Tire building Tire building is the process of assembling all the components onto a tire building drum. Tire- building machines (TBM) can be manually operated or fully automatic. Typical TBM operations include the first-stage operation, where inner liner, body plies, and sidewalls are wrapped around the drum, the beads are placed, and the assembly turned up over the bead. In the second stage operation the belt package and tread are applied and the green tire is inflated and shaped. All components require splicing. Inner liner and body plies are spliced with a square-ended overlap. Tread and sidewall are joined with a skived splice, where the joining ends are bevel- cut. Belts are spliced end to end with no overlap. Splices that are too heavy or non-symmetrical will generate defects in force variation, balance, or bulge parameters. Splices that are too light or open can lead to visual defects and in some cases tire failure. The final product of the TBM process is called a green tire, where green refers to the uncured state. Pirelli Tire developed a special process called MIRS that uses robots to position and rotate the building drums under stations that apply the various components, usually via extrusion and strip winding methods. This permits the equipment to build different tire sizes in consecutive operations without the need to change tooling or setups. This process is well suited to small volume production with frequent size changes. The largest tire makers have internally developed automated tire-assembly machines in an effort to create competitive advantages in tire construction precision, high production yield, and reduced labor. Nevertheless there is a large base of machine builders who produce tire-building machines.
Posted on: Thu, 13 Jun 2013 19:05:03 +0000