Screw Machining Solution Improves Uptime and Reduces Equipment Repair Cost 500x

Fabricating Acetal Spur Gears for Change Counters

An accurate, repeatable result in plastics fabrication begins with selecting the proper fabrication method for each individual part. At Cope Plastics, we feature the most extensive equipment arrangement of any plastics fabricator in North America, which allows us to experiment with several methods in order to be sure we find the most efficient way to produce every part we make. And our team doesn’t stop in the face of challenges. In this application, the Cope team’s dedication to creating a solution for the customer paid off in a big way.

The Customer

The customer distributes and maintains cash handling equipment for banks, ATMs, retail, and gaming across Illinois and Missouri. They found Cope Plastics while searching online for a plastics fabricator and approached us looking for a solution for a particular line of change counting machines.

The Challenge

The customer’s change counting machines featured an assembly composed of a small belt system, a tray with slots to sort coins by size, and two injection-molded spur gears. One of the gears in the machine had been exhibiting premature wear, lasting only around 6 months in many cases when the supplier estimated they should last years. The failing gears were causing the machines to jam, which meant increased maintenance calls for the customer’s team of technicians. 

The challenge was further complicated because the customer was unable to purchase the spur gears separately. In order to replace the gears, they would have to order an entirely new assembly, which ranged in price from $3,000 to $8,000 each. Due to the high cost of the assemblies, the customer did not keep parts on hand, which meant when a new assembly was needed, it would have to be ordered, fabricated, and shipped—leaving the customer’s end users without service for long periods of time.

The Solution

At first, our team wasn’t sure that they could find an efficient way to machine the gears due to the size and geometry of the part. The Cope fabrication team reached out to the experts at our screw machining plant in Genoa City to see if they could offer a viable solution. Screw machining is ideal for small, round, intricate parts that are under 2.75 inches in size, and the spur gears were well below that at just 0.75 inches in diameter.

Using the sample part, the branch manager in Genoa City created a new CAD drawing that he thought would be feasible on our screw machining equipment. He created a prototype of the part, tested the prototype with the sample motor and assembly provided by the customer, and determined that it was a viable solution for the application.

However, to make the spur gear solution a reality, our team still had work to do. We invested in new tooling for our screw machining equipment that produced accurate, repeatable parts within the customer’s strict tolerance requirement.

The Result

To fully verify the efficacy of the new screw machined spur gears, we performed testing at our facility while the customer also conducted their own assessment. Because the customer had provided us a sample motor used in their change counting machines, we were able to simulate how the gears would perform in the field. In both tests, the gears fit perfectly with the rest of the assembly and showed no signs of premature wear. 

Since implementing the new gears, the customer has experienced incredible time and money savings. The acetal gears are lasting longer than the injection molded gears, and because the customer is able to buy them separately, they can keep them in inventory and easily repair down machines without having to wait for parts to be ordered and manufactured. The cost of the screw machined parts also allow them to replace over 500 gears (read: fix over 500 of their machines) for the same cost as a single assembly with their previous solution. 

Conclusion

In this customer’s case, our team went above and beyond to find a solution—collaborating across divisions and using unconventional methods to discover a way we could help. This story demonstrates one of our core beliefs in action: with determination and teamwork, anything is possible.