Case study · Food packaging

17-Axis Servo Cake Packaging Line: Smart Belt, Lug Chain and Flow Wrapper

By the ONX Control engineering team · Published:

In short

On this line the cakes arrive from the upstream process at random spacing. The smart belt separates them, detects each one with a photo-eye and puts it in phase with the packaging machine's master axis. A lug chain carries the cakes into the horizontal flow wrapper, print registration is corrected on every pack, and the rotary jaws seal and cut. All 17 servo axes are coupled to the same master axis and run in sync. Commissioned in 2014 as a new machine, the line is controlled by CODESYS SoftMotion RTE on an industrial PC; Control Techniques Digitax servo drives are driven over EtherCAT with a 1 ms cycle. The line runs at up to 700 pieces per minute and a production speed of 70 m/min, with a registration (print mark) control accuracy of ±0.5 mm per pack and an empty pack rate of 1 in 1,000.

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Project summary

Industry
Food: cake packaging
Machine
Flow-wrapping line with smart belt and lug chain infeed
Servo axes
17, locked to one virtual master axis
Control
Industrial PC + CODESYS SoftMotion RTE
Drives
Control Techniques Digitax servo
Operator interface
PC application written in C#
Maximum speed
700 pcs/min · 70 m/min
Registration accuracy
±0.5 mm (per pack)
Empty packs
1 in 1,000
Fieldbus
EtherCAT, 1 ms cycle
Commissioning
2014, new machine

The starting problem

Cakes do not reach the packaging line from the upstream process at fixed spacing: some touch each other, others have gaps between them. The flow wrapper, however, runs at a fixed rhythm; exactly one product must arrive in every pack pitch, at exactly the right moment. If a product is late the jaws land on it, if it is early it shifts inside the pack, and if it is missing an empty pack comes out.

At 700 packs per minute each product has about 86 milliseconds. At this speed products cannot be aligned with pneumatic stops or fixed-speed belts; they have to be separated by servo belts, tracked one by one and put in phase with the machine's master axis. Film feed, print registration and the rotary jaws are coupled to the same master axis: when the speed changes, all 17 axes must speed up or slow down in the same ratio.

ONX Control's scope

  • Control architecture: CODESYS SoftMotion RTE on an industrial PC, EtherCAT and Control Techniques Digitax servo drives
  • Synchronised motion software for 17 servo axes on one master axis
  • Smart belt: product detection, gapping, product tracking and phase correction
  • Synchronised transfer between the lug chain and the flow wrapper
  • Print registration correction on every pack and rotary jaw motion
  • Operator interface developed in C#

The product's path through the line

  1. 1

    Accumulation

    Randomly spaced cakes are buffered in a short queue on the accumulation belt.

  2. 2

    Smart belt

    Consecutive servo belts separate the cakes; photo-eyes detect each cake and its position is tracked.

  3. 3

    Phasing

    The last belt speeds up or slows down each cake relative to the master axis to put it in phase.

  4. 4

    Lug chain

    The cakes drop between the lugs and are carried into the packaging machine in sync.

  5. 5

    Film and registration

    The film is formed into a tube around the product; the print mark is read by a photo-eye and corrected on every pack.

  6. 6

    Rotary jaws

    The rotary jaws seal and cut each pack; the jaw motion is coupled to the master axis.

Product phasing into a lug chain: a photocell measures each product and the servo phasing belt speeds it up or slows it down to land in front of the next suitable lug, in the same position every time; a slot that cannot be reached is skipped ← irregularly spaced products every product in front of a lug, same position → empty slot Infeed belt Phasing belt Lug chain Eye constant speed servo, speed per product machine speed, fixed lug pitch Phasing belt speed · early products slow down, late ones speed up empty slot chain © 2026 ONX Control. All rights reserved. This animation may not be copied or reused without permission. Source: https://www.onxcontrol.com/en/case-studies/17-axis-servo-cake-packaging-line ONX Control ONX Control · https://www.onxcontrol.com © 2026 ONX Control. All rights reserved. This animation may not be copied or reused without permission. Source: https://www.onxcontrol.com/en/case-studies/17-axis-servo-cake-packaging-line https://www.onxcontrol.com/en/case-studies/17-axis-servo-cake-packaging-line ONX-D12DC0A7 © ONX Control · onxcontrol.com
Principle animation: shows the logic of the motion; it is not a scaled drawing of this line.
Horizontal packaging machine: products are wrapped in film and the rotary jaws, driven by an electronic cam, match film speed in the seal zone and seal between products Infeed chain Film reel Eye Fin seal Rotary jaw (servo) sealed packs → Rotary jaw angular speed · one pack cycle seal: tip speed = film speed film speed © 2026 ONX Control. All rights reserved. This animation may not be copied or reused without permission. Source: https://www.onxcontrol.com/en/case-studies/17-axis-servo-cake-packaging-line ONX Control ONX Control · https://www.onxcontrol.com © 2026 ONX Control. All rights reserved. This animation may not be copied or reused without permission. Source: https://www.onxcontrol.com/en/case-studies/17-axis-servo-cake-packaging-line https://www.onxcontrol.com/en/case-studies/17-axis-servo-cake-packaging-line ONX-D12DC0A7 © ONX Control · onxcontrol.com
Principle animation: shows the logic of the motion; it is not a scaled drawing of this line.

