Electronic Versus Magnetic Clutch Capping Heads in Rotary Capping
With rotary capping equipment, the use of magnetic clutch capping heads has now become routine, relegating the old friction or disc clutch rotary cappers (if anyone remembers these) to the list of obsolete packaging machinery. Magnetic clutch heads have proven, over a twenty-five year history of use in thousands of applications, to be a reliable means for applying screw-on closures with consistent torque over many hours of operation in some quite severe packaging environments and have become the standard offering with all major rotary capping machine vendors. Two principal innovations to the magnetic clutch capping heads over the last several years have been the introduction of toolless torque adjustment and quick release chucks, features which provide both reduced downtime while requiring no tools or training to perform a cap change-over. With these innovations, it is expected that magnetic clutch capping heads will remain the industry standard for as long as packaging needs include the use of screw-on caps.
As good as this technology is however, there are occasions where the use of magnetic clutch heads fall short of an application's requirements. Cap orientation, application torque monitoring and reporting, screw cap profiling, expanded torque range, delicate cap handling, and aseptic packaging are all examples where magnetic clutch technology is either limited or simply incapable of performing satisfactorily. Given the very real need to address one or more of these requirements, electronic head technology has been developed and has proven to be the best possible solution to these high requirement applications.
Two opposing electronic head technologies have been developed, the first of which was introduced by Andre Zalkin & CIE, Paris France, initially in 1996. This technology relies on a motion controlled, brushless DC motor, fitted in a IP65 grade stainless steel housing, which is mounted at the end of the head slide where the magnetic clutch head would normally be mounted. The motor is custom built with a hollow shaft to allow a cam actuated push rod to extend through the motor to actuate the articulating chuck jaw segments for cap pick up and release. The alternate technology came into use circa 2003 and has been to be adopted by various other capping machine vendors. The majority of these companies use an off-the shelf servomotor supplied by Elau AG, headquarter in Marktheidenfeld, Germany to drive either by a gear/pinion or timing belt arrangement, a secondary shaft on which the cap chuck is mounted. As off-the-shelf servomotors are designed with a solid motor shaft however, the cap chuck used to hold the cap during application must either be a solid chuck, mounted directly on the servomotor shaft, or be mounted on the gear/belt driven secondary shaft with a hollow core to allow a cam actuated push rod to open and close articulating chucks jaws.
Electronic capping machines when properly configured provide excellent performance for all capping applications. The following examples make clear the superior advantage electronic capping holds over magnetic clutch capping for high requirement applications...