Novel techniques for manufacturing hand knotted / woven carpet

Abstract

A study of traditional and novel hand-knotted techniques was undertaken. Work was done in the study firstly to better understand conventional knot tying techniques by classifying knots into single and multi-warp types, analysing knot forming procedures and introducing the shearing and chemical washing processes. The frictional behaviour between pile yarns and warp threads was studied. The coefficient of friction (µ) calculated using Euler's Law was found to change with initial tension (To) and wrap angle (θ). Two sets of best-fit empirical equations, one set each for the static and kinetic cases, were derived from the measured results. Results showed that the surface frictional property of warp yarn was significantly changed when coated with latex.

The pile security of different knot structures was assessed. The relationship between tuft withdrawal force and wrap angle (of pile-to-warp contact), knot type (single or multi-warp; Persian, Kiwi or Wilton) and intermediate tensions was investigated. Mathematical models that can be used to predict knot security were derived.

Subsequent work was done to develop new carpet making techniques which were suitable for hand-knotted carpet manufacture. An experimental open-ended, face-to-face hand-weaving loom was assembled. A comparison of conventional and alternative techniques of knot forming was performed. The speed of carpet manufacture was significantly greater and the pile yarn waste was lower for the prototype loom than the conventional loom. The binding length of the Kiwi knot was longer than that of the Persian knot.

The open-ended, face-to-face loom was found to be capable of producing traditional style Persian knot carpet with no loss of design potential. It was shown that carpet could also be produced on the prototype loom using a novel double-warp knot structure proclaimed, the Kiwi knot. However, no simple procedure was found for inserting either the Turkish or Tibetan knots on the experimental loom.