Control architecture

All motion on the line runs in CODESYS SoftMotion RTE on an industrial PC; the control task runs with a 1 ms cycle. All 17 servo axes are locked to a single virtual master axis: when the machine speed is changed on the operator panel, the infeed belts, lug chain, film and rotary jaws speed up or slow down in the same ratio and keep their phase relationship.

The servo drives are Control Techniques Digitax, connected to the PC over EtherCAT; every 1 ms all axes receive a new position command. The operator interface was developed in C# as a separate PC application; machine speed and running information are managed and monitored from this screen.

CODESYS SoftMotion RTE

CODESYS SoftMotion RTE

Real-time control software on the industrial PC with a 1 ms cycle: master axis, synchronisation of 17 axes, smart belt and print registration.

Control Techniques Digitax servo drives

Servo drives for the infeed belts, lug chain, film, longitudinal seal and rotary jaw axes, driven over EtherCAT.

C# operator interface

PC application developed by ONX for machine speed, running status and operator commands.

Photo-eyes

Product detection on the smart belt and print mark reading on the film; positions are evaluated against the master axis.

Axis layout

Section Axes Task
Smart belt 12 Collects, accumulates and gaps the cakes; photo-eyes track the position of each one.
Phase correction belt 1 Puts each cake in phase with the master axis.
Lug chain 1 Carries the cakes into the packaging machine at a fixed pitch.
Film reel 1 Pulls the film from the overhead reel; the print mark is corrected on every pack.
Longitudinal seal discs 1 The disc motor seals the film tube lengthwise.
Rotary jaw 1 A two-knife rotary jaw on a single motor seals and cuts each pack crosswise.
Total 17

17 servo axes in total, all locked to the same virtual master axis.

Software

The software is built around a single virtual master axis; it is not tied to a motor and generates the machine speed and pack rhythm in software. All 17 servo axes are locked to this virtual axis by a ratio or a cam profile. The speed is changed with one value, and the axes keep the same position relative to each other at every speed.

On the smart belt every cake is followed by a tracking record: which belt it is on, where it is on that belt and which pack pitch it will go into. The phasing belt compares the cake's position with the master axis position and closes the difference while the cake is still on the belt. The same logic runs on the film for the print mark: the mark position measured on each pack is compared with the expected position and the film axis is corrected.

Results and their sources

Indicator Value Source / measurement condition
Maximum line speed 700 pcs/min ONX field data.
Production speed 70 m/min ONX field data. Together with 700 pcs/min this corresponds to a pack pitch of about 100 mm (calculated).
Registration (print mark) control accuracy ±0.5 mm ONX field measurement: print mark position measured on packs leaving the line.
Empty pack rate 1 in 1,000 (0.1%) ONX field measurement: empty packs counted over 1 hour of production; average value.
Speed seen in the video 608–643 packs/min Read from the operator panel in the field video.
Synchronised servo axes 17 Project scope: all axes locked to the same virtual master axis.
Control cycle time 1 ms CODESYS SoftMotion RTE task cycle, EtherCAT.

Limits of this page

  • Maximum speed, production speed, registration accuracy and empty pack rate are ONX field data; they have not been measured by an independent body. The 608–643 packs/min in the video is the momentary value read from the operator panel.
  • No measurement has been published for efficiency (OEE), downtime or energy consumption; this page gives no figures for them.
  • The customer is not named without permission. Technical visits or reference calls are arranged with the customer's consent.

Field videos

17-axis servo cake packaging line: smart belt, lug chain and flow wrapper (36 s summary)
17-axis servo cake packaging line: smart belt, lug chain and flow wrapper (36 s summary) Watch on its own page
Cake packaging line field footage (2014)
Cake packaging line field footage (2014) Watch on its own page

Frequently asked questions

Why does this line have 17 servo axes?

To put randomly spaced products in phase at up to 700 pieces per minute, the products have to be separated on several short servo belts and corrected one by one: on this line 12 axes are in the smart belt and 1 is the phase correction belt. One axis each for the lug chain, film reel, longitudinal seal discs and rotary jaw comes on top. Because all of them are coupled to the same master axis, the speed is changed with a single value.

Why use a smart belt and a lug chain together?

The smart belt separates the products and brings them into phase; the lug chain carries each product into the packaging machine at a fixed pitch, upright and without turning. For soft, light products such as cakes this pair keeps the product under control at high speed.

Can a similar line be applied to our existing machine?

Yes. In a retrofit the belt frames, the lug chain and the packaging machine's mechanics are usually kept; the belts are split into servo sections, photo-eyes are added and all axes are coupled to one master axis in the new control. Product dimensions, the target packs per minute and the current infeed layout are enough for a first assessment.

Let's talk about your packaging line infeed

Share your product, target pack speed and current infeed layout; we will come back with an axis layout, servo sizing and an architecture proposal.

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