The Tire Manufacturing Process
This blog post will discuss how rubber tires are manufactured and how pressure switches are used to ensure safety during the manufacturing process.
Tire manufacturers use large automated tire press machines to form individual tires in short time intervals by curing them. These are sophisticated and expensive pieces of capital equipment that must work safely through high pressures and temperatures.
Curing is the process of applying pressure to the green tire in a mold in order to give it its final shape, and applying heat energy to stimulate the chemical reaction between the rubber and other materials. In this process the green tire is automatically transferred onto the lower mold bead seat, a rubber bladder is inserted into the green tire, and the mold closes while the bladder inflates.
Protecting Against Overpressure
The inflating bladder pressure is not directly controlled by the pressure switches, but the switches are needed for overpressure protection in order to ensure the safe operation of the press; once the bladder is inflated with air, steam fills the bladder so the rubber sandwich is heated and formed against the mold where the tire then takes on the tread pattern and sidewall lettering.
Temperatures are in the area of 350 degrees Fahrenheit with pressures around 350 PSI. A pressure switch is used on the steam line for overpressure protection, ensuring not too much steam enters the tire, which could cause an extremely unsafe blowout.
When this curing process is complete, a vacuum is pulled on the bladder for it to deflate the finished tire, which is then removed from the mold. A switch is also installed for safety on this vacuum line to ensure mechanical integrity of the line itself.
Sometimes, after tire removal from the press, a post-inflator is used to ensure the size and shape of the tire while it completely finishes curing. Depending on the requirements, a pressure switch is used to maintain pressure inside the inflator for the remaining curing period.
Common CCS pressure switches used for this tire curing process would be our 604G, 605G, or 6900G series which are designed to handle the high steam temperatures of the tire curing machines.
For the vacuum line, a 604V or 605V series works well. If you have any questions regarding this process or the CCS switches used in tire curing presses, feel free to contact our general information email – switchnet@ccsdualsnap.com