Laser meets hydroforming
Dingolfing, Germany—The BMW Series 5 utilizes a hydroformed aluminum crossmember for the cowl section that is finished prior to installation by laser cutting. Schuler AG built and installed the hydroform station in the Summer of 2003 and integrated it with a Mobilas laser cutting station from Schuler Held Lasertechnik (Heusenstamm, Germany).
During the hydroforming process a welded aluminum tube is transformed over several stages to the desired shape of the crossmember. Subsequent 3D laser cutting ensures that the part connects perfectly with neighboring body parts.
The Mobilas laser cell consists of two machine towers positioned toward the part ends, which move along precision guides and bear one height-adjustable arm each. A laser focus head is attached to the arm and it has a rotating axis of +/- 250 degrees and a swivel of +/- 110 degrees.
An innovative material handling system consisting of two holding units, placed one above the other, each with pneumatic clamping and gauging technology, allows parallel loading and unloading of the cell. While one part is being cut, the other is being unloaded. The typical cutting cycle time is approximately 30 seconds and the daily production volume is 1800 units.
Because the crossmember is Alg 3.5 Mn aluminum, a high beam quality laser is necessary. Schuler chose the Rofin Sinar DC020 slab CO2 laser with output power to 2 kW. With its small spot (0.2mm) a narrow kerf is produced with little waste material.
An integrated beam switch can time share the beam from one laser should the other laser become unavailable.
The entire laser cuter is enclosed in a cabin to protect personnel during operation. An integral fume extraction with exhaust filter is provided. Disposal of cut scrap is facilitated by a conveyor system.
The Mobilas proves to be a flexible partner for the Schuler hydroforming system. For more details on the Mobilas laser cutting systems, contact Schuler Inc. (Canton, MI) through [email protected].