When Bending Capabilities Reduce Welding Requirements

This fabricator faced competitive demands for higher precision and faster job delivery. How did they respond? They purchased an advanced press brake that enabled them to exceed those competitive demands, reduce downstream operations and fill job orders at unmatched rates.

Established in 1968, Marlin Steel Wire Products (Baltimore, MD) manufactures carbon steel or 304 stainless steel custom wire baskets with welded frames and heavy wire mesh linings that are ideal for rough industrial handling applications, dipping, ultrasonic cleaning, sorting, degreasing, and parts storage. The company has grown to become a preferred fabricator of sheet metal and wire products made from carbon steel, stainless steel and exotic alloys that can have plated, electropolished and powder coated finishes.

Facing increased demands for higher precision, faster speed of delivery of sheet metal work and continued operator safety, the shop acquired a TruBend 3120 press brake from Trumpf (Farmington, CT) that provides 132 tons of force and a 122 in (3098 mm) bending length to accelerate delivery times. To improve the precision of the bends being made, the press brake has a superb 0.25 deg angle tolerance along the entire bed length of 122 in and a ram tolerance of 0.0004 in (10 microns).

As part of Marlin’s plan for expansion to meet increasing demands, this press brake enabled the plant to fill job orders at unmatched rates. Kashyap Alur, a Marlin Steel mechanical engineer who spearheaded projects for Delta Airline’s Pratt Whitney Engine racks and baskets, explains that “The four-axis backgauge enabled us to perform complex bends so that the designs can have fewer welds. This allows us the conditions to have sheet metal fabrications with the integrity and consistency of steel as opposed to welding. Bending is also faster to execute.” The beam on the brake moves at 200 mm/sec as it reaches the bending edge, allowing for faster cycle speeds.

Being able to replace welds with bent metal also meant reduced part inventory and carrying costs, open floor space, increased welding capacity downstream, and an overall reduction in the speed of job delivery.

Christopher Elwood, another Marlin Steel mechanical engineer that launched the Becton Dickinson and Medtronic project, insists the best part of this press brake for sheet metal fabrication is its ability to download the part directly from the same AutoCAD software used to design the shop’s punch layout programs, leaving software formats fully integrated. Most significant is the elimination of transposition errors. According to Elwood, “There is more than $50,000 in software alone to integrate all these systems. We have the most seamless system in the industry.” The system simplifies the process of designing parts, which allows the company to ship faster and more efficiently.

“Quality is the king here,” smiles Marlin Steel mechanical engineer Daniel Hegarty, who was instrumental in the manufacturing of telecommunication racks and forms shipped to China, Singapore and Ireland. Combined with a self-regulating crowning system, the brake uses four-cylinder drive technology to reduce sagging in the beam and its flat construction leaves plenty of edge clearance for precision bending. Production cycle times are improved further by reducing rejected parts with an automatic controlled bending sensor that enables the first bent part to be a finished part.

The ultra-precise tooling on this press brake means the shop can handle an array of angled bends by using up to four CNC-controlled backgauge axes. All of these capabilities bring flexibility to all job specifications, no matter their shape, size or placement, notes Tony Witt, a Marlin Steel mechanical engineer who was responsible for the Northrup and Raytheon projects. He adds that the “long bed and 132 tons of force broadens our ability to quickly bend thicker and bigger sheets than ever before.”

Most importantly, the TruBend 3120 reflects the championing of safety in this shop by conveniently integrating a BendGuard safety mechanism that combines operator safety and productivity into the bending process. This system uses laser technology to sense interfering obstacles, such as a human hand. Even at rapid speeds of up to 220 mm/sec, the operator is safe due to two laser bands which move ahead of the pressure bar. Only after the lower laser band (which consists of three beams like the one above it) reaches the mute point does the pressure bar move at working speed. If one of the two laser bands is broken by an obstacle, the machine stops.

After the obstacle is removed, the bending process can continue at rapid speeds when the operator reactivates the foot pedal. Interfering contours that sometimes arise when bending basins or boxes are carried out with the same productivity by using the “box bending mode.” All of the programming functions and displays are integrated into the TASC6000 machine control system, so a separate control unit is unnecessary.

Another advantage of BendGuard happens during the setup of tools on the press brake. While other safety systems must be pushed to the side and then readjusted, this mechanism easily and conveniently lowers into a vertical setup position. After the setup it is lifted back into a defined working position that saves the operator lots of time.

These intrinsic values of performance, quality, reliability, and safety are blended into the factory workspace and its machine technology by the advanced drive technologies used on this new press brake that guarantee low energy consumption, including the automatic shutdown of its hydraulics in longer downtimes to reduce energy consumption.

According to Drew Greenblatt, the president of Marlin Steel, “Along with purchasing this machine, we have ramped up our intellectual horsepower with the hiring of two more mechanical engineers. This is our secret sauce: 30 percent of our team is mechanical engineers or designers.” This emphasis on innovation is super charging the company’s growth. Marlin Steel was recently selected for a 2012 “Inner City 100” award by the Initiative for a Competitive Inner City (ICIC) that spotlights the fastest-growing companies in America’s inner cities. The list of winners, chosen from among 1,000 nominees, will be presented with awards in May in Boston.