A study of low force fabric characteristics and vibrational behaviour for automated garment handling

One of the fundamental concepts in automated garment assembly is that the orientation of a fabric panel should never be lost. However, if a panel does become distorted, several techniques, such as vision, air flotation tables, and vibratory conveyors are available to restore the orientation. This thesis has investigated the behaviour of a fabric panel on a vibratory table. Several table parameters such as amplitude of vibration, frequency and angle of inclination, together with some important fabric properties as friction and compressibility are required to understand the behaviour. However, most work on friction in textiles considers fibre-fibre or fabric-fabric friction, which is not appropriate to this and so low force frictional properties between unloaded fabric and engineering surfaces (i.e., aluminium, Formica and rubber) have been studied. The influence of several experimental variables on friction is demonstrated, in particular, the effect of humidity and velocity. Further, an in depth study is made on the stick-slip of fabric panels wherein a novel measuring technique is introduced. An estimate of the damping, which is required to model the fabric, has been obtained from an in-plane vibration test.The second significant fabric property to be studied is the compression both static and impact. Again, only low-force compression tests are carried out since these are the typical forces experienced by fabrics on a vibrating table. The static compressibility of knitted and woven materials is verified with van Wvk's equation. which gives a near indistinguishable fit with the experimental data

Abstract CURVED FENCES FOR PART ALIGNMENT

In automated packing or assembly it is often necessary to bring randomly oriented parts into uniform alignment. Mechanical methods such as vibratory bowl feeders are often used for this purpose, although there is no theory for the systematic design of such feeders. A slanted “fence ” attached to the stationary sides of a conveyor belt is also capable of orienting a stream of parts and a sequence of such fences has been shown [14] to function as a systematically designable linear parts feeder. A limitation of fence alignment is that once a part has left contact with a fence, its final orientation is confined to a narrow range of angles but is not unique. Here we consider the design of an individual fence, consisting of a straight slanted section followed by an optimal curved tail. The straight section selectively aligns certain edges of the part, while the curved tail preserves this alignment precisely as the part leaves contact with the fence. We have found th