In-Die Hydraulics to Manage Force Distribution
|Adding a programmable hydraulic cushion to this die, which stamps a stainless-steel range top, eliminated the need to use a press equipped with a programmable cushion.|
“The ability of all-hydraulic systems to manage in-die force distribution,” says Bogre, “has led to a surge in the use of these systems, from a relatively low installed base just a few years ago to where the systems now have become industry-acceptable.” Suppliers of hydraulic in-die force-management systems, including Hyson (Brecksville, OH), have developed products that generate as much as 4500 PSI while managing the amount of heat generated during stamping.
Next-Gen Hydraulic Components
“All-hydraulic pressure systems now are more robust than previous generations of products,” says Steve Reilly, Hyson’s manager of product engineering. “Cylinder and valve designs have been optimized, including the cylinder’s ability to flex under load should die alignment become less than perfect. Previous generations of hydraulic systems used more rigid cylinders that restricted motion and required precise die alignment. Not so today.”
Also, state-of-the-art hydraulic systems are more self contained than their predecessors, making them more user-friendly. The packages are much simpler to retrofit to existing dies.
“Metalformers can retrofit the self-contained hydraulic system to add tonnage to an existing die,” says Bogre. “Or, consider the case of a stamper that must move a die from a press with a locking cushion to a press lacking such a cushion. To maintain the locking capability for the die, a hydraulic-system retrofit to eliminate the need for a locking press cushion offers the perfect solution. Having that delay technology as part of the die, rather than the press, provides additional flexibility. Otherwise, the work might have to be outsourced to another stamper that has time on a press with a hydraulic cushion. Keep the force-control technology in the die, and any press can do the job.”
Benefiting New Die Builds
More significant benefits come from using the systems in new-die construction, for those applications where “stampers want to be able to help their customers leverage opportunities to improve their part designs but may be limited in press tonnage,” says Hyson’s general manager Hank Kelm.
“Yet one more trend,” Reilly continues, “lies with companies that operate more than one stamping facility and look to move work among their plants. Keeping the delay technology with the die gives them the flexibility to do this. We recently experienced this with an appliance OEM that took a stove-top design developed and initially stamped in Italy. When the market for this product expanded into the United States, engineers studied best practices and determined that a pad delay was required. However, the U.S. supplier lacked available press time on its cushion-equipped presses, so, it added a delay system to the die using an all-hydraulic setup.”
Also Popular with HVAC OEMs
In addition to automotive and appliance stampers, HVAC OEMs and their suppliers have taken to using in-die hydraulic systems to manage the force profile in the die.
“The new SEER ratings (Seasonal Energy-Efficiency Rating) handed down a few years ago,” says Kelm, “led to the development of thousands of new dies, many of which required delays due to complex part features and forms. Many of these new dies incorporated hydraulic force-control systems—in one case an OEM was able to significantly reduce blank size by 20 percent, resulting in a return on investment for the hydraulic system much quicker than anticipated.”
Summarizing the benefits of recent developments that have made all-hydraulic control in the die accepted practice in stamping shops, Bogre says: “This is technology that allows the stamper to say ‘yes’ to product designers looking to gain an edge on their competition, and ‘yes’ to OEMs specifying the use of advanced high-strength steels.”
“And we’re not stopping there,” adds Kelm, describing continued development efforts underway to help stampers become more efficient and improve productivity. One of the more recent introductions is a press custhion that removes the variability of running dies on different presses.
“For example,” explains Kelm, “consider the common case of a die that’s been developed and tried out in one press, then is expected to run production on another press. Production presses likely have a lot of wear and tear, guidance issues and other mechanical variations that can require the stamper to spend a lot of time tweaking a die that ran perfectly in tryout to get it to run in production. Next-generation press cushions will take that variability out of the equation, by being able to provide the identical force-distribution pattern regardless of the press the die runs in. This will ensure that dies will run perfectly in production immediately after moving from tryout, significantly reducing time to market and providing OEMs in any industry yet another competitive edge.” MF
See also: Hyson Products
Related Enterprise Zones: Tool & Die
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