Cutting tool (machining)
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Joined: Sep 2010
01-10-2010, 12:24 PM
Cutting tool (machining)
In the context of machining, a cutting tool (or cutter) is any tool that is used to remove material from the workpiece by means of shear deformation. Cutting may be accomplished by single-point or multipoint tools. Single-point tools are used in turning, shaping, plaining and similar operations, and remove material by means of one cutting edge. Milling and drilling tools are often multipoint tools. Grinding tools are also multipoint tools. Each grain of abrasive functions as a microscopic single-point cutting edge (although of high negative rake angle), and shears a tiny chip.
Cutting tools must be made of a material harder than the material which is to be cut, and the tool must be able to withstand the heat generated in the metal-cutting process. Also, the tool must have a specific geometry, with clearance angles designed so that the cutting edge can contact the workpiece without the rest of the tool dragging on the workpiece surface. The angle of the cutting face is also important, as is the flute width, number of flutes or teeth, and margin size. In order to have a long working life, all of the above must be optimized, plus the speeds and feeds at which the tool is run.
Diamond is the hardest material known to man kind. When used on tools, diamond grinds away material on micro (Nano) level. Diamond is the hardest substance known and is given a value of 10 in the Mohs hardness scale, devised by the German mineralogist Friedrich Mohs to indicate relative hardness of substances on a rating scale from 1 to 10. Its hardness varies in every diamond with the crystallographic direction. Moreover, hardness on the same face or surface varies with the direction of the cut.
Diamond crystallizes in different forms. Eight and twelve sided crystal forms are most commonly found. Cubical, rounded, and paired crystals are also common. Crystalline diamonds always separate cleanly along planes parallel to the faces. The specific gravity for pure diamond crystals is almost always 3.52. Other properties of the diamond are frequently useful in differentiating between true diamonds and imitations: Because diamonds are excellent conductors of heat, they are cold to the touch; Most diamonds are not good electrical conductors and become charged with positive electricity when rubbed; Diamond is resistant to attack by acids or bases; Transparent diamond crystals heated in oxygen burn at about 1470Â° F, forming carbon dioxide.
read more about DIAMOND CUTTING TOOL AND COATINGS: topicideashow-to-diamond-cutting-tool-and-coatings#ixzz0uqBpzKQE
Diamond cutting tools are the result of a technical know-how that brings about optimum tool performance providing fast cutting without sacrificing their long lifespan.
They are manufactured with International quality standards but offered at highly economical prices enabling them to give optimum yet low cost cutting.
Cutting tool are used as a requirements of diverse industries such as marble, granite, concrete, reinforced concrete, glass and so on with high quality diamond tools.
Precision and high quality is built into all our industrial diamond cutting tools, carbide tools and boron tools. Starting with the design of each part where fail-safe performance is the foundation of every boron, carbide and diamond tool product; to manufacturing where precision equipment is utilized; to thorough inspections for the highest quality assurance requirements. Westec Diamond Tools will get the job done – time and time again.
About Cutting tools:
Diamond cutting tools such as a diamond core drill and a disk-shaped diamond saw which are used to grind and cut hard articles in order to bore or cut hard articles. The diamond cutting tools comprise a tool body and a diamond blade portion attached to an outer end of the tool body. The diamond blade portion has a plurality of outer cuts formed at an outer end thereof and a plurality of inner slots formed under and between the outer cuts and higher than the bottoms of outer cuts by a certain depth. The diamond cutting tools can carry out effectively boring or cutting work until the expensive diamond blade portion is completely worn away.
A diamond tool, e.g., cutting tool, dresser, wire drawing die, etc., having excellent wear resistance, heat resistance and oxidation resistance and with an improved tool life is provided, which is mainly composed of a synthetic diamond single crystal containing boron or boron and nitrogen.
In this study, a general defect characterization in diamond-cutting tools used in marble, granite and natural stone cutting has been investigated. An important factor determining the performance of the PCD tool and the quality of the cutting operation is the bond characteristic obtained during hot pressing as a function of the pressure, sintering temperature and time. Successful diamond tool design starts with the appropriate choice of high-quality matrix powders and diamonds. The matrix should support the diamond particles without damaging them. During cutting the matrix is expected to wear to some extent provided the tips of the diamond particles run easily and also chip flow smoothly. The bond reaction of the diamond surface and surrounding metal matrix is effective for efficient tool performance. With this type of cutting/abrasive material produced by the PM techniques the primary important factor for their properties is cleanness (cleanness of operation media, cleanness of powders and diamonds used). In general, a weak diamond-matrix bond as well as oxide films and inclusions in the matrix overtake the role of crack initiation. Also the diamond particles can act as defects through their size, form and area distribution (clustering). In this study for a micro-structural optimization, the defect characterization should be realized primarily. Transverse rupture tests which are generally used for hard material were carried out with different matrix and diamond compositions. The toughness of the tested materials were determined and the defects leading to crack formation are classified
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Joined: Sep 2010
14-10-2010, 11:40 AM
PERFORMANCE EVALUATION OF CUTTING TOOL MATERIALS.pptx (Size: 2.96 MB / Downloads: 244)
PERFORMANCE EVALUATION OF CUTTING TOOL MATERIALS
SATHISH KUMAR P M
FIRST YEAR M-TECH ( TOOL ENGG)
GOVT. TOOL ROOM AND TRAINING CENTRE
When a material is being loaded in uni-axial tension, compression, or simple shear it will behave elastically until a critical value of normal stress or shear stress is reached and then it will behave plastically.
If the applied loads are relatively low, the crystal responds by simply stretching or compressing the distance between the atoms. The basic lattice unit does not change, and all of the atoms remain in their original position relative to one another.
Elastic deformation stretches atomic bonds in the material away from their equilibrium radius of separation of a bond, without applying enough energy to break the inter-atomic bonds.
Joined: Apr 2012
26-07-2012, 03:42 PM
Cutting_Tools.ppt (Size: 1.43 MB / Downloads: 108)
Cutting Tool Properties
Cutting tool material must be 1 1/2 times harder than the material it is being used to machine.
Capable of maintaining a red hardness during machining operation
Red hardness: ability of cutting tool to maintain sharp cutting edge
Also referred to as hot hardness or hot strength
May contain combinations of tungsten, chromium, vanadium, molybdenum, cobalt
Can take heavy cuts, withstand shock and maintain sharp cutting edge under red heat
Generally two types (general purpose)
Molybdenum-base (Group M)
Tungsten-base (Group T)
Cobalt added if more red hardness desired
Carbide Cutting Tools
First used in Germany during WW II as substitute for diamonds
Various types of cemented (sintered) carbides developed to suit different materials and machining operations
Good wear resistance
Operate at speeds ranging 150 to 1200 sf/min
Can machine metals at speeds that cause cutting edge to become red hot without loosing harness
Five types of powders
Tungsten carbide, titanium carbide, cobalt, tantalum carbide, niobium carbide
One or combination blended in different proportions depending on grade desired
Powder mixed in alcohol (24 to 190 h)
Alcohol drained off
Paraffin added to simplify pressing operation
Used extensively in manufacture of metal-cutting tools
Extreme hardness and good wear-resistance
First used in machining operations as lathe cutting tools
Majority are single-point cutting tools used on lathes and milling machines