Spinning an der Hochschule Hof

 origin of fibre
 staple / filament fibre, monofilament
 cross section
 spinning process
 linear density / diameter
 number and direction of twisting
 number of twisted yarns
 finishing
 other properties
 winding

spindle picker and stripper

 The fibres are delivered packed in bales.
 Within the bale the are not all oriented and the density varies significantly.
 Specially in bales of natural fibres you will find dirt, dust and many rests.
 Natural product do have a great range of their properties: that's why they need to be mixed
intensively in various steps to get products with a definable range.
 Only those fibres in the yarn that are oriented longitudinal to the yarn do increase the tearing
forces of a yarn: that’s why it needs a lot of effort to get as many of them in the longitudinal
direction. This is done by many steps spinning.

 a spinning mill’s capital
 fibres where often bought in big lots to
minimize price and transport
 fibre prices vary significantly:
 a good purchasing policy makes the
difference between profit and loss
 fibres are sensitive to climate conditions
 fibres need good protection
 dirt and dust, specially other types of
fibres
 against fire
 against fungi or vermin
 when getting moved to the blowing room the
bales need acclimatization to about 23°C
(73°F) and a humidity of 45-50% for around
24-48h (!).

 several bales are
positioned in a line
 the bale breaker mills off
by passing over all bales
 by putting various lots
together you get a more
equalized quality over a
long term production
 speed by passing the
bales: 5-15 m/min
 cotton: 20-48 bales used
simultaneously
 man-made fibres: 6-12
bales

 The Blending of fibres is a key function of the
blowroom
 The mixing of fibres is needed e. g. for
 levelling the differences of various natural
fibre lots from various regions to
 achieve the required technical data
 to add several lots to one big mixture
to reach a constant quality
 add the positive effects of various types
of fibres like
 combine the soft touch of cotton with
the low price of polyester
 improve the fire resistance by adding
mineral fibres

 at the bale opener
 by specific fibre mixing tools
 by adding several slivers to one sliver
 by plying together different yarns
 by using different yarns while producing a
fabric
 by laminating several fabrics together
 …

 The recycling gets way more difficult

 The fibres coming from the bale breaker arrive
at the top of the machine
 By an airflow they are equally distributed to
every of the funnels (1)
 Because the quality of fibres differs from bale to bale and within the bales now in every layer
within the mixing unit is different.
 Because the way of these layers from the top of the machine to point (2) to the belt with hooks is significantly different long in every funnel the
layers get mixed.
 Finally they get dissolved and again mixed in
the airstream

Fibres are very expensive. That’s why fibres found in
the “waste” are tried to get cleaned an recycled to the
spinning process
 a constant, fixed percentage of waste fibres should be
added to the fibre blend
 within this fixed proportion of waste, there should be a
constant, fixed percentage of waste fibres of different
sorts
 comber waste is mainly used in the rotor spinning mill
 recycled fibres can be returned to the blend from which
they arose
 Typically added waste:
 ring-spun yarns: carded up to 5%; combed up to
2,5%
 rotor-spun yarns: coarse up to 20%, medium up to
10%, fine up to 5%

 Feeding a card has to produce a very
homogeneous, constant stream of material
 The card itself is not able to balance faults
 Two alternative ways:
 scutcher line by Trützschler
 UNIstore by Rieter

-A chaotic mixture of fibres gets
separated and brought in a line

-The oriented fibres are formed to a
sliver an gets elongated

-The sliver gets twisted up to an optimal
level

-The yarn gets winded to a cops