Anna Chatzimichali

From composite material technologies to composite products: a cross-sectorial reflection on technology transitions and production capability

Materials, since the dawn of time, have played a crucial role in the development of civilization. Pre-history ages are fundamentally characterized by the material humans mastered, while the transitions to new materials have always marked a different socio-technical order. In this work we are going to investigate a relatively new material class, composites, in order to explain the issues the industry is currently facing. We are going to discuss material in the context of developing products that take full advantage of the benefits that composites can offer. The main idea behind this work is to understand how composite material technologies create growth and how the properties of those materials influence production capability and manufacturability. This work is the result of the EPSRC Centre for Innovative Manufacturing in Composites Platform research in the UK. It started with the bold intention to go beyond conventional research in composite material and explore the mechanisms of industrial change and growth through material. An examination of cases from a diverse range of sectors, acted as a platform to initiate a conversation on the issues practitioners are facing when adapting their products, or processes, to composite technologies, or when moving from a craftsman approach to state-of-theart material and process technologies. This paper presents insights from a sector/market agnostic point of view to probe the socio-technical considerations related to the diffusion of manufacturing innovation concerning composites and their production capabilities. The paper makes three main contributions. First, it presents a discussion on the capability issues regarding composites. Second, it presents empirical evidence on industrializing in composite material technologies. Finally, building on empirical evidence and previous literature, it describes the feedback loops during the composite product development process. The paper concludes with a reflection on current theories of innovation management on composite material technologies.

Hand layup: understanding the manual process

The hand layup of pre-impregnated woven materials is still a large part of the composite manufacturing industry, requiring the skills and experience of a human workforce to form flat plies into complex shapes. It is capable of producing high performance and complex parts, but can be an expensive and variable process. Despite its importance, there appears to have been very little research into the actual methods and techniques used by workers to manipulate flat sheets of composite material into shape during layup. This work presents the first known detailed study of the approach and techniques used by laminators. Four participants laid up onto 15 different shaped molds that replicated features commonly found on composite components. The actions used in layup were grouped into eight distinct techniques. Use of these techniques across tasks of different geometry, ramp angles, radii and drape path was identified using video analysis techniques from the ergonomics field. This revealed strong links between specific features and techniques, revealing a systematic approach to layup. This has enabled the first step toward producing a design for manufacture knowledge base surrounding hand layup. This could then be used to inform the development of the layup process, improve training methods and assist in the design of future automated solutions. Graphical Abstract

Exploring the discrete tools used by laminators in composites manufacturing: application of novel concept

Abstract This research investigates the handheld and often personally owned tools used by laminators to form advanced composites into components for aerospace, defense, and autosport; and reports on the application of a novel concept. The lack of formal knowledge that surrounds the existence and use of these tools presents an opportunity to explore what significance they have for process standardization and composites’ design and manufacture. The paper presents results from layup trials that were performed to test a prototyped tool, designed with user-centered and geometry-driven research in mind. The trials showed tool use is aligned with the laminator’s goals for the layup task; and suggest that it is also used as the laminator’s method for reporting quality feedback. The trials also raised questions about why the laminators habitually use their tools and the necessity of supporting a laminator through the decision processes involved in a layup task. This suggests the development of a prototyped tool can be of significant benefit in the realm of skills and training. Graphical abstract

Studying effects of preshearing on hand layup

Abstract Advanced composites are used extensively in many high performance applications. As they are taken up in a wider range of applications, the volume of demand is pushing manufacturing methods, especially hand layup of woven prepreg cloth, to their limits. An alternative approach to hand layup over complex geometries is proposed. The regular method of layup involves generating shear using grasps and pressures in the prepreg as and when it is needed during layup, leading to a sometimes complex and time consuming process. In the method proposed, all the shear deformation is created in the ply prior to any contact between the prepreg and the mold surface. Guidelines were drawn onto the prepreg surface to enable the correct shear distribution to be ‘presheared’ by hand. These were created by processing the outputs from a simple kinematic drape simulation within MATLAB. Once preshearing was completed, the ply is laid up onto the mold using regular hand layup techniques. The process was tested alongside regular manual lamination across three example parts and using video analysis effects of the process were investigated via a variety of metrics. This revealed that significant time savings and reduced likelihood of manufacturing variations are possible with this approach. There was also a significant simplification of the layup process, leading participants to comment that a previously ‘difficult’ layup had become ‘easy’. An improved bespoke system for communicating the required preshearing was subsequently developed, and successfully trialed on a fourth example part. Preshearing has the potential to make hand layup more economically viable for years to come. As well as the productivity and cost benefits, preshearing shows promise as a training aid, especially for beginner laminators. Concepts for integrating preshearing into existing industrial practice and its further potential in the field of automation are also discussed.

The Dibber: Designing a standardised handheld tool for lay-up tasks

We present an application of engineering and ergonomics principles in the design of a standardised tool, The Dibber, which is a tool with multiple geometric features to fit the diversity of lay-up tasks used in the composites industry. The Dibber is the result of a design process, which consists of a series of observations and prototyping to extract geometric requirements for lay-up tasks. To demonstrate that it is possible to design a standardised tool prototypes of the Dibber were distributed and 91 participants gave feedback. Our results are positive and show consistent patterns of use across industry sectors, as well as between novice and expert laminators.