Why worry about the life of your ground-engaging tools? The GETs themselves aren't terribly expensive. Replacement is simple, and can usually be performed during scheduled PM downtime. What's the big deal?
The big deal is the hidden cost. Worn GETs hamper machine efficiency, reducing productivity and driving up fuel expense. Operators compensate for GET wear by charging piles, which puts excessive shock loads on linkages and other assemblies. Badly worn GETs are no longer able to shield the more expensive parts they're designed to protect. Adapters, buckets and blades are worn away. Ground-engaging tools may be inexpensive, but buckets aren't.
You keep a lid on wear-part cost by making the GETs do the work. Operators have to know how to put tools into the ground in a way that maximizes their penetrating force, minimizes wear, and avoids unnecessary ground contact.
Use prudent approach speeds to reduce damage to GETs as well as other machine components. Operate equipment smoothly. Jerky motions create shock loads that can break GETs and damage other components. Avoid excessive prying forces to avoid breaking tips and adapters.
There are specific considerations for each machine that will ensure long GET life. And the best part about investing in this type of training is that these same operating techniques typically improve the machine's productivity.
Make sure the bucket enters squarely to minimize corner loading. Corner loading creates uneven GET wear and unequal loads on linkages and cylinders. Entering squarely also ensures full buckets.
Curl the bucket through the material, maximizing tip contact while minimizing bucket contact. Boom up before curling. Boom up and curl before the bucket bottoms out.
Operating techniques for excavators. Click on image to view details.
Use first gear when loading. Approach the face with the bucket at a 90-degree angle to minimize corner loading. Keep the bucket low to the ground when entering the pile, and after engaging the pile, raise the bucket before curling it.
Buckets load best and wear least when they enter the pile with their base edge parallel to the floor. Maintain the bucket leveler, and don't override it. A heel-down bucket attitude reduces penetration; wears GETs unevenly; and increases cycle times, bottom wear, fuel consumption, and possibly tire wear. A nose-down attitude increases penetration, but also causes excessive wear on the top and inside of the bucket. Additionally, it may increase tire damage by leaving behind rocks on the pit floor.
Operating techniques for wheel loaders. Click on image to view details.
Start with the blade angled forward for penetration. As the blade fills, roll it back so that the material is carried, not rolled. Lift the blade slightly as it is rolled back to minimize wear on the GETs and their attachment hardware. Minimize corner loading to reduce wear on the end bit and to prevent undue stress in that corner.
Start with the shank rotated rearward for maximum penetration. After initial penetration is achieved, rotate the shank forward (toward the belly of the machine) until the engine begins to stall, and then drop it back slightly. Never turn or back up with the shank in the ground. Never use the shank to stop the tractor. Never rip without a shank protector.
Rip in first gear at speeds of 1 to 1½ mph. Ripping at higher speeds, even in soft materials, can generate high heat at the ripper tip, which dramatically reduces tip life.
Operating techniques for rippers. Click on image to view details.
A combination of speed and down force creates wear. Keep speeds below 6 mph where possible, and never exceed 10 mph. Avoid excessive downward pressure. Use the accumulator to absorb shocks.
Maintain constant cutting-edge thickness by using a fixed blade angle. Angle the blade forward for initial penetration or when improved penetration is required. For most cutting applications, the top of the moldboard should be just ahead of the cutting edge. Rack the moldboard all the way back to carry, spread or comb material.
Unlike track-type dozers, wheel dozers are designed to roll material, not carry it. The back of the blade should be perpendicular to the ground, while the sole plate should be parallel to the ground. The GET should sit flat on the ground.
Tipping the blade back will cause the material to be carried, not rolled, and will wear the back of the sole plate. A blade-back attitude can reduce GET life and may damage the moldboard and hardware. Rolling the blade forward will increase penetration, but it will also wear the front of the sole plate and may damage the corners of the moldboard.
The most skillful operating practices won't change the fact that GETs are sacrificial parts designed to wear and they must eventually be replaced. Inspect them daily, watching for:
- excessive wear, bending or bellmouthing in corners
- cracked or worn-through areas at weld joints on the bucket and at the adapters
- badly bent or broken-through corner gussets
- missing tips and retainers
- worn adapters, especially adapter straps and noses
- missing or loose bolts
- wear or scalloping at the base edge.
Never operate equipment without the GET in place. Many owners store spare bucket teeth or other parts on the machine if possible, and they teach operators or make other personnel on site responsible for replacing lost or broken GETs.
When tips adapters, corner bits, edges or wear plates are ready to be reversed, rotated or replaced, they should be done immediately.
Wear patterns should be analyzed to identify and correct improper operating habits. Combine inspection information with analysis of replaced GETs to make sure you're using the right kind of tools. These products are engineered for specific applications, and variations in the length, thickness, shape, alloy, and hardness can mean the GET designed to work very well in some conditions won't last long at all in your conditions. Equipment dealers located near where your machines are operating can often help select the right GETs for the environment.
Improved operating techniques can greatly reduce GET wear and damage, as well as the accompanying costs. Combine smart operating with some basic maintenance, and you'll have an easy and inexpensive boost for your bottom line.
|Caterpillar, John Deere and Komatsu provided information for this article. Special thanks to Bob Klobnak, senior product consultant at Caterpillar.|