The coating of green tires with a separating agent is a relatively simple but very important step for productivity in tire production and for achieving consistently high quality in the final product.
The separating agent ensures that the tire does not stick in the mold or bladder in the curing press during the vulcanization. This is essential to ensure a clean, reproducible process and a long bladder operation time. Persistent faults in the coating process can lead to bottlenecks in the tire production or downtimes for the downstream machines. To prevent this, many tire manufacturers use coating systems from Ilmberger Maschinen- und Zahnradfabrik. Around 80% of all these coating systems are now supplied with Siemens Simatic controllers (PLCs) and Simatic HMI (human machine interface) systems. These systems enable the coating and cleaning process to be reliably and precisely controlled and conveniently operated and monitored for many years.
Reliability when needed, around the clock
The following steps are executed on the Ilmberger R4, a four-spindle carousel system equipped with accumulating roller conveyors for the feeding and removal of the tires:
The green tires arrive from the tire production area in random order and in varying sizes. Identification is done via a barcode reader, so that traceability can be ensured. In addition, the system detects the outer diameter and height as the tire enters the first station. It is precisely positioned, elevated, stretched at the bottom via a lifting cross, and picked up by the clamping fingers of one of the four spindles (Figure 1, above). During this process, the inner/bulge diameter is indirectly determined. Then the green tire is unambiguously determined (even without barcode reading) and the required coating program can be loaded and started from the controller or a higher-level database system.
The main drive positions the green tire over the servo-pneumatically controlled spraying system (Figure 2, above) which is positioned vertically and horizontally according to the recipe. The tire is accelerated to a defined speed and the separating agent is applied in one or two coats. This system only coats the inside. Other systems (R1, R8) from Ilmberger can also simultaneously coat the outside. The spray guns can be positioned with an accuracy of ±0.5mm. If desired, coating of the splice can be omitted.
A quarter turn later, the tire is placed on the outgoing conveyor belt, which leads to a buffer or directly to the curing presses.
The fourth and final step is the removal of separating agent residues from the clamping fingers using brushes.
In automatic mode, these steps run continuously, usually around the clock. R4 systems achieve an output of at least ten tires per minute. R8 variants with outer coating and drying processes generally output 12 tires per minute.
In terms of tire size, Ilmberger adapts its systems generally to the individual range of products and requirements of its customers.
Experienced systems integrator brought in
When equipping Ilmberger systems with control components, the mechanical engineer has been relying on the support of Stadler GmbH & Co. Elektro. Siemens and Stadler also program the machines and systems of the other Ilmberger divisions, commissions them on-site, and handles maintenance tasks. Thanks to reliable components, the downtimes of the machines are exceptional.
Stadler, in cooperation with the mechanical engineer, has created a modular automation project that follows the mechanical layout of the coating systems. This covers all of the possible equipment variants in a modular way and now accelerates the implementation of individual plants from the modular system.
The default controller in this is the Simatic S7 300, usually with CPU 315 2 PN/DP, with Profinet and Profibus interface(s). The sensors and actuators in the field are connected via Profibus and/or Profinet. This underscores the openness of the controller, which can communicate with practically all of the components of third-party suppliers.
In addition, the Profinet-capable CPU could easily be connected to the higher-level database system of the operator via a switch and allows the access for the remote maintenance by VPN.
For operator control and monitoring, Stadler now relies on the Simatic HMI Comfort Panel KP700 (Figure 3, above) featuring the Totally Integrated Automation Portal (TIA Portal) from Siemens.
“If even our rather conservative international clients are ready to take the step into the new world of automation with uniform controllers, HMIs, I/O and also drives, we are now prepared to use the Simatic S7-1500 controller with the compact I/O system Simatic ET200SP,” said David Koslowsky, project management and sales, surface engineering unit at Ilmberger. This also facilitates the integrated implementation of safety functions in a controller.
April 28, 2016
