Brushed 24V DC Gear Motor Assembly for Pharmacy Automation Equipment

Overview

Our customer, who is leading the way in the prescription medicine dispensing space, has been producing automated pill dispensers for hospitals and pharmacies for years. They approached our team at ISL Products for an electric motor that would be part of an internal labeling process within one of their RX vending machine product lines.

The ideal motor would have a rated voltage of 24VDC and be used to run a gear and pulley system for an internal prescription bottle label applicator within the piece of automated equipment. This meant that the system could be running periodically or continuously throughout the course of the day, depending on customer interaction. As with any automated vending machine, especially in the pharmaceutical space, quality and reliability were critical.

Challenge

Our customer had been using an off the shelf brush DC motor prior that caused performance concerns. Upon examination, we were able to determine that the specs of their incumbent brushed micro motor were not suitable for the application. We had determined that they would need to switch to a brushed 24V DC gear motor suitable to their performance requirements.

The previous motors contained in their machines didn’t have a gearbox therefore they were a bit shorter in length than our planetary gearbox motor. We had to collaborate with the customer to figure out how to increase the cavity to accommodate a slightly larger size motor.

Since the dispenser would be operational for nearly 24 hours a day at various work loads the solution needed to be able to handle the various duty cycles. The output torque and output power were not as important as the output speed, which allowed us some flexibility.

After having some discussions about ISL’s value-added capabilities, the customer was interested in having ISL supply a full motor sub-assembly. This sub-assembly would include the proposed gear motor in addition to lead wires and various connectors. The goal was to have a truly plug-and-play motor assembly to reduce installation time on their assembly line.

After researching some of the items on their B.O.M (bill of material) we found that one of the connectors had a lead-times in excess of 15 weeks! This put us and our customer in a tight position. We’re able to manufacture our gearmotors in roughly 10 weeks, but the overall lead time would be extended by at least 5 weeks due to the connector.

Solution

We started with defining the customers requirements for the motor since that was the most important piece of the puzzle. This part of the project turned out to be fairly straightforward, as we opted to go with one of our standard 24V DC gear motors that utilized a planetary gearbox with a 100:1 reduction ratio. The gearbox reduction allowed us to reduce the operating output speed to around 63 rpm, which was exactly what the customer needed for proper operation of the label applicator pulley system. The gear reduction also helped to provide a slightly quieter motor operation.

We worked with the customer to rearrange the internal layout to accommodate a slightly longer motor solution. The standard output shaft type D style flange was perfect for the mating pulley gear. We submitted an application prototype drawings for their approval and moved onto the initial sample production.

Once the gear motors were approved, we did a few small production runs so they could get initial prototypes and field replacements done before moving onto the next phase of the project, the sub-assembly.

At this point time was our most limiting factor, so we had to get creative with the long lead time connectors. With over 45 years in the electronic component industry, we have many strategic alliances at our disposal. We were able to provide a drop in replacement M12 circular connector that was not only in stock, but also cost 25% less than the incumbent M12 connector. The M12 connector connected the gear motor to the power supply and other auxiliary inputs so it was a critical component of the assembly.

We sent samples of the replacement M12 connector to the customer and they verified that these new connectors mated perfectly with their female socket.

The other connectors that were required were a pair of simple fast-on style wire crimp connectors. The previously designed connectors required a special crimping tool that cost thousands of dollars and took a bit more processing time to assemble, which the customer wasn’t fond of. Our solution was to change to a more streamlined connector that does not require any proprietary tools. This not only saved on assembly costs but also sped up wire assembly time. All in all, saving our customer’s money.

The final dc gear motor assembly consisted of stripped and tinned lead wires, a M12 circular connector, fast-on style connectors, and colored coded heat shrink.