Ultra-Deep Drawing for Long, Narrow Parts

Managing material flow, cracking and precision when the draw length is many times the component diameter.

The challenge of an ultra-deep draw

Deep drawing becomes progressively more difficult as the length-to-diameter ratio increases. Material must flow through many stages without tearing, excessive thinning, wrinkling or loss of straightness.

Balford develops multi-stage sequences for long, narrow components, including examples produced from a round blank through fourteen drawing operations. For suitable component sizes and materials, ratios around 20:1 and development work beyond that range can be evaluated.

Material behavior

Hardness, anisotropy, elongation and work hardening vary by material and heat. These properties determine the allowable reduction at each draw and whether intermediate stress relief is required.

In addition to conventional steels, development can include high-strength sheet, stainless steel, aluminum, copper and selected nickel alloys when geometry and material condition are compatible.

Preventing distortion and fracture

High draw loads can cause warping or cracks after forming. Engineers control blank size, stage reduction, punch and die radii, blank-holder force, lubrication and alignment to keep the wall stable.

Measurement between development stages reveals where strain is accumulating, allowing the sequence to be adjusted before production release.

High-strength and lightweight applications

Electric-vehicle and safety applications increasingly require strong, light components. Balford has developed deep-drawn parts in high-strength materials, including difficult geometries in sheet around 980 MPa class and approximately 2 mm thick where the final design permits.

Small holes can also be integrated into some high-strength drawn parts. Piercing direction and burr orientation are planned around assembly and safety requirements.

Tooling development

The forming sequence is calculated from the required finished part, not from a generic draw schedule. In-house tool design, manufacture and tryout support faster feedback between measurement and die adjustment.

Start with the functional requirement

Provide the target material, wall thickness, length, diameter, tolerance and annual quantity. The team can then determine the number of drawing stages and whether a process conversion could replace machining or welded construction.