July 07, 2015

Best Practices for Onboard Scale and Loader Maintenance

Quarries contain some of the hardest working equipment you'll find anywhere. It's big, tough, and built to perform. However, with the rapid, ongoing development of technology for quarry operations, today's machines are as much about brains as brawn.

Take, for example, the LOADRITE™ Payload Weighing System found in John Deere K-Series Four-Wheel-Drive Loaders. Because this technology is proven to help minimize errors, optimize payloads, and reduce cycle times, it has become as necessary as the loaders themselves at quarry operations big and small.

You already understand that regular preventative maintenance is critical to a loader's ongoing performance and overall service life. The addition of an onboard payload scale makes regular maintenance even more important. That's because the machine's performance has a direct bearing on the scale's performance. In other words, if the machine is off, the scale will be off, too.

Here are five practical checks that, when performed regularly, will keep your loader and its scale performing at their peak:

Calibrate
Calibration is always performed when the scale is installed. Generally speaking, you're only required to recalibrate after a bucket replacement or an equally serious upgrade or maintenance event. However, best practices cite regular zeroing (just like your bathroom or kitchen scale) as a simple, effective way to maintain a scale's accuracy.

The challenge:
Preventing fluctuations in the scale's accuracy.

The solution:
Ensure that your scale is reset to zero at the start of a shift. The process takes less than a minute, by simply performing three lifts with an empty bucket free of any built-up material.

The result:
Your scale will be reset to true zero.

Grease pins and bearings
As loader scales measure the pressure required to lift the bucket and convert it into weight data, mechanical friction in the lifting cycle, due to lack of grease and other factors, can be misinterpreted as extra weight. Also if the lift is not smooth, the bucket may "bounce," creating false readings and spikes and drops in the pressure measurements. Regular greasing of the pins and bearings prevents the potential for inaccurate data.

The challenge:
Preventing false weight and pressure readings.

The solution:
Visually inspect pins and bearings for fresh grease and lubricate as needed. If the loader has an automatic greasing system, fill the reservoir to ensure it continues to dispense properly.

The result:
A smooth-moving boom that won't affect scale readings.

Inspect and clean the cooling package
Like a car, a wheel loader performs best at its ideal operating temperature. If hydraulic fluid is too cold or hot, it will affect scale performance. Regular visual checks and cleaning will prevent the temperature spikes that occur as airborne dust and debris accumulate and begin clogging cooling vents. Many loaders, such as the John Deere K-Series, are now equipped with reversing fans that, when engaged regularly, are capable of removing excess debris with minimal operator effort.

The challenge:
Preventing airborne dust and debris from clogging cooling vents.

The solution:
Visually check cooling vents and manually clean as needed. If your loader is equipped with a reversing fan, run it before each shift to prevent debris buildup.

The result:
Smooth, efficient loader performance that will not negatively affect your onboard scale.

Inspect lift arms for damage
Left unchecked, damage incurred to lift arms by falling rocks and other debris will have a negative effect on the machine's overall operational performance. Visual inspections performed by an experienced operator will help you quickly identify liftarm damage, diagnose its severity, and plan for repairs. In some cases where damage has occurred, a repair amounts to nothing more than tightening loose hydraulic or sensor connections. When performed daily, inspections can prevent small problems from becoming big ones.

The challenge:
Ensuring rotary and stationary sensors rotate smoothly and exert sufficient spring force against the boom.

The solution:
Perform a thorough inspection of liftarm cables and their hydraulic and sensor connections, and tighten as needed. Pay special attention to areas displaying cracks, dents, and other visible damage.

The result:
Liftarms that enable machines and their operators to be productive regardless of wear and tear caused by falling rocks and debris.

Check the bucket
When allowed to accumulate in the bucket, the weight of materials such as mud, clay, and dirt will appear in your bucket payload calculations, rendering them inaccurate. Likewise, excess wear or damage to the bucket teeth or cutting edge and uncalibrated changes in bucket weight will also result in calculation errors. When using multiple attachments, it's imperative that the correct loader attachment is selected on your scale and that it has been calibrated for the machine. In order for the operator to accurately "zero" the scale, daily bucket checks are recommended.

The challenge:
Returning your onboard scale to an accurate "zero" reading.

The solution:
Remove debris buildup and confirm that the correct loader attachment is selected on your scale and confirm that it's been calibrated for the machine.

The result:
Peace or mind that damage, debris, and/or attachment changes will not negatively affect the accuracy of scale readings.

These best practices are easy to remember and follow, and can usually be covered in a simple walkaround of the loader at the beginning of each shift. When combined with your loader's preventative maintenance instructions, these steps will keep your machine and its onboard payload scale running accurately and efficiently for years to come.