) Ratchet wheel connected with standard wheel.

C) Standard wheel connected with change wheel and change wheel attach with change pinion by shaft.

D) Change pinion transmit motion to compound wheel which is connected with compound pinion by shaft.

E) Compound pinion transfer motion to take up wheel which connected with take up roller.

Working Principle:

1) The pawl move with sley sword which push the ratchet wheel for every beat up.

2) Ratchet wheel transfer motion to standard wheel.

3) Change wheel received motion from standard wheel, it transfer motion to change pinion.

4) Change pinion sent motion to compound wheel so compound pinion is also rotate.

5) Compound pinion transfer motion to take up wheel so take up roller received motion.

Calculation:

Circumference of take up roller is 15.8"

IF it rotate one time the no. of picks

= 1 X (96/15) X (89/24)  X (56/36)  X 24

= 886

PPI = 886 / 15.8  = 56

Loom Constant =  { 1  X (96/15) X (89/24)  X (1 / 36)  X 24 }  / Circumference of take up roller

= 1

PPI = Loom constant X  No. of Change wheel pinion Teeth

      = 1 X 56

     =  56

Result : Picks per inch = 56          

Conclusion:>>>>>>>>>>>>>>>>>>>

Study on let off mechanism of tappet loom.

 

Experiment name : Study on let off mechanism of tappet loom.

Introduction: The motion which delivers the warp yarns from the warp beam at the required rate that a suitable constant tension by unwinding it from a flanged bobbin called let off motion.

Types of let off motion:

• Positive let off motion.
• Negative let off motion.

Objective:

• To learn about let off mechanism.
• To Calculate PPI.
• To write a report according to this experiment.

Related machine parts:

• Sley sword
• Key
• Connecting rod
• Let off lever
• Hook rod
• Side lever
• Cam
• Back rest
• Dead weight side lever
• Pushing pawl
• Ratchet wheel
• Gear:

a.       Warm gear.

b.      Bevel gear.

c.       Helical gear.

• Beam driving wheel
• Beam flange
• Weaver beam

Figure:

Construction of the mechanism:

1.       A driving rod attached with sley sword contains pushing pawl. Which may adjusted by hook rod which one connected with lever and back rest.

2.       Pushing pawl push the ratchet wheel which connected with one set of bevel gear.

3.       Bevel gear transfer motion by a complex gearing method.

Working principle:

1.       The ratchet wheel received motion from the pushing pawl which push the ratchet wheel with every beat up.

2.       A Bevel gear achieved motion from ratchet wheel and transfer it to worm gear.

3.       Worm gear transfer motion to helical gear which transfer motion to beam driving wheel.

Calculation:

PPI   =     (116 X 17 X 37 X 10)   /   (23  X 1 X 25 X 23)

                = 55.17 PPI

Pick spacing  =  1/ 55.17      =  0.01812 inch/pick

Conclusion: >>>>>>>>>>  

Study on side lever under picking mechanism

 

Experiment Name: Study on side lever under picking mechanism.

Theory: Picking is the second of the primary motion of weaving. The object of picking is to insert the weft yarn through the warp shred during weaving. It consists in passing a pick of weft between the upper and lower lines of a divided warp. In side lever under picking mechanism,  a circular disk carrying a bowl is driven by the bottom shaft and the picking stick is held in position outside the loom frame. The term under pick mechanism means the picking stick moves from the bottom of the box and pivot of the stick is placed below the box.

Objective:

1) To learn about side lever under picking mechanism.

2) To learn about different parts used in this mechanism.

Figure:

Fig: Side Lever Under Pick Mechanism

Related Machine parts:

• Bottom shaft
• Circular Disk
• Picking Bowl
• Picking Shoe
• Side Lever
• Pivot
• Guide
• Elbow
• Picking Stick
• Returning Spring
• Rocking Shaft
• Buffer
• Picker
• Shuttle Box

Construction:

1) the circular disk received motion from the bottom shaft. The disk contain a bowl named picking bowl able to push down the picking shoe of side lever.

2) Side lever of loom pivoted with loom frame and the up-down motion of side lever is controlled by fixed guide.

3) Side lever is connected with elbow of picking stick which attached with returning spring on the top  of rocking shaft.

4) Each picking stick contains picker which push the shuttle through the passage.

Working Principle:

Due to motion of circular disk the picking bowl strike on picking shoe. For the strike lever pushed down. The front side of the lever push the elbow of picking stick, the result picking stick move forward and it hit the picker which push the shuttle to insert weft and the pushing force is enough to send the shuttle to opposite shuttle box.

Calculation:

Speed of bottom shaft :   (960 X 3 X 38) / (24 X 76)

                                              = 60

There are two picking mechanism : PPM = 2 X 60 = 120

Result : 120 PPM

Conclusion : >>>>>>>>>>>>>