Hood suggests doing a daily visual inspection of the roller, idler, and pads to monitor wear. Worn pads will also affect traction during milling, Chastain says.
Track pads will wear down naturally, but Chastain cautions about causing premature wear as well. This can be done from stationary turning while the machine is running. "You don't really want to turn the track pads flat around the ground," Chastain says.
Another habit to avoid is climbing up over the sidewall of a cut you've made. "When you climb up over a curb or over an edge of asphalt that you've just cut you're pinching that track pad, which can put a tear in the track pad. Once you've torn it then it's going to start breaking down the bonding, and you're going to start losing chunks of the track pad. And before long you've lost that track pad," Chastain adds.
How many conveyor belts a unit has depends on its size. Smaller utility milling units usually only have one belt that works as both the pick up and discharge belt, although some may have two separate belts. The half-lane milling units have separate pick up and discharge conveyors, Schmidt says.
Wear and tears in conveyor belts can become a serious issue. "If you get a slight tear in a conveyor belt it will go ahead and continue to rip on through. And if you lose a conveyor belt, effectively your milling job is done at that point in time," Hood says.
Cleats on the conveyor belt - raised rubber pieces that carry material along the belt - are also susceptible to wear and tears, Chastain points out. Worn or damaged cleats prevent the machine from carrying as much material as it normally does and could cause the material to go everywhere instead of where the belt is directing it.
The material being milled aids in the wear of the conveyor system. Chunks and abrasive asphalt can tear the belt, Hood says. Another possibility is the asphalt wears down the steel wear plates on the bottom side of the conveyor. If this happens a contractor may end up having to replace the entire lower assembly instead of just the belt, Hood says.
Washing down the conveyor system at the end of each day is an essential maintenance task. This prevents any material from building up on the conveyor. "If you have buildup and you can't see the components, then you can't judge if they're about to fail or not or if they need replacement. If you don't clean it you lose production time and will spend more money on repairs," Schmidt says.
But the belts aren't the only wear parts in the conveyor systems. It is also important to keep an eye on the rollers. "They all have drive rollers, return rollers, carry rollers, and cleaner rollers," Schmidt says. A worn roller can be just as detrimental to a milling unit as a worn belt.
Contractors should inspect rollers for uneven wear just like with teeth. Flat spots on a roller are a sign that the roller hasn't been turning and is wearing unevenly, Schmidt points out. And an uneven roller can cause even more downtime to the milling unit.
Uneven rollers will create more vibration. This vibration causes the belt to bounce, taking it out of constant contact with the rollers. This bouncing is another way to wear down the belts.
One other area of concern is the flashing on the conveyors. The flashing helps contain the material flow on the belt and prevents material spillage. "Flashing which is worn or adjusted too high creates a gap which allows material to escape from the belt, requiring more cleanup behind the milling machine as well as increasing material buildup, requiring further cleaning at the end of day," Schmidt says.
"Flashing which is adjusted too low, causes it to rub on the belt which can result in damage to the belt surface and, in extreme cases, even bond the flashing permanently to the belt."
The best way to monitor wear and tear on conveyors is to do visual inspections, Hood says. Chastain says to also make sure the belts are tight and cleaned on a daily basis. And make sure the belt is not angled. An angled belt will cause wear on the idlers, Hood adds.