Page 42 - November-December-2020

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IDF DIRECT SPINNING

Process shortening with This is a remarkable decline. The reasons for this can goal is to achieve a 1.3-fold total draft using a break

technological advantages be manifold and may be related to cotton cultivation draft of 1.15, then only a draft of 1.13 remains for the
and harvesting methods. However, a crucial aspect
main draft (1.15*1.13 = 1.3). This means that the
is that the economic pressure on spinning mills and
levelling dynamic is limited to 13 percent. This is
their production costs is increasing, leading to the
use of ever shorter fibers. much too low to respond to short-wave fluctuations.
For comparison: With the autoleveller draw frame,
the main draft and thus the levelling range often
Development history of the IDF at Truetzschler exceeds 400 percent.
It takes time for optimised processes to establish
themselves on the market. This is because process IDF 1 IDF 2
shortening initially presents a challenge in the Feeding sensor
spinning mill. It must be ensured that the same yarn Break draft Feeding sensor
quality is achieved in terms of processing Main draft One zone drafting system
parameters such as strength, elasticity or
appearance. In the mid-nineties, at the beginning of Output measuring sensor Output measuring sensor
the IDF development, it was unimaginable that yarn Delivery rollers
could be produced from 100 percent noils, but today Delivery rollers
this is certainly the case. This is also a way for large Mechanical di erences between IDF 1 and IDF 2
combing mills to include their own waste in the value
chain and selling it with added value. Truetzschler By eliminating the break draft in the IDF 2, the entire
has significantly advanced this development and drafting takes place in one drafting zone. Thus the
implemented the IDF system in 1999, based on levelling range is fully utilised. Fluctuations are ideally
Spanish market requirements for the card TC 11. In compensated this way. If two parameters must be
the following years, it was continuously developed optimised simultaneously, it is much more difficult to
and improved. find the technologically better setting. This is
because break draft and main draft must be varied
In 2013 Truetzschler presented a fundamental and constantly adapted to material changes. The IDF
revision: The Integrated Draw Frame IDF 2. The 2 is thus not only the better technological solution,
special feature was the reduction of two drafting but also simplifies handling. This is a particular
zones to one. Thus, the IDF 2 responds to the advantage, since nowadays many spinning mills
increasingly urgent demands of our customers for have to deal with the problem of having hardly any
production cost reduction on the one hand and a qualified personnel available to technologically
high quality standard despite poor raw material evaluate settings of this kind.
qualities on the other. This is because only the
High yarn quality is becoming less and less heavily occupy the minds of our customers. For one, 1-zone drafting system allows particularly low drafts, When using a normal-width drafting system, larger
dependent on the presence and experience of the shortening of processes means lower staff which are the decisive guarantee of success for the masses are accelerated and decelerated again
employees in a spinning mill. Nowadays, it is numbers are possible, whilst the IDF also provides a processing of particularly short fibers. during levelling, which can lead to increased energy
significantly influenced by futuristic plant solutions solution for tackling the increasing demand for consumption. For this reason the width of the bottom
and intelligent machine systems. In the world of spinning high-grade yarns from inferior raw material. The main difference between IDF 1 and IDF 2 lies in and top rollers of the IDF 2 has been reduced to the
spinning, options for shortening processes, and thus the drafting system itself. Experience has shown that width of a sliver. This also allowed the introduction of
reducing outlay in production, are becoming more For years, Truetzschler has been watching the trend low total drafts are the key to success – especially the clever solution of rotating top rollers, which has
and more relevant. One example is the IDF that fiber lengths used in the rotor yarn sector in with short-staple cotton, which is usually used in led to a doubling of the service life before grinding.
integrated draw frame from Truetzschler which so far particular are becoming shorter and shorter. In 2003, rotor spinning. However, dividing this small draft into
is superior to all competitor solutions. It can be used the average fiber length for our customers’ rotor yarn break draft and main draft results in more The IDF 2 also introduced the sliver loop storage.
to combine two important aspects which currently installations was 28.5 mm, today it is only 26 mm. disadvantages than advantages. For instance, if the This driven deflection roller levels the sliver loop by

November/December 2020 November/December 2020

means of an integrated light barrier, resulting in actual tension being applied. (IDF 1 break draft 1.0).
perfect synchronisation between card and IDF. The The second diagram illustrates that IDF 2 and IDF 1
levelled loop permits high change speeds. This both have the same trend, i.e. that the yarn strength
ensures a higher efficiency at the card, especially decreases with increasing total draft. Compared to
when using small rotor cans. IDF 1, IDF 2 shows overall strength at a higher level.
This confirms the statement that the use of only one
drafting zone has a positive effect on the yarn
properties.
Development of the IDF 2
The IDF 2 has been established on the market for
seven years. The advantages of the system are now
recognised by the entire professional community,
competitors and customers. Initially, the shortened
process was only used with 100 percent cotton –
preferably from the recycling sector – but today it is

The combination of Truetzschler cards with IDF 2
gives customers an advantage, because they
produce a thin, stable web which is perfectly suited
to be drawn directly to the desired sliver count – at
highest production rates and lowest drafts. If cards
produce a heavier web, the use of low drafts is not
possible at all, as, for example, from 12 ktex to 5 ktex
a draft of 2.4 is applied.

One versus two drafting zones – technological no longer limited to this. The system is successfully
advantages applied in the processing of 100 percent raw cotton
In order to show the influence of the distribution of and other materials. It thus offers an answer to the
drafts on main draft and break draft as opposed to requirements of our customers with regard to
only one draft zone, a yarn of 100 percent raw cotton increasing and necessary flexibility in the production
(Mato Grosso) with Ne27 was spun in the direct process.
spinning process with a card production of 170kg/h.
With IDF 1, break drafts of 1.0, 1.05 and 1.16 with The handling of the IDF has also been improved. For
different main drafts were combined. The IDF 2 was example, there is now a retention lock that prevents
run with drafts of 1.2 to 1.95. The tests showed the the cover of the IDF from always having to be
trend across all parameters that IDF 2 with its 1-zone opened completely during the piecing process.
drafting system has clear advantages over IDF 1. Similarly, the use of maintenance-free deep groove
ball bearings entirely eliminates the need for
The first diagram shows the influence on yarn relubrication at the delivery rollers: The number of
evenness for a total draft of 1.7. There is clear lubrication points is thus reduced to four. The
evidence that the break draft in the IDF has a
negative influence on yarn parameters. It is self-adjusting lap monitoring of the top rollers,
noteworthy that for all quality parameters, the already known from the draw frames, has now also
presence of the first drafting zone in the IDF 1 alone found its way to the IDF. There is no need to readjust
has a negative effect on the results, without any after grinding intervals and changed settings.