Showing posts with label Picking. Show all posts
Showing posts with label Picking. Show all posts
30 December 2012
Study on over picking mechanism // How to Increase PPM
Experiment name: Study on over picking mechanism.
Introduction:
Picking is the second primary motion in weaving. The action of inserting weft yarn through the warp yarns is called picking.
Introduction:
Picking is the second primary motion in weaving. The action of inserting weft yarn through the warp yarns is called picking.
The functions of picking mechanism are:
1.To deliver the shuttle along the correct flight length.
2.To throw the shuttle at a predetermined speed.
Main Parts:
 |
| Over picking |
- Picking arm
- Picking strap
- Picker
- Bottom shaft
- Picking spindle
- Shuttle
- Picking cam
- Vertical shaft
- Cone
- Bowl
- Angular
- Crank shaft
Features of Over Picking Mechanism:
1.Picking arm is over shuttle.
2.Suitable for narrow loom.
3.Higher picks per minute.
4.Less power required.
5.Works more smoothly.
6.Shortening the picking strap and changing the shape of the cam can increase picking force.
Mechanism of Over Picking:
Over picking mechanism is used on cotton and jute loom. It is robust and easy to adjust and maintain. The spindle is situated over the shuttle box and is essential to guide the shuttle along the correct path. It is normally set slightly up and slightly towards the front of the loom and its inner end.
The back end of the shuttle will thus receive a similar lift at the end of the stroke, so that its leading end will receive correct delivery down and into the shed. A flexible leather-picking strap is used to control the picker, which has tendency to stretched slowly in use, and vary with regard to its elastic property.
The cone over pick motion consists a vertical shaft placed either inside or outside the loom framing. The shaft serves as fulcrum of the picking arm, it is held against the loom frame. There is a spiral spring at the picking shaft, which causes the picking arm and picker to move back after the delivery of the pick.
At the two end of the bottom shaft, two picking cams are fixed. In revolving its nose the tappet strikes the cone shaped ant frictional roller strut, positively rotates the shaft and causes the pick to move inward with sufficient velocity to drive the shuttle across the loom. The timing of the picker begins to move can be attend by turning the picking tappet on its boss.
How to Increase PPM:
1.By increasing motor speed.
2.By setting the cone stud nearer to the picking tappet.
3.By decreasing the picking strap.
4.By altering the position of picking arm towards the centre of the loom.
5.By decreasing the length of the stroke of picking tappet.
Uses:
This is used for narrow and fast running looms, weaving light and medium weight fabrics and for many narrow and wide looms for weaving heavy fabrics.
Conclusion:
The over picking motion is negative one; the exact amount of power is required to drive a shuttle. By this experiment we learned about the over picking mechanism and how it works. This experience will help us in our future practical life.
1.Picking arm is over shuttle.
2.Suitable for narrow loom.
3.Higher picks per minute.
4.Less power required.
5.Works more smoothly.
6.Shortening the picking strap and changing the shape of the cam can increase picking force.
Mechanism of Over Picking:
Over picking mechanism is used on cotton and jute loom. It is robust and easy to adjust and maintain. The spindle is situated over the shuttle box and is essential to guide the shuttle along the correct path. It is normally set slightly up and slightly towards the front of the loom and its inner end.
The back end of the shuttle will thus receive a similar lift at the end of the stroke, so that its leading end will receive correct delivery down and into the shed. A flexible leather-picking strap is used to control the picker, which has tendency to stretched slowly in use, and vary with regard to its elastic property.
The cone over pick motion consists a vertical shaft placed either inside or outside the loom framing. The shaft serves as fulcrum of the picking arm, it is held against the loom frame. There is a spiral spring at the picking shaft, which causes the picking arm and picker to move back after the delivery of the pick.
At the two end of the bottom shaft, two picking cams are fixed. In revolving its nose the tappet strikes the cone shaped ant frictional roller strut, positively rotates the shaft and causes the pick to move inward with sufficient velocity to drive the shuttle across the loom. The timing of the picker begins to move can be attend by turning the picking tappet on its boss.
