Drawing Process, Drawing process in spinning, drawing process of cotton, Drawing Process general information, Drawing Process introduction, pkspiny.

 

Drawing Process

General Information 

Ø Introduction

This chapter on drawing will cover the fundamental aspects that apply to all draw frames in the Rieter line. However additional considerations will be given to the auto leveler draw frame RSB D30,D40,D-24.

RSB Draw frame

 

 

Key:

1. Sliver creel

2. Scanning roller                   

3. Drafting system 

4. Delivery discs                  

5. Evened and leveled sliver

6. Sliver deposit   

  

Ø  Product concept Rieter  

 The drawing operations are extremely important in the yarn manufacturing process in that they improve the sliver quality:

 Prepare and refine the sliver for the yarn spinning steps by aligning the fibers in the sliver Reduce sliver to sliver variations by combining, or doubling, several slivers and drafting them into one blended sliver, Establish the yarn count. Normally, drafts in subsequent steps should not be adjusted to accommodate for variations in sliver weight.  Reduce yarn count variation by the use of a short-term auto leveler.On the other hand, any fault created by the drawframe cannot be corrected and will result in processing problems and/or yarn and fabric defects. Such faults include:

• Incorrect sliver weight.

• Compacted splicings.

• Drafting waves.

• Clearer waste.

 To monitor the product delivered at the draw frame a sliver quality control monitor can be used. These are being widely accepted because one defective machine can produce up to 250 kg/hr of bad sliver and this can be spread throughout the plant creating a major problem in a short period of time. Several years ago, the single delivery draw frame was successfully introduced for high-speed operation. Previously, there were two and four deliveries per machine. As production rates increased, the machine efficiencies were reduced because all of the deliveries on a machine stop when one delivery is stopped for any reason. The use of the single delivery machine can result inefficiency gains of 10 to 15 %.

Two delivery draw frames are still used where floor space is limited or where the sliver supply is very consistent and the creel cans are relatively large. The following is from the sales information and shows the advantages of single delivery drawing.

 

Advantages of single delivery

 

 

m/min

 

 

   

Ø  Principle features

Materials: Cotton, man made fibers, wool, recycled fibers and blends. Fiber length up to 80 mm staple.Total feed weight from 12 to 50 ktex ( 280 to 705 grains /yard) Delivery sliver weight from 1.25 to 7 ktex ( 18 to 100grains/yard)

 

Ø  Doublings:

Normally 6 to 8, but for slivers of very short fibers, such as comber noil or  regenerated fibers, a draft of approx. 4 may be maximum and consequently the doublings may be as low as three (3)

 

Ø  Creels:

Static creel (pull over) with stop motions Power creel with positively driven feed roller and stop motions.

Ø  Draft:

Total draft (V) is 4.5 to 11.7 depending upon the materials and the requirements of the subsequent processes. Break draft (VV) from 1.05 to 2.20 depending upon fibers and the input material. Pneumatically loaded 4 over 3 drafting system with pressure bar.Automatic top Roll pressure release to eliminate flat spots on the top rolls and reduce roller lapping. Simple adjustment of the top rollers

Ø  Delivery speeds:

Delivery speed from 250 to 1000 m/min. in increments of 50 m/min depending upon materials and subsequent processes.Programmable slow speed start up after can change.

Ø  Quality monitoring:

  Sliver quality monitoring at the delivery. Prevents “off quality” production by stopping the machine when  pre-set tolerances are exceeded. Provides sliver quality data. Integrated Dust Extraction Dust and very short fibers are liberated as a result of drafting. The removal of dust and fly is critical to the operation of the draw frame.Accumulations of dust and fly create sliver and yarn defects.

The machines exhaust to:Automatic can changer

Autoleveling (Optional) short, medium and long term sliver weight control.1.5  mm of fed sliver.

Ø  CANlink (Optional)

 Minimizes operator related machine downtime. Increased machine efficiency. Automatic can feeding from trolleys Automatic trolley traverse Compact can filling by combined longitudinal and transverse movements. round cans.