Helical milling operations are used to generate or enlarge boreholes by means of a milling tool. The bore diameter can be adjusted through the diameter of the helical path. The kinematics of helical milling on a three axis machine tool is analysed firstly. The relationships between processing parameters, cutting tool geometry characters with machined hole feature are formulated. The feed motion...

How animals sense, process, and use magnetic information remains elusive. In insects, magnetic particles are candidates for a magnetic sensor. Recent studies suggest that the ant Pachycondyla marginata incorporates ironcontaining particles from soil. We used leaf-cutter ants Atta colombica to test whether soil contact is necessary for developing a functional magnetic compass. A. colombica is th...

Abstract For a drill bit, the cutter is most important part to break rock. In oilwell drilling, polycrystalline diamond compact (PDC) bit widely used shear rock formation. this paper, finite element model with including axe-shaped PDC and formation developed study breaking behaviours. Results show that effect of on better than planar cutter. The front rake angle face angel play significant role...

The Enterobacteriaceae bacterium strain FGI 57 was isolated from a fungus garden of the leaf-cutter ant Atta colombica. Analysis of its single 4.76-Mbp chromosome will shed light on community dynamics and plant biomass degradation in ant fungus gardens.

1. The thermal sensitivity of locomotor performance has often been described in terms of speed, but the trajectory of locomotion may play an equally important role in capturing prey or escaping predators. Hypotheses based on physical constraints or behavioural plasticity predict relationships between the speed and the tortuosity of running, which should affect the thermal sensitivity of locomot...

In this paper, the straight flute end-milling cutter used for machining of Al-Si-Mg-Fe alloy work pieces was investigated. The machining processes could induce residual stresses that enhance greatly the performance of the machined component. Machining residual stresses correlate very closely with the cutting parameters. In the experiments, the residual stress on the surface of workpiece was mea...

Tool Condition Monitoring (TCM) systems can improve productivity and ensure workpiece quality, yet, there is a lack of reliable TCM solutions for complex and flexible industrial manufacturing. TCM methods which include the characteristics of the cut seem to be particularly suitable for these demanding applications. In the first section of this paper, three process-based indicators have been ret...

This paper presents a new model for the estimation of cutting forces in micromilling based on specific cutting pressure. The proposed model includes three parameters which allow to control the entry of the cutter in the workpiece and which consider also the errors in the radial position of the cutting edges of the tool. The presented model is orientated to adaptive control in the micromilling p...

'Self-cutting' is a specific type of emergency presenting to accident and emergency departments. All cases presenting in Sheffield in a 6-month period were studied. The self-cutter is most often a young, unemployed man: this is the group most likely to cut repeatedly. At least 45% of all cutters had a past psychiatric history, and a quarter of them were judged a high suicidal risk. The seriousn...

An important step in planning the manufacture of a component by CNC machining is the selection of cutting tools. Although it has long been known that the choice of cutter sizes can have a dramatic effect on the overall machining time, few algorithms for optimisation have been available to the production engineer. This paper describes a method for determining a theoretical optimal combination of...