Fabricating system achieves one-piece flow for exhaust manifolds

Images provided by transfluid Maschinenbau GmbH

Situation

An exhaust manifold manufacturer looked for a way to make exhaust systems in an uninterrupted flow. An assembly of parts made from stainless steel, the manifold would require bending, forming, and end calibration. More than performing bending, end forming, and cutting, the production system would provide parts for two styles of manifold, made from either four or six unique tube lengths. Furthermore, if a single tube would fail at the welding stage, the cell would generate a signal to cue the system to produce a replacement tube. Finally, the system would reduce the cutting and trimming operations by forming up to 20 units from a single length of tube, separating each component from the mother tube after forming.

In other words, the customer wanted a versatile system that would provide true one-piece flow, including replacement parts, if necessary.

Resolution

Equipment manufacturer transfluid Maschinenbau GmbH developed a workcell that relies on a central robot for transferring each tube from station to station.

After retrieving a single tube from the magazine, the system uses an eddy current system to find the weld seam so the tube can be oriented properly. A linear handling system feeds the tube to a bending machine, which uses one of four bending tools, then cuts the tube with a carbide cutter for a deformation-free end. The first end of each component then is sized internally and externally at the same time with a finger expansion. After the second end is deburred, the robot takes the component to a combination forming machine for an axial forming process that makes an asymmetrical geometry at the remaining end, and the last step is a final cut to length made by a chipless orbital cutting system.

At this point the robot deposits the component into the appropriate container.

The workcell has one more step to go, one involving an exhaust gas recirculation tube bent by a separate process. Making a 1.75-in. flange on this tube, which has been formed with a bend near the end of the tube and which has a longitudinal weld seam, takes some finesse. The bend’s location limits the clamping length, and the weld seam is more brittle than the parent material, so splitting the tube at the seam is a risk. The process uses a progressive rolling technique that successfully flares the tube despite these challenges.