INSIGHT
MAINTAINING EXCAVATOR EXCELLENCE
By Kim Kemp
Correct machine operation, coupled with regular maintenance, significantly reduces undercarriage wear, improves operating efficiency, and reduces the running costs of tracked excavators.
Alex Ackron, managing director of HPE Africa, points out that there is a misconception around the maintenance of an excavator’ s undercarriage, which often leads to unnecessary expense.“ Because they have a strong solid steel construction, maintenance of the undercarriage components of an excavator is often neglected and this is an expensive mistake,” he cautions.
Ackron refers to research showing that repairs to the undercarriage of a tracked excavator can account for as much as half of all repair costs over the life of the machine.
According to the MD, ensuring that you have a well-trained excavator operator is vital.“ After thorough investigation, the HPE Africa technical team realised that just a few operational tips and a simple maintenance programme would significantly extend the life of the undercarriage components and reduce the operating costs of the excavator.”
The research manual includes the following tips:
• Do not travel long distances in reverse as this causes pin, bushing, and sprocket wear because the excavator is designed to travel with the idler at the front of the machine and the sprocket at the rear.
• Travelling long distances in high-speed mode is also not encouraged, as the faster the speed, the greater the relative load between components, increasing wear.“ Over long distances, friction causes heat build-up within the rollers, idlers, and drives and this can damage internal seals,” Ackron explains.
• As an excavator does not have an independent suspension, travelling at high speed on rough or hard terrain or inclines, means that both tracks are stressed by an uneven surface.
• Do not dig or excavate with the boom over the sprocket. The overhead dig / dump cycle causes stress and wear at the point of sprocket / bushing contact over the sprocket. These forces should be over the idler, where minimal chain rail wear occurs.
• Work up and down a slope rather than along a gradient or slope, because the machine tips to one side, increasing the load / stress on the lower track, and accelerating overall wear on this track.
• Because the dig-slew-dump cycle puts pivot stress on the undercarriage on the dump side of the machine, the operator should balance the slew direction by turning the excavator around in the middle of the shift, balancing the slew direction under the load.
HPE
• Excavators are useful in restricted work areas because they can make pivot turns, but the operator should try to make wider turns to prevent grouser corner wear.
HPE Africa experts have identified four maintenance tips that will reduce undercarriage wear:
Daily maintenance – remove packed debris and dry material from the undercarriage at the end of every day, using a shovel, steel bar, or water. Dry material increases track tension and prevents rollers from turning freely, which accelerates wear of components.
Daily maintenance – check track tension— this takes no more than 10 minutes. A track tension that is too tight puts extra load on the engine, which wastes fuel and can also be the cause of premature undercarriage wear. A track that is too loose may come off and can also cause additional shock loads and side-to-side wear of components.
Weekly maintenance – inspect the undercarriage for problems and if necessary, take action. Look out for a loose track shoe, a broken link pin, or chipped sprocket teeth.
After every 1 000 hours of operation – a specialist undercarriage company should be commissioned to check the undercarriage. Excessive wear on one component causes accelerated wear on other components in the system. HPE Africa recommends that track shoes, chains, rollers, and sprockets are replaced together, rather than matching new and used components, which results in excessive wear of the new component.
It is also important to look at parameters of the excavator, like total hours of travelling versus digging, and total hours
Alex Ackron is the managing director of HPE Africa, part of Capital Equipment Group( CEG) of Invicta Holdings. travelled in high-speed mode versus low-speed mode. Torque setting on all the bolts on the undercarriage should also be checked— including roller and top idler brackets, track shoes, sprockets, and final drives, Ackron concludes.
Please complete the contact page on the HPE Africa website at www. hpeafrica. co. za to request the full research manual. ■
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JULY 2018