Fabrication Shop Bends to Today's Needs

A state-of-the-art panel bender enables a Minneapolis, MN-area metal fabricator to meet its customers' needs for precision-formed parts, on time, at competitive prices.

By Leo R. Rakowski, Contributing Editor

Why would a metal fabricating job shop buy a panel bender? "To stay competitive, we must have the capabilities that customers are looking for," explains Mike Einan, president of Dalsin Industries, Inc., Bloomington, MN.

"We have some special capabilities that help to make us stand out from the competition, but we always are looking for new technologies that will enable us to broaden the range of services we can offer to our customers," adds Dave Dalsin, one of the firm's principals. "Metalforming is the core of our business. Our panel bender allows us to form many parts more efficiently than we could using more conventional methods. That, in turn, allows us to add more value to our customers' parts. This adds up to better, more consistent parts at more competitive prices."

"Production demands keep increasing," Einan says. "If we did not invest in modern processing technology to improve our efficiency, our costs would rise to the point where customers would find our parts too expensive. Investing in equipment like the panel bender helps us to keep our competitive edge."

Dalsin Industries purchased its Model P4-2112 panel bender from Salvagnini America Inc., Hamilton, OH. The P4 is a CNC forming machine that bends flat, prepunched, sheet metal blanks into completely formed parts with one or more bends along one or more sides. An almost unlimited number of up and down bends can be made in the panel without removing it from the machine.

The Salvagnini P4-2112 can accommodate sheet steel blanks up to 48 in. by 84 in. or 94 in. measured diagonally. It can handled steel thicknesses ranging from 0.015 in. to 0.098 in. (approximately 12 gage).

This Salvagnini P4 CNC panel bender enables Dalsin Industries to meet its customers' needs for precision-formed parts, delivered on time, at competitive prices.

Once the flat blank is loaded, machine operation is completely automatic. This includes rotating the blank to present one or more edges to the bending tools and forming of the bends. The operator's responsibilities primarily consist of loading and unloading the machine, and monitoring its operation.

Because presentation of the blank to the tooling and bending operations are controlled by the machine rather than the operator, bends are accurate and results are consistent from part to part and from batch to batch. Depending upon the skill of the operator, the potential for human error, which characterizes more traditional forming methods, are eliminated with the panel bender.

The dedicated CNC control on the P4 is designed for easy programming by the operator or a setup person, right at the machine. Preparation of a bending program typically takes about 15 minutes and consists of keying-in part dimensions for the representative blank shown on the control's CRT display. Programming can be done at the machine while a job is running, and the operator can check the program before it runs by viewing a simulation on the control display.

The P4 panel bender uses universal bending tools. This reduces the costs associated with buying, maintaining and storing forming tools. It also eliminates downtime associated with tool changes. The operator or setup person not only is spared having to change tools, but the CNC control automatically adjusts the tool setup based upon specific requirements for each bend in the part.

P4 panel benders can operate both as stand-alone machines and in flexible lines, which not only bend, but also shear, punch, profile, draw and weld.

Setup time is a major concern at Dalsin Industries. That is why the shop has embarked on a program to reduce setup times by 50 percent. The panel bender is helping to achieve this goal since it can be set up for a new job much faster than a press brake. The setup person (usually an experienced press brake operator) can program a new part in about 15 minutes and be running the first part after a setup time of only three to five minutes.

Kurt Dalsin, manager of production support at Dalsin and one of the next generation of Dalsins being groomed for management of the family business, provides some rules of thumb used to determine when a job is assigned to the panel bender instead of to one of the shop's several press brakes: "The closer the dimensional tolerances for the job, the more likely it is that the job will run on the panel bender," Dalsin notes. "The complexity of the part is another determinant. Some parts that are difficult-to-impossible to form on a press brake can be handled fairly easily on the Salvagnini P4.

"Cycle time also is a factor," Dalsin continues. "Some parts could take 10 times longer to form on the press brake than in the panel bender. Quality must be considered as well. This is because parts that would take about the same amount of time to produce on either machine can be formed more accurately and with more consistency on the panel bender."

In general, the more complex the formed part, the greater the amount of improvement that can be achieved by forming it on a panel bender rather than on a press brake. However, combine the panel bender with a little design ingenuity and the results can be dramatic--even for simpler parts.

"Each of our customers is assigned a customer service coordinator, who learns as much as possible about how that customer's parts and products are used," Einan explains. "Knowing how a given part will be used enables us to review its design and look for ways to improve it. We continually look for ways to add value to the products and services we provide to customers.

"We also determine the processing sequence that will provide the highest quality part at the best possible price," Einan continued. "For many new jobs, that sequence usually includes our panel bender."

