Magnetic-Field-Guidance System for Magnetic Abrasive Finishing

Guides Magnetic Flux Flow to the Surface for Polishing

This magnetic-field-guidance system facilitates widespread use of automated magnetic abrasive finishing (MAF) processes for polishing freeform components. Freeform surface finishing is a challenge for standard automated manufacturing processes. Because of their nonstandard geometries, many components, such as medical prosthetics, turbine blades, dies, molds, and small machine parts, often require manual polishing, which increases manufacturing costs and can lead to undesirable surface finishing variations. MAF is a finishing process that employs a slurry of magnetic and abrasive particles driven by a magnetic field to polish the surface of a workpiece. However, since the process requires an appropriate magnetic field for polishing, MAF suffers from long lead times required for designing and manufacturing the magnetic-field-guidance, which prevent MAF’s adoption into the large-scale manufacturing of freeform components.

Researchers at the University of Florida have developed a flexible fixture filled with magnetic media for MAF that adjusts to the shape of freeform components. The fixture configures to a specific workpiece geometry and ensures appropriate magnetic flux density throughout the component in the presence of a magnetic field. Since it conforms to various workpiece shapes, the fixture eliminates the need for a custom magnetic field guidance system, reducing the lead time and enabling widespread utilization of MAF to polish freeform components.

Application

Magnetic-field-guidance system that adjusts to the shape of freeform components to generate appropriate magnetic field at the component surface during magnetic abrasive finishing

Advantages

• Conforms to the shape of freeform components, adapting the secure hold on workpieces for a variety of polishing jobs
• Forms a vacuum within the fixture to retain the workpiece shape, enabling more secure gripping of the workpiece, if needed
• Establishes the ideal magnetic backing for magnetic abrasive finishing (MAF) of freeform surfaces, ensuring appropriate magnetic field for uniform polishing
• Provides a reusable magnetic-field-guidance system for MAF surface polishing, eliminating the need for complex custom jigs and reducing lead time and production costs
• Facilitates widespread use of MAF, improving the manufacturing process of many variably-shaped components such as prosthetics, airfoils, dies, molds, cutting tools, optics, and precision machine parts

Technology

A flexible bag filled with magnetic media deforms to the shape of the freeform component. The system acts as the ideal magnetic backing to guide the magnetic field to the component’s surface during MAF polishing. If needed, a vacuum formed in the bag’s interior causes it to retain that shape. Removing the vacuum allows the bag to reconfigure to the shape of another freeform component, eliminating the need for a custom steel guidance jig for each polishing job and facilitating widespread use of the MAF process.