Rotary Package Sealing and Cut-To-Length with Stacking Control Applications
Rotary Package Sealing Application
Machine: Conveyor system with side seal heated rolls and rotary cutter/sealer drum
Application Description: A series of product, such as candy bars, is fed into the sealing machine equally spaced on a conveyor. A second inline conveyor is lined with plastic wrapping material supplied from a supply spool underneath the conveyor. A second supply spool is above the conveyor. As the product transfers to the second convey the product gets sandwiched between the upper and lower plastic wrap. Heated rolls seal the plastic at the ends of the product while a heated cutter/sealer drum seals and parts the product.
Application Solution: The EMAX 1-1/2 axis controller is ideally suited for this master/slave application. A servo motor is connected to the seal/cut drum via a precision gearbox. A line encoder is connected to the conveyor system to sense the speed and position of the conveyor. A product sensor is positioned to detect the incoming product and to compensate for slight product pitch variations.
An application program for the EMAX controller is developed using the Emerald Motion Language PC software to create the following sequence:
- The seal/cut drum is positioned so the knives are horizontal and clear of the plastic web.
- The conveyor starts running and product is fed onto the second conveyor.
- When the sensor detects a product the servo driving the cutter/sealer drum synchronizes to the web motion to cut and seal the leading edge of the first product.
- An electronic cam in the EMAX controller driven by the line encoder is used to control the motion of the cutter/sealer drum to create a seal and cut between each product.
- The pitch of the cutter/sealer is electronically adjusted using the product sensor to compensate for product spacing.
- If the product flow terminates or a jam is detected the cutter/sealer drum is positioned horizontally and the heater controls are turned off.
Additional Application Features:
- Touch-screen operator interface is utilized for batch count, parameter entry, diagnostics and error messages
- Control of the conveyor prime mover motor
- Control of heaters for the cutter/sealer drum and side seal rollers
Cut To Length With Stacking Control Application
Machine: Cut to length process using rotary knife cutter and stacker
Application Description: A web of material is fed into the machine by feed/pinch rolls. The machine must cut the web into regular length pieces registered with a mark on the web. The cutter speed must be synchronous to the web speed while the cutter is engaged with the web. Once cut, the pieces are stacked into a pile of product of a certain count size.
Application Solution: The IIS Emerald EMC-2100 automation controller coordinates the motion of all three servos in this master slave application using a SERCOS network. A servomotor is connected to each of the three main sections, feed/pinch rolls, rotary cutter and stacker wheels.
An operator interface is connected directly to Emerald and is used for programming the cut length, stacks count, and line speed and is also used for diagnostics and error messages.
An application program for the Emerald controller was developed using the Emerald Development Environment PC software to implement the following motion requirements:
- A software "motor" or pacer was configured to be the master for all three servomotors. The pacer was programmed to make one turn per product pitch.
- The web feed/pinch servo is programmed using an electronic ratio from the pacer. The ratio is set such that the programmed amount of web is fed. The electronic ratio of the feed/pinch roll servo is modified based on the registration sensor #1 just downstream of the feed/pinch rollers. Modifying the ratio keeps the registration marks aligned with the cutter.
- An electronic cam, driven by the pacer, is used to control the motion of the rotary cutter. The cutter is programmed to make one revolution per product pitch in coordination with the pacer. The cutter axis matches line speed during the angle of cutter blade engagement then may speed up or slow down depending on the product length.
- The stacker axis is also driven by the pacer axis via an electronic cam. The stacker runs above line speed when the cut piece first engages the stacker rollers to create a gap between the current and next product. The stacker rollers then slow down significantly below line speed to gently drop the cut piece on the stack.
Additional Application Features:
- Cutter can be phase adjusted on the fly to align cut with registration mark.
- Emerald controller uses I/O points via the Emerald Series SERCOS servo amplifier for control of auxiliary equipment and PLC interface.
- Operator warning for loss of registration mark detection.
- Jog to registration mark startup sequence.
- Warning buzzer for stack count completion.
- Line speed display.
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