PERSPECTIVES

OEM’s Pneumatic vs. Servo Test Demonstrates Specific Savings

Matt Reynolds, Packaging World

Dave Brownson, engineering manager at Forpak, was the fi rst engineer hired onto the food stacking equipment OEM when it opened its doors more than 30 years ago. With three decades under his belt as an engineer with the company,

Brownson remembers the days when pneumatics were the only actuator game in town for Forpak machinery applications. He also recalls the fi rst introduction of linear servo in the place of incumbent pneumatic technology about six or seven years ago.

“I was looking for a IP69K solution for a project that we had, so I went to my vendors and they came up with [linear drive system supplier] LinMot,” he says. “I was introduced to them, and we’ve never looked back.”

More recently, Brownson set his sights on building an all-electric, pneumatic actuator-free stacker. But it was a matter of waiting for the right size and shape of linear motion tech to be ready, as nothing existed on the market that could fi t his application.

“I had kept on pushing Peter [Zafi ro of LinMot] to make a smaller and smaller motor, and he asked me, ‘How many would you buy?’” Brownson recalls.

“I answered, ‘Well, how many can you make?’ Because if I can make an all-electric stacker, it would really make e ciencies go up.”

Brownson fi nally saw the LinMot prototype that would do the job at a recent PACK EXPO. Forpak is now developing a machine that is 100% electric with no pneumatic technology. The plan is to exhibit the new machine at PACK EXPO International, to be held Oct. 23-26, 2022 in Chicago.

It bears mentioning that pneumatics aren’t going anywhere, and they are fi rmly ensconced in the controls and automation tool kit. And some operations require pneumatics for safety reasons—in explosive environments for instance—so switching out pneumatic for electric isn’t always possible.

Still, Brownson sought an all-electric model because he says LinMot linear servo motors save energy and are highly e cient for his specifi c set of applications and customer base. Plus, they allow for a lower total cost of ownership thanks to their comparatively few wear items, and that results in less downtime—especially unexpected downtime. In his experience, these factors bring real-world, longterm savings that are attractive to Forpak’s CPG and brand-owner customers.

But so far, that’s just been Brownson’s anecdotal experience— one man’s opinion. To test the effi ciency and power savings, Zafi ro enlisted Brownson, along with Joel Geisel and Adam Shank, both from Hamilton Automation, a LinMot manufacturer representative, and JB Korte of Van Meter Inc., a LinMot distributor. The OEM, automation supplier, and distributors together devised a test of Forpak’s machine using pneumatic actuators compared to all-electic actuators. The idea was to establish actual power consumption and energy savings data. What follows are the results of this test.

Equipment tested

Forpak stackers occupy a niche in baked product and protein packaging lines that exists between upstream freezers and downstream fl ow-wrapping, bagging, or hand-packaging. Typical products might be frozen hamburger patties, wa es, or cookies that exit the freezer randomly or semi-organized. That product needs to be oriented, laned, and stacked for downstream packaging equipment.

“The slide plate and push parts of the stacking were pneumatic, and they always have been, up until just recently,” Brownson says. “Now that LinMot developed the right size actuator, we’re able to do both traditional pneumatic and all-electric, and we performed this test to see the di erence.”

Forpak assisted by allowing the team access to a typical stacker machine in operation at many enduser sites. The stacker machine is a four-lane machine, with eight pneumatic actuators operating in a horizontal direction.

With the help of Korte from Van Meter Inc. and a Rockwell Automation Power Monitor 5000, actual power consumption was recorded. The Power Monitor traced data points including amperage, time, and kWh from an independent, high-e ciency 7 cfm electric air compressor. The team ran the machine for 30 minutes and sampled every 10

But so far, that’s just been fi ciency and power savings, Zafi ro enlisted Brownson, along with Joel Geisel and Adam Shank, both from Hamilton Automation, a LinMot manufacturer representative, and mation supplier, and distributors together devised a test of Forpak’s machine using pneumatic actuators compared to all-electic actuators. The idea was to establish actual power consumption and energy The above Forpak stacker (Model Number GSS5-8) is a typical electric vertical stacker with pneumatic horizontal

cylinders used for stacking products. The Stacker can be manufactured in three to 10 lanes depending on production demand. The test model was a four-lane unit (Model Number GSS5-4). The picture also shows a takeaway conveyor attached for manual or downstream automated packaging.

msec. This setup does not account for pneumatic line losses as the air provided to the cylinders had a very short run from the compressor, with no other devices operating on the same air supply.

