Strategies For Cost Control in Automotive Stamping

This paper draws on practical experience to investigate effective strategies for managing die development costs and boosting profitability in automotive manufacturing. By focusing on optimized stamping process selection, die structure design, material utilization, and judicious die material choices, these measures offer substantial practical value for cost control in vehicle production.

The Cost Challenge in Automotive Industry

High manufacturing costs bring a critical challenge to the automotive sector, constraining new vehicle market performance and eroding corporate profits. While automakers can readily lower vehicle prices to attract buyers, reducing production costs remains a formidable task. Manufacturers must relentlessly pursue innovative cost-reduction strategies to strengthen market competitiveness and thrive amid intense rivalry.

Vehicle bodies are assembled by welding numerous stamped sheet metal components, with stampings accounting for over 60% of parts. Material costs, in turn, constitute more than 60% of stamping production expenses. Consequently, refining cost-control measures in automotive stamping—through process optimization, die design improvements, and material efficiency—plays a pivotal role in overall cost management.

Impact of Stamping Process Selection on Manufacturing Costs

The efficiency of stamping process directly affects production costs and reflects the economic viability of process designs. Domestic die manufacturers have honed extensive expertise in process optimization to curb expenses.

Streamlined Process Design

Reducing the number of process steps through optimized sequences can significantly lower development costs. For instance, a right-side body panel mold for a specific model originally required five processes (excluding blanking) and ten dies. In newer designs, this has been streamlined to four processes and eight dies, eliminating two molds and boosting production efficiency.

Joint Installation Techniques

Integrating multiple processes into a single die enhances efficiency. Take the fuel filler door as an example: its original design demanded five dies and five presses. By consolidating the final three dies into one, the total was reduced to three dies, cutting press usage and accelerating production.

Scrap Die Integration in Drawing Tools

Embedding scrap-cutting functions within drawing dies eliminates additional steps. Integrating scrap dies into the drawing tool removes the need for separate blanking dies, reducing costs for complex parts with significant curvature variations. This approach is widely adopted for door inner and outer panels.

Bilateral (Left/Right) Shared Molds

Using shared molds for symmetrical components enhances material utilization. For instance, a specific model’s fender production achieved a material utilization rate of 33.5% with shared molds, compared to 26.8% with separate molds. This saved 2.8 kg of material per part and eliminated five molds, slashing development costs.

Optimizing Die Structure Design

Effective die structure design is key to balancing functionality and cost. Strategic improvements in this area can lead to significant savings without sacrificing quality.

Universal Blanking Dies

Designing adjustable blanking dies for symmetrical parts, such as fenders, allows a single die to serve multiple components. This universality hinges on consistent material types and thicknesses.

Simplified Structures

Complex die designs inflate costs, but simplifications can yield savings:

• Replacing solid support blocks with hollow designs to reduce damage risks.
• Eliminating unnecessary feed and exit guides.
• Reducing the number of scrap dies to enhance operator efficiency.

Enhanced Casting Quality

Domestic die casting ribs (typically 45mm thick) exceed international norms (35–40mm). Thinner ribs lighten molds but demand superior casting quality to maintain strength, balancing cost and durability.

Material Segregation for Cost Efficiency

• Punch Inserts: Pair molybdenum chromium cast iron (GM246) inserts with FC30 steel bases, saving ¥5,000–10,000 per ton.
• Die Cavities: Combine SKD11 tool steel inserts with FC30 bases, cutting costs by approximately ¥10,000 per ton.

Maximizing Material Utilization

Smaller Draw Pads

Reducing draw pad sizes and strategically positioning draw beads minimizes material waste without compromising quality.

Optimized Blanking Layouts

Efficient blank layouts can significantly boost material use. For example, comparing three configurations for an A-pillar inner panel revealed that compact arrangements markedly improved utilization rates.

Strategic Die Material Selection

Choosing the right materials for dies ensures durability and cost-effectiveness. A balanced approach to material selection can align performance with budgetary goals.

• Ball-Molded Gray Iron (KSCD-800IS): Preferred for drawing dies due to its cost-effectiveness and excellent weldability compared to alloy cast iron.
• Low-Carbon Steel (ICD5): Ideal for trimming thin materials (<0.8mm), offering a balance of durability and affordability.
• Lifespan Adjustments: Tailoring die lifespan targets (e.g., 400,000 vs. 500,000 cycles) to production volumes can further reduce material costs.

Conclusion

The pursuit of minimal processes, maximum material efficiency, and cost-effective die design remains a cornerstone of the automotive industry’s evolution. For automotive sector to compete on the global stage, systematic cost-reduction strategies must be embedded across all production phases. By integrating these proven measures, manufacturers can enhance profitability while maintaining a competitive edge in an increasingly demanding market.