Published on November 23rd, 2022 📆 | 5107 Views ⚑0
How stamping manufacturers retrofit presses with linear servo technology
Many stampers struggle with deciding what to do with their older presses that incur frequent downtime, are no longer able to stamp complex parts, and are limited by an outdated controls infrastructure. The resolution for these challenges just might be a servo retrofit.
It’s widely known that the complex systems used to power and build force within aging hydraulic and mechanical stamping presses are prone to unplanned, extended downtime and costly repairs. In-house maintenance personnel with the capability to maintain or repair the presses are rare, leaving many manufacturers at the mercy of OEM scheduling or third-party repair contractors.
Recent press technology uses linear servo actuators that eliminate these maintenance challenges and provide substantial performance benefits. By retrofitting existing hydraulic and mechanical presses with fully electric systems, stampers may gain the benefits of servo presses at a fraction of the cost and lead time.
Linear servo actuation systems are simple, modular, and built using standard, off-the-shelf components that can be used to replace hydraulic or mechanical flywheel systems on existing presses. This renders crankshafts, flywheels, and hydraulics obsolete, reducing 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 servomotors 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 also is an option for high-temperature applications like automotive hot stamping and aerospace-related titanium hot forming because it eliminates the risks associated with traditional fluid power systems, such as fires, oil leakage, overheating, and part contamination.
Linear servo actuators provide users with many benefits compared to their hydraulic and mechanical counterparts, bringing significant improvements in performance, uptime, reliability, and part quality.
Full Tonnage at any Point. One main benefit is the ability to provide full tonnage at any point in the stroke. This eliminates rated tonnage points from bottom dead center, preventing users from derating tonnage on long draws and stroke. With the ability to initiate maximum pressing force at any point through the stroke, users can control several 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 simplify die setup times because they do not require the use of parallels or adjustments for counterbalance. The technology also includes built-in tonnage monitoring and overload protection with each stroke.
Rigidity, Force Accuracy. Precision linear servo actuators provide excellent rigidity plus high precision and force accuracy. Some of the linear servo actuation systems available today can reach positional repeatability up to +/- 0.0005 in. In addition, they have force and positional feedback at a rate of one sample per millisecond.
Energy Efficiency. Because linear servo actuators use energy only on demand, energy consumption can be lowered by up to 70% compared to traditional hydraulic systems. This is especially important during long dwell cycles and complex draw work.
Clean, Safe. The elimination of flywheels, crankshafts, external lubrication systems, energy management systems, and hydraulic power units renders these presses safe, clean, and sometimes more reliable than their hydraulic or servomechanical counterparts.
For stampers with existing press frames that still have life left in them, a linear servo upgrade may be an excellent option for increasing production throughput on their existing presses.