Automobile Manufacturer Reduces Design Time 10% and Equipment Costs 5% with Assembly Line Simulation

Japanese automobile manufacturers historically designed assembly lines using conventional methods built around engineering experience, manual calculations of worker utilization, machine utilization, and line productivity — without simulation. When a major automobile manufacturer needed to design a new welding manufacturing line for a vehicle component project, this approach created a fundamental problem: no reliable way to evaluate competing configurations before committing to equipment procurement and fabrication. With assembly line construction timelines running 8 months or more, and equipment and robot purchases representing substantial capital outlays, selecting the wrong configuration meant expensive redesign and re-fabrication cycles. The absence of simulation tools left engineers dependent on historical intuition rather than evidence-based analysis.

Rockwell Automation's Arena Simulation Software was deployed to model the new welding assembly line across the full design lifecycle, functioning as a discrete-event digital twin of the proposed manufacturing system. The simulation supported seven distinct workflow stages: understanding project requirements, make-or-buy analysis, initial line design, handover validation, market demand analysis, line modification design, and re-handover after modifications. Multiple configuration alternatives were evaluated within the simulation environment and benchmarked against reference data from previous similar projects sourced from the company's Finance Division. This approach replaced experience-based estimation with a quantitative comparison framework, allowing the project team to select the optimal line configuration before any physical equipment was ordered or fabricated.

The simulation-based design process delivered measurable improvements across both time and cost dimensions compared to the conventional baseline:

• 10% reduction in total project design time
• 5% savings on total equipment investment cost, achieved by avoiding unnecessary line modifications

Beyond the headline figures, actual trial results from five days of pilot production closely matched the simulation predictions — validating the model's accuracy. Worker skill levels in the physical trial produced failure times shorter than simulation conditions, meaning real-world performance met or exceeded the modeled targets. The designed line successfully satisfied all production targets and was handed over to the factory for full manufacturing operations.

• Discrete-event simulation of assembly line configurations can reduce automotive plant design time by 10% and cut equipment modification costs by 5% — savings that scale with project size.
• Validating simulation outputs against historical project reference data from finance teams builds cross-functional confidence and accelerates capital approval decisions.
• Simulation-based line selection eliminates or reduces the scope of physical pilot builds, which represent the most capital-intensive validation method available.
• The methodology applies across manual, automated, and hybrid line types, making it broadly applicable within automotive manufacturing operations.
• Investing in simulation during the design phase front-loads discovery of feasibility issues before equipment procurement commitments are made.