Deep drawing is the core process in closure cap manufacturing. Successive cold-forming stages—such as cup drawing, flanging, and thread rolling—place extremely high demands on the uniformity of plasticity, dimensional precision, and microstructural consistency of the aluminum material. Even minor fluctuations in material properties can lead to production defects, including cracking, wrinkling, or uneven edges. Haomei Aluminum has developed aluminum sheets for deep-drawn closure caps. By strictly controlling key deep-drawing parameters—from alloy composition and rolling processes to heat treatment—we provide global bottle cap manufacturers with high-quality base materials optimized for high-speed stamping lines.

Haomei aluminum sheets for deep-drawn closure caps primarily utilize 8011 and 3105 alloys, selected to meet specific drawing ratios and strength requirements.

The 8011 aluminum-iron-silicon alloy is available in H14 and H16 tempers. The H14 temper offers a tensile strength of 125–155 MPa and an elongation of ≥2%; with its high plasticity, it is well-suited for standard tamper-evident caps and easy-open ends with drawing ratios up to 1:1.5. The H16 temper provides a higher tensile strength of 160–195 MPa and greater structural rigidity, making it ideal for bottle caps that require higher stiffness and involve moderate drawing ratios.

The 3105 aluminum-manganese-magnesium alloy (H14 temper) offers a tensile strength of 150–200 MPa, balancing structural strength with the toughness required for deep drawing. It is specifically engineered for large-diameter, high-draw-ratio bottle caps, ensuring uniform wall thickness after forming and minimizing the risk of thinning or fracturing.

Available in a thickness range of 0.15–0.30 mm, the material can be precisely customized to meet specific cap designs and press parameters.

Earing ratio and thickness tolerance are the two critical factors determining the yield rate in deep-drawing processes, and they remain the primary focus of our production control. Through directional grain rolling and multi-stage homogenization annealing, we maintain an earing ratio of less than 2%—significantly better than the industry average of 3%–6%. This results in a clean, uniform edge after deep drawing, with a height variation of ≤0.1 mm, eliminating the need for secondary trimming and increasing material utilization by over 4%. Regarding thickness precision, our closed-loop, fully continuous cold-rolling measurement system ensures a thickness tolerance of ±0.005 mm across the entire coil, with a variation of ≤0.003 mm between the head and tail ends. Furthermore, the strip flatness is maintained at ≤2 mm/m, ensuring consistent deformation resistance throughout the deep-drawing process and preventing localized excessive thinning or sidewall wrinkling.

The properties of the surface and coating ensure functional integrity following deep-drawing. The aluminum closure sheets undergo a multi-stage degreasing and passivation pretreatment, resulting in a pristine surface free from oil, pinholes, or roller marks. It is fully compatible with food-grade epoxy-polyester coatings, achieving a Grade 0 rating in cross-hatch adhesion tests. The coating remains intact—without cracking or peeling—even after deep drawing, flanging, and thread rolling. In testing, the coating showed no discoloration or leaching after 72 hours of immersion in 40% alcohol at room temperature. Aluminum ion migration levels comply with both U.S. FDA 21 CFR and EU DGCCRF standards for food-contact materials, making the alloy safe for use with a wide range of alcoholic beverages, food products, and pharmaceutical contents.

Drawing on over a decade of experience serving the bottle cap industry, we have found that batch-to-batch consistency in deep-drawing materials has a greater impact on a client’s overall costs than the peak performance of any single batch. We have implemented a comprehensive, end-to-end batch traceability system, keeping the variation in tensile strength within 5% for any given batch—a measure that helps clients minimize the time lost to frequent mold adjustments. For instance, a Southeast Asian manufacturer producing one million bottle caps daily previously faced a persistent scrap rate of approximately 2.5% due to fluctuations in the material’s "earing" rate (an indicator of anisotropic behavior during deep drawing). After switching to our deep-drawing quality aluminum closure sheets, their scrap rate dropped to below 0.6%, resulting in monthly savings of nearly 20,000 RMB in material waste costs.

Haomei Aluminum currently offers aluminium sheet for deep drawn closure caps in both coil and sheet formats. We provide customized slitting widths and sheet dimensions to meet specific client requirements, accompanied by a full suite of multilingual inspection reports and compliance documentation. We offer expert material selection guidance based on your bottle cap blueprints and support everything from small-scale trial orders to stable, high-volume supply—helping you improve deep-drawing yields and reduce overall production costs.