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Railroad Car Wheels Re-Turning By Using Solid CBN Inserts

In virtually all countries of the world where trains are used for freight and human transportation, wheels re-turning is a frequently required operation. For fast and smooth movement, the railroad car wheels need to be re-turned using either an under floor lathe, a universal lathe or a dedicated portal wheel. This will help to remove rust, dents and cracks thereby restoring a smooth and even surface. pcbn inserts are now a vital part of the new tools used to re-turn railroad wheels. Here are some facts about the inserts used for re-turning railroad car wheels.

CBN Inserts for Machining of the Outer Wheel and Rim
Modern tool inserts can machine the whole of the outer wheel in a just one cut. They have two main cartridges fitted with a set of tangentially mounted CBN inserts. For longitudinal turning, a clamped insert with a 2mm corner radius and 19mm length is frequently used. The long side is positioned opposite the machining direction. This kind of insert can be used to handle relatively large cutting depths for either rough or for semi-finishing turning applications.

To machine the rim zone, which is sometimes subjected to great erosion and uneven cracks, a tangentially clamped insert with a radius of 2mm and a length of 19mm will provide faster machining and top quality finish. The depth of cut used while machining is usually between 0.3mm and 12mm. Machining depth is determined by the outer condition before it is set up on the machine for re-turning. When using the cbn turning inserts for deep cutting, the CNC machine carries out the operation over several cycles to extend the tools useful life.

Sizes and Grades of CBN Inserts for Wheels Re-turning
Solid CBN inserts are one of the most suitable kinds of inserts for machining of rail wheels. Rail wheels are made of different grades of cast iron, so that they can withstand the strain imposed when the brakes are applied with a fully loaded train. Due to the toughness of these wheels, it is important to use inserts that can work at very hight temperatures, absorb heat, and provide excellent performance at very high speeds.

Various shapes of solid cbn inserts may be used including: diamond, round, square, triangle and hexagon. But he most widely used for turning rain wheels are the square and round shapes. Examples of CBN inserts that may be used for this type of operation include: RCMX191000V, RCMX201200V and RCMX251200V. These round shaped solid cbn inserts have a cutting length of 19 mm and above. So they can remove more metal in a single pass.

In addition to these solid cbn inserts, dimpled-design clamping inserts may also be used for rail wheels re-turning. These inserts sit more securely inside the tool cartridge and they can withstand the shocks and dynamic loads that occur when machining wheels with deep cracks on the surface. All the vibrations that occur will not prevent the cutting tool from producing a very smooth finish. Examples of dimpled inserts for turning railroad car wheels include: CNML120612, CNML120608, CNML120604, RCMS120600, RCMO120600.

It is very important to use the correct grade of cbn insert while carrying out roughing, semi-finishing or final finishing operations. For low speed cutting, which is usually used for rough machining, the following grades are recommended: CBN350, CBN360, CBN900. For higher speed turning during semi-finishing or finishing operations, it is better to use the following grades: CBN700, CBN750, CBN760, CBN950, CBN960.

Conclusion
Those are some of the important characteristics of solid cbn inserts used for railroad car wheels re-turning. It is important to note that you will obtain the best performance from these inserts if you inspect the wheels thoroughly before machining, and adjust the cutting speed based on the level of damage or corrosion on each wheel.

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