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Adaptive forming takes Delta Elevator to the top floor

Written by March, 30 2009
b_150_100_16777215_0___images_stories_files_2009_issues_359.jpgWhen Delta Elevator Co. Ltd., Kitchener, ON wanted to enhance its lean manufacturing operation, the company immediately realized that it would have to upgrade its bending capabilites.

“We’re always looking for ways to make our operation leaner,” says John Guderian, vice president of manufacturing, P. Eng., CQE, with Delta Elevator. “That means reducing setup times and controlling quality at the source. The problem with our old press brake was that it usually took several attempts before the operator achieved an accurate bend. With the large amount of custom work that we do this was just not an acceptable way to operate.”

Delta Elevator, which began operations in 1967, manufactures, installs, services and maintains elevators. A privately held company, it is one of a few fully integrated elevator companies in Canada. Delta produces a range of passenger, handicap and freight elevators.

In a highly competitive market, Delta differentiates itself with a high quality custom product, strong service and fast delivery. “We’re in a very mature, competitive business with a lot of multinationals,” says Guderian. “We’ve positioned ourselves on the high end, with customized, low volume type of work.”

When Delta began looking at reducing setup times on bending operations and replace the conventional bottom forming method it was employing, the firm considered a number of competing press brakes before selecting an Easy-Form 190/14 press brake from LVD Strippit, Akron, NY (lvdgroup.com).

During the search for a new press brake, Guderian and his staff considered a host of criteria. “We constructed a decision analysis chart that weighed 76 different factors including cost, warranty, service, accuracy, repeatability, setup time, various performance characteristics, various features, ease of programming, training, footprint, recommendations of other users,” says Guderian. “LVD came out on top.”

Producing consistently accurate parts without trial and error bending was a key factor for Delta, and pivotal in its selection of a press brake was an adaptive bending system. “Our elevators end up in some very classy buildings,” explains Guderian. “The stainless steel trim and fascia need to fit perfectly, and with the price of stainless steel these days, a trial and error approach is not an option.”

The accuracy of a bend depends on a number of parameters related to the quality and mechanical characteristics of the material, which can change with each material batch and from sheet to sheet. Delta found that its mechanical press brake could not adequately compensate for material variations, thus impacting bending quality.

“To minimize waste, we save cut-off pieces to run some of our larger volume stock parts,” explains Guderian. “A batch of punched parts is often made from a large number of sheet cut-offs with different grain direction, hardness, and even thickness. Our old press brake had a lot of trouble dealing with these variables and we consequently had a high degree of variation in our bend angles.”

Delta wanted to employ a method for angle measurement and real-time angle correction in order to achieve accurate bending results from the first piece and consistent parts throughout a production run. “Other press brake manufacturers have adaptive bending technology, but we ran tests on other equipment and found that LVD’s Easy-Form Laser was the most accurate and easy to use,” he notes.

The Easy-Form Laser system Delta employs uses measurement at the front and back of the die to determine the exact value of the angle of the workpiece. The system projects straight lines composed of multiple light points onto the workpiece and the vertical part of the die, providing a measurement calculation every 20 milliseconds.

The sensing device transmits information in real time to the CNC control unit, which processes it and subsequently recalculates the correct depth adjustment to obtain the correct angle.

Using the Easy-Form system, Delta is assured of constant bend angles from the first bend. Changes in material characteristics no longer influence the bending results, as the system allows the machine to adapt to variation in material consistency and compensates for any changes in radius as a result of grain direction changes.

“We run every part using the Easy-Form system so every part ends up being within 0.3° of nominal regardless of grain direction or material hardness,” says Guderian.

The press brake also features self-seating hydraulic clamping, which has significantly reduced Delta’s tooling changeover time. “As a lean company, we strive to keep our batch sizes very small,” says Guderian. “Since we have a very high product mix -for example, fine, stainless steel trim for cabs versus heavy structural elevator hoistway components-we end up doing a lot of tool changes.

“Our old press brake had 12 ft. long dies that required two people to change them,” Guderian adds. “Whenever the operator wanted to change dies, he had to go find someone to help him. He would often have to wait until that person finished doing whatever they were doing, and the whole thing would end up taking a lot longer than it should have. Now, with small, segmented dies and punches the operator can quickly change the tools himself. We opted for the hydraulic clamping option, so he just pops the tools in and hits the clamp button. A minor tool change now takes about one minute and changing 12 ft. of die takes about five to six minutes.”

Delta’s ongoing commitment to lean manufacturing calls for cross training of its workforce, and the press brake’s intuitive features make it easy to use and learn. “We decided to train three operators, since we were planning on another shift and we also wanted one backup,” says Guderian. “As it turns out, with the increased efficiency, we didn’t need to start a second shift.”

By achieving first part, good part accuracy and reducing setup and tool changeover time Delta is able to keep its manufacturing environment as lean as possible, maintaining reduced inventory levels and producing parts in less time. “In the past, the shop was typically given three weeks to produce something,” says Guderian. “Now we’re getting the work orders usually about a week in advance, and issue them to the floor a week in advance and sometimes less.”

This article was supplied by LVD Strippit, Akron, NY.

lvdgroup.com

Last modified on April, 03 2009

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