Dramatic Results

"A case in point is a rectangular frame that we were asked to make for a retail store display manufacturer," explains Bob Borgerding, manufacturing manager for Dalsin. "The frame originally had been made from four pieces of 1 in. sq. tubing. It had to be miter cut, welded at the corners and the welds ground smooth. The process was time consuming and costly.

Close-up of the P4 panel bender during a bending sequence.

"We redesigned the part to be made from sheet metal formed in the panel bender," Borgerding continues. "The part is formed from a punched flat blank with a large, tabbed rectangle in its center. Each edge receives two 90-deg. bends, giving it the appearance of the original square tube design. After the sides are formed, the tabbed rectangle is knocked out to effect the center opening. Only a few hidden tack welds are required after forming. The resultant sheet metal frame provides the same structural strength as the original tubular design.

"The redesigned frame is completely formed on the panel bender in less than 30 seconds," Borgerding continues. "The panel bender produces a cleaner, more exact part. Corners are clean, tight and consistent from piece to piece.

"When a blank is formed in a press brake, it usually is gauged from a sheared edge or other feature. This means the accuracy of the formed part depends upon the accuracy of the sheared edge," Borgerding explains. "The panel bender does all of its indexing from punched notches, so the blank is located within positioning tolerances of the punching machine, which in our case is 0.004 in. This provides a major improvement in part repeatability."

With the panel bender, Dalsin was able to save a customer time and money by converting its steel drawers from a three-piece assembly to a one-piece design, producing them in one setup.

30 Percent Savings

Using the panel bender, Dalsin Industries produces the display part faster, more accurately and at less cost than was possible with the original design. Using sheet metal as the raw material resulted in a 30-percent cost savings for the part. Savings included material expense for the more costly square tubing, as well as savings gained through elimination of tube cutting, welding and grinding.

Dalsin's panel bender also is well suited to the shorter turnaround time requirements for many of today's jobs. This was demonstrated by a line of modular steel cabinets that the firm was called upon to reproduce. The cabinets are made in one size but with several drawer arrangements. The customer had no engineering prints for the cabinets; so Dalsin had to reverse engineer the entire product line.

In addition to producing cabinet components, Dalsin Industries arranged to assemble the cabinets, send them out for finishing, complete final assembly of the painted cabinets, package and ship them.

Because the customer needed the first batch of cabinets in a hurry, Dalsin decided to form the components on its panel bender. Accordingly, the programmer fed the dimensions of the parts into the panel bender control, which automatically generated the required bending programs. Rapid production of cabinet components on the panel bender enabled Dalsin to complete the first batch of cabinets with time to spare.

Another Example

The panel bender also resulted in significant cost improvement for another Dalsin customer--a firm that had been fabricating steel access panels and drawers in-house on conventional press brakes for years.

Made from 14-gauge steel in 10 different sizes, the access panels require hemming, return flanges and other details. They have to be flat to permit a tight, weatherproof seal, yet they tend to warp during forming operations on a press brake and during secondary flange-flattening operations. The larger panel sizes are heavy and difficult to manipulate in the press brake. Operators considered them a headache to manufacture. When a Dalsin representative called on them with suggestions for a better way, the firm was ready to listen.

"The customer was forming their access panels in stages using two press brakes," Dalsin's Borgerding explains. "We were able to produce them on the panel bender with a much faster cycle time, freeing up their press brakes for other work.

"The customer then asked if we could help them with their storage drawers," Borgerding continues. "We redesigned the three-piece drawer as a one-piece design, which we formed in one setup on our Salvagnini panel bender at a considerable savings. The Dalsin-made drawers provide accuracy and drawer-to-drawer consistency that cannot be achieved with press brake-formed parts." Dalsin provides the drawers in racks, as shown in the photo, ready for installation by the customer.

Synergistic Benefit

"We are always looking for new technologies that enable us to broaden the range of services we can offer our customers," Dave Dalsin repeats. "The panel bender is just such a technology. It allows us to make better use of the capabilities of other new technologies that we have invested in recently. For example, the P4's greater forming accuracy enables us to carry the accuracy of blanks produced on our laser cutting center through the forming process and into assembly. Using these two technologies, we have broadened our capabilities to handle more demanding, close-tolerance work."

At Dalsin, the panel bender rapidly is becoming the method of choice: "If the part can be formed in the panel bender, most of our customer service coordinators would rather have it run there because it will be formed within tolerances to meet the most demanding quality standards," Dave Dalsin concludes. MF

Dalsin is on the Internet at http://www.dalsinind.com. Salvagnini's web site address is http://www.salvagnini.com.