Material separation mechanisms during rough grinding with large CBN grains

Grinding is the quality-defining final process in many value chains, particularly for hardened steels (e.g., 100Cr6). New CBN tools with very large grains (>300 µm) promise significantly higher material removal rates, lower forces, and more favorable heat dissipation via the chip. However, robust models and process windows for practice are lacking: chip formation mechanisms, heat partitioning, the influence of grain geometry, and the effects on surface/subsurface integrity (residual stresses, microstructure) are unclear. Companies risk grinding burn, scrap, tool damage, and unnecessary trial-and-error. Sound understanding is a prerequisite for safe high-performance rough grinding, shorter cycle times, stable quality, and reduced unit costs.

Objectives

The project elucidates the material separation mechanisms and energetic phenomena in rough grinding with CBN grains >300 µm. The focus is on heat partitioning and surface/subsurface loading, as well as the influence of grain geometry and orientation on forces and chip formation. Based on experimental analyses and scale-bridging modeling, validated process windows and parameter guidelines will be derived. Grinding shops, tool manufacturers, and the automotive and rolling bearing industries benefit from higher material removal rates, shorter cycle times, reduced forces and energy inputs, reliable surface/subsurface integrity, and fewer try-outs.

Benefits

• Validated process windows and simulation for rapid process design
• Less grinding burn, scrap, and wear
• Shorter cycle times and lower costs

Approach

AP1 determines process limits and temperatures in HSG/HEDG and quantifies the heat partition into the workpiece during the process. AP2 investigates single-grain grinding with varied undeformed single-grain chip thickness and orientation, capturing forces, chip thickness compression, and segmentation. AP3 analyzes in-situ chip formation via interrupted cutting up to 120 m/s and correlates it with surface/subsurface integrity metrics (XRD, EBSD, roughness). AP4 integrates the insights gained into our material removal simulation IFW-CutS to further improve the quality of the simulation results.

Are you also interested in a cooperation project?

Contact Lennart Puls via email at puls@ifw.uni-hannover.de or by phone at +49 511 762 18850.