Bending Accuracy Regardless of Material Variation

An additional independent programmable crowning V-axis system on these press brakes automatically compensates for asymmetric variations in material thickness and material properties to assure bending accuracy over the entire length of a work piece.

LVD Strippit (Akron, NY) offers Smart Crowning, a programmable crowning V-axis system, for its line of PPEB-H Series and Easy-Form® Series press brakes. Smart Crowning provides an additional independent crowning axis on top of a conventional V-axis to automatically compensate for asymmetric variations in material thickness and material properties and thus assure bending accuracy over the entire length of a work piece.

A press brake’s crowning system ensures the ram and table are parallel during the bending process. Traditional crowning tables compensate for the symmetric deflection of the press via a single V-axis and are ideal when material properties are the same over the length of the part. When properties are inconsistent (particularly with heavier or longer work pieces), Smart Crowning provides an additional axis that allows for additional independent asymmetric compensation.

The Smart Crowning system uses Smart Segments and Smart Actuators that operate individually to provide independent compensation. Smart Segments are mechanically connected in a ‘caterpillar’ linking configuration so it’s impossible to program an inappropriate step in crowning which prevents damage to the crowning table and tooling.

Easy-Form® servo-controlled precision press brakes are equipped with state-of-the-art hydraulics and built on a rigid frame design to ensure accuracy. The machines use the Easy-Form® Laser adaptive bending system for working lengths from 5 ft to 50 ft (1.5 m to 15 m) with tonnages up to 3000 tons. Easy-Form Laser is a unique angle measurement device that uses a laser to monitor the angle in real time during the bending process, producing accurate bending results from the first piece. The system uses symmetrical measurement at the front and back of the die to determine the exact value of the angle of the workpiece.

Easy-Form Laser 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. The bending process is not interrupted and no production time is lost. Unlike mechanical angle control systems, Easy-Form Laser does not extend the cycle duration and provides accurate results consistently. It does not require calibration after each set-up.

In automatic mode Smart Crowning, in conjunction with the Easy-Form® Laser, measures angles at several points along the length of the sheet under pressure, up to a maximum of 16 points. Spring-back is then measured in the center of the press brake and values for individual Smart Crowning actuators material are identified. The Smart Crowning system then adjusts to provide an accurate bend angle over the complete work piece length. [email protected], www.lvdgroup.com