Automotive Hemming

Hemming (Automotive)Hemming is a technology used by the automotive industry to join inner and outer closure panels together (hoods, doors, tailgates, etc.). It is the process of bending/folding the flange of the outer panel over the inner one. The accuracy of the operation affects significantly the appearance of the car’s outer surfaces and is therefore a critical factor in the final quality of a finished vehicle.

Hemming Processes

Press Hemming

Hemming presses are widely used in automotive manufacturing for hemming of sheet-metal body components. The process uses traditional hydraulically operated ‘stamping presses’ to hem closure parts and being the last forming process in stamping, it determines the external quality of automotive outer parts such as doors, hood and trunk-lid.
[http://www.dvautomation.co.uk Information on Hemming]

Hemming press features and benefits

* Die storage systems
* Fully automatic die-changing systems
* Pressing capacity typically 150 or 180 tons
* Large panel size capacity
* More than one part can be produced on same line

Hemming Press Limitations

* Restricted to flat un-complicated panel profiles
* High Cost

Table Top Hemming

Tabletop hemming machines are utilised for the manufacture of medium to high production volumes, with the ability to achieve cycle times as low as 15 seconds. [Information on Table Top Hemming [http://www.dvautomation.co.uk] ]

Table Top features and benefits

* Optimum panel quality guaranteed through the hemming principle of the closed ring (corresponds to hemming in the stamping tool)
* Hydraulic or electro-mechanical drive
* Complicated panel geometries can be hemmed in one single machine (flange angle in some areas up to 150°)
* Ease of access for loading and unloading

Table Top Limitations

* Dedicated to one panel

Robot (Roller Hemming)

Robot hemming uses a standard Industrial Robot integrated with a roller hemming head to provide a flexible solution to closure manufacture. The flange of the outer panel is bent over the inner panel in progressive steps by means of the roller hemming head. The process allows the advantage of using the robot controlled hemming head to hem several different components in a single cell. Minor changes and modifications to panel hemming conditions can also be accommodated allowing a quick and cost-effective reaction.
* [http://www.dvautomation.co.uk More information on Robot Hemming]

The robot can also be used for other tasks for example, by equipping it with a tool changing system. This will allow it to also operate dispensing equipment for adhesives and sealants, or a gripper which will enable it to carry out panel manipulation within the assembly cell.

Robot Hemming features and benefits

* The ideal solution for low to medium volume production demands
* Flexibility as robot can hem various panels and can perform other tasks with economical implementation of panel changes
* Simple and quiet in operation
* Low cost simple hem roller tooling and use of standard Industrial robot
* Reduced mechanical effort for tryout
* Flexible production with regard to different types and variants

References