A major mail order pharmacy was planning a new facility so they approached their long time supplier of automated solutions, Tension Packaging, to design a system that would reduce their cost per prescription and produce 1,000 validated and labeled pieces per hour.
Contributed by | MagneMotion
Tension Packaging of Kansas City, MO, designs and builds modular, scalable automation systems for mail order and central fill pharmacies. When approached by their customer to design an automation system for their new mail order pharmacy, Tension looked to MagneMotion’s QuickStick® LSM Intelligent Conveyor System as part of the solution. The resulting system achieved a 20-40% increase in throughput over the customer’s original goal.
THE CHALLENGE
When a major mail order pharmacy was planning a new facility they approached their long time supplier of automated solutions, Tension Packaging, to design a system that would reduce their cost per prescription and produce 1,000 validated and labeled pieces per hour. As Tension analyzed the current system and requirements, they concluded the pharmacy was burdened by the repetitive operations of labeling and verification. While the current method produced an adequate number of pieces per hour, the cost per script was negatively affected by the amount of labor needed to fill each order. It was apparent that an automated solution was needed to achieve the customer’s goals.
The automated processing of pharmaceutical bottles and boxes is traditionally performed using an A-Frame system where totes move through the center of the machine, stopping at stations to collect each item in a patient’s order from the correct product storage chute. “While these systems are highly automated, they were not automated enough for our customer,” stated Ken Meyers, Tension’s Director of Packaging and Design. “An A-Frame system requires up to 10 labeling technicians and 2 Pharmacists to label and verify the contents of the totes once they were processed,” added Mr. Meyers.
Tension’s engineering group developed a system, the Linear Dispensing Unit (LDU), designed to accommodate and dispense 150 products of varying sizes. The products were loaded into channels located on the backside of the machine and dispensed onto a vehicle moving bi-directionally. Each piece was then sent through an escapement where it was verified and labeled and, finally, deposited into a tote that moved directly to the packaging area. This was a great improvement over the existing process where items were manually labeled and verified.
The LDU concept appeared to satisfy all the customer’s needs by reallocating 3 pharmacists and 6 laborers to more productive roles in the facility and producing the required number of pieces per hour. However, the challenge still existed of how to move the vehicles bi-directionally, quickly and accurately while maintaining a clean environment.
THE SOLUTION
Tension investigated a number of possible transportation solutions for moving the vehicles in their LDU. Among these were rack and pinion, belt and pulley, screw systems and linear synchronous motors. The following conclusions were made:
Belt and Pulley
- Thrust is limited to the tensile strength of the belt.
- Accuracy and repeatability suffer from inherent limitations of the belt travel system. Mechanical windup, backlash and belt stretching contribute to inaccuracies in the system.
- Using the best reinforced belts has some compliance when positioning +/- 1 encoder counts . This compliance will cause a settling delay at the end of a very quick move, making it impossible to push the LDU to a higher throughput.
- The system does not support multiple vehicles.
Rack and Pinion
- This system is mechanically stiffer than belt and pulley and provides more thrust capability.
- The lack of accuracy is the major drawback. The gearbox and pinion gear will have bi-directional inaccuracies and over time will wear and increase the problem.
- The system does not support multiple vehicles.
Screw System
- The required high rotational speeds to achieve throughput can cause a screw to whip or hit a resonant frequency, causing instability and vibration. The problem is magnified as the length of the screw increases. This limits the ability to increase the LDU’s throughput.
- The system does not support multiple vehicles.
Linear Synchronous Motor
- System can reach speeds of 2.5 m/s and position the load within 0.05 mm or better.
- There is no backlash or windup, a direct-drive linear synchronous motor will have consistent repeatability to one encoder count.
- Settling time is not a concern because the load is directly connected to the moving carrier and there is no inherent backlash in a linear synchronous motor system.
- Even as mechanics wear over time, the direct coupled linear synchronous motor and encoder will always provide the most accurate positioning.
- The system supports multiple vehicles, independent and bi- directional payload propulsion and control.
- Built in anti-collision features prevent damage to vehicles.
After determining that a linear synchronous motor system would work best in their design, Tension began to search for the right company and product.
“We had discovered MagneMotion at a tradeshow and saw that they were a leading supplier of Linear Synchronous Motors,” explained Mr. Meyers. “After discussing our application, we asked them to provide a prototype system and it exceeded our performance expectations,” Mr. Meyers continued. “In addition to advantages of speed, accuracy and cleanliness, the QuickStick LSM product supplied by MagneMotion had the advantage of built-in collision avoidance.” Based on the advantages offered by LSMs and the success of MagneMotion’s prototype, QuickStick was selected as the transportation system for Tension’s LDU machine.
MagneMotion’s QuickStick LSM had the speed, accuracy, and flexibility that were needed for the LDU to be successful. The QuickStick could also handle multiple vehicles and maintain its precision in the clean environment that is vital to phar- maceutical packaging.
Results
Tension’s LDU with MagneMotion’s QuickStick LSM was successful in exceeding the expectations of Tension’s customer.
The LDU was able to achieve 1,200 to 1,400 parts per hour; a 20 – 40% increase in throughput over the original goal of 1,000 pieces per hour.
Tension’s customer has since ordered six more systems and is working on plans for two more. “MagneMotion’s QuickStick LSM was key to the success of this program”, concluded Mr. Myers. “Our customer is very pleased and we are very pleased. We look forward to continuing our relationship with MagneMotion and using QuickStick LSMs in future projects.”
About MagneMotion
MagneMotion provides assembly and process automation, material handling, and transportation solutions based on our advanced electro-magnetic technology and controls. At the core of MagneMotion's products and services is a new generation of Linear Synchronous Motor (LSM) technology that provides significantly higher performance than conventional transportation and factory automation systems. The company's success comes from a problem-solving approach and years of research focused on creating optimal solutions to address current and emerging market needs. MagneMotion has proven to be the front-runner in providing innovative and cost-effective linear motor solutions sought by industry leaders in the manufacturing and transportation sectors, by major OEMs and by government agencies such as the DOT, DOE, DOD, and NASA.
The content & opinions in this article are the author’s and do not necessarily represent the views of RoboticsTomorrow
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