Design and Validation of a Modular Fixture for Milling Thin-Ribbed Linkage Brackets

Abstract

Thin-ribbed linkage brackets are difficult to machine because their low local stiffness makes them sensitive to both cutting-induced bending and clamping-induced distortion. This study presents a design-oriented procedure for developing a modular milling fixture for linkage brackets containing a central bore, two cylindrical end bosses, and slender connecting ribs. The procedure integrates functional requirement definition, deterministic location, force-path design, analytical sizing of cutting forces, finite-element verification, prototype manufacture, and proof-of-concept machining trials. The fixture employs a fixed and a movable 45° V-block to support the cylindrical bosses, a central locator to control longitudinal position, a rigid base plate, and relief regions that prevent direct contact with the thin ribs. Soft interface layers are introduced at selected contacts to limit surface damage and reduce local pressure concentration. For the investigated milling condition, the estimated tangential, radial, and axial force components were 300, 195, and 90 N, respectively. Static finite-element results indicated a maximum von Mises stress of approximately 72.55 MPa and a maximum displacement of 1.59 × 10⁻³ mm under the modeled loading and boundary conditions, remaining below the assumed material yield strength. Prototype trials with aluminum and polymer brackets showed stable seating, unobstructed tool access, and no visible slippage or rib damage. Because the experimental assessment was qualitative and no comprehensive metrological uncertainty study was available, the results should be interpreted as evidence of functional feasibility rather than as complete industrial qualification. The work provides a compact fixture-design framework for deformation-sensitive linkage components and identifies the measurements required for subsequent quantitative validation.