Rieter

The roving frame as a necessary evil

Index

Fig. 1 – View of a roving frame

The  drawframe produces a sliver that already exhibits all the characteristics required for the creation of a yarn, namely an ordered, clean strand of fibers laying parallel to one another. It is a fair question to ask why this sliver is not used as infeed material for the ring spinning machine, instead of being processed in an expensive manner to create a roving as feed material for spinning. The roving machine itself is complicated, liable to faults, causes defects, adds to production costs and delivers a product that is sensitive in both winding and unwinding. Use of the machine is forced upon the spinner as a necessary evil for two principal reasons.
The first reason is related to the required draft. Sliver is a thick, untwisted strand that tends to be hairy and to create fly. The draft needed to convert this to a yarn is in the region of 300 - 500. The drafting arrangements of ring spinning machines, in their current forms, are not capable of processing this strand in a single drafting operation to create a yarn of short-staple fibers that meets all the normal demands on such yarns. The fine, twisted roving is significantly better suited to this purpose.
The second reason is that drawframe cans represent the worst conceivable mode of transport and presentation of feed material to the ring spinning frame. In spite of this, considerable effort has been expended over decades to eliminate the roving frame. The effort is justified, but unfortunately in relation to ring spinning it remains without success. On the other hand, in all new spinning processes in the short staple spinning mill, the roving frame has been made superfluous.