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Understanding the Makeup of Tungsten Carbide Inserts

Having a firm understanding of the way that tungsten carbide inserts are made will provide you with valuable insight into the best ways to optimize performance. On average, a single work shop can go through thousands of carbide inserts in just one year. An operator can handle dozens of these inserts every day and never stop once to thing about the complex science from which they are derived. Just the basic knowledge of how these inserts are made will do more than impress coworkers at the shop with trivial tidbits. The Carbide Insert Formula The creation of tungsten carbide inserts begins with raw materials. Most of the inserts of today are made up of cemented carbide. Cemented carbide is made by combining cobalt with the tungsten carbide. The hard particles found in the inserts are tungsten carbide, while the cobalt acts as the glue that holds the whole thing together. The simplest way to alter the cemented carbide properties is with the grain size of the tungsten carbide. Large grains that fall in the three to five micron range will give you softer material. However, the rate of wear will be much higher. The smaller grains that are less than a micron will provide you with a harder material that is much more resistant to wear. On the other hand, inserts made with small grain tungsten carbide will also be much more brittle that those made with the large grains. For use in applications with incredibly hard metals, tungsten carbide inserts with small grains are going to be the best option. On the contrary, when the application involves interrupted cuts or situations where a tougher insert is required, the larger grains will be the ideal choice. By altering the ration of cobalt to tungsten carbide, it is possible to manipulate the insert properties. Cobalt is a much tougher and softer material than tungsten carbide. Therefore, reducing the amount of cobalt in the formula will result in a much harder insert. However, while the insert may in fact be harder, it is going to lose a considerable amount of its resistance to wear and it will also be more brittle as well. When you are aware of the way that the grain size of the tungsten carbide and the ratio of cobalt can affect the durability and strength of tungsten carbide inserts, you will be able to choose the ones that will work perfectly for your specific...

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PVD Materials: Focus On Thermal Evaporation

When it comes to thin film deposition, various techniques and materials are available to the industry. A common choice for some industries is physical vapor deposition (PVD) using PVD materials. It is popular for producing reliable and suitable components for the electronic and optical industries. Exact application of this thin film coating involves one of several techniques. They include sputtering, ion plating and evaporation. Thermal Evaporation One of the most simple and common means of PVD is thermal evaporation. In essence, it involves the heating of the right materials in a vacuum chamber. They remain in this state until the surface atoms of the materials are energized enough to vacate the surface. They rise in something described best as a “particle cloud”. This allows them to travel across the vacuum chamber until they reach the substrate material. They then coat it. The coating may be thin or thicker. The former is applicable to plastic coatings. Depending upon the thickness of the thin film coating, the result will be more decorative (thin) than protective (thicker). The distance between the substrate and the coating materials is crucial to the technique of applying PVD materials successfully as is the choice of heat source. Heat Sources for Thermal Evaporation Two principal means of heating the PVD material are: Filament Evaporation E Beam Evaporation Each has its advantages and disadvantages yet both are simple and cost-effective sources of heat for the process. Filament Evaporation This comes in many types or style including “boats.” A filament is an electrical resistive heat element. It works with low voltage but requires high current voltage to function as required. E Beam Evaporation Using an electron (e) beam as its heat source, this device is much higher tech than that of filament evaporation. It requires caution since the voltage is as high as 10,000 volts. For heating up PVD materials and completing the transfer to the substrate, an operator will use what is called an e-beam “gun.” For those who employ this method of evaporation, it is essential to pay extemely close attention to all safety measures. PVD Materials and Thermal Evaporation The choice of what technique a company will use to achieve the desired result will depend upon several factors including the substrate material, the purpose for the application of a thin film coating and, of course, the choice of the PVD material. Thermal evaporation, while no longer as popular as it has been in the past, still enjoys its proponents. They cite its simplicity as reasons for their choosing this method over others. In addition, using the right PVD materials as part of an environmentally friendly option, does make the technique more...

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