How to Increase PPM:
1.By increasing motor speed.
2.By setting the cone stud nearer to the picking tappet.
3.By decreasing the picking strap.
4.By altering the position of picking arm towards the centre of the loom.
5.By decreasing the length of the stroke of picking tappet.
Uses:
This is used for narrow and fast running looms, weaving light and medium weight fabrics and for many narrow and wide looms for weaving heavy fabrics.
Conclusion:
The over picking motion is negative one; the exact amount of power is required to drive a shuttle. By this experiment we learned about the over picking mechanism and how it works. This experience will help us in our future practical life.
23 September 2012
Study on under picking mechanism.
Experiment name: Study on under picking mechanism.
Introduction:
Picking is the second primary motion in weaving. The action of inserting weft yarn through the warp yarns is called picking.
Features of under picking mechanism:
1.Picker arm is placed under the race board.
2.Suitable for wider loom.
3.Under picking works less smoothly.
4.More direct action.
5.Rough in action.
6.More clean mechanism.
7.Consumes more power.
8.Used for heavy weight fabrics in silk and rayon looms.
Under picking mechanism:
In under picking mechanism a race board is situated over picking arm. Under picking is controlled by picking cam which is fixed on the bottom shaft. At first the motion comes from motor and m/c pulley.
Then the motion comes in to the bottom shaft and thus picking cam. When picking cam rotates and its nose portion comes in contact with treadle lever and pushes it then the treadle lever pushes the angular lever. The picking arm gets motion from angular lever which is connected with picking arm.
A picker is placed in the picking arm which pushes the shuttle. When shuttle gets motion by picking arm then shuttle begins to move to and fro on the race board. Thus picking is done.
A spring is situated which causes the picking arm and picker to move back after the delivery of the pick. At the two end of bottom shaft, two picking tappets are fixed. By increasing nose length picking speed may be increased.
How to increase PPM:
1.By increasing motor seed.
2.By increasing the nose shape of picking tappet.
3.By decreasing the length of picking arm.
Uses:
This mechanism is used in all non-automatic cotton looms. It is also used in jute looms.
Conclusion:
This picking mechanism is very important for loom. In the loom under picking is directly done by picker and picking arm. Again under picking is necessary for weft yarn insertion. So we should learn about this mechanism very carefully.
Introduction:
Picking is the second primary motion in weaving. The action of inserting weft yarn through the warp yarns is called picking.
The functions of picking mechanism are:
1.To deliver the shuttle along the correct flight length.
2.To throw the shuttle at a predetermined speed.
Main parts:
1.Picking arm
1.To deliver the shuttle along the correct flight length.
2.To throw the shuttle at a predetermined speed.
Main parts:
1.Picking arm
2.Picker
3.Picking cam
4.Picking bowl
5.Race board 6.Shuttle
7.Bottom shaft
8.Treadle lever
9.Angular lever
10.Crank shaft
3.Picking cam
4.Picking bowl
5.Race board 6.Shuttle
7.Bottom shaft
8.Treadle lever
9.Angular lever
10.Crank shaft
Features of under picking mechanism:
1.Picker arm is placed under the race board.
2.Suitable for wider loom.
3.Under picking works less smoothly.
4.More direct action.
5.Rough in action.
6.More clean mechanism.
7.Consumes more power.
8.Used for heavy weight fabrics in silk and rayon looms.
Under picking mechanism:
In under picking mechanism a race board is situated over picking arm. Under picking is controlled by picking cam which is fixed on the bottom shaft. At first the motion comes from motor and m/c pulley.
Then the motion comes in to the bottom shaft and thus picking cam. When picking cam rotates and its nose portion comes in contact with treadle lever and pushes it then the treadle lever pushes the angular lever. The picking arm gets motion from angular lever which is connected with picking arm.
