Forpak Power Study
Testing done on November 2nd 2021
Completed by Adam Shank (Hamilton Automation) and JB Korte (Van Meter Inc)
With the help of Dave Brownson (Forpak)
Evaluation & Analysis completed by Joel Geisel (Hamilton Automation)
Summary of Opportunity
LinMot linear servo motors have a proven track record saving energy and providing highly efficient linear motion. In addition to efficiency and power savings, LinMot linear motors provide lower total cost of ownership due very few wear items and much lower downtime, especially unexpected downtime, resulting in real world long-term savings.
To test the efficiency and power savings, Van Meter and Hamilton Automation tested a Forpak machine with pneumatic actuators to establish actual power consumption and develop actual energy savings data.
This testing does not quantify any costs associated with the frequent scheduled maintenance or unexpected downtime operating pneumatic cylinders in a production environment. These costs must be added to any energy costs to operate the pneumatic cylinders.
Test Set Up
Forpak assisted by allowing access to a typical stacker machine in operation at many end-user sites. The stacker machine is a four-lane machine with 8 pneumatic actuators operating in a horizontal direction.
With the help of JB Korte, 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 efficiency 7 cfm electric air compressor. The team ran the machine for 30 minutes and sampled every 10 msec. This set up 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.
Findings
We ran into one limitation during the test run - the amount of data points to store in the PLC. The data pulled was for 15 minutes run time. The average power was very consistent throughout the study. Running the machine for an additional 45 minutes proved that the data would not have changed. The compressor never turned off the entire 60 minutes. The team was confident that the data pulled for the entire 60 minutes would have been nearly identical as the 15 minutes test data (extrapolated for the 60 minutes test).
The power consumption was consistent at 5161 kWh throughout the test.
LinMot’s Lin Designer program shows this specific 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 from the pneumatic cylinder factory expected energy consumption.
For this specific cycle, LinMot’s Lin Designer program estimates 4575 kWh power consumption.
We will use the LOWER of the two values to calculate pneumatic cylinder energy operational cost:
4575 kWh times a fully loaded $0.20 per kWh (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 8000 hours of operation per year. Since this machine uses 8 pneumatic cylinders, the operating cost for this specific machine would be $7320 per 8000 hours of operation per year.
The equivalent LinMot provided linear motor yields the following power consumption result:
The same cycle resulted in 243 kWh for a PS01-23x80F-HP-SSCP-R20 motor in a 175 mm cycle in 200 msec and -175 mm in 200 msec with a 600 msec dwell time.
243 kWh times a fully loaded $0.20 per kWh would equal $48.60 per LinMot actuator. All eight actuators would cost $388.80 to operate 8000h of operation per year.
The savings here are tremendous:
$6,931.20 per calendar year
If a plant operates to a 6000h per year schedule, the savings would be $5198.40 per calendar year.
Still a tremendous savings.
These values do not include any frequent maintenance or any unexpected downtime costs when a pneumatic cylinder takes a dump.
Typical plant downtime is valued at $15,000 to $20,000 per hour.
Replacing one pneumatic cylinder usually takes between 30 to 90 minutes.
Results
The test study was successful pointing out that running 8 pneumatic cylinders costs significantly more than 8 linear motors.
As per the world’s two largest pneumatic cylinder manufacturer data, the Carbon Emission savings would be over 4600 lbs. per cylinder or over 36000 lbs. of CO2 emission savings for this specific machine with the 8000h per year operation.
Adding this to the over $6,900 worth of electricity cost savings and the case can be made that LinMot linear motors not only save the environment, they also save a lot of direct energy costs that flow immediately to the customers bottom line.
Accounting for frequent pneumatic cylinder downtime, keeping airlines clean plus the unexpected downtime that occurs with pneumatic cylinder applications, especially with frequent cycling applications such as this study, and the case can be made that using electric actuation with direct drive linear motors brings significant profitability to the machine user.
