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Product category: Stepper and Servo Drives, Motors, Controls
News Release from: Baldor UK | Subject: NextMove BX
Edited by the Engineeringtalk Editorial Team on 30 May 2003

Multitasking motion control speeds
packaging

An advanced five-axis motion control system is at the heart of the first continuous 'cross-web' zipper applicator for continuous vertical form-fill-seal and horizontal flow-wrapping equipment.

An advanced five-axis motion control system is at the heart of 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/minute, providing a breakthrough in food packaging technology

By applying zippers across the web, food producers gain considerable packaging flexibility compared with conventional inline 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 innovative machine uses three zip applicators mounted on looped belts, each driven by a rotary servomotor.

The applicators work in a sequence: while one is applying a zip - accelerating to web speed and synchronising 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 plastic web material, controls the movement of a heating element that synchronises 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/minute, this axis can be accelerating at rates in excess of around 2.4g, or 23m/s2.

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, etc.

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 required for the new machine, and wrote the application software using the popular MintMT motion language.

Development time was greatly reduced by means of MintMT's built-in multitasking operating system.

Baldor used this feature to divide the major control functions of the machine - controlling the belt and linear motor axes, and the man-machine interface - into separate tasks.

This greatly simplified software development, allowing the control program to be written in a couple of days, ready for download onto the prototype.

With testing, the application software was produced within a week, helping to keep Line Equipment's development project on target.

The availability of application-level software in the form of 'keywords' within the Mint language also contributed significantly to fast software creation.

In particular, Baldor used Fly, a high level command which will synchronise the movement of two axes while controlling the position of one - providing an elegant solution for the continuous zip attachment process.

A further keyword then allowed Baldor to correlate the zip-attach and linear motor heating element axes to the web material - so that the applicator automatically tracks the web speed.

This command has the additional facility of being able to operate virtually, allowing the machine to be set up without wasting material.

"The consumer-friendly virtues of resealable packaging formats are being pushed by retailers and food producers alike, creating a demand for higher speed, and retrofittable automation", explains Line Equipment Managing Director John Blashkiw.

"Baldor's ability to work alongside our engineers, and provide a completely operational motion control package, has helped us to create an innovative automation solution for this emerging market need". Request a free brochure from Baldor UK ...

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