3‑Roll Pyramid Roller Calculator (Calibrated)
Sheet Metal Roll Calculator
This calculator provides a direct mapping between desired cylindrical radius and bottom‑roll DRO settings for three‑roll pyramid sheet and plate rollers. The underlying model is based on a machine‑specific neutral‑axis response curve generated from constraint‑based geometry rather than closed‑form roll equations.
Conventional roll calculators often rely on simplified three‑point geometry or sagitta‑based approximations. Those methods become unstable or misleading at large radii and near‑flat rolling, where contact conditions change and the radius approaches infinity. This calculator avoids those failure modes by using a calibrated neutral‑axis curve that preserves the correct asymptotic behavior observed in geometry‑driven modeling.
Inputs are provided in inches, including fractional values, to reflect common fabrication practice. Both inside‑radius and outside‑radius specifications are supported. These are converted internally to a target neutral‑axis radius, which is the only radius directly governed by rolling kinematics. Thickness is incorporated through neutral‑axis offset using an adjustable k‑factor rather than by attempting to analytically rebuild roll contact geometry.
The calculator outputs bottom‑roll DRO positions in millimeters for direct entry into industrial roll controls. The output remains stable and monotonic across the full usable range of the machine, from tight rolls through near‑flat conditions.
Material presets are included to automatically assign typical neutral‑axis factors for common fabrication materials, including mild steel, high‑strength steel, stainless steel, aluminum, and an idealized geometry‑only mode. These presets can be overridden manually when required.
The model is designed to be extensible. Thickness correction layers can be added as additional calibration data becomes available, allowing refinement for heavier plate without altering the validated baseline geometry. This layered approach reflects how industrial rolling equipment is typically calibrated and avoids introducing numerical instabilities or artificial limits.
The calculator is intended for situations where repeatable roll settings, predictable large‑radius behavior, and integration with downstream fabrication operations are required.
Technical Summary
This sheet metal rolling calculator computes bottom‑roll DRO settings for three‑roll pyramid benders using a calibrated neutral‑axis response curve derived from constraint‑based geometry. It supports inside and outside radius inputs, fractional inch dimensions, common sheet and plate thicknesses, and material‑based neutral‑axis factors.
Unlike analytic roll formulas, the model preserves correct infinite‑radius behavior near tangency and remains stable for large‑radius and near‑flat rolling. Thickness effects are applied through neutral‑axis conversion and optional correction layers rather than explicit roll contact equations.
The calculator outputs millimeter DRO values suitable for direct machine entry and is applicable to rolled components such as duct, enclosures, shells, jackets, and large‑radius cylindrical parts.