The text appears to be a passage on the use of PCBN (Polycrystalline Cubic Boron Nitride) tools in machining processes. Here are the main points:
* PCBN tools have lower resistance compared to carbide tools, making them suitable for treating hardened steel, wear-resistant alloys, and grey cast iron with high hardness.
* PCBN tools require high cutting forces, which demand a machine-tool system with high rigidity, particularly when machining hardened steel.
* To prevent tool damage, the tool overhang should be kept as short as possible, and any awkward shapes or inclusions on the part surface should be removed before machining.
* For parts with high hardness and irregularity, PCBN tools are brittle and susceptible to impact, so a chamfered edge should be applied before machining.
* The two examples provided demonstrate the use of PCBN tools in machining processes, with varying part materials and machining conditions.
* Cubic boron nitride has specific requirements for machining, such as cutting dosage, feed, and depth of cut.
The geometric parameters mentioned include:
* Main angle of deviation
* Arc radius
* Tool overhang
* Chamfer angle and length
These parameters are crucial in determining the performance and lifespan of the PCBN tool.