A picker is placed in the picking arm which pushes the shuttle. When shuttle gets motion by picking arm then shuttle begins to move to and fro on the race board. Thus picking is done.
A spring is situated which causes the picking arm and picker to move back after the delivery of the pick. At the two end of bottom shaft, two picking tappets are fixed. By increasing nose length picking speed may be increased.
How to increase PPM:
1.By increasing motor seed.
2.By increasing the nose shape of picking tappet.
3.By decreasing the length of picking arm.
Uses:
This mechanism is used in all non-automatic cotton looms. It is also used in jute looms.
Conclusion:
This picking mechanism is very important for loom. In the loom under picking is directly done by picker and picking arm. Again under picking is necessary for weft yarn insertion. So we should learn about this mechanism very carefully.
8 June 2012
Identification of End (Warp) & Pick (Weft) :
Identification of End (Warp) & Pick (Weft) :
Warp and weft yarns have different demands placed on them and may differ in their structure or fiber type. Thus, a fabric may not have the same performance characteristics for warp and weft. The warp must withstand the high tensions of the loom and the abrasion of weaving, so the warp yarns are stronger and more uniform with higher twist. Filling yarns are more often fancy or special-function yarns such as high-twist crepe yarns, low-twist napping yarns, or boucle yarns. We can define end and pick in the following way.
End:
1. An individual warp yarn. A warp is composed of a number of ends. 2. An individual sliver, slubbing, roving, yarn, thread, or cord. 3. A short length or remnant of fabric.
Pick:
In a woven fabric, the yarn running from selvage to selvage at right angles to the warp. Each crosswise length is called a pick. In the weaving process, the filling yarn is carried by the shuttle or other type of yarn carrier. The picks interlace with the warp ends to form a woven fabric.
Identification of End & Pick:
Warp and weft yarns have different demands placed on them and may differ in their structure or fiber type. Thus, a fabric may not have the same performance characteristics for warp and weft. The warp must withstand the high tensions of the loom and the abrasion of weaving, so the warp yarns are stronger and more uniform with higher twist. Filling yarns are more often fancy or special-function yarns such as high-twist crepe yarns, low-twist napping yarns, or boucle yarns. We can define end and pick in the following way.
End:
1. An individual warp yarn. A warp is composed of a number of ends. 2. An individual sliver, slubbing, roving, yarn, thread, or cord. 3. A short length or remnant of fabric.
 |
| Warp (End) and Weft (Pick) |
In a woven fabric, the yarn running from selvage to selvage at right angles to the warp. Each crosswise length is called a pick. In the weaving process, the filling yarn is carried by the shuttle or other type of yarn carrier. The picks interlace with the warp ends to form a woven fabric.
Identification of End & Pick:
Differentiating between warp and weft is
possible by carefully examining both the fabric and the length-wise and
crosswise yarns.
- Most fabrics have lower elongation in the warp direction.
- The warp yarns lie straighter and are more parallel in the fabric because of loom tension.
- Fancy or special-function yarns are usually in the filling direction.
- Fabric crimp is usually greater for weft yarns since they must bend or flex over or under warp yarns due to the way the loom operates.
- Fabric characteristics may differentiate between the warp and weft directions. For example, poplin has a weft rib and satin has warp floats.
- The selvedge always runs in the lengthwise (warp) direction of all fabrics.
- Warp yarns tend to be smaller, are more uniform in structure and appearance, and have higher twist.
20 October 2011
Study on over picking mechanism.
Experiment name: Study on over picking mechanism.
Introduction:
Picking is the second primary motion in weaving. The action of inserting weft yarn through the warp yarns is called picking.
Introduction:
Picking is the second primary motion in weaving. The action of inserting weft yarn through the warp yarns is called picking.
The functions of picking mechanism are:
1.To deliver the shuttle along the correct flight length.
2.To throw the shuttle at a predetermined speed.