Results

The test team ran into one limitation during the test run—the number of data points able to be stored in the PLC. As such, the data pulled was for 15 minutes of run time, and the average power was consistent throughout the study. Running the machine for an additional 45 minutes to achieve an hourly count proved that the data would not have changed. The compressor never turned o in the entire 60 minutes. So, the team says it’s confi dent that the data pulled for the entire 60 minutes would have been nearly identical as the 15 minutes test data, extrapolated for the 60-minute test. The power consumption was consistent at 5161 kWh throughout the test. LinMot’s Lin Designer program shows this specifi c horizontal pusher application and provides for calculated power consumption for the LinMot actuators and an equivalent pneumatic cylinder. Lin Designer’s pneumatic cylinder power consumption calculations are based on the two most popular

pneumatic cylinder manufacturers’ energy power consumption calculations. These are direct-fromthe-factory expected energy consumption rates.

For this specifi c cycle, LinMot’s Lin Designer program estimates 4575 kWh power consumption. The test used the lower of the two values to calculate pneumatic cylinder energy operational cost, as follows:

The 4575 kWh multiplied by a fully loaded $0.20 per kWh (test note: this value is usually much higher, especially when plants run during peak surcharge periods during the daylight hours for most of the calendar year) would yield an expected cost of $915 per cylinder per 8,000 hours of operation per year. Since this machine uses eight pneumatic cylinders, the operating cost for this specifi c machine would be $7,320 per 8,000 hours of operation per year.

The equivalent machine using LinMot actuators provided linear motor yields the following power consumption result:

The same cycle resulted in 243 kWh for a PS0123x80F-HP-SSCP-R20 motor in a 175 mm cycle in 200 msec and -175 mm in 200 msec with a 600 msec dwell time. The 243 kWh multiplied by a fully loaded $0.20 per kWh would equal $48.60 per LinMot actuator. All eight actuators would cost $388.80 to operate 8,000 hours of operation per year.

The savings here are calculated to be $7,320 (pneumatic) minus $388.80 (electric), or $6,931.20 per calendar year. If a plant operates at lower output, say to a 6,000 hours per year schedule, the savings would be $5198.40 per calendar year.

Zafi ro, Geisel, and Korte note that these values do not include any maintenance or unexpected downtime costs when a pneumatic cylinder fails.

“Such fails are more common in with frequent cycling applications, such as the one in this study,” Brownson notes. “I’d estimate that replacing a pneumatic cylinder usually takes between 30 to 90 minutes, with typical plant downtime being valued at $15,000 to $20,000 per hour. Even though it’s not considered in this test, downtime is huge.”

“There are very few mechanical pieces with this type of actuator, so you essentially limit the amount of wear that could happen,” Geisel adds. “And by limiting the amount of wear, it requires less maintenance than a pneumatic cylinder would require. You don't have seals that are breaking down. You're not losing air, and you're not having to replace cheaper components more often. There’s just very little wear or necessary downtime.”

Emissions and electricity savings

The test study revealed that, at least for this specifi c application, running eight pneumatic cylinders costs signifi cantly more than eight linear motors. According to data from the world’s two largest pneumatic cylinder manufacturers, the carbon emission savings would be over 4,600 lbs. per cylinder, or more than 36,000 lbs. of CO2 emission savings for this specifi c machine with the 8,000 hours per year operation.

Adding this to the more than $6,900 worth of electricity savings, Brownson was impressed. This test was done on a four-lane Forpack stacker machine. A typical Forpak stacker uses between six and 10 lanes, meaning the savings will be higher when extrapolated over more lanes.

“I was expecting savings, but I wasn't expecting this amount of savings,” Brownson says. “It really will help me in showcasing the new machine in the future—as far as at PACK EXPO International, and for sales in the future. It shows that the cost of ownership on the front side is going to be a little bit higher, but over the life of the machine, it'll be less.”

(product images not to scale)

XCSR RFID Safety Sensor & XUSL4M Light Curtains with muting for automated machine shutdown, XCSLF switch for entry prevention, & XY2CED Double-sided Cable Pull Switch for fast emergency manual shutdown.

...because just ONE workplace accident is too many...

For over 90 years, Telemecanique Sensors has developed quality sensor products, helping engineers ensure their machines are safe; meeting all the applicable safety standards. Who,

then, should you trust for all your safety sensor solutions?