Rieter Spun Yarn Systems, Switzerland, reports its BT 904 Rotona® rotor core yarn system combines
rotor yarn benefits with core yarn possibilities. The system wraps rotor yarn around the core to
provide a stable structure and entails fewer steps than ring-spinning systems. Rotona yarns have
low unevenness and reduced hairiness. They can contain elastic or hard-core filaments. Bobbins
weigh up to 3 kilograms and hold longer running lengths without splices or knots.
Rieter also has added new features to its BT 903 and BT 905 rotor-spinning machines,
increasing their length to up to 320 rotors and rotor speed up to 100,000 revolutions per minute
(rpm). The direct rotor bearings contain Rieter’s exclusive state-of-the-art ball bearings, which
have increased durability and require lubrication less often, according to the company. A new spin
box modification permits use of a new type of rotor in conjunction with an enhanced external
suction device and enables spinning of yarns from high-trash-content materials, as well as
specialty yarns. Independently driven machine sides also are available, allowing flexible
The BT 903 features the IQclean® yarn clearer and the electronically controlled AMIspin®
piecing device, which works with Rieter’s Qtop® system to eliminate damaged fibers prior to
piecing. The BT 905 now has the option of four robots per machine to provide maximized performance.