R. Burke

Intelligent Assembly Time Analysis Using a Digital Knowledge-Based Approach

The implementation of effective time analysis methods fast and accurately in the era of digital manufacturing has become a significant challenge for aerospace manufacturers hoping to build and maintain a competitive advantage. This paper proposes a structure oriented, knowledge-based approach for intelligent time analysis of aircraft assembly processes within a digital manufacturing framework. A knowledge system is developed so that the design knowledge can be intelligently retrieved for implementing assembly time analysis automatically. A time estimation method based on MOST, is reviewed and employed. Knowledge capture, transfer and storage within the digital manufacturing environment are extensively discussed. Configured plantypes, GUIs and functional modules are designed and developed for the automated time analysis. An exemplar study using an aircraft panel assembly from a regional jet is also presented. Although the method currently focuses on aircraft assembly, it can also be well utilized in other industry sectors, such as transportation, automobile and shipbuilding. The main contribution of the work is to present a methodology that facilitates the integration of time analysis with design and manufacturing using a digital manufacturing platform solution.

Use of Digital Manufacturing to Improve Operator Learning in Aerospace Assembly.

The process of learning in any manufacturing enterprise contributes significantly to product lead times, final cost and ultimately, competitiveness. It effects all contributors to the product development cycle including individual operators and supervisors on the shop floor, as well as those involved in the upstream disciplines of engineering, tooling design, methods, production control and design. Any improvement in learning can significantly reduce the number of hours tied up in the learning curve thereby reducing costs, especially in the preliminary stages of new product manufacture. A relatively small percentage improvement in the time taken to build the first five fuselage assemblies for a regional aircraft would result in a financial saving that is of the order of

Digital Lean Manufacturing (DLM) for Competitive Advantage

100k. The primary goal of this work is to quantify any benefits that an animated, digital instructional format can have on aerospace assembly learning when compared to more traditional, paper based instructions. Hard copy, illustrated assembly instructions and digital, animated assembly instructions were authored for two engineering assemblies. The first was a relatively simple rear wheel hub from the Queen’s University Belfast, Formula Student racing car the second was the more complex apron and uplock assembly from the Bombardier RJ900 Regional Jet. Controlled experiments were carried out to measure the build times that resulted from the use of each of the two instruction types. The results showed that the average time taken to complete five builds was faster for the groups using digital, animated instructions. This was the case for both the wheel hub and the aircraft panel. The total time taken to carry out the thirty builds for the wheel hub was 20% lower for the group using digital instructions. For the less intuitive panel build, the total time taken to carry out the twenty builds was 14% lower for the group using digital instructions. These results clearly demonstrate that the use of animated build instructions can improve build times. The improvement in learning is less for the more complex aircraft panel assembly.

An Integration Methodology for Automated Recurring Cost Prediction using Digital Manufacturing Technology

The presented work sets out a research programme with the core aim of developing digital manufacturing capability for integration into the Integrated Product Process Development (IPPD) process. As part of the business process the key phase being addressed is the concurrent integration of manufacturing requirements at the stage when design geometry has been released. The digital manufacturing platform is used to provide simulations of the assembly process that have been developed in order provide simultaneous estimation of the associated learning curves, cycle time, recurring cost and throughput. These estimation processes form research projects within their own right as part of their development within the overall programme framework. Consequently, their findings will be presented at this stage in the programme. The integration of Lean principles at the programme and functional levels will also be addressed as the Lean approach underwrites the entire programme. Fundamentally, the compression of lead time, increase in value added effort and reduction in waste and inefficiency are the key Lean challenges being addressed. Consequently, a Lean Implementation Methodology will be presented while the Lean characteristics of the functional development will also be highlighted. The later also includes the development of a Lean Flow Accounting Methodology which addresses the Lean flow of work through a plant in order to maximise value added effort according to a top-down assessment of financial value and optimal through-put, thereby reducing Work In Progress (WIP).

A Quantitative Metric for Workstation Design for Aircraft Assembly

The need to account for the effect of design decisions on manufacture and the impact of manufacturing cost on the life cycle cost of any product are well established. In this context, digital design and manufacturing solutions have to be further developed to facilitate and automate the integration of cost as one of the major driver in the product life cycle management. This article is to present an integration methodology for implementing cost estimation capability within a digital manufacturing environment. A digital manufacturing structure of knowledge databases are set out and the ontology of assembly and part costing that is consistent with the structure is provided. Although the methodology is currently used for recurring cost prediction, it can be well applied to other functional developments, such as process planning. A prototype tool is developed to integrate both assembly time cost and parts manufacturing costs within the same digital environment. An industrial example is used to validate this approach.

