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Press Brakes

Italians in two minds over bending machines

By Dr. Andy Sanford

The Italian city of Bologna is renowned for its medieval towers, tortellini and bolognaise sauce. What the casual tourist might not realize is that it is the center of a thriving industrial region that is noted for innovation and keen to embrace new technology.

Typical of many of the smaller firms in the region is Curti Lamiere, a subcontractor providing profiled and formed parts to a wide variety of customers in sectors as diverse as agricultural machinery and packaging equipment.

The company is run by three members of the Curti family, has 13 employees and turns over ap­proximately 3 million Euros, yet it operates a Trumpf 3050 laser with full automatic sheet handling, a Mazak flat-bed laser, a Prima five-axis laser, a Trumpf laserpress and a Starmatic robotized bending cell based around an LVD press brake.

According to Claudio Serra, managing director and the founder’s son-in-law, the company pioneered automated systems in the 1990s and was the first in Italy to install the Trump Liftmaster sheet-handling system.

"We went for automation for flexibility along with allowing us to increase production without taking on more people," says Serra. "Not just because people are expensive, but in a smaller company you have a better relationship with your staff. They’re like a family. Once you get about 20 to 25 people everything is more formal, and we think people work better when you have this informal rapport.

"As regards the press brake automation, the primary factor driving this is the weight of some of the parts we bend," he explains. "The law in Italy says that one person cannot lift more than 15 kg unaided, and if you don’t have a robot to lift your heavy parts you have to use a crane or hoist. So you need two people, one to maneuvre the sheet and one to operate the crane, and if you’re going to have to buy a crane you might as well invest in a robot.

"We do parts which are around 2,000 mm long and weigh 60 kg where you have 2 m of plate sticking out of the press brake and you would need three people to handle the sheet," says Serra. "But batch sizes are small, and the next job might be a small part that one man could manage on his own. If you have three press brakes and all your operators are working on one part, then two of the machines are standing idle."

Curti Lamiere has around 700 active customers, with batch sizes ranging from one-offs to 1,000 and covering a wide variety of shapes and sizes. So when it came to specifying a robotic press brake cell, it was easy to define what it had to do, says Andrew Battistini, sales director of LVD Italy.

"I asked what the system had to do," says Battistini. "They said everything. That covers material from 1-mm mild steel to 20-mm stainless, with minimum batch sizes of around 50 parts for smaller components and smaller batches of heavy components. So it had to be a very flexible system.

"They knew the size and thickness range they needed to be able to cover," he says. "So based on those parameters, we knew we needed a 4-m-bed, 300-ton press brake. To give maximum flexibility, Starmatic then added the most powerful robot possible. This was the latest Fanuc R2000, a robot specially designed for bending with a maximum load of 165 kg, which means you can lift everything. A normal system might have a robot that can lift 50 kg, and the difference in price is around 20,000 Euros. But without that investment you wouldn’t be able to do half the work."

He says that another feature that gives extra flexibility is a rail that the robot moves along parallel to the bed of the press brake that operates as a seventh CNC axis. This gives two main advantages. First of all, because the robot arm does not have to always be at right angles to the bed of the press, you can approach it at an angle to accommodate longer components. So this gives more flexibility on the type of things you can bend. Secondly, it means that you can take the robot out of the cell completely and run the cell manually.

"You may use it, you may not, but it gives you the opportunity to do small batches of small components without having to program the robot. So it gives you more flexibility, and the cost of that flexibility is another 20,000 Euros," says Battistini.

One of the ways the Fanuc R2000 has been adapted to make it into a specialized bending robot is that the upper part of the robot arm is shorter than normal. This makes the robot lower, so that when it’s handling larger sheets, they can pass over the top of the robot with the press brake bed at the normal height. A lot of press brake cells have the bed set high off the ground to allow for this, but if the cell is also going to operate manually, then this would make it awkward for the operator.

Another key element of the cell is a preloading and plate referencing unit.

In the preloading area, plates are de-stacked by a simple cartesian robot that places them on an inclined referencing table. The plate settles under gravity into a right-angle referencing fixture so that the robot knows its exact position and orientation when it comes to pick it up. This reduces the cycle time as the robot can simply pick, bend and store the part without having to reference each sheet. This extra productivity costs around 25,000 Euros.

At the heart of the system though, says Battistini, is the LVD Easy-Form Laser Press Brake.

This robot cell can bend through the night unmanned, and it doesn’t care whether it is producing the right angle or not,” he explains. “When you are bending plate that is 8 mm or 10 mm thick, there are always problems with material consistency. The thickness can vary, the tensile strength can vary, and the grain direction will also have an effect. So you have to have a system such as the Easy-Form Laser to make sure that the angle is correct.”

The Easy-Form Laser uses two laser beams, one on either side of the die, to measure the bend angle in real time while the press brake is operating. It measures the actual springback and can compensate for this within the bending cycle to ensure that the correct angle is always achieved.

The robot lacks flexiblilityRobot automation might have provided the right solution for Curti, but half an hour down the road in Forli another company is taking its robot cell out and putting in more press brakes.

