The graphite is one of the crystalline minerals of carbon elements. It has high-temperature resistance, corrosion resistance, thermal shock resistance, high strength, good toughness, high self-lubrication strength, thermal conductivity, electrical conductivity, plasticity, coating performance, and other unique physical and chemical properties. Widely used in metallurgy, machinery, electronics, batteries, diamond superhard materials, the nuclear industry, chemical industry, light industry, military, national defense, aerospace, refractory and other industries, is the development of high-tech essential non-metallic materials.
Although the industry favors graphite, many manufacturers have been troubled by its poor mechanical properties, brittleness, machining difficulties, and high cost. To reduce these impacts, ZY Super Hard has developed it from the perspective of satisfying customers’ mass production: PCD302, PCD025, and PCD010 three materials, PCD diamond tool can be milling, drilling, and engraving for graphite products.
Properties of graphite materials
Graphite is soft and dark gray; Greasy can pollute the paper. Hardness is 1-2; along the vertical direction, with the increase of impurities, its hardness can be increased to 3-5. The specific gravity is 1.9-2.3. Specific surface area range concentrated in 1-20㎡/g, under the condition of oxygen isolation, its melting point above 3000℃, is one of the most temperature-resistant minerals. It conducts electricity and heat. Pure graphite in nature is not, which often contains SiO2, Al2O3, CuO, and other impurities. These impurities usually take the form of minerals such as quartz, pyrite, and carbonate. In addition, there is water, asphalt, and so on.
Because of its unique structure, characteristics as follows:
(1) Good plasticity: graphite toughness is good, and people can roll it into a skinny sheet;
(2) Good stability: Good chemical stability: graphite has good chemical stability at room temperature, acid, alkali, and organic solvent corrosion resistance;
(3) Good smoothness: The lubricating properties of graphite depend on the size of graphite scales; the more significant the chip, the smaller the friction coefficient, and the better the lubrication performance;
(4) Thermal shock: graphite at room temperature, when used, can withstand drastic changes in temperature without destruction or temperature mutation; the volume of graphite changes little and will not produce cracks;
(5) high-temperature plasticities are good: graphite melting point is 3850±50℃, coefficient of thermal expansion is minimal. Graphite strength increases with the increase in temperature. At 2000℃, the power of graphite doubles.
(6)Good thermal and electrical conductivity: Good thermal conductivity and electrical conductivity: the conductivity of graphite is one hundred times higher than that of general non-metallic ore. The thermal conductivity exceeds that of steel, iron, lead, and other metal materials. The thermal conductivity decreases with increasing temperature, and graphite becomes an insulator even at extremely high temperatures.
Precautions for graphite processing tools
I believe that friends in the machining industry are no strangers to tool wear. In production and processing, the amount of wear will affect the cost of tool loss, processing time, and processing quality. Here, graphite electrode processing is taken as an example to illustrate the factors of tool wear. We divide wear areas into the front and back tool faces. The impact contact between the tool and the broken chip area on the front face produces impact wear, and the chip sliding along the tool surface creates sliding friction wear.
ZYsuperhard summarized several factors of tool wear according to many years of processing experience:
(1)Material of the tool itself: cutting tool materials is the fundamental factor that determines the cutting performance of the tools, which has a significant impact on the processing efficiency, processing quality, processing cost, and tools’ durability. The higher the hardness, the better its wear resistance, the lower the impact toughness, the more brittle the material. For diamond-coated graphite tools, the choice of hardness is relatively good; that is, the cobalt content is slightly lower;
(2)Geometric Angle of the tool: the suitable geometric Angle of the graphite processing tool is helpful to reduce the vibration of the tools; on the contrary, the graphite workpiece is not easy to collapse. The influence of the change of tool Angle on tool wear, milling force, and the front Angle produces cutting vibration, back Angle, and helix Angle, so we must pay more attention to the selection. Through extensive testing of graphite processing characteristics, ZY Super Hard has optimized the geometrical Angle of related products, thus significantly improving the overall cutting performance of the tool;
(3)Coating: the diamond-coated tool has the advantages of high hardness, good wear resistance, and low friction coefficient. At present, the diamond coating is also the best choice for graphite machining tools, and it has superior cutting performance; The advantage of the diamond coating tool is that it integrates the hardness of natural diamonds and the strength and fracture toughness of hard alloys. The geometric Angle of diamond-coated tools fundamentally differs from that of ordinary-coated tools. Therefore, when designing diamond-coated tools, the geometric Angle can be appropriately increased without affecting the wear resistance of the cutting edge due to the particularity of graphite processing. However, the wear resistance of standard coated tools has been significantly improved compared to common uncoated and diamond-coated tools. In graphite processing, we should reduce the geometric Angle to enhance the wear resistance of graphite.
. As high-end domestic tool manufacturers invest a lot of human and material resources in the research and development of coating technology, some domestic brands have achieved good results. The graphite processing tool developed by ZY Super Hard also uses the world’s advanced coating technology for the surface treatment of the cutters, thoroughly ensuring the tool processing life and stability;
(4) Cutting-edge passivation: high-speed graphite machining requires tool performance and stability, especially diamond-coated tools that must be passivated before coating to ensure peace and service life. The purpose of tool passivation is to solve the defects of the micro-notch of the tool edge after grinding so as that reduces the edge value or eliminate it to achieve the purpose of smooth and smooth, sharp and robust, and durable
PCD diamond tool
PCD blade ( inserts) is a national standard model with a lathe rod, easy to remove and replace the blade, generally used in CNC lathe and machining center, compared with the traditional alloy blade, can use higher linear speed processing.Tool life is also greatly improved.
PCD INSERTS
PCD turning tool
PCD turning tool is a welding tool, and the tool handle together can repeatedly be grinding use.
PCD milling cutter
PCD milling cutter includes two kinds; one is through the center of the milling cutter when used vertically along the axis into the work-piece surface; for the milling pit type of work-piece, efficiency will improve significantly. The other is the center of the milling cutter; this milling cutter is generally along the radial cut into the workpiece, through the CNC programming track, milling boss, step, surface, and other parts.
PCD drilling bit
PCD bit, generally according to the diameter, alloy matrix, or steel matrix. PCD drill directly drills into the workpiece, and there is no hole in the workpiece itself, so the precision is not high. PCD bits must use in machining centers.
PCD bits mainly include PCD reaming bit, PCD step bit, PCD twist bit, PCD flat drill, etc.
PCD Diamond coated cutting tool
Technicians use the CVD method to deposit a layer of a 1-25μm diamond film directly on the carbide matrix, which can operate in various geometrically complex cutting tools. Still, because of the thin coating, some areas are gradually replaced by PCD milling tools.
Performance advantage:
· high hardness, excellent wear resistance;
· good self-lubrication and chemical stability;
· high thermal conductivity, low thermal expansion coefficient;
· work smoothly; the cutting tool edge is very sharp, and the workpiece is out of shape, not easily.
· the knives’ service life is not coated diamond tool N times.
Type of tool suitable for coating: blade, milling cutter, drill, reamer.
ZY Super hard PCD tool material Grit Size table
