Diamond Tool in Machining of

Diamond material known as the 21st century material, in this era of ultra-precision machining. Diamond tools and wear-resistant materials in the non-ferrous metal processing applications, has excellent flexibility. In the use of diamond tools, users have two options: one is the polycrystalline diamond (PCD), the other is relatively new chemical vapor deposition (CVD) diamond.

First, a new family of diamond

Chemical vapor deposition (CVD) diamond is a pure diamond material with high abrasion resistance, non-adhesive. Diamond deposition is divided into two forms: one is the thick-film diamond deposition as a whole, granite sheet, then cut into desired size; the other is thin film diamond deposition in the carbide blade or rotary cutter.

To date, CVD diamond is the most promising uses of processed graphite. However, NortonDiamondFilm company selling a variety of purposes but is used for CVD diamond processing non-ferrous metals, plastics and composite materials. Norton's application technology manager for that, CVD diamond for almost all non-ferrous metals. In the intermittent cutting high silicon aluminum alloy and pre-sintered cemented carbide, brass, copper and carbon fiber materials processing, good results are achieved. Norton has marble believe: CVD diamond in the processing of a wide range of aluminum alloy materials (including 6061 and others), can and PCD evenly matched.

Application Technology Manager, Norton Company also believes that, CVD diamond and PCD compared, the main advantage of the quality of the cutting edge. Although CVD is polycrystalline, but it does not contain cobalt binder, is a pure diamond, so the cutting edge is continuous. This would use a higher cutting speed and to obtain better surface roughness, because the tool is not easy to heat up. He also firmly believes that BUE is not a problem of CVD diamond.

By Norton company information, CVD diamond thermal conductivity 50% higher than the PCD. The reason is that CVD diamond blade as a whole, you can immediately put the heat export. The thermal conductivity of PCD to the blade through the cobalt - diamond composite, thermal conductivity backward some.

CVD diamond also has a low coefficient of friction. Carbide and PCD will bond the workpiece material, CVD diamond is non-stick. At the same time, low coefficient of friction also makes CVD diamond cutting tools can withstand a greater load, making cutting faster and more efficient.

CVD diamond is rendered in the use of thermal and chemical stability. The PCD and carbide in this regard to be a metal content of binder. Into hydrochloric acid in the CVD diamond, nothing will happen. However, if the PCD diamond into them, acid will eat the cobalt binder. This means that CVD Jingang Dan can withstand some of the material to generate acid in the processing of the stone, such as phenolic resins, rubber urinary abdominal, lower carbonate and so on.

Although all forms of diamond (including PCD) and black at high temperatures should be super-alloy metal or a chemical reaction of some components, but we all know, for most materials, the diamond is still chemically inert. PCD and carbide with cobalt binder for cutting high temperature chemical stability was reduced when the phenomenon occurs. CVD diamond does not contain binding agents, to avoid this phenomenon. In addition, CVD diamond also good lubricity and thermal conductivity, it has the high-speed and dry cutting in the use of the key advantages.

CVD diamond last advantages are: high temperature, even in the cutting, still maintain high hardness and wear resistance. Norton's application technology manager Nagy said: "because there is no loose diamonds wrapped in cobalt, so the blade hardness uniform."

Second, CVD cutting tools in machining of

CVD includes tools (mainly machining), thermal applications and so on. Currently, CVD products have the following main categories:

CVD ordinary tools, precision tools;

CVD wheel dressing pen;

CVD drawing dies and finished mold;

New high-pressure CVD, the water jet nozzle wear;

CVD processing tools for laminate flooring;

CVD precision bearing support device and wear devices.

CVD does not contain any metal or non-metallic additives, mechanical properties of both the advantages of single-crystal diamond and PCD, but also to some extent, overcome their shortcomings. Practice shows that a large number of welding-type CVD tool life of more than PCD tools, the impact resistance than single-crystal diamond film. Thus, CVD is considered non-ferrous materials processing industry an ideal tool material, such as aluminum, silicon, aluminum, copper, copper alloys, graphite and various glass fiber and carbon fiber structure of materials processing.

