An advanced five-axis motion control system from Baldor is at the heart of what is claimed to be the first continuous cross-web zipper applicator for continuous vertical form fill seal and horizontal flow wrapping equipment. The new machinery for manufacturing resealable pouches, developed by Line Equipment for inserting Supreme Plastics narrow zippers, is expected to achieve throughputs of over 80 pouches/min.
By applying zippers across the web, food producers gain considerable packaging flexibility compared with conventional in-line zip application techniques – boosting fill ratios, saving material, and allowing one machine to be programmed for form fill seal operations on a much wider spectrum of pouch sizes.
To achieve continuous manufacturing, Line Equipment’s machine uses three zip applicators mounted on looped belts, each driven by a rotary servo motor. The applicators work in a sequence: while one is applying a zip – accelerating to web speed and synchronizing with a registration mark – the next is having a zip loaded, and the third moving into the start position. A fourth rotary motion control axis feeds and cuts zip lengths into the applicators as they reach the loading point in the loop.
A fifth axis, located under the plastics web material, controls the movement of a heating element that synchronizes with the plastic web and applicator and seals the zippers into place. This axis uses a linear motor, because of the sheer accelerations required to track the zipper applicator – before applying heat – and then return to the start position in readiness for the next applicator. At 80 pouches/min, this axis can be accelerating at rates in excess of around 2.4 G, or 23ms/s
The motion control system uses a panel mounting Baldor NextMove BX motion controller to manage the zipper applicator and linear motor axes, plus a stand-alone intelligent Flex+Drive to control the zip feed and cut axis. The two motion control subsystem elements link to a Baldor operator panel using a CANopen fieldbus, which allows the operator to define zip length, pouch size, and other parameters. Both units include the I/O required for the various sensing and actuation functions associated with the process, such as registration mark detection and zipper knife control.
Baldor provides all motion, I/O and human-machine interface system components for the new machine, and wrote the application software using the popular MintMT motion language. The applicators work with Supreme Plastics’ patented Keyseal narrow (7mm wide) zipper technology, which is said to reduce material costs and enhance sealing compared with standard zippers on regular in-line equipment – and allow more zipper per reel – reducing downtime from change-overs.
The co-extruded Keyseal zipper is applied across the film and secured within the cross-seal, without being crushed, unlike conventional longitudinal, in-line application, where the closure extends to the edges of the pack, increasing the potential for leakers. The zipper is also designed to prevent finely grated or powdered contents from impeding closure. Extra sealant layers also enable fast, effective sealing at lower temperatures, without risk of distortion or perforation.
| Baldor UK
Tel: +44 (0)1454 850000
External weblinksConverting Today is not responsible for the content of external internet sites.Baldor UK