Thurne brings home the bacon thanks to advanced vision
04 July 2016
Thurne-Middleby offers a comprehensive range of slicing systems for fresh and precooked bacon, cooked and cured meats, natural products and cheese applications.
The company’s commitment to innovation has led to the design of a slicer dedicated to the pre-cooked bacon market – the IBS 4600 Vision Slicer.
This is the world’s first slicer to have four independent blades and feeds. It needed a robust and accurate control solution and, as a result Thurne turned to Rockwell Automation.
Thurne is a Rockwell Automation OEM Program Participant, demonstrating that it has a commitment to offering high-quality, innovative machinery and equipment that uses Rockwell Automation solutions. As an OEM Program Participant, Thurne is dedicated to helping manufacturers increase business agility, optimise productivity and achieve sustainability objectives by delivering flexible and efficient equipment.
The main challenge with bacon slicing is accuracy, in order to help ensure more consistency and less wastage. The older style machines rely too much on an antiquated approach, so Thurne opted for a solution that tied in a precision vision solution.
Other slicers for the pre-cooked bacon segment using gravity-fed slicing technology do not offer full product control and are unable to deliver consistently cooked individual slices every time. They might produce overlapping slices and variations in thickness that would result in overcooking and undercooking, therefore wasting slices or increasing giveaway (giveaway is the extra weight above the weight indicated on the packaging). To deliver consistent weight slices with minimum giveaway, Thurne had to bring the lean and fat into the equation and opted for a solution that paired precision vision solution with accurate control.
According to John Kelsey, Product Specialist for the IBS4600 slicer, the four-bladed cutting solution is very tightly controlled using signals from an advanced vision system. For every single revolution of the blades the vision system takes two images of the bacon slice face and from that identify the lean and fat areas. Using this information, which is fed back to the primary controller, the company is able to adjust the slice thickness and obtain slices of a set weight.
For this vision approach to be effective, Thurne needed a control solution that could move the product feed quickly and accurately to help ensure the target weights were consistent.
At the heart of the control infrastructure is an Allen-Bradley ControlLogix L71 programmable automation controller (PAC). An in-house developed vision system sends data to the PAC which calculates the slice thickness for a particular weight. The PAC’s eight Allen-Bradley Kinetix 6000 servo drive/motor combinations control the blades and the product feed drives. The feed drive rate is altered to obtain the desired thickness.
In addition to the motion solutions, Thurne has deployed Allen-Bradley PowerFlex 40 variable speed drives with Ethernet cards to control the infeed and outfeed conveyors. Allen-Bradley Flex I/O is also used for communication as sometimes there can be up to 30m distance between the panel and the machine. This is due to the way the microwave cooking system works, where the microwave transmitters are upstairs with the oven downstairs.
Hard wired Allen-Bradley Guardmaster 440R safety relays are also used and conform to EN13849 – the whole machine is performance level E. These relays are configurable without having to use a PC or proprietary programmer; instead it can all be done using DIP switches, making them easy to use and very flexible.
The final part of the control solution is an Allen-Bradley PanelView Plus 1250 HMI, which is used to provide a visual overview and for adjusting parameters, such as the blade speed, slice thickness and weight – all of which can be stored as preconfigured recipes.
Kelsey explains that the beauty of the machine is that it is consistent and dull. What he is referring to is its ability to produce 500,000 slices per day, running at 16 hours a day, six days a week and 50 weeks per year.
Thurne has calculated that the greater accuracy and reduced giveaway can result in a significantly lower cost of ownership, with a payback period of less than a year. It is also capable of accurate out feed-belt placement, which removes the need to discard overlapping product prior to microwave cooking – saving more time and money for the customer.
Kelsey explains that the company is seeing multiple benefits of the Rockwell Automation based system. Its knowledge of the devices and its closeness to Rockwell Automation has allowed the company to streamline its design time.
The Ethernet backbone also helps a great deal, especially in combination with the Ethernet cards used within the PowerFlex drives. Thurne receives super quick diagnostics of the drives via a web page. It can look at an inverter’s web page and open up a window that updates every three seconds, delivering all the important parameters. This really helps with training – you don’t even have to open Logix. It is great using Ethernet to vary the speeds of the drives and to tie it into Logix is a joy.
In addition to easier testing and validation Thurne is also looking to the future and is considering the addition of Web modules. The idea being that the machines can report how they are doing and if Thurne had service agreements with customers, the machines would flag up when they need a service.
By using Ethernet as the communication backbone, Thurne has the option to expand the machine even further into the Connected Enterprise. This will allow it to offer a broad range of additional value-add functions to its customers, including the collection of real-time performance data, historical data for performance assessments and maintenance schedules and connectivity beyond the shop floor into enterprise systems that can help manage the equipment even more precisely in line with other assets on site.
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