Main Parts:
|
| Over picking |
- Picking arm
- Picking strap
- Picker
- Bottom shaft
- Picking spindle
- Shuttle
- Picking cam
- Vertical shaft
- Cone
- Bowl
- Angular
- Crank shaft
Features of Over Picking Mechanism:
1.Picking arm is over shuttle.
2.Suitable for narrow loom.
3.Higher picks per minute.
4.Less power required.
5.Works more smoothly.
6.Shortening the picking strap and changing the shape of the cam can increase picking force.
Mechanism of Over Picking:
Over picking mechanism is used on cotton and jute loom. It is robust and easy to adjust and maintain. The spindle is situated over the shuttle box and is essential to guide the shuttle along the correct path. It is normally set slightly up and slightly towards the front of the loom and its inner end.
The back end of the shuttle will thus receive a similar lift at the end of the stroke, so that its leading end will receive correct delivery down and into the shed. A flexible leather-picking strap is used to control the picker, which has tendency to stretched slowly in use, and vary with regard to its elastic property.
The cone over pick motion consists a vertical shaft placed either inside or outside the loom framing. The shaft serves as fulcrum of the picking arm, it is held against the loom frame. There is a spiral spring at the picking shaft, which causes the picking arm and picker to move back after the delivery of the pick.
At the two end of the bottom shaft, two picking cams are fixed. In revolving its nose the tappet strikes the cone shaped ant frictional roller strut, positively rotates the shaft and causes the pick to move inward with sufficient velocity to drive the shuttle across the loom. The timing of the picker begins to move can be attend by turning the picking tappet on its boss.
How to Increase PPM:
1.By increasing motor speed.
2.By setting the cone stud nearer to the picking tappet.
3.By decreasing the picking strap.
4.By altering the position of picking arm towards the centre of the loom.
5.By decreasing the length of the stroke of picking tappet.
Uses:
This is used for narrow and fast running looms, weaving light and medium weight fabrics and for many narrow and wide looms for weaving heavy fabrics.
Conclusion:
The over picking motion is negative one; the exact amount of power is required to drive a shuttle. By this experiment we learned about the over picking mechanism and how it works. This experience will help us in our future practical life.
1.Picking arm is over shuttle.
2.Suitable for narrow loom.
3.Higher picks per minute.
4.Less power required.
5.Works more smoothly.
6.Shortening the picking strap and changing the shape of the cam can increase picking force.
Mechanism of Over Picking:
Over picking mechanism is used on cotton and jute loom. It is robust and easy to adjust and maintain. The spindle is situated over the shuttle box and is essential to guide the shuttle along the correct path. It is normally set slightly up and slightly towards the front of the loom and its inner end.
The back end of the shuttle will thus receive a similar lift at the end of the stroke, so that its leading end will receive correct delivery down and into the shed. A flexible leather-picking strap is used to control the picker, which has tendency to stretched slowly in use, and vary with regard to its elastic property.
The cone over pick motion consists a vertical shaft placed either inside or outside the loom framing. The shaft serves as fulcrum of the picking arm, it is held against the loom frame. There is a spiral spring at the picking shaft, which causes the picking arm and picker to move back after the delivery of the pick.
At the two end of the bottom shaft, two picking cams are fixed. In revolving its nose the tappet strikes the cone shaped ant frictional roller strut, positively rotates the shaft and causes the pick to move inward with sufficient velocity to drive the shuttle across the loom. The timing of the picker begins to move can be attend by turning the picking tappet on its boss.
How to Increase PPM:
1.By increasing motor speed.
2.By setting the cone stud nearer to the picking tappet.
3.By decreasing the picking strap.
4.By altering the position of picking arm towards the centre of the loom.
5.By decreasing the length of the stroke of picking tappet.
Uses:
This is used for narrow and fast running looms, weaving light and medium weight fabrics and for many narrow and wide looms for weaving heavy fabrics.
Conclusion:
The over picking motion is negative one; the exact amount of power is required to drive a shuttle. By this experiment we learned about the over picking mechanism and how it works. This experience will help us in our future practical life.
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