This presentation was made at NAFEMS UK Conference 2018, Taking Engineering Analysis and Simulation to the Next Level".
The NAFEMS UK Conference 2018 brought together all those involved in analysis and simulation from every corner of industry and academia, giving them an opportunity to advance their knowledge, give their organisations a competitive advantage, and a chance to be part of improving the technology itself.
Computer aided engineering methods have been applied to the simulation of manufacturing processes for many years. Techniques such as finite element analysis (FEA) and computational fluid dynamics (CFD) were applied to trouble shoot problems arising in production.
Existing general purpose solvers were initially applied, particular those with the ability to deal with highly transient, non-linear behaviour – including material plasticity & failure, geometrical nonlinearity and contact between workpiece and tooling. Over time, the specific details of manufacturing processes led to the development of more specialised solutions, tailored to certain processes, making it easier to define the problem, solve it efficiently and post-process the results to extract the required information.
Manufacturing simulation software developments have also included streamlining of the problem definition to allow non-CAE experts in the production environment to successfully use these methods. This “democratisation” has been important in moving the use of simulation from a post-design trouble-shooting role to an upfront product and process design aid. With the dedicated software tools now available, engineers can expect not only to confirm that their manufacturing process will make the component without defects but can also optimise the process to obtain the best quality part for the lowest cost. Nevertheless, the quality of the outcome still depends on the quality of the input data and its correct application in the calculations.
Other than ensuring a more reliable manufacturing process, a second benefit from applying simulation is enhanced information on the component properties. Manufacturing affects material properties – and the final part geometry will likely not be exactly to the CAD data due to warpage from residual stress or cooling. Information about these changes in the component can give a better understanding of its performance when loaded; e.g., crash structure impact energy management can be affected by both the thickness changes and work hardening that takes place when a sheet metal part is formed.
Manufacturing process simulation today is established as a tried and tested tool in the automotive sector. Sheet metal forming (Figure 1), injection moulding (Figure 2), casting, forging and other processes are routinely analysed by the engineers responsible for confirming the process to be used in production. New materials and manufacturing methods can be examined before committing to production. Indeed, parts will generally not be signed off for manufacture without some level of simulation to confirm feasibility.
In fact the benefits of applying simulation are maximised when the methods are applied as early as possible in the product development cycle. This is where the greatest opportunity lies to modify the component to ensure that it has geometry that is easily formable and has the lowest cost in terms of material utilisation, process and tooling. However, the only geometry available at this early stage is the part itself, not the full tooling, and the process will be only sketchily defined; this leads to a requirement for intelligence within the software to create a suitable representation of the likely process and tooling geometry. Moreover, as the product designer may not be a manufacturing expert, the software needs to guide the user on the required countermeasures to remove and issues identified.
Furthermore, these benefits are best realised when the simulation is available to all involved in the part’s design and production – the CAD design team, the engineering team assessing functional performance, the manufacturing engineers defining the process, and even the purchasing department responsible for buying the raw material and tooling, and selecting a production source. The simulation software needs to be accessible and easily understood by all concerned.
The next generation of simulation software will therefore need to not only maintain and enhance the current level of accuracy in prediction of forming feasibility but also address these additional challenges of upfront use and cross-departmental use; this will drive further integration with knowledge-based methods and product life-cycle management tools.
The presentation will include examples of manufacturing simulation for a range of processes involving metal and plastic parts, highlighting the benefits from its application. Questions such as who should do the simulation and when will be addressed. The presentation will conclude with ideas for future developments to ensure the best manufacturing processes are achieved, in terms of formability and overall cost.
|Date||17th July 2018|