Objective

Minimize the scratches on the finished Femoral Head to maximize productivity by reducing the amount of hand polishing.

Process

Finish the OD of a Femoral Heads using multiple wheels of decreasing grit size to achieve the desired finish and geometry.

Component

Femoral Head

Material

Cobalt Chrome

Hardness

50 Rc

Stock Removal

150 Microns (0.006″)

Coolant

Light Mineral Seal Base Oil

Requirements

Roundness: 5 Microns (0.0002″)

Diametric Size: 15 microns(0.0006″)

Finish: 0.015 um Ra (0.6 u” Ra)

Machine Setup

3 Silicon Carbide Wheels – Turret Mounted

Wheel Specification

GC320-50DV2S

GC800-50IV2S

GC1200-65FV2S

Wheel Size

34 x 45 x 24mm (1.340″ x 1.75″ x .945″)

Results

Darmann implemented the use of wheels having coolant release holes that helped to keep the wheel/part interface free of debris. This new wheel design improved part quality and reduced process costs resulting in:

A 30% reduction in hand polishing

A 25% improvement in overall productivity

Improved quality and part appearance by reducing scratching on the surface of the part