Research on Aluminum Extrusion Die Design for New Energy Vehicle Profiles
Research Background and Purpose
New Energy Vehicle Aluminum Profiles: With the development of a low-carbon economy, aluminum profiles for new energy vehicles (NEVs) have seen widespread adoption, accompanied by increasingly complex structures, posing higher demands on die design.
Design Key Points Analysis: This paper aims to elaborate on the critical aspects of aluminum extrusion die design for NEV profiles by analyzing extrusion processes and die design elements.
Structural Characteristics of Aluminum Profiles
Thin-walled Floor Profiles: With the thinnest wall thickness less than 2.0mm, commonly using 6063 aluminum alloy, these profiles face issues related to flatness and wall thickness consistency.
Beam Frame Profiles: Characterized by multiple cavities and intersecting internal ribs, often made from 6005 or 6061 aluminum alloy, die design must enhance structural strength.
Reinforcing Beam Profiles: With wall thicknesses ranging from 3.0 to 18.0mm, utilizing 6082 aluminum alloy, these profiles are prone to deviations in perpendicularity and flatness during production.
Composite Profiles: Combining thick-walled solid sections with thin-walled hollow ones, these profiles experience uneven metal flow, leading to deformation and surface quality issues.
Large-walled Hollow Profiles: The welding quality of extrusion seams significantly impacts alloy performance, necessitating optimized seam positions in die design.
Extrusion Processes and Die Design Elements
Extrusion Ratio and Pressure: The extrusion ratio (λ) affects the extrusion pressure (P), with an increase in λ leading to a corresponding rise in P. Controlling the extrusion coefficient ensures production stability.
Dividing Ratio and Die Design: The dividing ratio (K) determines the difficulty of the initial metal deformation. Appropriately sizing the port areas of dividing holes reduces extrusion pressure.
Die Strength and Dividing Bridges: The layout of dividing bridges must consider core pin deformation limits, unhindered aluminum flow, and resistance to extrusion pressure.
Specific Die Design Points
Dividing Hole Layout: Allocate dividing hole areas based on the extrusion coefficient and distance from the extrusion cylinder center, optimizing weld line positions.
Profile Cavity Design: Reduce backhole connections to accelerate metal outflow, positioning solid sections of hollow profiles away from the die center.
Die Strength Verification: Determine die thickness and dividing bridge dimensions through bending stress and shear stress checks to ensure die strength.
Profile Hole Sizing: Address asymmetric tolerances, adjust scaled profile hole sizes, and apply pre-deformation compensation.
Bearing Length Design: Determine bearing length based on profile hole positions and wall thickness differences, using two-stage welding chambers to control metal flow rates.
Conclusion and Outlook
Die Design Challenges: The complexity of NEV aluminum profiles poses challenges to die design, requiring rational designs to reduce extrusion pressure and enhance production efficiency.
Future Directions: Die design must become more sophisticated, utilizing high-quality materials and optimized heat treatment processes, in conjunction with premium alloy materials and rational production processes, to reduce costs and improve production efficiency.
Thin-walled Floor Profiles: Featuring an ultra-thin design (<2.0mm) with a large width-to-thickness ratio, these profiles are prone to flatness issues during extrusion. Commonly used alloy is 6063.
Multi-cavity Beam Frame Profiles: Characterized by numerous small internal cavities and significant wall thickness variations (2.0 to 15.0mm), these profiles affect die strength. Common alloys include 6005 and 6061.
Reinforcing Beam Profiles: Large in size with multiple internal cavities and pronounced wall thickness variations (3.0 to 18.0mm), these profiles require high-performance alloys, typically 6082. They pose challenges in controlling perpendicularity and flatness.
Thick-walled Solid and Thin-walled Hollow Composite Profiles: Exhibiting extreme wall thickness variations, these profiles suffer from uneven metal flow during extrusion, impacting surface quality.
Large-walled Hollow Profiles: The quality of welds significantly affects alloy performance. Die design must optimize weld locations.
3.4 Extrusion Processes and Die Design Elements
Extrusion Ratio (λ) and Extrusion Pressure (P): Positively correlated, they influence the difficulty of metal deformation. Optimize extrusion pressure by adjusting the dividing ratio (K) and die structure.
Dividing Hole Layout: Allocate dividing hole areas based on extrusion coefficients to ensure balanced metal flow and improve forming quality.
Weld Line Position: Optimize weld positions for "structural" profiles to enhance weld quality.
Die Strength: Verify bending and shear strengths, and arrange dividing bridges rationally to ensure die pressure resistance.
3.5 Key Points of Die Design
Dividing Holes and Welding Chambers: Allocate dividing hole areas appropriately and optimize welding chamber structures to control metal flow rates and improve product precision.
Die Profile Holes and Working Zones: Accurately determine profile hole sizes and adjust working zone lengths based on wall thickness differences. Use secondary welding chambers when necessary for additional control.
Die Materials and Heat Treatment: Select high-quality die steel and optimize heat treatment processes to enhance die durability and production efficiency.
3.6 Conclusion
The design of aluminum extrusion dies for new energy vehicles must comprehensively consider product structural characteristics, extrusion process requirements, and die strength. Through precise design, high-quality materials, and reasonable process integration, production costs can be reduced, and production efficiency improved.