You might not think of finding a high-tech, modern robotic laser cutting system in Conway, Arkansas, a small town about 20 miles from Little Rock. However, this is a wholly owned subsidiary of IC Trucks, Inc. - International Truck and Engine Corporation - nowadays 16 and 20 standard thickness galvanized sheet stampings for the manufacture of school buses and complex depths Pull parts for laser trimming and cutting. The two six-coordinate Motoman (West Carrollton, Ohio) UP20 robots can perform precision laser cutting on more than 40 shapes for flat sizes ranging from 20.9 to 47.2 inches wide, 93.7 inches long, and 6 to 9 inches deep. And the outer circumference of the shaped part is trimmed.

Jim Krieger, Project Manager of the Excellence Manufacturing Center, which supports all branch offices, said: “The modern robot production center is a new technology for the factory. The employees of the factory have already accepted the robot. The sheet metal parts manufacturing equipment works in two shifts per day, each shift. With 82 sets of parts, the robot has proven to be very reliable."

Krieger said: "The flexible production center has been designed to laser cut four school bus parts, which are outer end caps, inner end caps, bulkheads and wheel sockets - they are used in the Conway bus assembly plant and in Russia. A sister bus assembly plant in Tulsa, Okla."

The Motoman robot was installed in the second half of 2003 and is equipped with a TRUMPF (Plymouth, Michigan) HL703D Nd:YAG laser unit mounted on a steel base support structure. Mounting robots on these support structures saves floor space and makes it easier to machine large, complex parts—pieces that are attached to a Motoman MSR-1000 AC dual-position 180-degree indexable positioner. This high-load positioner features an H-framed countertop design with a load capacity of 2,200 pounds per end and an indexing time of 7 seconds at full load. The opaque front wall in the center of the locator and the unique automatic seal guard protect the operator from laser radiation. The robot is completely sealed in a CDRH Class 1 laser work cell seal with a safety interlock door. The process is monitored using a CCTV camera and surveillance system. The laser related equipment is placed in a separate room.

Motoman also offers two sets of flexible clamps on each side of the indexing positioner. The part is supported on the outer structure by a positioner and held in place by a vacuum cup. Although the same type of parts are typically machined on both sides of the positioner, the system can also machine different parts on both sides. The cycle time varies from part to part. The outer end cap takes about 300 seconds, while the wheel socket requires less cutting time and takes about 110 seconds.

The switching between the four part types, the outer end cap, the inner end cap, the bulkhead and the wheel socket, is done manually and takes less than 15 minutes to switch the self-positioning fixture. The parts are machined in batches, and the operator changes the number of parts per batch by selecting the appropriate robot program for the part to be machined – using a PC-based color touch screen on a separate base. The Allen-Bradley SLC 5/05 programmable logic controller (PLC) provides comprehensive unit control and I/O monitoring, while the robot and positioner are controlled by the Motoman XRC 2001 robot controller.

Two operators per shift are used to load and unload large parts produced on the robot unit. Operator operations include: loading a part, cleaning the loading area monitored by the dual laser scanner, and activating the cycle start button on the operator station. When the current cycle is completed, the unit turntable automatically indexes and transports the next part to the robot. The robot will perform peripheral trimming and perform laser cutting from 6 to 110 times on each part. The operator removes the cut parts and attaches the parts to be cut to the fixture, and then repeats the process. The laser system is machined to a tolerance of ± 0.030 inches and a positional tolerance of ± 0.060 inches.

The unit also includes a 12-inch wide, 16-foot electromagnetic belt conveyor with a waste chute that collects and discharges laser-cut metal shavings. It also includes an exhaust system consisting of a blower with a venting speed of 9000 cubic feet per minute, a pressure blast system and a duct to remove fumes from the unit.

Krieger added: “The cycle time of the Motoman system is 10% faster than we planned. Before the robot was used, the production of these parts required a high manual labor intensity. Each part was manually cut by plasma, manual It is loaded onto the press and trimmed with a pneumatic shear. The pattern of the dressing must be tracked before cutting. This process requires multiple stages, multiple operators, and requires a large amount of material handling between different processes. By using the robot unit, many 'in-process' material handling operations are eliminated. Robotic automation improves the quality of the final product. Precision control reduces the amount of waste per part. The original manual method, the noise is very large, using a band saw The deep, bathtub-shaped outer end cap is cut into two parts. With the new model, the space that needs to be trimmed between the two parts is less than 1 inch instead of the previous 6 inches. The laser system we choose needs With very little maintenance, the cost of parts is much lower than the plasma-based cutting we have studied. . "

The ROI's return on investment cycle is approximately 2.5 years.