Experiment name :
Study on drafting and draft constant calculation of simplex m/c.
Introduction:
It is an important factor to make fibres long and thick by drawing while making yarn from fibres. It is known as drafting. This work is done by pairs of rollers. In simplex m/c using any of the following drafting system drafts applied.
1.Conventional/roller drafting system.
Description:
There are 4 pairs of rollers which are situated up and down in pairs. Usually the bottom rollers are made of steel and snarled type, which are kept on u type bearing. Usually the front roller can not be moved but the others can be moved according to fibre length. There is a steel trap at the back of the last roller which is spreaded along the full length. This strip has a hole through which the sliver is entered. These holes are called guide hole. These guide holes help the sliver to pass through the specific place of the rollers and the stip moves to and fro by a cam so that the rollers are not harmed in same place. The top rollers are coated with leather, flannel etc and loaded on the bottom rollers. The total draft given to the sliver is divided in to two. In back zone that is between the 3rd and back roller, the draft given is called break draft. This draft prepares the sliver for the final draft of the front zone and break the twist if remains in sliver. Its amount depends on twist, amount of feed, characteristics of fibre etc. It is usually form 1.1 to up to 2. The rest draft of the total draft is given between 1st, 2nd and 3rd rollers. The total draft in simplex is usually 10-15.
Objects:
Study on drafting and draft constant calculation of simplex m/c.
Introduction:
It is an important factor to make fibres long and thick by drawing while making yarn from fibres. It is known as drafting. This work is done by pairs of rollers. In simplex m/c using any of the following drafting system drafts applied.
1.Conventional/roller drafting system.
- 3 over 3 roller drafting system
- 4 over 4 roller drafting system
- With apron
- b.Without apron
Description:
There are 4 pairs of rollers which are situated up and down in pairs. Usually the bottom rollers are made of steel and snarled type, which are kept on u type bearing. Usually the front roller can not be moved but the others can be moved according to fibre length. There is a steel trap at the back of the last roller which is spreaded along the full length. This strip has a hole through which the sliver is entered. These holes are called guide hole. These guide holes help the sliver to pass through the specific place of the rollers and the stip moves to and fro by a cam so that the rollers are not harmed in same place. The top rollers are coated with leather, flannel etc and loaded on the bottom rollers. The total draft given to the sliver is divided in to two. In back zone that is between the 3rd and back roller, the draft given is called break draft. This draft prepares the sliver for the final draft of the front zone and break the twist if remains in sliver. Its amount depends on twist, amount of feed, characteristics of fibre etc. It is usually form 1.1 to up to 2. The rest draft of the total draft is given between 1st, 2nd and 3rd rollers. The total draft in simplex is usually 10-15.
TWIST : is the spiral turns given to a yarn to increase the strength of the yarn. But in speed frame machine vary small amount of twist is given to the roving to make it able to wound onto a bobbin. For a fibrous material twist is measured by the parameter twist per inch (TPI), twist per centimeter or twist per meter (TPM). For the cotton sample twist is measured by TPI.
In speed frame machines twist per unit is varied with the variation of raw material and its different parameters. This variation of twist is inserted by changing a wheel that is connected with the main driving shaft named twist change pinion (TCP). And the multiply of TCP and TPI, present in a machine is called twist constant. This value is applicable for any required twist with corresponding TCP. So we can find out the required TCP to get a given TPI. The generalize formulae is as below:
In speed frame machines twist per unit is varied with the variation of raw material and its different parameters. This variation of twist is inserted by changing a wheel that is connected with the main driving shaft named twist change pinion (TCP). And the multiply of TCP and TPI, present in a machine is called twist constant. This value is applicable for any required twist with corresponding TCP. So we can find out the required TCP to get a given TPI. The generalize formulae is as below:
Objects:
- To find out the total draft of m/c.
- To find out the draft of every zone.
- To find out the draft constant of m/c.
- twist constant.
GEARING DIAGRAM:
CALCULATION:
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