- Created: 2017-06-06
Hydraulic clamping systems help fabricators find competitive advantages
by Steve Brown, press brake product manager, Wilson Tool International
Clamping systems help press brake operators bring increased efficiencies to part runs and reduce wasted mundane movement. But to be competitive with shorter lead times and higher quality products, job shops and production/OEM environments must gain efficiencies with faster setups and more streamlined production. New advancements in hydraulic clamping systems help fill this need.
Time-consuming setups are often a major cause of downtime for fabricators, which was especially true before the advent of the first hydraulic clamping systems. The manual labor for securing the punches and dies involved tightening setscrews or clamp plates. Depending on the length of tooling, significant downtime could occur as a result.
When hydraulic clamping systems came to the market, the simple addition of hydraulic power allowed operators to clamp and seat all the punches and dies in a setup – with the simple press of a button.
Hydraulic power allows operators to clamp and seat all punches and dies in a setup, just by hitting a button.
Early hydraulic clamping systems, however, presented numerous challenges. Under rigorous production schedules, many of the systems simply didn’t have the quality necessary to sustain production. Hydraulic leaks and poor working surface durability were common.
Faced with these challenges in the field, tooling manufacturers were motivated to create more dependable hydraulic clamping products to ensure manufacturing uptime to help maintain production goals.
To give some background, these early systems operate in part whereby a urethane bladder filled with hydraulic fluid pushes a pin inside the beam as the bladder expands with fluid. This action secures the tang of the punch or die in place, which also seats the punch.
Over time, the repeated expansion of the bladder causes it to leak or rupture, leading to hydraulic fluid spilling on the clamping system and press brake. This, in turn, causes considerable unplanned downtime and maintenance to clean up the mess and obtain a new bladder.
Beyond poor-quality bladders, durability concerns arise in the form of worn beams inside the hydraulic clamping systems. Simply put, the beams are not constructed to hold up to the rigorous production levels found in most shops. Within months of installing a new hydraulic clamping system, the soft beams exhibit wear from loading hard tooling, leaving fabricators with concerns about achieving a return on their investment.
The Express Rail modular design allows for faster and less costly repairs to damaged beams.
Push for improvement
Not only were quality and dependability core factors for improving hydraulic clamping systems, decreasing lead times measured in weeks and months was essential. Out of these efforts came the Express Rail and Express Rail 2000 from Wilson Tool International, which deliver an improved bladder made with a urethane composite designed for rigorous press brake operations.
With the Express Rail, the quality of the beams was improved by using a through-hardened 70 RCS (Rockwell C scale) material, making the new beams dramatically more durable compared to early systems, which weren’t hardened at all. As a result, the new beams deliver longer life and greater production efficiencies.
In addition to an improved bladder and a through-hardened beam, fabricators benefit from a modular beam designed to curb maintenance costs and reduce downtime. With the modular beam, damaged components can be replaced without having to replace the entire beam, which isn’t possible with the earlier versions of hydraulic clamping systems. By introducing the modular beam, repairs to damaged beams became less timely and costly.
With the Express Rail 2000, fabricators were provided with an even more durable system, but at a more cost-effective price point. While both systems include the higher quality urethane bladder and through-hardened beam, the Express Rail 2000 offers a uni-body design. While the single beam is through-hardened to 28 to 32 RCS, the Express Rail 2000’s uni-body design costs less but is not as flexible if damage occurs. Because of the uni-body design, damage can lead to replacement of the entire unit.
The uni-body design of the Express Rail 2000 gives fabricators increased durability.
Safety and controls
Key to ensuring safe operations with a hydraulic clamping system is the use of safety tangs. Many older and planer-machined punches don’t feature safety tangs, which can lead to safety issues on the brake. Without a tang, punches can fall out of the system when unclamping or during a power outage, which puts the operator at risk for injury and the machine at risk for damage.
Safety tangs come in many forms and can be retrofitted to most punches used in a hydraulic clamping system. Designed as small hooks or tabs, safety tangs can also be created as buttons that allow the tang to retract.
Retrofitting existing punches or purchasing those already equipped with safety tangs is an important consideration for maintaining safety on the shop floor. Most precision tooling has a safety hook built into the style of tooling as modern clamping systems are designed for precision.
Many clamping designs powered by hydraulics or air incorporate a groove in the tang of the tool to act as a way to secure the tool in the brake and, in the case of punches, seat the tool in the brake. Seating the tool during the clamping process saves a step in the setup, as the brake is ready to bend. Without the seating groove, an additional step may be needed to seat the tooling prior to bending.
Power to the clamp
When implementing a new hydraulic clamping system, fabricators must choose to use a standalone pump to control the system or integrate the clamping system into the press brake controls and hydraulic source. Most commonly, when retrofitting an existing press brake with a modern clamping system, an external hydraulic supply is added to the press brake. If the machine is being purchased new, however, it’s recommended to work with the machine manufacturer to integrate the machine control and hydraulics with the clamping system prior to the machine shipping from the factory.
Should there be a loss of power to the hydraulic clamping system, it will hold onto the punches if the power source features a one-way valve. In power setups that do not include a one-way valve, when the power source fails and there is a loss of hydraulic fluid to the system, punches could fall as a result of the system unclamping.
Allowing punches to fall out of the clamps could cause serious press brake and tooling damage and risk operator injury. Of course, safety tangs would prevent the punches from falling during potential loss-of-power situations. Safety tangs should always be used when operating a hydraulic clamping system for operator safety.
Maximizing time and labor
Seeing a return on investment is crucial for any major purchase. To achieve a quicker ROI, a valuable benefit of hydraulic clamping systems is reduced setup time. A quick-clamping system brings fabricators greater time and labor savings, which, in turn, increase operational efficiencies.
As well as changeover time, fabricators can garner even greater long-run cost savings by choosing a modular hydraulic clamping system that is made of a quality material. Even though the higher initial cost may be a harder hit to the budget upfront, the modular systems can save ample amounts of time down the road. Because the modular beam delivers a higher durability, the beams will last longer. And, when they require repairs or replacement, the modular sections deliver more cost-effective maintenance when compared to replacing a uni-body beam.
With numerous hydraulic clamping systems available, fabricators can assess their existing press brakes and setup requirements to determine the best solution for their production goals and budgets. From simple retrofits to add safety tangs to straight-tanged punch tools or investing in a fully modular hydraulic clamping system, greater efficiencies can be achieved. And greater efficiencies mean leaner practices, more streamlined production, and more competitive prices and lead times.