The shape of a continuous cutting edge of a drill bit

In the whole lunar surface drilling and sampling task, it is critical to make the operation of the drilling and sampling impact system efficient and reliable. This paper focuses on how to improve the impact stress obtained at the cutting edge of the drill bit. Firstly, with the objective of maximizing the output impact energy, the design parameters of the percussive mechanism are optimally selected; based on the one-dimensional stress wave transfer theory, the collision input model and transfer models of impact stress in the drilling tool are established. Secondly, in order to verify the above design parameters and theoretical models, the percussive drive characteristics’ test and the transfer characteristics’ tests of impact stress in the drill stem and drilling tool joints are carried out in turn. The experimental results are consistent with the theoretical analysis, which clarifies the transfer characteristics of the impact stress at the various stages of generation, incidence, and transfer to the cutting edge. It was finally found that increasing the percussive frequency and impact energy of the percussive mechanism as well as the contact stiffness of the collision surface can increase the incident impact stress of the drilling tool, while reducing the length of the screw connection between the drill bit and the drill stem can reduce the impact stress loss. This provides a theoretical reference for the design of the percussive mechanism and drilling tools in lunar surface drilling and sampling tasks.

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The Simulation of the Influence of Honed Edge Radius on the Cutting Force and Torque in Drilling 42CrMo with K-Grade Carbide Drill Bit

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.130-134.1779 ◽

2011 ◽

Vol 130-134 ◽

pp. 1779-1784

Author(s):

Tao Wang ◽

Ya Shi Ke ◽

Yi Dan Zhou

Keyword(s):

Cutting Force ◽

Metal Cutting ◽

Simulation Software ◽

Cutting Edge ◽

Drilling Process ◽

Drill Bit ◽

Cutting Simulation ◽

Edge Radius

This paper uses a metal cutting simulation software AdvantEdge FEM as the platform, and simulates the drilling process of three different honed cutting edge K-Grade carbide drills. The aim is to study the influence of different magnitude of honed cutting edge on the the cutting force and torque. According to the simulation, the z-axis force and torque increase while the margin of the fluctuation decrease with the honed edge radius increase. In this paper, the z-axis force and torque reach the maximum and the margin of fluctuation in the smallest when using the honed edge radius of 0.10mm.

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The Simulation of the Influence of Honed Edge Radius on the Maximum Temperature in Drilling 42CrMo with K-Grade Carbide Drill Bit

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.399-401.1848 ◽

2011 ◽

Vol 399-401 ◽

pp. 1848-1851

Author(s):

Yi Dan Zhou ◽

Tao Wang

Keyword(s):

Metal Cutting ◽

Cutting Temperature ◽

Simulation Software ◽

Cutting Edge ◽

Maximum Temperature ◽

Drilling Process ◽

Drill Bit ◽

Cutting Simulation ◽

Edge Radius

This paper uses a metal cutting simulation software AdvantEdge FEM as the platform, and simulates the drilling process of 42CrMo with three different honed cutting edge K-Grade carbide drills. The aim is to study the influence of different magnitude of honed cutting edge on the maximum temperature of cutting area. According to the simulation, the maximum temperature does not absolutely increase with the honed edge radius increase. The cutting temperature reaches maximum when the honed edge radius is 0.06mm in this paper, meanwhile the margin of fluctuation in the smallest.

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Plastic Deformation in Microtomed Sections

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100066346 ◽

1971 ◽

Vol 29 ◽

pp. 458-459

Author(s):

J. Temple Black

Keyword(s):

Plastic Deformation ◽

Plastic Strain ◽

Applied Stress ◽

Elastic Strain ◽

High Strain ◽

Tool Material ◽

Cutting Edge ◽

Material Structure ◽

Geometrical Constraints

The output of the ultramicrotomy process with its high strain levels is dependent upon the input, ie., the nature of the material being machined. Apart from the geometrical constraints offered by the rake and clearance faces of the tool, each material is free to deform in whatever manner necessary to satisfy its material structure and interatomic constraints. Noncrystalline materials appear to survive the process undamaged when observed in the TEM. As has been demonstrated however microtomed plastics do in fact suffer damage to the top and bottom surfaces of the section regardless of the sharpness of the cutting edge or the tool material. The energy required to seperate the section from the block is not easily propogated through the section because the material is amorphous in nature and has no preferred crystalline planes upon which defects can move large distances to relieve the applied stress. Thus, the cutting stresses are supported elastically in the internal or bulk and plastically in the surfaces. The elastic strain can be recovered while the plastic strain is not reversible and will remain in the section after cutting is complete.

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Preparation of cross-sectional samples for near-surface TEM studies

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010012669x ◽

1987 ◽

Vol 45 ◽

pp. 380-381

Author(s):

R.C. Dickenson ◽

K.R. Lawless

Keyword(s):

Standard Sample ◽

Surface Region ◽

Specimen Preparation ◽

Thick Sheet ◽

Drill Bit ◽

Sample Holder ◽

Metal Interface ◽

Cross Sectional ◽

Near Surface ◽

Cold Worked

In thermal oxidation studies, the structure of the oxide-metal interface and the near-surface region is of great importance. A technique has been developed for constructing cross-sectional samples of oxidized aluminum alloys, which reveal these regions. The specimen preparation procedure is as follows: An ultra-sonic drill is used to cut a 3mm diameter disc from a 1.0mm thick sheet of the material. The disc is mounted on a brass block with low-melting wax, and a 1.0mm hole is drilled in the disc using a #60 drill bit. The drill is positioned so that the edge of the hole is tangent to the center of the disc (Fig. 1) . The disc is removed from the mount and cleaned with acetone to remove any traces of wax. To remove the cold-worked layer from the surface of the hole, the disc is placed in a standard sample holder for a Tenupol electropolisher so that the hole is in the center of the area to be polished.

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