Advances in Apparel Production

Catherine Fairhurst

• Publisher: Woodhead Publishing
• Year: 2008
• ISBN:
  9781845694463
• Topic: Technology & Engineering
• Subtopic: Industrial Engineering
• Index: Technology & Engineering

Apparel production is a complex process often involving an international supply chain which must respond rapidly to the changing needs and tastes of consumers. This important book discusses the technological improvements which are transforming the speed, flexibility and productivity of the industry.The first part of the book reviews advances in apparel design. There are chapters on modelling fabric and garment drape, computer-aided colour matching, yarn design and pattern making. Other chapters discuss key issues in apparel sizing and fit, and the role of 3-D body scanning in improving garment fit and design. The second part of the book surveys advances in production, beginning with product development before looking at advances in knitting, sewing, printing, finishing and fabric inspection.With its distinguished editor and international team of contributors, Advances in apparel production is a standard work for those researching and working in this important industry.

• Discusses the technological improvements transforming the speed, flexibility and productivity of the industry
• Examines computer aided colour matching, garment drape and yarn design
• Explores key issues in apparel sizing and fit, the role of three-dimensional body scanning in improving garment fit and design

Part I

Advances in apparel design

1

Measuring and predicting fabric and garment drape

L. Hunter CSIR and Nelson Mandela Metropolitan University, South Africa

J. Fan The Hong Kong Polytechnic University, Hong Kong

1.1 Introduction

A critically important, in fact essential, property of a textile fabric and one which distinguishes it from other materials, such as paper or steel, is its ability to undergo large, recoverable draping deformation by buckling gracefully into rounded folds of single and double curvature.¹ It is this characteristic that plays a critical role in the fit, body conformation and wear comfort of garments and when translating three-dimensional (3D) body shapes into two-dimensional (2D) patterns and vice versa. According to the Textile Terms and Definitions of the Textile Institute,² drape is defined as ‘the ability of a fabric to hang limply in graceful folds, e.g. the sinusoidal-type folds of a curtain or skirt’. It refers to the fabric shape as it hangs under its own weight; Cusick³ defined the drape of a fabric as ‘a deformation of the fabric produced by gravity when only part of the fabric is directly supported’. Drape, together with the effect of seams, determines the way in which a garment moulds itself to the shape of the body, this being a critical factor in comfort and aesthetic-related aspects of a garment and its fit. Ayada and Niwa⁴ showed that the visual beauty and total quality of gathered skirts are closely related to the fabric mechanical properties of bending, shear and fabric weight and can be described by the parameters of formability, elastic potential and drape. Drape, in which the fabric shearing properties play a dominant role, is also a critically important parameter in the application of body scanning, mass customisation, computer-aided design and computer-aided manufacturing (CAD-CAM) and automatic pattern making to clothing design and manufacturing. The most significant developments in recent years have been the empirical prediction and modelling of drape as well as the move towards 3D design, simulation and virtual modelling (3D virtual prototyping) which enables the designer to ‘drape and validate’ their design onto a computer-generated manikin or one built off a body scan of a fit model, taking into account technical information, fabric type, colour, drape and stretch as well as the effect of seams.⁵ Transforming 2D patterns into a 3D configuration that follows a body surface (and vice versa), of necessity, involves modelling the fabric physical properties^6,7 such as drape.

It is important to note that drape appearance depends not only on the way the fabric hangs in folds, but also upon the visual effects of light, shade and fabric lustre at the rounded folds of the fabric, as well as on the visual effects of folding on colour, design and surface decoration.⁸ A fabric is said to have good draping qualities when it adjusts into folds or pleats under the action of gravity in a manner that is graceful and pleasing to the eye.⁹ In practice, drape is usually assessed visually or subjectively and the actual assessment greatly depends upon often changing factors, such as fashion, personal preference, human perception. Bhatia and Phadke¹⁰ discussed the influence of drape on clothing styles.

Drape is therefore a complex combination of fabric mechanical and optical properties and the seam properties, as well as of subjectively and objectively assessed properties. Furthermore, there is frequently an element of movement, for example the swirling movement of a skirt or dress, and therefore dynamic, as opposed to static, properties are also involved. As a result, in recent years, a distinction has been made between static and dynamic drape. This chapter deals with the measurement of drape and the empirical prediction and modelling of drape, but only briefly refers to drape models in CAD and Internet systems, these being dealt with in detail in Chapters 6 and 7.

1.2 Measurement of drape

Fabric drape characteristics and behaviour are manifested in the appearance and fit of the garment and are usually assessed subjectively. Nevertheless, considerable research and development has been directed to the routine objective measurement and characterisation of drape and to relate drape, so measured, to objectively measured fabric mechanical properties, notably bending stiffness and shear stiffness. Chung¹¹ presented a detailed review of studies on drape, both static and dynamic, on both unseamed and seamed fabrics, and investigated the effect of seam allowance, type and position on woven fabric drape. She found that bending length increased with the insertion of a vertical seam, while drape coefficient increased with the addition of radial seams; increasing the seam allowance had little effect. The highest drape coefficient occurred with the circular seam located just out of the pedestal. Schenk et al.^5,12 developed a new method to measure the effect of seam stiffness on the stiffness of adjacent fabrics.

Early work concentrated on the development of instruments to measure bending stiffness because of its predominant effect on drape. Instruments (cantilever type) were designed to measure fabric bending length (the length of fabric that bends to a definite extent under its own weight), which provided a fairly good measure of the fabric draping properties, more particularly of the 2D drape, as opposed to the 3D drape that occurs in practice. It was soon realised, however, that, in addition to the major role of fabric stiffness, fabric shearing properties also play an essential role in determining fabric draping characteristics. Two-dimensional drape tests (cantilever method) are, therefore, unable to reflect fabric drape accurately, since the latter involves 3D double curvature deformations, which involve fabric shear. Therefore, to better quantify the fabric shear, various objective measurement techniques have been designed to include fabric shear and to simulate the subjective methods (e.g. laying the fabric over a pedestal or mannequin, allowing the fabric to fall naturally into folds and assessing the size and frequency of the folds). At present, the most widely adopted method is still to allow a circular disc of fabric to drape into folds around the edges of a smaller circular platform or template. Such instruments are commonly referred to as ‘drapemeters’. Major developments are, however, taking place in the better quantification and understanding of the draped shape and dimensions produced by means of such drapemeters. These developments are discussed later in this section.

Pioneering work was carried out by Chu et al.¹³ who developed a method of measuring drape by means of the F.R.L. Drapemeter, quantifying drape as a dimensionless drape coefficient (DC%). Cusick^3,14 subsequently developed what has become known as Cusick’s drapemeter (Fig. 1.1) and which is still the standard and most common method of...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright page
• Contributor contact details
• Woodhead Publishing in Textiles
• Introduction
• Part I: Advances in apparel design
• Part II: Advances in apparel production
• Index