New Robotic Tube Bending Cell from Unison

Tag : Tube Bending Machines

Unison's first implementation of Uni-vercell is for fabricatingtubular parts with diameters up to 3/4 inch (16 mm), and sits in afootprint of just 48 square feet (4.5 square meters). The machineincludes a tube loader, 6-axis robotic arm with a 13.23 pound (6kg) payload, 2-stage end-former, a multi-stack mandrel-less tubebender, and vision system.
"The integrated vision system allows the cell to operateunmanned with 100% inspection of bend angles and end formshapes," said the spokesperson. "The programmability ofthe system also makes it easy to integrate further functions suchas product labeling, which can easily be fitted into the extensivefree vertical space.
"Unison is well-known as the pioneer of 'all-electric,'servomotor-controlled tube benders. These provide substantialset-up, repeatability and scrap reduction advantages compared withtraditional hydraulic-powered machines, and have become the defacto choice for most new machine purchases for smaller tubediameters up to six inches (150 mm). The same architecturalprinciples are exploited in this new machine, which features asoftware-centric architecture that gives unprecedented control overtube part fabrication.
"Two major innovations are at the heart of Uni-vercell. Thefirst is the replacement of a tube bender's carriage with anarticulated robotic arm. By adapting the arm with a simple colletfor gripping and rotating the tubular part, the arm is able to holdand manipulate the part continuously from pick up, through endforming, tube bending and inspection stages, to final release. Thiseliminates the cost of the carriage and the large space requiredfor the carriage bed, as well as numerous intervening referencepoints, jigs and handling equipment that might normally be requiredwhen building a cell from discrete components.
"The second major innovation is the development of anall-electric end former, to provide software-controlled, two-stageend forming (flaring and compressing). Compared with conventionalhydraulic end formers, this approach eliminates the pump andtubing, and the associated heat, noise, energy consumption andenvironmental issues.
"Uni-vercell delivers remarkable performance. It can fabricateparts to an overall accuracy of 0.1 mm. Although the cell isoptimized for repetitive volume applications, the flexibility ofthe robot arm allows it to be configured easily for batchproduction as well. Accuracy and repeatability are assured, becauseof the system's use of closed-loop electronic control. Thedrift-free performance offered also means that the machine can beinstantly set up to fabricate parts just by loading a program,rather than making and scrapping trial parts until theconfiguration is right.
"The new cell is designed for continuous use and can easilyfabricate thousands of parts a day. With a typical energyconsumption of around 1.5 kW (measured using an example part withthree bends and one end form, including stacking at the end of theprocess, and 100% inspection,) daily electricity running costs arearound $10.
"The software-controlled nature of the machine delivers manyfurther technical advantages, including much greater control overthe bending process. Fine adjustments to torque levels or movementprofiles can be made, for example, to optimize bend quality.Complicated shapes that might be difficult to make on aconventional hydraulic machine can also be produced easily, becausethe machine is able to make intervening adjustments or movesbetween stages, to avoid a collision for instance. Thisprogrammability can equally be exploited to optimize cycle time -by making only the minimum movements required.
"Programming the cell for an application can be achieved veryrapidly thanks to Unison's powerful front-end software package,Unibend, and the friendly teaching software supplied with therobot. Programming bends and end forms requires only the input ofdata such as position, angle, rotation and torque, and the machinesets up automatically. All of the intervening movements required bythe robot may then be programmed by simply positioning the armmanually and capturing the data. Using these simple techniques, acomplete cell program can easily be produced in less than an hour.The fabrication processes and movement-related operations are alsodiscrete stages of a cell program, allowing modifications such asfine-tuning of bending or end forming, or movement optimization tobe made quickly, and without generating a new program.
"Energy saving is a further major advantage of Unison's newcell, as it only consumes a significant amount of electricityduring the actual bending and forming operations. No hydraulicsystem needs to be maintained at pressure, for either the bendingor end forming tools. Typical energy consumption rate for acontinuously processing cell is around 1.5 kW per hour."