Before the Rubber Meets the Road
December 1, 2011
Building Tires At Goodyear’s Danville Plant
At its Danville, Virginia plant, Goodyear recently promoted the merits of the “fleetHQ” nationwide roadside repair network with a live demonstration of the response and repair system. Among other neat features, the smartphone-friendly system enables the service dispatcher to precisely locate the downed truck, shaving considerable time off a typical service call.
As part of the demonstration event, we also had the opportunity to tour the Danville plant, which occupies more than 48 acres under roof, to see how Goodyear builds some of its newest tire designs. Since it first opened in December, 1966, the Danville plant has built more than 100 million truck and aircraft tires. Situated on a 710 acre site, the plant is currently operating 24 hours per day, seven days per week.
Perhaps the most interesting aspect of the tour was that in spite of decades of mechanization and automation, building a truck tire still requires the hands-on effort and attention of many skilled human operators.
While some components were already pre-assembled by the point at which we began our tour, we did follow the process from tread extrusion, to assembly, to molding/curing, to inspection, and finally to shipping.
We joined the manufacturing process at the point where multiple types of sheet rubber are gathered, mixed and extruded into what will eventually be the tread surface of the tire. To create the tread rubber the extrusion machine gobbles up the sheet rubber through four hungry mouths, each feasting on multiple pallets of rubber simultaneously.
By feeding the extrusion machine various types of rubber, Goodyear engineers are able to precisely control the recipe of the tread rubber, imparting the specific attributes called for in each tire design, such as low-rolling resistance, long tread life, traction, or scrub resistance.
Once the rubber is collected, mixed and heated to the appropriate temperature, it is extruded, or pressed out through a die opening similar in shape similar to the finished cross-section of the tire tread. Produced in a continuous ribbon, the tread rubber is visually and mechanically inspected before being cooled and cut to length for use in assembling tires. At this point the rubber is not yet cured, and the tread pattern has yet to be stamped into the surface.
The next stop on our tour was at one of the stations where anywhere from three to four dozen individual components are brought together to build a tire. On the day of our tour, the station we visited was building Goodyear’s G394 SST Wide-Base, Dura-Seal truck tires.
What looks like a long-strip of yellow taffy at this point in the process is actually a gel-like sealing material layered in between the tire’s inner liner, and the belts that give the tire its strength. If the finished tire receives a puncture up to 1/4” diameter in the tread surface
area, the Dura-Seal gel will seal the hole and prevent air loss.
One operator assembles the flexible components including the liner and Dura-Seal layer, ensuring the seams in each layer are precisely aligned and joined, while the operator at the other side of the machine builds up the pre-assembled components. Once the two operators finish their separate build-up steps, the two sub-assemblies are joined together with the sidewall components and the tread surface in the center of the machine.
At this stage, referred to as a “green” tire, the tread pattern has yet to be stamped into the tire, and the rubber is still to soft for use on the road. As the green tires leave the assembly station, they are sent to either warehouse storage, or immediately to the curing process. The curing process uses mechanical pressure, pneumatic pressure and heat to mold the tire into its finished shape, fuse the separate components, and “vulcanize” the rubber to give it the needed strength.
Everything on the outside of the tire, from the tread pattern, to the tire model name, to the fine print is molded into the tire during the curing process. The tread portion of the curing mold is divided into several expandable segments, allowing the mold to be easily removed from the tire once curing is complete. Because the curing process takes substantially longer than the assembly process, it takes more curing presses to keep up with each assembly station.
After leaving the curing presses and cooling a bit, every tire built in the Danville plant is subjected to both a visual inspection, and an x-ray inspection, ensuring that any defects are caught before the tire ever leaves the plant. From the inspection area, the tires travel by conveyor to a robotic stacker that creates stacks of 4-6 tires, depending on the tires size and weight, for immediate loading onto a waiting freight trailer.•