Many punchers struggle with deciding what to do with their older presses that experience frequent downtime, can no longer punch complex parts, and are constrained by outdated control infrastructure. The solution to these challenges could only be a servo retrofit.
It is well known that the complex systems used to drive and generate power in obsolete hydraulic and mechanical punch presses are prone to unplanned, prolonged downtime and costly repairs. In-house maintenance personnel with the ability to service or repair presses are scarce, leaving many manufacturers at the mercy of OEM scheduling or external repair companies.
Newer press technology uses linear servo drives that eliminate these maintenance challenges and provide significant performance benefits. By retrofitting existing hydraulic and mechanical presses with all-electric systems, punchers can reap the benefits of servo presses at a fraction of the cost and lead time.
Linear servo drive systems are simple, modular, and made up of off-the-shelf components that can be used to replace hydraulic or mechanical flywheel systems on existing presses. This makes crankshafts, flywheels and hydraulics obsolete and reduces the number of press components by up to 80%. Fewer components mean less maintenance time, faster troubleshooting and millions of cycles before maintenance is required. Standard servo motors are readily available and accessible with comparatively short lead times.
Best Applications, Benefits
Any forming or stamping application that requires up to 500 tons of force is a candidate for a linear servo retrofit. This retrofit is also an option for high temperature applications such as automotive hot stamping and aerospace hot titanium forming, as it eliminates the risks associated with traditional fluid power systems such as fire, oil leakage, overheating and part contamination.
Linear servo actuators offer users many advantages over their hydraulic and mechanical counterparts, bringing significant improvements in performance, uptime, reliability and part quality.
Full tonnage at every point. A key benefit is the ability to provide full tonnage at any point in the lift. This eliminates nominal tonnage points from bottom dead center, preventing users from derating tonnage on long draws and strokes. With the ability to initiate maximum press force at any point in the stroke, users can control multiple cycle parameters including position, pressure and speed.
Parallelism. The nature of linear servo controls results in extreme parallelism during each cycle. This in turn results in improved die handling and lower die maintenance costs compared to traditional presses. Actuators help reduce tool set-up times because they do not require the use of parallels or counterbalance adjustments. The technology also includes built-in tonnage monitoring and overload protection on each stroke.
Rigidity, force accuracy. Precision linear servo actuators offer excellent rigidity as well as high precision and force accuracy. Some of the linear servo drive systems available today can achieve position repeatability of up to +/- 0.0005 inch. They also have force and position feedback at a rate of one sample per millisecond.
energy efficiency. Because linear servo actuators consume energy only when needed, energy consumption can be reduced by up to 70% compared to traditional hydraulic systems. This is especially important for long holding cycles and complex pulling work.
Clean, sure. The elimination of flywheels, crankshafts, external lubrication systems, energy management systems and hydraulic power packs makes these presses safe, clean and sometimes more reliable than their hydraulic or servo-mechanical counterparts.
For punch presses with existing press frames still alive, a linear servo upgrade can be an excellent option to increase production throughput on their existing presses.