✕
☰

Simulating success: How to get automotive parts right the first time

Robert Held, group manager - Education Injection Moulding | Additive Manufacturing at SKZ explores how simulation software can advance product development in the automotive industry. By identifying potential issues early in the design process, simulations can save time and money as well as minimising the need for costly mould redesigns.

Key Highlights:

Simulation technology is a powerful tool that has revolutionised the entire product development process, from article design to series production. It enables engineers and designers to identify technical risks and develop solutions suitable for series production long before an injection mould is built, and a real moulded part is produced. This article highlights the opportunities and risks of simulation as well as common mistakes in product development.

Simulations provide invaluable insight into the behaviour of thermoplastic materials at different stages of the manufacturing process. If a simulation calculation is implemented correctly, design errors can be minimised and the time to market for products can very often be greatly reduced. Simulations also help to avoid time-consuming and cost-intensive changes in later development phases. It is said to have happened that no usable parts could be produced from an injection moulding tool and a completely new tool had to be built. However, it is essential that the calculations are carried out with the necessary expertise and care.

There are a variety of sophisticated simulation software packages on the market, each with its own strengths and specialties. Although many of these packages deliver similar results, they differ in terms of user-friendliness, specialisation in certain processes and, of course, price. Choosing the right software often depends on the specific requirements of the project and the budget. Solutions integrated into CAD systems are also available for simple calculation tasks. Here, the article designer can often carry out the first optimisation towards a component design suitable for injection moulding. The design of wall thicknesses or the number and position of injection points are the dominant calculation objectives in this first phase. However, no further results can be expected here, as there is not yet sufficient information about the mould concept or the planned process control at this stage. Material properties and pressure distribution or cooling behaviour in the tool are not considered with sufficient accuracy in this calculation phase. In this first phase, the feasibility of the design is only roughly checked.

Time is a critical factor in product development. The pressure to get to market quickly can often lead to poorly developed decisions. A second, extended simulation is required as soon as the article has reached a largely mature design stage and a precise mould concept is already available. In this second phase, real material data is absolutely essential for the calculation. Very often, calculations are still made using outdated or inaccurate data that does not describe the material behaviour accurately enough. Bear in mind that in a simulation calculation, a large number of calculation results build on each other and only minor deviations in the partial results can have a major impact on the overall result due to cumulation.

SKZ

It is important that a team consisting of the article designer, mould designer and injection moulder, together with the simulator, take the time to carefully analyse the boundary conditions before the calculation and the results of the simulation after the calculation and ensure that they are realistic. This is where the simulator's experience comes into play. The result of the calculation is only as good as the person sitting in front of the computer. Very often the mistake is made that the next project is already in progress long after the project has been completed and the simulators do not have time to compare the results of previous calculations with reality. This is the only way to live “lessons learned”.

A project can also fail if team members - from the purchasing department to the mould maker to the plastics processor - are not working towards the same goal. Everyone has their own point of view and priorities, which can lead to conflicts and misunderstandings. Clear communication and jointly defined goals are crucial for success. Very often, a lot of time is lost because the goals and tasks have not been defined precisely enough and, for example, simulations, mould sampling or mould adaptations have to be carried out several times.

The "Champions League" of simulations deals with the prediction of shrinkage and warpage. These are decisive characteristics for the quality and precision of the end product and are often the cause of assembly problems or deviations from the product specification. Only a few mould makers can "bomb" an injection mould with negated calculation results in such a way that a component with a tendency to warp falls straight out of the mould at the end. This requires a great deal of experience and absolutely error-free simulation. Many companies often overestimate their skills or underestimate the complexity of the entire process chain.

To summarise, it can be said that simulations are an indispensable tool in modern product development, beginning from the first article designs, the tool-design and optimisation and process simulation. In each “Simulations-Phase” the results and prediction of the real part quality will be better and the risk of cost and time-consuming tool changes/optimisations after the tool is already built will be reduced. When carried out correctly, they offer the opportunity to optimise products, minimise risks and save costs and time. The correct use of simulation tools, clear communication between team members and careful selection of materials are crucial to the success of a project.

Back to topbutton