THE TOP 7 OPERATIONAL PRACTICES THAT REDUCE UNDERCARRIAGE WEAR
To operate a tracked excavator correctly an operator needs to “unlearn” the skills they use when operating a wheeled vehicle.
Training your excavator operator to use an excavator correctly is the easiest way to extend your undercarriage life.
In order of importance here are the do’s and don’ts off excavator operation:
1. DO NOT travel long distances in reverse.
An excavator is designed to travel with the idler at the front of the machine and the sprocket at the rear. Travelling in reverse is the greatest cause of pin, bushing and sprocket wear.
– In reverse the track bushes rotate exactly at the point of greatest torque contact with the sprocket, wearing the bushes, pins and sprockets (in forward movement they rotate at the point of least torque resulting in minimal wear)
– Reverse travel puts the track adjuster spring into tension on the idler, which tightens the chain and reduces the ability of the spring to absorb shock loads, both of which increase and accelerate wear. (Idler in front travel enables the spring to operate in compression to absorb shock loads during travel which minimises wear).
2. DO NOT travel long distances in High Speed mode.
The faster the travel speed of the excavator the greater the relative load between the components (increasing wear). Over long distances friction causes heat to build up within the rollers, idlers and drives which can damage the internal seals.
– Sprocket teeth that are worn to look like wave caps (swept back in one direction).
– Leaking rollers and final drives.
3. DO NOT travel in High Speed mode on rough or hard terrain or on inclines.
Higher speed equals higher impact with the ground. As an excavator does not have an independent suspension this means that both tracks are stressed by an uneven surface encountered on any side.
– The high impact point loads damage the track shoes.
– High impact unbalanced loads accelerate wear on all moving components.
– Bent / Buckled grouser shoes.
– Grouser corner wear, the grouser wears back at the ends of shoe because it is sliding when making contact with the ground.
4. DO NOT Dig / Excavate with the boom over sprocket.
– The overhead dig / dump cycle causes stress and motion (i.e. wear) at the point
of sprocket / bushing contact over the sprocket (these forces should be over the
idler where minimal chain rail wear then occurs).
5. TRY NOT TO work along a gradient / slope. Work up and down a slope.
– Working along a gradient tilts the machine to one side. This increases the load /
stress on the lower track, accelerating overall wear on this track (especially idlers,
rollers and chain sides).
– The flange on the roller is designed to stop the chain sliding off the roller. On a
slope more weight is on one set of rollers and the chain slides towards the lowest
roller flange. This causes accelerated wear on this flange as well as on the side of
the chain link where it is forced to rub against the roller flange.
6. TRY TO BALANCE Slew Direction under load.
The dig-slew-dump cycle puts pivot stress (i.e. wear) on the undercarriage on the dump side
of the machine.
– Try to balance the slew direction if possible by (for example) turning the excavator
around in the middle of the shift.
7. TRY TO REDUCE Pivot / Counter Rotation turns.
Excavators are useful on restricted work areas because they can make “pivot” or “counter
rotation” turns. However, on sloping and hard / rocky ground, pivot turns accelerate wear.
– Try to make sider turns or Y turns. Turn on level ground if possible.
– Grouser corner wear, the grouser wears back at the ends of shoe during pivot
turns on hard ground.