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Automated Punch-Press Setup Secures Production Boost

Saturday, December 1, 2018
 

With a single head punching machine, the entire punch moves the head up and down.
With a single-head punching machine, the entire punch moves the head up and down. This technology creates clearance for 90-deg. bends to 3 in. high, key to progressive bending.
Securing the savings of individuals and industries just doesn’t happen automatically; or does it? For Fort Myers, FL-based Vault Structures, Inc. (VSI), the answer is it does.

Founded in 1987, the company produces custom high-security blast panels, U.L.-listed modular vault panels, vault doors and safes, as well as lockers and safe deposit boxes for the banking, jewelry and pharmaceuticals industries. Business is so good that last year, with its safe-deposit-box output rivaling the industry’s biggest names, VSI recognized that in order to keep pace with increasing demand by commercial and financial institutions, it had to increase its automation efforts at its 40,000-sq.-ft. facility beyond the three older turret punches and press brakes, which are still in use.

As a result, CEO Kevin McNamara and design engineer Sara Cheney attended FABTECH 2017 in Chicago, where they evaluated systems by Akron, NY-based LVD Strippit, ultimately selecting a Model PX 1530, a 20-metric-ton single-head punch press that can punch, form, tap and progressively bend a 90-deg. angle to 10 ft. long. Paired with a stand-alone FA-P single-sided load/unload system to eliminate manual sheet handling, it can operate unattended until its metal supply runs out.

A CPA by background, McNamara knows his way around an ROI spreadsheet, but says he didn’t need one to evaluate the new equipment. “It was obvious,” he says, “that by having a machine that could load and unload itself, and perform secondary operations, the system was going to pay for itself very quickly. Automation was essential for meeting production goals, so it was a no-brainer.”

Since installation in early 2018, VSI has dedicated the system to producing sheetmetal parts for its American-series safe deposit box, made of 22-gauge galvanized steel.

“We need 5000 to 6000 shelves per month to meet demand,” says Cheney. “It used to take an operator about 40 hr. to make 1800 shelves. We now get those off of our new punch press without even needing an operator. Further, the cycle time for a complete part is within 1 min. of what it took us on our old punch press, and that was without any bends.”

Overall, Cheney estimates that moving to an automated system cut production time by 60 percent or more, as VSI now can produce 1800 shelves in 12 hr.

Enables Combined Operations

Parts remain tabbed togehter until ready for removal
Parts remain tabbed together until ready for removal. The punch separates them, followed by automatic removal via pneumatic grippers.
VSI’s more complicated sidewall parts measure 15 by 20 in., have three offset bends in the middle with two slots in each bend, a 90-deg. bend along the short edge with six countersunk holes, and three 90-deg. bends (all short tabs) with one countersunk hole each on the long edge.

Previously, operators would manually load a single blank on the press, punch the part, slots and holes, and keep the parts tabbed together. Once the sheet came off the punch, the operator would shake the parts out of the skeleton, stack them on a pallet and manually fold the skeleton. A fork truck would move the pallet to a press brake where an operator would bend the three offsets, make the 90-deg. bend on the short edge, and rotate the sheet to bend the tabs on the long side. The operator would then stack finished parts on the pallet and move them to the assembly area.

Now, a forklift driver places a stock of raw sheets on the automated system’s loading table, typically 200 to 300 sheets depending on size and thickness. The loading table then slides into position underneath the gantry. To eliminate double loading, a blast of compressed air hits a corner of the sheet while two of the loader’s 12 pneumatic grippers grab the corner and shake it. The gantry then loads the blank from the left side of the punch table, where three programmable and relocatable clamps grip it.

After punching, countersinking holes and bending (more details shortly), the loader’s pneumatic grippers lift a completed wall off of the table and place it on a pallet, stacking walls consistently. After removing all walls, the press grippers pull the skeleton to the right and push it through a drop chute.

