Customized CNC Upgrade Simplifies Railcar Axle Grinding

A comprehensive upgrade of classic high power centreless grinding machine tools is helping a leading railcar axle manufacturer to greatly simplify precision grinding operations on axle forgings. A key element of the project – which has been managed by APeC Integration Services, Inc – is the retrofit of customized CNC control based on NUM's powerful Flexium platform.

Based in Wattsburg PA, APeC is an electrical systems integrator specialising in upgrading machine tools with modern PLC and CNC control systems. Established in 1989, the company has built a reputation for enabling clients to maximise the longevity and performance of their machine investments. Key retrofit services include upgrading servo and spindle motors and drives, PLC integration and custom machine controls, and complete CNC replacement.

The machine tools in this particular project are high capacity Landis centreless grinders, which utilise a dressable grinding wheel and a plunge grinding cycle to create precision profiles on railcar axle journals. During grinding, both the axle workpiece and the grinding wheel rotate in the same direction, which means that the two surfaces are moving in opposite directions at the point of contact, resulting in smoother operation. Once the machine is up to speed, the grinding wheel is fed – or 'plunged' – into the workpiece and makes continuous contact with a single point along its length. The plunge action is controlled by a servo-driven axis grinding at several feed rates, with transition points monitored by in-process gauging. A built-in automated two-axis dresser system with a diamond tipped tool is used to dress the grinding wheel whenever necessary.

This is the second time that APeC has improved the performance of these grinders with control systems based on NUM CNC kernels. The original machines were hydraulically actuated and equipped with tracer type wheel dressing systems. In the mid 1990's, APeC performed a full mechanical and electrical upgrade on each machine that included retrofitting a modern CNC system and in-process gauging instruments. On that occasion, the company based the upgrades on NUM's Power 1060, which at the time was regarded as one of most flexible and user-friendly CNC systems on the market.

After a further 20 years' full-time service in a busy production environment, the machines became due for another mechanical and electrical upgrade. APeC had supported the machines and worked closely with their operators throughout this period, during which time it had also developed a number of ideas for making the machines even easier to operate and more productive. The upgrade program offered the ideal opportunity to put many of these ideas into practice.