Home >> Technical FAQs >> axle machining for railroad cars with pcbn inserts

axle machining for railroad cars with pcbn inserts

The axle connects two mono-block rail wheels together in a modern railroad vehicle. It is a very important component that withstands a great amount of stress and heat while ensuring safe and balanced movement of the train. Axles used for electric transit, locomotives and industrial use are usually made of carbon and alloy steels while passenger and freight car axles are made of carbon steels which may be heat treated. Standard indexable polycrystalline cubic boron nitride CBN inserts should be used to turn the train axles on a dual end drive axle lathe. Turning of railroad car axles is usually performed in three phases: roughing, medium machining and finishing. For each of these operations, suitable pcbn inserts with chipbreakers are available to provide efficient and economical production.

Rough Turning Inserts
At the roughing stage, a substantial amount of metal needs to be removed from the initial steel stock at a relatively high speed. Standard round or square shaped inserts such as the RNMG or SNMG series may be used at this stage. The round-shaped RNMG insert has a zero degree clearance angle so it offers the machinist the opportunity to use a cutter that may be set a various angles to achieve the desired rate of metal removal. This insert also has a tight tolerance which complies with the strict regulatory requirements for the machining of railroad wheel sets. Double chipbreakers are available for efficient formation and removal of the windy steel chips. RNMG 190600 and RNMG 250900 are recommended for rough turning of most rail axles.

Medium Machining Inserts
The TNMG 220432 insert may be used for semi-roughing or medium turning of the axle. Some TNMG inserts have three cutting edges while some are manufactured with six cutting edges for faster cutting. The multiple cutting edges make it easy to index the insert and eliminates the need for re-grinding. With double chipbreakers on both sides of the insert, and a cutting edge of 4.76 mm and 3.18 mm nose radius, this insert provides efficient and economical turning of the axle.

Finishing Inserts
Finishing inserts for axle machining are very important because they create the final surface finish. These inserts take off less material than the previous two stages but they must do so with high accuracy. Three types of inserts are commonly used for this phase: diamond, triangular and square shaped inserts. The SNMG 120412 pcbn insert is a solid corner cbn insert with multiple cutting edges. Some inserts are manufactured with eight cutting edges while some have four. Each cutting edge has a nose radius of 1.2 mm which is suitable for creating the desired surface finish. It also has double chipbreakers on the two sides of the insert. Similarly, the diamond-shaped CNMG 1906 insert may be used to finish the edges of various sections of the wheel axle.

Conclusion
The surface finish quality on the wheel axle has a direct impact on the smooth running characteristics of the train and its energy efficiency. Therefore, it is vital to select the right kind of pcbn insert that can provide an extremely high degree of precision and reliability as well as a cost-effective cutting process.

We export PCBN insert to world wide countries, such as USA united states, Germany, UK united kingdom, Italy, France, Turkey, Russia, Saudi Arabia, United Arab Emirates, Ukraine, Israel, Canada, South Africa, South Korea, Japan, Australia, New Zealand, Finland, Sweden, Norway, Danmark, Switzerland, Poland, Czech,Ireland, Holand, Belgium, Greece, Croatia, Spain, Portugal, Egypt, India, Philippines, Cambodia, Thailand, Malaysia, Singapore, Indonesia, Mexico, Brazil, Colombia, Chile, Argentina etc.