What is in this article?:
- Modernizing Controls for Finishing Forgings
- Adaptive Control for Out-of-Round Hammer Forgings
A remanufactured three-stage lathe line gets a boost in productivity thanks to a state-of-the-art CNC concept
- Hard-surface machining
- CNCs, motors, and AC drives
- Rebuilt overhead gantry
Standard Forged Products chose Euro Machinery Specialists to remanufacture a three-stage machining line designed 50 years ago to finish rail and locomotive axles.
Rebuilding equipment is standard practice for forging operations – but updating vintage machinery with advanced automation can be a revelation for operators so well schooled in traditional manufacturing processes. Standard Forged Products, McKees Rocks, PA, enlisted Euro Machinery Specialists to remanufacture a three-stage lathe machining line that has been used to finish rail and locomotive axles for at least 50 years. Owing to the change from hydraulic tracer to advanced CNC control, DC headstock to synchronized AC drive, and hydraulic to AC axes servo motion, converting steel billets into hammer forged finished axles has been substantially improved.
“Standard Forged Products was looking for a significant productivity increase to bring the ‘three stage’ system back to OEM-level cycle times, due to punishment from many years of heavy-duty machining around the clock,” recalled Karl Engelke, vice president of Euro, Menomonee Falls, WI. “Peak operating performance was originally about a four-minute cycle time for a completely machined axle, start to finish. Over the years, cycle times dwindled and, when we received the project, cycle time was over seven minutes per axle, due to numerous mechanical and electrical problems and failures — therefore, this Snyder line was in need of a total overhaul and remanufacture.
“Our overall three-year contract with Standard Forged Products for this project required complete rebuilding, from the ground up,” Engelke continued. “Since the old iron was extremely sound, it was an ideal candidate for remanufacture, including everything from the key motion control package, consisting of three Siemens Sinumerik CNCs, Simotics motors and Sinamics drives at each lathe, plus Simatic PLC and HMI as the master of the entire line.”
He noted that on all three machines, four-inch diameter ballscrews and bearing blocks capable of over 44,000 lbs. of thrust were designed to replace the original hydraulic cylinders. The line required complete rebuilding of all headstocks and hydraulic chucks, replacement of most gears, shafts, and Timken bearings. All new hydraulic and lubrication systems were designed and integrated.
Other notable improvements were double-way wiper systems and special sheet metal guarding to protect the operators and machine components from the heavy chips. The entire project required over 11,000 man-hours of work.
In addition to remanufacturing the three lathes, Euro re-engineered and provided an entirely new overhead gantry workpiece shuttle system. This massive automated system, having been converted from hydraulic to servo operation, performs barcode scanning and moves the raw forged axles into the roughing lathe’s Stage One position for left and right journal section machining. Then, it transfers the workpieces in sequence to the next two machining stages for center-section roughing (Stage Two) and finish cut (Stage Three) — finally transferring and offloading the completed workpieces to the holding area.
The turning line synchronizes left-head and right-head, 150-hp Simotics M-1PH8 motors for both Stage One and Stage Two roughing lathes. According to Engelke, the rough cut is “perhaps the most aggressive and impressive cutting operation in the machine tool industry today.”
On each tool block, multiple large diameter button nose cutting tools with high carbide content plunge into the forging at a minimum ½-inch depth of cut at approximately 0.200 inch-per-revolution. The high-carbon tool allows for extremely high tool pressure and resists high temperatures, which puts the heat into the chip, not into the cutting tool.
Standard Forged Products has the cutting formula down to a science — however, the challenge was to optimize the process even further, thanks to the incredible power and torque from the headstock motors and newly designed large ballscrews, gear reduction and servomotors versus the old hydraulics systems.
Because the axles are hammer-forged, the surface is extremely difficult to break and machine with any consistency; therefore, tool stability and rigid machine components are critical to the integrity of the process.