Robotic Sheet Metal Bending

Large lot sizes are no longer necessary to introduce robotics to the bending process

Robotic press brake bending

Increasing throughput, improving part quality, and reducing the labor content all can be achieved with robotic brake bending.

It wasn’t too long ago that robotic integration, on any scale, was an option available only to those with part lot sizes in the thousands, or even tens of thousands.

This was particularly the case when it came to sheet metal bending operations that created large, complex parts with multiple bending stages or smaller parts that were difficult for the robot to hold and manipulate.

Now, however, as the industry recovers from recession, every aspect of shop production is being re-examined. New technology, programming techniques, hardware, and software all allow robotic integration – even on a small scale.

“While every robot installation is different, it is no longer limited to applications in large lot sizes,” explained Paramount Machinery President Eric St. James.

Paramount Machinery recently completed several robot/press brake integrations at Toronto-area fabrication shops, and St. James has noticed a resurgence of interest in all areas of productivity-improvement technology.

“We have completed five robot installations recently. They were at five different companies with different press brakes and different circumstances, but each saw the need for a robot,” said St. James. “In each case, increasing throughput, improving part quality, and reducing the labor content in each part were important. These can all be solved with robotics.”

Throughput is perhaps the easiest to understand of all the benefits of robotic press brake bending. Robots can work 24/7 without the need for breaks. Adding a robot to a bending cell can free up an operator’s time, which can then be used elsewhere in the shop. Creating more parts per day is one of the easiest ways to reduce overall cost per part.

Part quality is also much easier to control in a robotic setup, with one caveat: Any automated system needs material of consistent quality to produce consistent parts. If the material has inconsistent quality, poor parts will be produced because the robot cannot make changes on-the-fly as could an experienced operator.

“These machines are so repeatable and accurate that they always will produce consistent parts so long as what you are loading into the system is consistent,” explained St. James.

Labor reduction is a trend that is affecting all segments of the manufacturing industry. In press brake bending a robot can remove the need for human-machine interaction. Not only does this reduce the cost of the part being made, it can make the shop environment safer and free up labor resources for other work.

Robotics in Action

One of Paramount’s recent installations was at Sable Metal Fabrication in Markham, Ont. This small fabrication shop integrated a Motoman HP50 robot with a 10-ft. Aizawa hydraulic press brake, and it is now seeing the benefits.

“This cell has produced more than 20,000 parts for us since it was put on the shop floor, and we even landed a contract that actually brought work back from China,” said Sable’s Technical Director Scott Harnett.

According to Harnett, this single contract, a small part with complex bends, justified the purchase of the robot. Today, as the company adapts to its new capabilities, more parts are being produced in the robotic press brake cell.

“After the success of the first part, it was pretty easy to tweak another one of our programs to be able to do it on the robot press brake as well,” said Harnett. “Obviously, the more work you do on the system, the easier it is to pay off.”

Bringing work back to Canadian shops that had been outsourced is possible, but only will happen if operational costs are reduced.

“Quality, safety, and delivery times are all important, but if the cost of the part is too high, [a Canadian shop] will be overlooked and work will be done in other countries with lower labor costs,” said Harnett. “The only benefit to producing parts in these other countries is the fact that they can be made much cheaper. Now, when automation is brought into the equation, you can compete on price, and work is now coming back.”

Bend Sequencing

In any bending operation, creating the part with the proper bend sequence is important. A part can be created in an almost infinite number of ways, but it is the job of the programmer to create a part in the most efficient way.

Robotic bending can make the programming a little more challenging because the program also needs to take into consideration the picking and stacking of parts and also the squaring of parts using a squaring table.

“Offline programming for robotic bending operations is a real game changer,” said St. James. “Programming a part using a teach pendant can take hours, and during this time, the cell is not running.”

The latest generation of software for press brake bending eliminates this machine downtime. Parts programs for the robot bending cell now can be created directly from a DXF file in a process that takes less than 10 minutes, in most cases.

These programs ensure that the robot picks a blank from a stack, squares it, bends it, and places it on a pile of finished parts.

The press brake itself hasn’t changed except for new sensors on the backgauge and a selector switch that enables the machine also to work as a standalone press brake.

The necessary end-of-arm tooling at Sable was created in-house to grip the suction cups needed to hold the part. This tooling can be customized and oriented in many ways to hold the part properly during picking, bending, manipulating, and stacking.

Local and global competition has made automation necessary in today’s shops, according to Harnett.

“This was definitely a big step for us,” said Harnett. “It has changed the way we manufacture, and it also changed the way we think about manufacturing.”

The addition of a robot to the production process not only has changed the way the company produces parts, but also the way jobs are quoted.

Safety also is a big concern in shops these days.

“When in operation that robot is going to move whether somebody is standing beside it or not,” said Harnett. “This makes safety even more important in our shop.”

According to St. James, metal fabricators no longer need to hesitate when adding a robot to a press brake.

“This is where the industry is heading,” said St. James. “Only through automation will we be able to compete, and automating press brake bending is no different than automating any other process. The technology is available, software is getting more powerful, and shops are beginning to see the benefits.”

For more information visit www.paramountmachinery.ca and www.sablemetal.com.