Post by khatunejannat on Feb 15, 2024 0:22:35 GMT -5
On the right, lever clamping tool holder with interchangeable cutting insert (Euskron SA). But plates welded to a handle still presented a problem, and that was sharpening. The most desirable alternative was a plate that was removable and interchangeable, with a specific geometry, to ensure repeatability. The welded plate was thus replaced by a mechanically fixed interchangeable plate. This brought with it the development of interchangeable inserts, beginning in the 1960s. It is worth highlighting the existence of the so-called CERMETS (the word comes from the CERAMIC – METAL symbiosis), a quality formed by ceramic particles in a metal binder. More specifically, it is actually made up of titanium carbide (instead of tungsten) and nickel as a binder metal. Among other advantages, it has high resistance to abrasion. The ceramic The most common ceramic materials are based mainly on alumina (aluminum oxide) and silicon nitride . The main advantages are that they offer high cutting speeds and can withstand a high temperature on the cutting edge (up to 1500º), which allows them to work without coolants .
The main drawback is its high fragility. Figure 3. Ceramic inserts for machining gray cast iron (Kennametal). New materials: CBN and Polycrystalline Diamond The discovery of cubic Cocos Islands Keeling Email List boron nitride or CBN (Cubic Boron Nitride) is due to RH Wentorf of General Electric, in 1957. However, it was not until the end of the 70s when the use of CBN became widespread. Due to its crystalline arrangement similar to that of diamond, it has high hardness even up to a temperature of 2000ºC and is more tenacious than ceramics. It is generated by the treatment of hexagonal boron nitride at high pressures and temperatures, in the same way that artificial diamond is generated from graphite . The binder is usually ceramic or titanium nitride. Figure 4. On the left, turning with CBN inserts.
On the right, detail of a “Wiper” insert with CBN tip (Mitsubishi). In the first half of the 1970s, polycrystalline diamond or PCD appeared, after General Electric's Schenectady Laboratories produced manufactured synthetic diamond in December 1954. Figure 5. Diamond-tipped turning inserts for aluminum (WNT Ibérica). It is the hardest known substance and therefore has the highest resistance to abrasion. On the other hand, it is extremely fragile, a temperature of 600° cannot be exceeded in the cutting zone, and due to its high chemical affinity with iron it cannot machine ferrous materials. It is currently used for turning and milling operations , specifically when excellent surface finish and precision are required. For comparison, they can reach cutting speeds of up to 2000 meters/minute in aluminum machining.
The main drawback is its high fragility. Figure 3. Ceramic inserts for machining gray cast iron (Kennametal). New materials: CBN and Polycrystalline Diamond The discovery of cubic Cocos Islands Keeling Email List boron nitride or CBN (Cubic Boron Nitride) is due to RH Wentorf of General Electric, in 1957. However, it was not until the end of the 70s when the use of CBN became widespread. Due to its crystalline arrangement similar to that of diamond, it has high hardness even up to a temperature of 2000ºC and is more tenacious than ceramics. It is generated by the treatment of hexagonal boron nitride at high pressures and temperatures, in the same way that artificial diamond is generated from graphite . The binder is usually ceramic or titanium nitride. Figure 4. On the left, turning with CBN inserts.
On the right, detail of a “Wiper” insert with CBN tip (Mitsubishi). In the first half of the 1970s, polycrystalline diamond or PCD appeared, after General Electric's Schenectady Laboratories produced manufactured synthetic diamond in December 1954. Figure 5. Diamond-tipped turning inserts for aluminum (WNT Ibérica). It is the hardest known substance and therefore has the highest resistance to abrasion. On the other hand, it is extremely fragile, a temperature of 600° cannot be exceeded in the cutting zone, and due to its high chemical affinity with iron it cannot machine ferrous materials. It is currently used for turning and milling operations , specifically when excellent surface finish and precision are required. For comparison, they can reach cutting speeds of up to 2000 meters/minute in aluminum machining.