Food – Flow Wrapper – Burtons Biscuits, Blackpool – 2020

Chocolate Flavoured Coating Shortcake Biscuit Flow Wrapper Machine

The Project:

Burtons Biscuits, a leading snack manufacturer, tasked UCS with upgrading an existing flow wrapper machine. The machine consisted of two stages a single product wrapped and multipack wrapper. The project included the replacement of the existing magnetic safety switches for upgraded models.

UCS spent a lot of time understanding the operation of the machine before commencing any work, the details of this are noted in Understanding the Process. This machine was unique, in that is used a constant speed conveyor belt, moving it back and forth, to space the product. On further research the UCS Engineer found it was one of the few machines left remaining in operation, most of the other machines were taken out of service and replaced due to the problems in keeping them running. This was not an option for the client.

Surveying the Project:

As with all flow wrapper machine the timing on the actual wrapper itself had to be carefully considered, due to the existing design it was decided that an additional ethernet encoder would be used to synchronise the machine, instead of one of the servo axes.

After a lengthy survey to understand the core operation of the flow wrapping machine, we identified a couple of concerns.

• Could the existing movement for spacing be recreated?
• Could the reliability of the machine be improved, minimising downtime?

The UCS Engineer spent several days watching the machine operation, understanding the complex movements required on the single wrap, multi wrap and spacing conveyor and the interaction with the sensors on it. Unfortunately, the existing machine could not be slowed down enough to physically see the sensors and the conveyor reaction.

In 2020, UCS Automation delivered and installed the replacement control panel and commissioned a fully operational upgraded flow wrapper.

Follow up conversations with the client confirmed the upgrade was successful. Not only had UCS implemented a unique upgrade, but as a result the new control and servo solution had greatly increased the machine operating efficiency, and a notable reduction in maintenance costs and downtime.

Our Services:

We provided the following services for this project:

• Electrical AutoCAD design drawings. See our Design page
• Control Panel Manufacturer. See our Manufacture page
• PLC & HMI Software design. See our Software Design page
• Operation manual
• Risk Assessments and Method Statements for the installation
• Disconnection and removal of the existing mechanical system
• Installation, Testing and Commissioning of the system. See our Installation and Commissioning pages

Control System:

Control of the entire system was handled by Rockwell Automation’s Allen Bradley line of PLCs. A CompactLogix PLC, PanelView Plus 7 HMI, Kinetix 5700 servo drives, and Powerflex 525 inverters were utilised on this project. All interconnections between the control equipment were handled via Ethernet, allowing full control and alarm handling over the network, minimising wiring requirements.
The PanelView Plus 7 HMI was a 10.4” colour screen, allowing the operator to control and monitor the machine and adjust operation parameters. It also allowed the operators and maintenance team on site to identify and resolve any faults very quickly, minimising downtime.

Understanding the Process:

As part of the process UCS Automation needed to learn and fully understand the operation of the final machine to develop the control panel and software required to operate it. The line was grouped into several, smaller functions, for the development process.

A) Single wrapper:

Firstly a registration sensor reads the position of each wrapper. The system then moves a set distance to put the wrapper into the correct position, any deviations would result in misplaced packaging seals. Encoder monitoring based on registration sensor will be used to keep machine in position. Speed adjustments considered, product incoming speed, not always consistent, must monitor incoming spacing and adjust speed of wrapper accordingly. Tension also controlled with slack.

B) Spacing conveyor:

Following the single wrapper a spacing sensor detects and adjusts the spacing between single bars out of the single wrapper. The spacing is controlled by a physical movement of the conveyor because the feed conveyor speed is fixed. If the spacing is too large then the conveyor is moved towards the single wrapper, but if the spacing is too small the conveyor is moved toward the multi-wrapper. Distance limitations also utilised when no product is detected. Uniform spacing is required for the input into multi-wrapper, otherwise incorrect quantitys may be packaged. The speed of the process is high, estimated at 250-300 bars processed every per minute. Conveyor spacing is calculated one each bar then it is adjusted. The conveyor position alters after each calculation.

C) Multi-wrapper:

Next the multi-wrapper is fed from spacing conveyor with the registration sensor detecting marks and feeds appropriate distance to wrapper as with the single wrapper. Depending on the bar spacing from the spacing conveyor determines whether a full pack is wrapped correctly. Because the spacing is critial any incorrect spacing will result in incorrect pack sizes and potential damaged product.