Krispy Kreme Unit Retrofit |  Automation world

Krispy Kreme Unit Retrofit | Automation world

Donuts are, of course, the first thing that comes to mind when you hear the name Krispy Kreme. But for those interested in automation and manufacturing, you’re missing out on much of Krispy Kreme’s story if you’re not familiar with the company’s machine building operations.

This aspect of Krispy Kreme’s operations is nothing new, as the company has been designing and building proprietary machines since the company’s early days. Today, the company’s headquarters in Winston Salem, NC, houses an area of ​​10,000 square feet. manufacturing facility hosting research, design, testing, engineering and manufacturing activities.

John Priddy, Krispy Kreme’s manufacturing manager, installs the G120 kit in the fryer section of a donut machine. Source: SiemensThe machines and processing equipment built there use Siemens drives and controls, complemented by Think PLC, Krispy Kreme’s automation engineering consultant.

“They design and manufacture all of their production machines, from extruders and conveyors to packaging, including their famous enamel cascade,” says Bobby Cole, president of Think PLC.

Cole says the speed at which an extruded donut moves through the store is “a big deal. Throughout the process, the shortening is kept within a precise temperature range. The donuts are cooked on both sides to a precise number. seconds on each side and the cooling conveyor runs through the store at a specified number of minutes.

Upgrade via retrofit

Recently, Krispy Kreme updated its manufacturing operations based on the insights of the company’s service technicians, store managers and customers. Patrick Betson, director of equipment manufacturing at Krispy Kreme, says this feedback has led to numerous improvements to address the increased uptime and mean time to failure.

“Before there was a lot of publicity about Industry 4.0 and the Internet of Things (IoT), Bobby Cole and I often talked about the data that could be generated by more advanced machine monitoring,” says Betson. “It became increasingly clear that by integrating the latest Siemens drives and controls into our machines and connecting them using Profinet communications, we could start making that data work.”

To enable consistent automation upgrades and retrofits in existing stores and plan to implement equipment in new stores, Think PLC needed to determine the fastest and most cost-effective way to integrate Siemens Sinamics G120 Variable Frequency Drive (VFD) technology. in more than 600 stores around the world.

This led Betson and Cole to develop a retrofit kit that would allow each store to quickly add new components and software to existing hardware.

The key to the Think PLC retrofit idea was to take advantage of the SD cards used on Siemens drives and controls already in Krispy Kreme stores. It was a viable approach because Krispy Kreme kept each shop’s unique set of crafting and processing parameters on SD cards. As a result, stores only need a local contractor to upgrade legacy control panels, including parts for safety and power wiring.

Betson and Cole adapted every Krispy Kreme store in Australia in five days using their technology retrofit kit concept.  Source: SiemensBetson and Cole adapted every Krispy Kreme store in Australia in five days using their technology retrofit kit concept. Source: Siemens“The main purpose of the kit was to replace the old Siemens Micromaster units with Siemens Sinamics G120 units,” explains Cole. “The SD card in the kit has software that we modified; and with a couple of turns of a few switches, the unit is programmed automatically. Someone with no control experience can reload the new software into new drives and new PLCs ”.

According to Cole, the retrofit kit allows a shop to replace units and controls in about two hours, saving the significant time and cost associated with having a control technician go to a Krispy Kreme shop to get the job done.

To demonstrate the retrofit kit concept, Krispy Kreme and Think PLC tested the installation and use of the kit at their manufacturing facility in Winston-Salem, NC, followed by tests at various stores in the region. During these tests, the new drives and PLCs were installed without problems and the SD cards updated automatically and matched all previous shop parameters. To further test the concept, Cole and Betson adapted all Krispy Kreme stores (more than 30) in Australia in five days using the kits.

Frying control

During the donut frying process, pumping the heated shortening is critical to maintaining optimal donut quality and product count. When the flow rate is not maintained at the desired constant, viscosity problems become a problem as the bits of dough cannot be properly filtered out of the melted fat. This leads to changes in temperature, causing the development of hot spots.

The Sinamics G120 drive solves these pump motor problems by reporting the operating status of each motor. The drive also ensures that the pump motor temperatures are kept below the threshold for heat damage.

Cole explains that the drive can solve pump motor problems due to its ability to set and maintain a curve that ensures the most efficient flow at low and high speeds, from 7 hertz to 90 hertz. With the new units, “the accuracy of the frying time has increased by 12%, resulting in a more consistent product with a lower waste yield,” he says. “A big advantage of the drive is that it can make an engine run slowly without the usual rise in engine temperature. When running a motor at very low hertz, a lot of eddy currents are generated. It’s so hot you can’t touch the engine. And when an engine’s laminations overheat, engine life is greatly reduced. But we can monitor every drive through the Siemens TIA (Totally Integrated Automation) portal and have seen the amperage reduced by almost 17% and the motor temperature reduced by 34%. We expect this to double the life expectancy of each pump. “

Sinamics G120 units also address worker safety concerns through their triple quadruple redundancy, says Cole. “The new drives and PLCs installed in each shop integrate with existing Siemens safety monitoring circuits, including automated safety mechanisms and emergency stop buttons. For example, if a hose breaks on the shortening pump, the flow stops within 100 milliseconds, ”he says.

Remote access via TIA

Using the Siemens TIA portal, Think PLC can remotely access any Siemens G-120 unit.

Cole describes using the TIA portal via his smartphone as if it were like staying in a Krispy Kreme store at the unit’s operator interface.

A store can produce a thousand dozen donuts per hour.  The performance of the pump motor drive in the shop can be viewed through the Siemens TIA portal to diagnose, troubleshoot, maintain and prevent production flow disruptions.  Source: SiemensA store can produce a thousand dozen donuts per hour. The performance of the pump motor drive in the shop can be viewed through the Siemens TIA portal to diagnose, troubleshoot, maintain and prevent production flow disruptions. Source: Siemens“When you open the drive door, a large display shows any error messages,” he says. “You select an error message and you are given the related error code that you should have looked up in the user manual in the past. Now, all the information you need, the details, what to check, how to reset, is on the display. The diagnostic screens allow you to debug the problem. In addition to this, faults and alarms can be logged in the cloud so that you can study trends over the course of a year and identify and resolve faults for a particular machine. I can also look at how many cuts have been made on the extruder today. I can look at how many breakdowns occurred on that machine during the day. I can see what the average temperature was in the shortening tank. I can call the local service manager and say, “Hey, next time you do preventative maintenance at that shop, you need to send in a new pump motor, because you get more breakdowns in a short period of time. Keep those parts on yours. truck and you won’t need to make a second trip. ‘”

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