Firorini specializes in refrigerated water storage and distribution systems for air conditioning plants and is one of Europe’s major manufacturers of these products. It supplies complete pump and tank kits for all of the major OEMs including Daikin, York, Delonghi and Saunier-Duval with around 70 percent of its production being shipped directly to the end user under the OEM’s own label.

The company employs approximately 70 people and every aspect of manufacture is vertically integrated in house. It turns over approximately 13 million Euros and ships around 20,000 units every year.

The sheet-metal facility was set up in 2001 when Fiorini decided to stop subcontracting it out. The equipment installed at that time included a Bystronic Bytrans 3015 laser with automatic sheet loading, a Beyeler press brake and a Starmatic robot bending cell built around an LVD PPEB 320-ton Easy-Form Laser Press Brake. But since then the way the company has to operate has changed significantly.

As Firorini’s chairman, Antonio Fabbri, explains, "Our customers used to hold stocks of our equipment in their warehouses, so we used to be able to plan our production and produce parts in batches of 50 to 60. Now everything is sold before it’s made. We receive the order direct from our customer’s customer and have to produce the units in parallel with what they are producing so that they can all be delivered at the same time. This means that we have to be very flexible. Every job is a special."

He says that because of this, batch sizes are getting smaller and smaller and the robot just isn’t flexible enough to cope with this. The main problem here is the programming time, which becomes more and more of a problem as batches get smaller.

"The smallest economical batch size for us is 50, but now our normal batch size is less than 50 and may even be as low as one," Fabbri says. "It’s not worth running the robot for small series production."

So if there is no other reason for using a robot, such as coping with heavy or ungainly components, then it might only take a small change in the way a company works to make it uneconomical. For many, Fiorini’s solution might seem surprising; getting rid of the robot cell and the Beyeler press brake and replacing them with three new manually operated LVD Easy-Form Laser Press Brakes. Parts can be made economically in smaller batches, when needed, and overall production will actually increase.

"In Italy even big companies like Electrolux are taking out robots and replacing them in production with manual assembly," says Fabbri. "In Italy, and in Europe in general, the work that we have now is for customized products, and all the high-volume products are made in China, Mexico or wherever. If you are a company like Fiat with just a few product lines you can automate, but for the 200,000 or so normal Italian companies, the only option is to work with smaller batches." FFJ

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Company Profiles

AIR FILTRATION

IRONWORKERS

NESTING SOFTWARE

SERVICE CENTERS

Camfil APC - Equipment Trilogy Machinery Inc. Metamation Inc. Admiral Steel
Camfil APC - Replacement Filters

LASER TECHNOLOGY

PLASMA TECHNOLOGY

Alliance Steel
Donaldson Company Inc. AMADA AMERICA, INC. Messer Cutting Systems Inc.

SOFTWARE

BENDING/FOLDING

Mazak Optonics Corp.

PLATE

Enmark Systems Inc.
MetalForming Inc. MC Machinery Systems Inc. Peddinghaus Lantek Systems Inc.
RAS Systems LLC Murata Machinery, USA, Inc.

PLATE & ANGLE ROLLS

SecturaSOFT

BEVELING

TRUMPF Inc. Davi Inc. SigmaTEK Systems LLC
Steelmax Tools LLC

LINEAR POSITION SENSORS

Trilogy Machinery Inc. Striker Systems

COIL PROCESSING

MTS Sensors

PRESS BRAKE TOOLING

STAMPING/PRESSES

Bradbury Group

MATERIAL HANDLING

Mate Precision Tooling AIDA-America Corp.
Burghardt + Schmidt Group Fehr Warehouse Solutions Inc. Rolleri USA

STEEL

Butech Bliss UFP Industrial

PRESS BRAKES

Alliance Steel
Red Bud Industries

MEASUREMENT & QUALITY CONTROL

AMADA AMERICA, INC.

TUBE & PIPE

Tishken Advanced Gauging Technologies Automec Inc. BLM Group

CONVEYOR SYSTEMS

METAL FABRICATION MACHINERY

MC Machinery Systems Inc. Prudential Stainless & Alloys
Mayfran International Cincinnati Inc. SafanDarley

WATERJET

DEBURRING/FINISHING

LVD Strippit

PUNCHING

Barton International
ATI Industrial Automation Scotchman Industries Inc. Hougen Manufacturing Flow International Corporation
Lissmac Corp. Trilogy Machinery Inc.

SAWING

Jet Edge Waterjet Systems
Osborn

METAL FORMING

Behringer Saws Inc. Omax Corp.
SuperMax Tools FAGOR Arrasate USA Inc. Cosen Saws

WELDING

Timesavers MetalForming Inc. DoALL Sawing American Weldquip

HYDRAULIC PRESSES

MICROFINISHING TOOLS

HE&M Saw Strong Hand Tools
Beckwood Press Co. Titan Tool Supply Inc. Savage Saws T. J. Snow Company
Triform

 

 

 


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