Overview of Digital Autoleveller in Draw Frame
Dept.of Textile Technology
Maharaja Saiyajirao University, Baroda, India
Draw frame is a machine for combining and drawing slivers of a textile fiber. For making high-quality yarn, staple fibers must first be subjected to extensive processing. In this process, the drawing frame is a major quality driver. Drawing is the operation by which slivers are blended, doubled and leveled. In short staple spinning the term is only applied to the process at a draw frame.
Objects of Draw Frame:
- To straighten and make the fibers parallel in the sliver by drafting
- To eliminate thick and thin places in sliver, to get the sliver as even as possible
- To mix the fibers by feeding several slivers through draw frame
- To remove the light impurities.
The high performance draw frame is the only one equipped with autoleveller and fully digital electronic draft system. It operates based on the principle of open loop control, measuring variation in the sliver mass up to + or – 30%.
Overview of digital autoleveller is point out below:
1. The drive system operates via servomotor which ensure absolute precision.
2. The mass of the fed sliver is controlled through the tongue and groove system.
3. This system achieves extremely fast and result in a very regular sliver in short, medium and long term.
4. The digital d-T&G system is based on the well-proven principle of TONGUE and GROOVE and performance constant measurement INDEPENDENT OF FEEDING SPEED at very short distances. Tongue and groove rollers also called as scanning rollers.
5. The tongue and groove principle ensures low friction between fibers and metal, decreases the deposits in the pneumafil and allows the application of higher compression force on the incoming sliver, being able to measure with greater accuracy in the sliver feeding mass.
6. This constant compression force is exerted by a high precision spring on measurement disc in the T&G system.
7. The signal is transmitted by a total digital “dual laser sensor” with no need to Analog-to-Digital conversion in the other T&G system.
8. After detection of feed sliver mass variation by the d-T&G, the measured signal are transmitted to the TMS-25 CPU, and then send commands to the highly dynamic servomotor , correcting the mass variation inside of the main draft.
9. Quality measurement sensor is located in the measuring funnel at delivery side and measure continuously mass deviation and irregularities, sending visible alerts to controlling panel.
10. The advantage of a totally digital system is the higher precision in readings of the sliver feeding mass which leads to a high precision and constant auto leveling with the electronic drafting help to great regularity in produced sliver.
Advantages of Autolevelling:
- All variations are corrected.
- Count c.v.% will be consistent & good, hence the yarn will be suitable for knitting.
- Ring frame breaks will come down, hence pneumfil waste will be low.
- Fabric quality will be good because of lower number of fluff in the yarn.
- Labour productivity will be more.
- Machine productivity will be more.
- Work ability in warping & weaving will be good, because of less no. of
- thin places & lower end breaks in spinning & winding.
- Production will be more accurate in autoleveller draw frame
- Compared to non autoleveller in draw frame.
- Fabric appearance after dyeing will be excellent.
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Founder & Editor of Textile Learner. He is a Textile Consultant, Blogger & Entrepreneur. He is working as a textile consultant in several local and international companies. He is also a contributor of Wikipedia.