Stress band plot

Temperature band plot

Simulation of a Cutting Process

Cutting processes play a significant role in the production of almost all metal products. Process features such as tool geometry and cutting speed directly influence chip morphology and segmentation, cutting forces, and tool wear. To produce high quality products, the optimal range of the cutting parameters must be known; however, establishing these parameters is difficult and requires considerable investment of time and resources.

In this Brief, we use ADINA to simulate a process of machining, in which a block of high strength steel is cut using a tool with a positive rake angle. Of primary interest is the determination of the temperature distribution and the residual stresses in the workpiece, tool and chip.

During the machining process, substantial heat is generated due to plastic deformations of the solid and frictional sliding at the tool-workpiece interface. The temperature attained can be quite high and can have a considerable influence on the mechanical response. The ADINA simulation accounts for these heat generation effects, and the full thermo-mechanical coupling. ADINA can also be used to account for heat conduction between contacting bodies, where the gap conductance can be a function of clearance, pressure, and/or time.^*

The movies above show the stress and temperature results for the cutting problem. Although the tool is modeled as rigid in this simulation, the actual compliancy of the tool could have been modeled to investigate its effect on surface roughness and tool chatter.

In the movies, segmented shear localized chip formation is observed to occur. The arbitrary crack initiation and propagation is modeled using the ADINA rupture feature; see Figure 1.

Figure 1  Fracture is modeled using the ADINA rupture feature

An inspection of the machined surface reveals that the cut surface is not smooth. The material experiences large compressive stresses as it flows under the tool tip, followed by rapid elastic relaxation. This relaxation accounts for some of the surface roughness. Surface roughness and the state of residual stresses have a significant effect on the fatigue life of the component and, consequently, are of engineering interest. The ADINA model predicts these effects.

This Brief demonstrates how the powerful thermo-mechanical coupling capabilities in ADINA can be used to analyze a wide range of machining processes such as turning, drilling, boring, and milling. ADINA’s reliable and proven technology is crucial in obtaining physically realistic results for these analyses since contact, large deformations, and material nonlinearity play a major role.

Keywords:
Manufacturing processes, machining, cutting, thermo-mechanical coupling, gap conductance, heat generation, element death upon rupture