“Our punch can make progressive bends, so we now bypass the press brake completely,” says Tony Mendez Jr., VSI shop foreman, who’s also the programmer and one of three punch-press operators. “Because the machine can run unattended, it frees me to take care of the rest of the shop, which takes a lot of time.”

This gantry runs unattended, loading blanks and unloading finished parts
This gantry runs unattended, loading blanks and unloading finished parts from the right side of the system.

In addition to unattended operation, McNamara quickly ticks off the benefits of an all-in-one, automated operation: “We make a complete part without secondary or tertiary operations. We eliminate a lot of the planning. There are no material-flow delays, because once a part comes off of the punch, it’s ready to go to the safe-deposit-box department. Previously, punched material could sit on the floor if brake presses were tied up with other jobs. Now, all we really need to know is when the safe-deposit-box department needs parts.”

Replaces Press-Brake Work

VSI employs many previously used custom tools. “We countersink from the bottom up,” Cheney says. “We use offset rolling tools, and we also do the offsets from the top down and the bottom up. The PX 1530 has a movable die section along with a movable punch section on top. It opens the ability to do different things. We also use a bending tool when progressive bending. We can bend to 3 in. high in our applications, which is important for certain product lines. No other machine on the market can bend to that height.”

Progressive bending employs a 3.622-in. tool to create a bend of about 30 deg. After the first bend, the table moves the sheet 3.622 in. and the tool then makes another 30-deg. bend, and so on. A 90-deg. bend takes three passes.

“That normally is a press-brake operation,” says Cheney. “When forming, where we add 90-deg. bends and offsets, that’s actually two operations on a brake press, unless using fully staged tooling. We’ve found that, over a period of time, staged tooling on a press brake will wear and not provide quite the same bend parameters. We actually perform several forming operations on every part for our safe deposit boxes. We preform counter sinking and 90-deg. bends. These all would require other operations without the PX 1530.”

Learning to Maximize Sheet Use

Cheney and Mendez work as a team to maximize sheet utilization.

“It’s a challenge to figure out how small of a skeleton we can leave,” says Cheney. “Because this machine can operate in a lights-out mode, we slow the speed. If we run it full-speed, and we’re trying to leave very little metal to hold things together, it will fold up the sheet during punching or bending. It was a learning curve to figure out speeds to give us the best sheet usage and the best production speed.”

Finished shelves for safe deposit boxes
A completed VSI American-series safe deposit box
Finished shelves for safe deposit boxes stack up, waiting to be moved to the assembly area. A completed VSI American-series safe deposit box.
Mendez notes that faster is not always better when trying to move a 5 by 10-ft. sheet. “That’s a lot of sheetmetal to move around a table when it’s held just by three grippers on one edge,” he says. “Smaller parts have more skeleton and we run them faster, but when we get into larger parts where we produce six to 12 parts from a big sheet, that doesn’t leave very much skeleton to pull the sheet around.”

Cheney adds that leaving large parts tabbed together may result in sharp points that require deburring. To eliminate this hazard, the press punches out the tabs as the final step before removal of a finished shelf.

More Applications Ahead

Due to high customer demand, VSI has only had the time to program its automated system for a limited number of parts. When the company enters its slow season in winter, it will develop designs and programs for other parts, such as vault-door parts made from 12-gauge steel. This part must be punched out and have holes made and tapped, which currently requires moving the part to the machine shop.

“With a system that can punch, form, tap and bend, we can send a completed part straight to the door department,” says McNamara. “For fabricators that run punch presses eight to 10 hr. per day to make large quantities of parts, an automated system that eliminates secondary operations is a clear choice. Even for a small company, a job shop with maybe three or four employees, a machine that runs by itself frees those employees to do something else.”

“The Strippit setup is by far the biggest investment we made in turret punches,” says Cheney. “It has paid off well in the way it produces parts and eliminates secondary and tertiary operations. It was a good move.” MF

Article supplied by LVD Strippit, Akron, NY; 716/542-4511/ 800/828-1527, www.lvdgroup.com.

 

See also: LVD-Strippit, Inc.

Related Enterprise Zones: Automation


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