Examples of Recent Research Projects
Industrial Collaborators Include:
Airbus UK, BAE Systems, Delcam, Landmark Components, Miracle Engineering, R T Palmer, Pilkington, Rolls-Royce, Wedgwood.
--------------------------------------------------------------------------------
Geometric Surface Modelling
This project was funded by EPSRC and Delcam, and was followed by technology transfer secondments at British Aerospace and Delcam. A purely geometric approach to surface modelling has been established where a surface shape is characterised by a grid of points lying on the surface. The construction of grids is relatively straightforward and equally appropriate to physical objects (reverse engineering), computer models (data exchange) and conceptual designs.
Algorithms have been developed to fully automate the construction of high quality surfaces from specified grids of points. The surface interpolation is defined recursively and is based on the generalised Cornu spiral which ensures monotonic curvature variation between data points. The point-based construction has been tested with a variety of automotive and aerospace surfaces and has consistently achieved high quality results that cannot be matched by conventional CAD constructions.
In summary, there is the capability to construct free-form surfaces from relatively sparse grids of points and confidence that the resulting shapes are of optimal quality. It is a powerful tool not only for surface modelling per se but also for tackling a variety of problems in CAE. In particular there is potential in geometry-based mesh generation, modelling of manufacturing processes and 5-axis machining.
back to top
--------------------------------------------------------------------------------
Quality Surface Wrapping for Manufacture
The project is funded by EPSRC with industrial support from BAE Systems, Delcam, Pilkington and Wedgwood.
Many manufacturing processes involve wrapping a sheet of material over a surface. The shape of the surface, the material properties of the sheet and the method of wrapping are all factors in the modelling. The research programme concentrates on wrapping processes where there is essentially free movement of the sheet,with only bending and minimal strains as the sheet is smoothed over the surface.
There is a tacit assumption that wrapping and unwrapping are, predominantly, geometric operations. They are modelled as isometric mappings with distortions that are expected to be relatively small.
For developable surfaces there is no distortion and the operations are purely geometric. Otherwise the distortion needs to be minimised by criteria compatible with the material properties of the sheet and the form of the manufacturing process.
A selection of case studies provided by the industrial partners will be used to optimise the geometric algorithms. Consideration can then be given to refining surface shape to facilitate wrapping and to improve the quality of manufacture.
The overall aim of the research programme is to develop an integrated CADCAM approach to surface wrapping, with consideration to the geometric form, material properties and manufacturing process. The specific objectives of the project are:
-
To design and implement geometric algorithms for wrapping and unwrapping almost developable surfaces.
-
To apply the geometric wrapping algorithms to a range of
-
manufacturing processes.
-
To facilitate wrapping by refining surface shape within specified tolerances.
-
To determine overall allowance for shrinkage in the manufacture of ceramic pots.
-
To implement an integrated CADCAM solution for decorating ceramic pots.
The geometric algorithms for wrapping and unwrapping and the procedures for refining shape will be applicable to many manufacturing processes in a wide range of industrial sectors. The breadth of application is indicated by the examples proposed by the industrial partners: shoe lasting, gravity sag bending and press bending of glass, laying up of carbon composite panels and decorating ceramic pots.
back to top
--------------------------------------------------------------------------------
Point-based Plug-ins to Enhance the Quality of Geometric Data for Computer Aided Engineering
The project is funded by EPSRC with industrial support from Abaqus UK, Airbus UK, BAE Systems, Delcam, Landmark Components, Miracle Engineering, R T Palmer and Rolls Royce.
CAE is, in a sense, a mature technology. It is taken for granted that we can create photo-realistic images of the most exotically shaped components, analyse the performance using FEA and CFD, manufacture the tooling and control the production.
The technology has transformed engineering over the past twenty-five years but widening access and increasing expectations of accuracy and reliability are exposing fundamental problems. There are also expectations of automation and integration which need to be met.
The research programme will establish a new methodology for the development of robust design tools for CAE and will address specific issues in creep forming simulation, quality surface machining and NURBS representation. The algorithms will exploit the capability to construct automatically an interpolating surface of optimal quality through a specified grid of points.
There is a tacit assumption that high quality CAD surfaces are a fundamental requirement for successful CAE integration and the plug-ins will guarantee the quality, with the point-based surface construction.
The overall aim of the research programme is to improve the quality and reliability of existing CAE software by incorporating point-based surface modelling. The main objectives are:
-
To optimise NURBS approximation to point-based surfaces of arbitrary topology
-
To improve visual quality of tool surface machining
-
To automate tool modification to compensate for springback in creep forming.
Many companies over a wide spectrum of industrial sectors use CAEor the design and manufacture of free-form components, and the investigators are committed to wide dissemination to maximise the impact of the research. The immediate beneficiaries will be the industrial partners but the relative simplicity of implementing the point-based plug-ins should facilitate its general uptake.
back to top
--------------------------------------------------------------------------------
Design and Manufacture of an Orthotic Walker
This was a Teaching Company Scheme Programme in collaboration with R T Palmer Ltd with the aim to design, manufacture and supply an Orthotic Walking Trainer. The project involved Product Engineering, CADCAM, Finite Element Analysis, Ergonomic Design and Marketing. It was the first step in changing the Company profile, from one specialising in prototype manufacture and small batch production to one with a fully integrated design and manufacturing capability.
Established in 1978 as a one-man toolmaking business, R T Palmer Ltd has expanded steadily and now has more than twenty employees. Heavy investment in computer-based technology over the years has established a well-equipped machine shop with CNC lathes and CNC milling machines, and has enabled the Company, using AUTOCAD and various pieces of CAM software, to specialise in subcontracted one-off prototype manufacture and small batch production of high precision components. The Company operates within the automotive supply chain as a second tier supplier to Rover and Ford.
In late 1992 the Company was assigned the unencumbered manufacturing rights for an orthotic walker which had been specifically designed to assist children suffering from cerebral palsy. This walker is intrinsically difficult and costly to adjust as the child grows and cannot accommodate children with waist height greater than 75 cms.
A product/industrial designer was employed as the Teaching Company Associate, to lead the design and manufacture of an enhanced orthotic walker to benefit stroke victims and many other disabled people as well as children. The Associate guided the walker through all the stages of the Total Design Process and prepared it for product evaluation, including clinical trials. A marketing/licensing strategy was developed and publicity material produced. In the longer term the Company will be able to offer a fully integrated design and manufacturing capability.
back to top
--------------------------------------------------------------------------------
Total Design Modelling
This is a Teaching Company Scheme Programme in collaboration with Landmark Components Ltd. The Company is engaged in the supply of electrical and decorative zinc and aluminium diecastings including surface coatings into the Automotive, Electrical, Domestic and General Engineering markets.
The aim of the project is to implement manufacturing process re-engineering to enable lean manufacturing. The entire Landmark business will be modelled using the principles of Total Design. This will be carried out in two phases oriented respectively to the manufacturing processes and the systems processes. In the first phase the thrust of the project will be to consider a selection of Rover 75 components and to fully characterise the procedures and processes from start to completion. Of particular interest will be the automatic polishing machine.
All aspects of its use and application will be considered with a view to improving efficiency.
back to top