2.2. Cycle Time Comparison with Front Shovel

They have poor mobility. So, that is why it is preferable to place a truck very close to the excavator. So, very commonly you can see that the truck is placed at 90 degrees. So, the truck is placed at 90 degrees, this will be 90 to the bucket position. So, this is a common position. So, basically the angle of swing is nothing but the horizontal angle between the digging and the dumping position.

In this chunk, the text explains the mobility challenges faced by excavators. It is suggested to position trucks close to the excavator for efficiency. Typically, the truck is aligned at a 90-degree angle relative to the excavator's bucket. This standard position minimizes the distance the bucket must swing to load the truck, enhancing productivity by reducing cycle time.

Imagine a basketball player trying to make a shot. If they stand too far from the hoop, it takes more effort and time to make the basket. Similarly, positioning the truck closer to the excavator makes 'loading' more efficient, akin to taking a shorter shot from the free-throw line rather than the three-point arc.

As the truck moves further away, your angle of swing would increase. As the angle of swing increases, you can see that your cycle time will increase, and productivity will decrease.

This section discusses the correlation between the angle of swing and cycle time. If the truck is positioned far from the excavator, the angle at which the bucket has to swing to load the truck becomes larger. This larger swing increases the cycle time— the time needed for the excavator to complete its loading operations—which in turn decreases productivity.

Think of swinging a door open. If the door hinges are at the end of a long corridor, opening it takes longer. But if it's close to the wall next to it, the door swings open quickly. In the same way, a larger angle makes the excavator's work slower, affecting how quickly it can work.

Ideal condition for shovel is based on a 90-degree swing. The actual height of cut in your project site should be the same as the optimum height of cut. That combination will give you ideal production.

The text emphasizes that ideal shovel productivity is achieved when the angle of swing is 90 degrees, meaning the truck’s position is optimal. Additionally, the height from which material is cut should match the optimum cutting height for the machine. Meeting these conditions maximizes the excavator's efficiency and production output.

Imagine preparing a sandwich: if you have all the ingredients (like having the right heights and angles), making the sandwich is easy and quick. But if you have to stretch or reach awkwardly for ingredients (like an inefficient truck position or incorrect height), it takes longer and may not turn out as well.

Now, let us see what are all the adjustment factors we have to apply while doing the productivity estimation based upon the height of the cut of material actual height of cut of material in your project site and based upon the angle of swing that depends upon the position of your truck relative to the position of your excavator.

This chunk introduces the concept of adjustment factors that need to be considered when estimating productivity. The actual height of the cut and the angle of swing require careful evaluation. If these parameters deviate from ideal conditions, correction factors must be applied to accurately estimate productivity.

Think of adjusting a recipe when cooking. If a recipe assumes you have perfect ingredients (like the ideal height and angle), but you use what's available, you may need to adjust the quantities or cooking time. Similarly, adjustments ensure productivity calculations reflect real-world conditions.

If the actual height of cut is the same as optimum height of cut, it means the percentage is 100%. If this percentage is 100%, it means actual height of cut and optimum height of cut are the same, and in that case, you need not apply any correction factor.

This part explains how correction factors are determined. If the actual cutting height matches the optimum cutting height (100% efficiency), no corrections are needed. However, if the actual height is less or more than optimal, productivity decreases, requiring correction factors to adjust estimates.

Imagine a student taking a test. If they know all the answers (100% effort), they likely score well without extra preparation. But if they only know some answers (less than optimal), they may need to study more (apply a correction), affecting their overall score.

When the angle of swing is more than 90 degrees, the correction factor is reducing, it shows that your productivity will reduce, but if your angle of swing is less than 90 degrees, you can see that the correction factor is increasing.

This section indicates how the angle of swing affects correction factors. A swing angle greater than 90 degrees decreases the productivity correction factor, while an angle less than 90 increases it, improving efficiency. Therefore, maintaining a lesser swing angle positively impacts the machine's overall productivity.

Consider throwing a basketball: if you throw from a position directly in front of the basket (less than 90 degrees), it's easier to make a basket versus trying from an angle (greater than 90 degrees) where you have to compensate for distance. The clearer the shot, the better the outcome!

There should be some space left for the tail swing of the shovel. That means you can have a complete 360-degree swing. When it rotates, you should make sure that the tail of this shovel should not collide with the truck.

This chunk highlights the importance of truck spotting clearance. While it’s beneficial to position the truck close to the excavator for efficiency, there must be enough room for the shovel’s tail to swing fully without hitting the truck. This clearance is crucial for safe and efficient operation.

Think about driving a car in a tight parking space. Even if you park closely to the wall for convenience, you still need enough space to open the door comfortably. Like that, ensuring room for the back of the excavator keeps operations safe and effective.

Another important factor is haul unit exchange time. The time needed for the loaded truck to leave its position and for a new truck to take the position.

This section discusses the importance of haul unit exchange time. This is the time it takes for the loaded truck to leave and for another empty truck to arrive for loading. If there is a delay in this process, it increases cycle time, leading to decreased productivity, so minimizing this time is vital.

Consider a fast-food drive-thru: if cars take too long to place their orders or pick up meals, the time between orders increases, slowing service. Similarly, if trucks take longer at the excavator, it slows down production and increases overall wait times.

Now let us see how to estimate the productivity of the shovel. The production of the shovel depends upon the heaped volume of your bucket, adjust with the bucket fill factor, and divide it by the cycle time.

This part outlines a method for estimating shovel productivity. It relies on the heaped volume capacity of the shovel's bucket, adjusting for material type using the fill factor, and finally, calculating by dividing this adjusted volume by the cycle time to predict how much material can be moved in a specific time frame.

Think of filling a jar with candy. If you know the jar’s volume (bucket capacity) and how much space each type of candy takes up (fill factor), you can easily determine how much candy to buy based on how quickly you want to fill it (cycle time).

We have to adjust the productivity based upon the swing depth factor depending upon the actual height of cut of the material in your project site and the angle of swing.

This chunk discusses the need to adjust productivity calculations based on the swing depth factor, which accounts for variances in actual cutting height and swing angle. This adjustment ensures accurate productivity estimates that consider real-world conditions and machine performance variability.

Think of a person resizing a canvas for painting: if they only use one size without considering the available space or tools (swing angle and height), they might not create their best work. Adjusting the canvas size allows for more creativity and a better final piece.

Another important thing is we are supposed to multiply the production of the shovel with the job efficiency, based on how much time your machine is going to work in an hour.

This section emphasizes the importance of considering job efficiency when estimating productivity. Job efficiency reflects how many minutes a machine can actively work during an hour. By multiplying the estimated shovel production with this efficiency metric, we determine the actual work output for that time period.

Consider a student studying for an exam. If the student studies actively for 45 minutes out of an hour, their 'efficiency' is 75%. Just like calculating effective study times, the shovel's effective output must also reflect its active working minutes.

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