AutoForm Robustness Solution:
Application Examples

The AutoForm Robustness Solution is used to increase stamping process reliability and to reduce down-time and reject rates in production. This solution enables the users to benefit from the power of maximized stamping robustness, thereby maximizing the efficiency and productivity in their own environment.
 

Robust Forming Processes at Volvo Car Corporation

The objective of the project between Volvo Car Corporation and AutoForm Engineering was to study the influence of the scatter in mechanical properties on the sheet metal forming simulation results. The front side member inner of the Volvo S40/V50 model was analyzed. This part was selected as it had splitting problems in production that were not visible in the final forming simulation. The study showed that the AutoForm robustness analysis enabled the engineers to estimate and improve production robustness.
 

The deterministic simulation, based on the result variable failure, didn’t show any critical spots. The variability and noise were incorporated into the simulation in order to improve the prediction of the reliability of the production. The variability and noise were analyzed through incorporating a bandwidth of input parameters in the robustness analysis.
 

This bandwidth of input parameters resulted in a bandwidth of output results. Analyzing these results with the help of the statistically based quality control measures showed a probability of failure at the red spot indicated in the figure. The position of failure coincided exactly with the place where the failure had also been detected in practice.
 

The final step was to optimize the production robustness. For the studied part, a small geometrical change resulted in a stamping process that is less sensitive to the variability and noise of the input variables. This validation study, based on a real world example, showed that systematic stochastic simulation tools enabled the engineers to estimate and improve robustness.
 

Mr. Anders Skogsgårdh, Manager of Engineering and Simulation at Volvo Cars Manufacturing Engineering in Sweden: “The goal in future car projects is to develop even more robust forming processes, which will produce quality parts, thereby benefiting the production output.”
 

AutoForm-Sigma Wins Prestigious 'Excellence in Productivity' Award

AutoForm is proud winner of the international award ‘Excellence in Productivity’, received at the 2006 INDUSTRIE trade show in Paris. The award was given for AutoForm-Sigma, a new, innovative product that improves user productivity.

AutoForm-Sigma automatically carries out multiple stamping simulations, changing design and process parameters and performing statistical analysis, until it finds the ‘robust optimum’ stamping conditions. This robust optimum corresponds to the most reliable overall conditions for stamping parts that meet a company’s quality and production specifications. With AutoForm-Sigma, companies can therefore address stamping robustness issues during the earlier phases of product and tooling design. This results in faster time-to-market for new products, with obvious advantages in time and cost savings.

Robust Engineering

In the production of a front fender, a critical factor to consider is the variation of springback due to variations in noise variables. AutoForm-Sigma plots process capability corresponding to the upper and lower tolerance limits on the part. Now by simply looking at the part, the engineer can see where and to what extent the current forming process will result in part rejects.

For this fender, the quality department has defined tolerance limits for springback of ±4 mm. The large green area indicates a reliable process with respect to springback tolerance. However, the red areas near the wheel housing and the headlight indicate unacceptable process reliability with a part reject rate of about 5%. Therefore, by analysing process performance and process capability, one can improve and validate the stamping process and reduce or eliminate part rejects.

Designing for Robust Stamping – During Product and Tooling Design

At DaimlerChrysler, AutoForm-Sigma has been used to validate stamping process reliability, with respect to springback caused by material variability and process variation. This provides valuable information and insights to optimize body assembly operations where springback and clamping issues are involved.

At Volvo Cars, AutoForm-Sigma has been used to investigate the influence of variability of material properties on stamping production yield, with the goal of developing even more robust forming processes.

For the automotive industry in general, the trend to using sheet metals with more complex properties requires a better understanding of the effects of these properties on stamping robustness – which AutoForm-Sigma helps to provide.