Broadly there are two types of capping lines – “Pick and Place” and “Pick-off” methods.

“Pick and Place” type systems place the closure in a horizontal position beside the capping head so that the capping chuck will come down vertically over the closure and then the capping chuck will close around the closure and pick it up and then present the closure to the bottle face in the horizontal position.

This system suits exceptionally large closure formats (such as 110mm closures) often applied by a single capping head at only two closures per minute, all the way up to 36 head rotary cappers that can easily achieve 600 bottles per minute.

The capping head needs a level of top load so that it pushes the closure down as it rotates onto the bottle neck until the closure ‘S’ thread meets the bottle ‘S’ thread at which point the closure will screw down onto the bottle neck until it fully seats against the bottle neck face.

“Pick-off” system is widely used in medium speed capping lines circa 60 to 120 bottles per minute (particularly the white milk market). This system presents the closures at about a 30° angle to the bottle face. As the bottles passes below the closure it meets with the leading edge of the angled closure and pulls the closure from the dispensing ramp. The bottle will then travel forward to the capping chuck that then pushes the closure further down onto the bottleneck moving the closure from 30° to the horizontal position as it turns the closure onto the bottle.

For both systems, it is critical that the bottle is held tightly when capped. If not, the bottles can slip, and you will get widely varying on torques and potential leakers. The closure will also need to be held firmly in the closed capping chuck. A quick test is to slip your closure into a closed stationary chuck and see if you can forcibly make the closure turn in the closed chuck. If it does spin, you will need to service and adjust the capping chucks.

   (Refer technical article “checking your capping chucks”).