Fine-blanking V-ring height is a tooling dimension tied to the sheet, tool layout and process. A published study of a 2.5 mm C1100 copper heat spreader tested three height levels for the blank-holder V-ring and three for the cavity V-ring. The table below keeps those source-specific levels separate and expresses them in millimetres and as a percentage of that study’s sheet thickness. Use them to understand the reported experiment, not as a universal die-design chart or a production setup recommendation.

Fine Blanking V Ring Dimensions

The study varied the height on two different tool elements. “Blank holder” identifies the upper holding-side V-ring; “cavity” identifies the lower cavity-side V-ring. The listed height values are parameter levels in the study’s L18 Taguchi design, not six finished tooling prescriptions. The percentage column is calculated as height ÷ 2.5 mm × 100. For example, a 0.20 mm blank-holder level equals 8% of the 2.5 mm test sheet thickness.

Read height in its tooling context

Height is only one part of V-ring geometry. Ring angle, distance from the cutting line, ring location, material response, blank-holder force, counterpunch force and die clearance interact. A height copied without those conditions can produce a different indentation and material flow. The referenced work used finite-element analysis and then checked a selected multiobjective parameter set with an experiment; it did not establish a single dimension that suits every alloy, thickness or part shape.

Keep the two location series separate when reviewing the table. The blank-holder levels are 0.10, 0.20 and 0.30 mm. The cavity levels are 0.15, 0.30 and 0.45 mm. Their ranges are not interchangeable: each belongs to its own tool element in the studied arrangement. The percentages make their scale easier to compare against the same 2.5 mm blank, but they do not turn the source into a general thickness-scaling rule.

What the optimization reported

For minimizing fracture-zone depth, the paper’s single-objective combination selected a 0.20 mm blank-holder height and 0.45 mm cavity height, with a 60° V-ring angle and a 2 mm V-ring position. For minimizing die-roll width, it again selected 0.20 mm and 0.45 mm heights, but used a 90° angle and 1.5 mm position. Its later multicriteria choice used those same heights with a 90° angle and a 2 mm position. These outcomes show why the target matters: the optimal combination changes with the quality measure and the other process parameters. They should be read as results for that study, not recommended starting settings for unrelated tooling.

Limits before using a dimension

The test material was 2.5 mm C1100 copper plate formed as a CPU heat spreader. A steel blank, a different copper temper, a different thickness, a different feature perimeter or a different press can respond differently. The source does not supply a full production drawing for the listed rows, and this compact table intentionally omits V-ring width, radii and offset dimensions that cannot be read as height levels from the stated parameter table. Do not infer those missing dimensions from the heights.

V-ring height is not punch-to-die clearance. Clearance is the gap between cutting edges; V-ring height describes the projecting ridge that clamps the sheet. Also keep blank-holder and cavity sides distinct in drawings and measurement records. Before cutting production tooling, use the governing die-design method, confirm the chosen geometry with the toolmaker, and validate cut quality on representative material using the required press and inspection procedure.

Source

Height levels and study conditions are from Kuo, Liu, Li and coauthors, “Numerical simulation and optimization of fine-blanking process for copper alloy sheet,” International Journal of Advanced Manufacturing Technology 119 (2022), 1283–1300. The article is open access under CC BY 4.0. The percentage values shown here are calculated from the published height levels and the paper’s 2.5 mm sheet thickness.