In the hemming process, the edges of car doors, deck lids, hoods, lift gates, and other automotive products are bent and then flattened, which finishes the peripheries by making a hem.

Hemming is the process of folding metal to create a finished edge. Outfitted with roller EOAT , industrial robots easily outperform traditional press machines. Commonly used within the automotive industry, hemming can also link two panels - bending one metal flange over another. EOAT can be adjusted and switched to create different styles of edging.

Typically, this process is done with large presses, which have quick cycle times but are not flexible. Presses are also costly to tune-in — if a company has five models of automobile, it needs five different presses. This takes up a lot of floorspace and requires a high investment. So, in lieu of presses, many vendors provide automated systems with robots that do the hemming. Hemming cells feature one robot or multiple robots, depending on the production volume. An optional robot loads and removes parts from the cell.

On the end of each hemmingrobot arm is a special roller tool. The robots finish peripheries by going around the panel edges, bending a lip of the metal over with the edges bent in successive passes. Typically, One robot does the part's upper section, while the others are hemming the sides and bottom. And the hemming robots use small rollers that easily get inside small areas or small curves, which can't be done with presses.

See the video in the link here to get a better idea on the proces http://www.youtube.com/watch?v=rPF_XUBIF5Y

"Roller hemming is also a big advantage when bending certain types of material such as aluminum 6111,"  "This type of aluminum provides an excellent ratio between way and rigidity of the part for crash testing. However, with typical hemming processes, 6111 tends to crack. Roller hemming is a much smoother process then hemming with a press, and it doesn't damage the metal's crystalline structure.Because it's just a rolling action and there is no friction, wearing is minimal, which reduces maintenance costs.

Overall, as and when Robotic Roller Hemming is getting popular, there is a request to simulate this by Software. Thru CENIT/DELMIA , we Provide capabilities to simulate Roller Hemming process. Accurate CATIA curve information can be reused in defining the path for the Robots including the TCP offsets required or even AMP (Arc Macro programming) can be used for creation of Robot Path quickly. Video below would illustrate the capability with DELMIA and CENIT FASTCurve.