Automated Assembly Time Analysis Using a Digital Knowledge Based Approach

This paper is to study an activity-time-based metric, called Non-Value-Added-Ratio (NVAR) which is the ratio between the time consumed by all non-value added activities and the total assembly time, for measuring the goodness of workstation design. With this metric, the manager will have a good sense of shopfloor operation, and the planner will have a target for designing workstations. This metric is specific to an assembly procedure in a workstation. To implement the metric, the shop floor activities are classified into three types, i.e., non-value-added (NVA), value-added (VA) and non-value-added-but-necessary (NVAN) activities. A closed-loop systematic approach is introduced for applying the new metric for continuous productivity improvement. Preliminary results with an industrial case study are presented. Although this metric is currently focusing on the aerospace industry, it can be equally well applied to other industry sectors.

An Integrated Lean Approach to Aerospace Assembly Jig and Work Cell Design Using Digital Manufacturing

[Abstract] Aircraft assembly is a labor intensive and time consuming process which accounts for one third of the total manufacturing cost. The accurate estimation and analysis of aircraft assembly times are important for both process planning and cost control. The optimization of processes using accurately predicted assembly times can result in the reduction of throughput times so that new products can be introduced to the market place as quickly as possible. Traditional paper-based time estimation can be a time consuming, error prone and most critically non-traceable process, which is becoming less suitable for 21 st century production planning and aerospace market conditions. The implementation of effective time analysis methods fast and accurately in the era of digital manufacturing has become a significant challenge for aerospace manufacturers hoping to build and maintain a competitive advantage. This paper proposes a structure oriented approach for intelligent time analysis of aircraft assembly processes within a digital manufacturing framework. A time estimation method based on MOST, is reviewed and employed in the digital realization of time analysis for aerospace assembly. Information capture, transfer and storage within the digital manufacturing environment are extensively discussed. Configured plantypes, GUIs, expert systems and functional modules are designed and developed to implement time analysis automatically. An exemplar study using an aircraft panel assembly from a regional jet is also presented.

An interactive and immersive human–computer interface for rapid composite part production design

This paper examines the use of integrated digital manufacturing methods for the design of an aircraft panel assembly jig and its associated work cell. The existing jig design and assembly sequence for the Bombardier CRJ700/900 regional jet apron and uplock panel assembly was reviewed. A digital simulation of the new CRJ1000 apron and uplock assembly incorporating a conceptual design for a new jig, was produced. When the jig format was finalised its simulated performance was compared to that of the CRJ700/900 to identify any process improvements in terms of tooling cost and panel build time. It was predicted that the digitally assisted changes had brought about a 4.9% reduction in jig cost and a 5.2% reduction in panel assembly time. It was concluded that the reduction in assembly time was due to improved jig functions and ergonomics as well the implementation of lean principles to the work cell design. The cost was reduced by applying design for manufacturing and assembly (DFMA) principles through the digital medium as well as the reduction in design iterations required because of the use of digital manufacturing.

MIXED-MODEL PRODUCTION SYSTEM DESIGN FOR AIRCRAFT ASSEMBLY

This article addresses the need for better retention and exploitation of tacit knowledge for intelligent computer-aided design. It presents an automated design framework for the development of individual part forming tools for a composite stiffener incorporating parametrically developed design geometries. This work develops existing principles in knowledge-based engineering and parametric modelling beyond product design in the manufacturing planning domain. Outcomes demonstrate chronological benefits of automated process design methods as well as learning enhancements as the tacit knowledge data set can now include an applied element through an auto-generated virtual build environment. A virtual environment presenting a design concept to the planner for interactive assembly assessment was generated in twenty seconds and enabled the completion of virtual builds in support of the development of an optimal forming tool arrangement. This principle enables the addition of an experiential tacit knowledge feedback loop to further improve assembly planning for design concepts as they evolve. Challenges still exist in determining the level of reality required to provide an effective learning environment in the virtual world. Full representation of physical phenomena such as gravity, part clashes and the representation of standard build functions require further work to represent real physical phenomena robustly.