Technology | Necking
Slim waist, attractive shoulder - fine feathers make fine birds! This kind of shaping is called necking and it is technically demanding because the cans have already been printed and lacquered.
Who looks good and is still shaped to be handy has got strong selling arguments as a can on its side. The sophisticated necking process is worth the while in any case!
Step by step to the perfect shoulder
Several operations gradually form the shoulder of the can, others follow: The shoulder edge is curled, sometimes a thread is cut and the orifice is face-milled exactly so that it closes tightly. And to fix the cap, finally a profile is rolled below the shoulder.
As aerosol cans are under pressure the bottom of the can has to be curved inward. This step is performed by the necking-machine, too.
Printing and lacquering increase the requirements
Shaping an aluminium can individually? A challenging task, the more as the can has already been printed and lacquered. Additional demands on the necking machine and the lacquer are the result. The lacquer must be elastic enough to withstand the deformation. And the shaping tools are always spick and span in order not to damage the lacquer and the print image.
A matter of function: the orifice of the can/h2>
The shoulder’s main focus lies on an attractive appearance, whereas the technical functions are of major importance for the can orifice, depending on the cap type: spraying head, valve, hand pump or a screw cap with thread. The orifice shape has to be adapted in any case.