1.CVD tools for metal cutting

CVDD can be used for production of turning, milling, planer, knives and other times machining tool.

Past two years, various types of diamond films Tool, key knife was used in dozens of domestic enterprises and foreign countries to promote positive, its application as follows:

Instead of carbide cutting tools, more than tenfold to a hundredfold increase efficiency, reduce labor intensity, the workpiece machining accuracy is significantly improved significantly lower surface roughness.

Superhard materials and organic composite materials, the ideal processing tool;

And compared to PCD tools, CVD tool surface roughness is low, a good edge;

Can be replaced in some areas, natural diamond tools.

On the domestic auto industry silicon aluminum alloy used in point of view, about 12% silicon content, on the one hand because of its material is uneven, with hard points, currently occupies most of the PCD cutting tools market, CVD share very little, such as wheel Yi tools, such as slot cutting tools. On the other hand, due to the current CVD is not conductive, and conductive properties of PCD, both in the tool so that the existence of differences in the production process, PCD can be processed by processing power, and CVDD is not, if a good solution to CVD tool making process issues, be made with the PCD tool in the automotive industry to compete against.

Practice shows that, CVD tool with the correct geometry, after lapping is fully capable of non-ferrous metals and superhard materials as a precision cutting tool, such as turning the motor of copper knife (also called commutator knife) and so on. Have been tested, the following conditions:

Tool: CVD Tool, wiper tip L = 1mm, front 8 °, after the angle 8 °, the main angle 60 °, edge roughness Ra0.1μm;

Machine: CJ6125;

Environment: precision machining laboratories;

Workpiece material: 8% silicon aluminum alloy, copper;

Cutting parameters: n = 1400r/min, f = 4mm/min, ap = 0.015mm / r

In these experimental conditions, the roughness of the workpiece after turning Ra0.012μm, this is not achieved PCD products. Thus, CVD tool to achieve the effect by turning instead of grinding and processing to mirror roughness, and its cost much lower than natural diamond (single crystal diamond) tools.

2.CVD for metal processing

CVD of its high wear resistance, also in the popular woodworking tools. If the wood floor is hot nowadays, due to the performance of Al2O3 laminate flooring is better than melamine wood flooring, the wear-resistant layer is more rigid, hard alloy cutting tools have been powerless Al2O3 laminate flooring, you must use diamond tools. Two years of market survey, CVD is a high-quality woodworking tool materials.

For stone and other hard and brittle materials, glass fiber, carbon composite materials and organic composite materials processing, CVD is the ideal tool material.

3. Precision Tool

Common tool materials (such as high speed steel) and carbide materials due to its own properties (such as wear resistance, hardness, etc.) influence, it is difficult to achieve very high accuracy, such as plate making industry with the plate finishing knife, used in jewelry industry Jewelry knife (commonly known as split took knife) and so on. Such tool requires its own high precision and low surface roughness (roughness Ra0.05μm), using high-precision grinding machine (spindle runout to 0.1μm), made of the surface roughness of CVD Ra0.05μm Precision Tool , the size accuracy 5μm, has been used for plate processing and security trademark processing, the effect is good, the surface roughness of up to Ra0.012μm.

Currently, CVD has been widely used in super-finishing tool, finishing, semi-finishing and continuous cutting, PCD cutting tool wear resistance than the 2 to 10 times higher, the cost performance is superior to other diamond tools. Foreign periodicals in 1998, according to reports, the cutting blade with the CVD market is about 1.5 billion U.S. dollars.

Third, the bright future

Department of super-abrasive, GE NortonDiamondFilm companies that: a lot of the production site is currently not fully diamond advantage. The reason is that many machine tool speed and torque are not enough to guarantee the efficient functioning of the tool.

In addition to mechanical problems, there is the difficult problem is to convince people of the production plants, Do not just staring at the diamond (PCD or CVD diamond) set the initial price, but to see it, cost savings and performance improvements benefits. You can make diamond tool at a higher than normal speed operation (depending on machine performance may be), to improve output. At the same time, tool change times less. Assumed life of diamond carbide is 50 times more than 100 times, you do not often stop by.