Material handling systems are paramount to the tire and rubber manufacturing process. To ensure optimal production throughput, often a complex system of conveying, buffering, and storage units are deployed to the production floor. One critical material handling challenge applies to un-cured, green, tires. Tire building equipment often dramatically out-paces curing throughput capacity. Green tire inventory must be carefully managed to ensure uptime for tire builders, and steady output to the curing stage.
For many years, the tire and rubber industry has pushed for automation in the green tire handling process. Often a mix of custom Automated Storage and Retrieval Systems (ASRS), custom conveying apparatus and Manufacturing Execution Systems (MES) are deployed to address green tire inventory management challenges. This combination of technologies and mechanical solutions can make controls development challenging, as a wide breadth of software expertise is required.
As a leading automation software development group, DMC successfully partnered with equipment builders, contractors, and the manufacturing end-user to define and deploy a custom ASRS solution for green tire handling. A single ASRS system manages over 5,000 tires daily while maintaining high reliability, with advanced material tracking and flow control customization. Utilizing an engineering team of multifaceted expertise, DMC provided software architecture design and development services from the lowest level machine controls, through external communication interfaces with the plant MES solution.
The green tire ASRS control system utilizes high bay storage (HBS) infrastructure to provide inventory for over 5,000 tires in transit from tire building to curing processes. Using core robotic structure sourced from Gudel, and motion controls platforms provided by Siemens, the primary ASRS worker traverse over a 50-meter trench, handling tires in pallets of four each. Primary loading controls consist of two dual acting Gantry systems, that are responsible for conveyor loading and unloading operations.
Managing Production Demands
The green tire ASRS manages production demands in several ways. The first primary servicing maintains steady infeed from upstream tire building conveyors. As tires enter the system, serial number, model number, and storage operation data are received from plant MES, dictating how the ASRS should handle individual tires. Tires can assume three status indications from the infeed: store, reject, priority bypass. The ASRS processes the tires, palletizing like tires for storage in the high bay, rejecting tires for quality reasons, or bypassing priority tires to meeting curing demands.
Another mechanism by which the ASRS services production demand is automated retrieval. For pallets stored in the high bay, the plant MES system is capable of scheduling and requesting retrieval of specific tire types to service curing and order needs. The plant MES queues requests and then the green tire ASRS dispatches the primary pallet handling platform and gantries, all while balancing inventory recall with infeed demands.
The green tire ASRS operates on Siemens controls platforms. Utilizing customized PLC and Motion control software, the central control systems provide support for product tracking, robotic dispatching, and operator interfacing. The flexibility of Siemens control platforms was critical to improving system functionality, reliability, and safety. The Siemens toolchain aided significantly in supporting a multi-developer team, aiming to deliver in a high demand production environment.