An experimental and numerical study on optimization of number and position of the clamps in sheet metals fixture

Abstract

The accuracy of the machining process is highly dependent on how well a workpiece is constrained in a fixture. A well-constrained workpiece has high stiffness and shows minimum deformation under the application of load. Workpiece can be constrained by the proper positioning of fixture elements. This research introduces a finite element-based numerical methodology to automatically select optimum number and position of clamps in the sheet metal, necessary for good quality of manufacturing process. The objective function is to minimize the total deformation normal to the plane of sheet metal while keeping maximum deformation of individual nodes upto 2 mm. The N-3-2-1 fixturing principle is used to place clamps on primary plane of the workpiece. The proposed method consists of two stages; in first stage, the initial number of clamps are determined. In second stage, initial number of clamps and their positions are optimized using genetic algorithm. The proposed method implemented on the case studies successfully reduced the total deformation with optimized number of clamps. The maximum deformation in individual nodes was kept upto 2 mm. An experimental setup was developed to verify the numerical results. The numerical and experimental results fully justify the proposed method.

Keywords:

• Clamps
• FEM
• fixtures
• genetic algorithm
• sheet metals

Acknowledgment

The authors appreciates the assistance provided in this research work.

Disclosure statement

No potential conflict of interest was reported by the authors.