The internal transport systems of Flowsort powered by 2K wheels
The intralogistics market relies on automated sorting systems to quickly and accurately sort random product flows. To adapt to varying volumes, Flowsort developed and launched its modular sorting machines. The sorting machine can be assembled via a plug-and-play system, tailored to the customer’s specific capacity and requirements.
For the standardized concept, plastic components were used. Fleur Plastics was brought in early to optimize these components and prepare them for production.
Together, the requirements and challenges of the products were mapped out. One of the key requirements was to ensure a smooth integration of the entire system to prevent resistance in the moving parts. Additionally, it needed to withstand loads of up to 50 kilograms.
The Challenge
- Optimize injection-molded components;
- Select appropriate materials with strong adhesion and friction for the friction sleeve;
- Develop an efficient mold design to keep investment costs low;
- Achieve high precision in injection-molded parts to reduce system resistance.
The Solution
The Flowsort system is built from the following plastic components:
- Wheel Housing;
- Sorter Wheel (consisting of a Wheel Hub and Friction Sleeve);
- Logocap;
- A set of three gears.
The Wheel Housing holds four Sorter Wheels with 2K friction surfaces. These are driven by the three gears, allowing the system to sort packages at high speeds (6,000 packages per hour) with a 180-degree range. The Logocap covers the rotating parts.
The Molds
To keep the investment costs low, various alternatives were explored for Flowsort. For example, a decision was made to manually overmold the Sorter Wheels rather than opting for a complex (and expensive) 2K mold. Through inventive mold solutions, the entire process was divided into three molds:
- The Wheel Hub and Logocap are produced separately in a single mold. By using interchangeable parts, the mold can easily be converted into an overmold mold. This is then used to apply the Friction Sleeve (the TPU running surface) to the Wheel Hub;
- The trio of gears is produced from a single cavity mold. This mold can also be adapted with inserts to create different versions;
- The Wheel Housing is produced in a separate mold.
The Material
Polyacetal (POM) was used for moving parts such as the Wheel Housing and the Sorter Wheel. This choice aligns well with the application. Due to its low moisture absorption, the parts remain dimensionally stable, the good sliding properties reduce friction, and the strength meets the 50-kilogram requirement.
The tread surface of the 2K wheel is made of thermoplastic polyurethane (TPU). This adheres to the POM inner core through mechanical bonding. Even at higher speeds, the TPU tread remains securely in place and provides excellent grip on a variety of packages.
The Logocap is produced in ABS to make the texture and high gloss visibly attractive on the sorters and diverters.
The Injection Molding Process
The Sorter Wheels make a high number of revolutions during use. Even a small deviation can quickly become noticeable, increasing resistance.
Therefore, the first trial molding was conducted with an oversized core. This allowed for analysis of the impact of the 2K overmolding on the inner core. Based on several trial moldings and measurements, the core was then adjusted to size. This reduced the deviation to a level that was more than acceptable to our client.
The Result
By looking at smart mold constructions, we achieved significant savings on investment costs for Flowsort without compromising product quality.
The products were thoroughly analyzed during the mold setup and the trial injections using our expertise. By producing the products with high accuracy, the resistance in the system is minimized, making it more energy-efficient.
The sorters and diverters have already been successfully introduced to the market and have generated significant interest.
