3.1. Using Production Curves

So, this cutting and pushing will go together. So, the time required to push, backtrack and maneuver into position, so that is called as a cycle time of the bulldozer. So, you are going to cut the earth, push the earth, dump it at the required place, then backtrack, backtrack in the sense you are going to return, return back to the original position where you want to do the dosing operation again.

Cycle time refers to the total time required for a bulldozer to complete one full operation cycle. This operation includes cutting the earth, pushing it to a designated area, dumping, and then returning to the starting position (backtracking). Understanding cycle time is vital because it directly affects the productivity of the bulldozer—the faster you can complete these operations, the more efficient the work is.

Think of the bulldozer's cycle time like the time it takes to bake a batch of cookies. First, you need to prepare the dough (cutting), then place it in the oven (pushing), and finally take them out when they're cooked (dumping). Afterward, you may need to clean up and prepare for the next set, which is similar to backtracking. Just like in baking, the total time taken for all these processes will determine how quickly you can produce your cookies.

So, we call this as fixed time, this is fixed time and this one is variable time, your push and backtrack it is called this variable time, why do we call this push time and backtrack time as variable time? Because it is variable depending upon your haul distance. So, greater your haul distance greater will be a push time and return time or backtrack time.

In the context of bulldozer operations, fixed time refers to the consistent time needed for tasks such as maneuvering (changing speed or gears), while variable time changes based on factors like haul distance. Push time and backtrack time are variable because the greater the distance that material needs to be pushed or returned, the more time it takes. This variation makes planning and estimating productivity essential for efficient operations.

Imagine you are moving boxes from one room to another. If the room is close by, it takes only a minute to make a trip (fixed time for moving boxes). However, if that room is far away, each trip takes longer (variable time). Depending on how far away the room is, the total time to complete the task can significantly increase.

So, to know the push time and the backtrack time, I need to know the travel distance or the dozing distance or the haul distance. I need to know the travel distance and I also need to know the speed. So, you very well know how to determine the speed.

To calculate the push and backtrack times, it is essential to know both the travel distance (how far the bulldozer has to move material) and the speed at which the bulldozer operates. The speed can often be derived from performance charts that indicate various factors affecting how quickly the bulldozer can operate under specific conditions.

Think of driving a car. Before you can calculate how long a trip will take, you need to know how far you're going (the distance) and how fast you can drive (the speed). If you know you have to travel 60 miles and can drive at an average speed of 30 miles per hour, you can easily calculate that the trip will take about 2 hours.

So now let us see what is this maneuver time? So, already I told you maneuver time is nothing, but the time needed for changing your speed accelerating, changing the gears, or reducing the speed, so that is what is called as a maneuver time. So, this maneuver time will depend upon the type of transmission.

Maneuver time refers to the time it takes for the operator to change speeds or gears in the bulldozer. This time can be affected by the type of transmission—either a manual gear change (direct transmission) or an automatic system (torque converter). In general, automatic transmissions have shorter maneuver times because the system manages gear changes without operator input.

Think about driving a manual versus an automatic car. When driving a manual, you need to physically change gears, which takes time and skill (longer maneuver time). In contrast, with an automatic car, the car takes care of shifting gears for you, allowing you to focus on the road and speed up quickly (shorter maneuver time).

Now let us see how to estimate the productivity of the bulldozer. So, we are going to estimate the productivity in loose meter cube per hour. As I told you whenever you express the volume, you should be very specific that whether you are expressing the volume in the loosen state or bank state, that is natural state or in the compacted state.

Productivity in earthmoving operations is typically measured in loose cubic meters per hour. It's important to specify the state of the material—whether loose (after being dug up) or in bank state (natural, undisturbed). Knowing the blade load (how much material can be moved at once) and the cycle time of the bulldozer (how long it takes to complete one cycle of operation) is crucial to calculating this productivity accurately.

Think of a team of workers who are moving sand. If they're measuring how much sand they can move in an hour, they need to decide whether to count the loose sand (after it's dumped from a truck) or packed sand (in its natural compacted state). Just like how counting different states can yield different totals, estimating bulldozer productivity needs to consider how the material is measured.

These production curves are drawn based upon ideal conditions. What are all ideal conditions? It is drawn assuming 100% job efficiency, that means your machine is going to work for 60 minutes in a hour, so that is what is the assumption.

Production curves represent ideal conditions, like assuming the bulldozer operates for the full hour without interruptions and under optimal conditions. In reality, factors such as machine efficiency, operator skill, soil type, and environmental conditions can all affect productivity. Adjusting estimates based on these factors ensures more realistic and applicable calculations.

Imagine you have a perfect sewing machine that works flawlessly 100% of the time. This is a hypothetical situation. In reality, machines can jam, operators might take breaks, or certain materials might be harder to sew. Understanding that ideal conditions don't always exist helps us estimate more accurately in real-life scenarios, like predicting how long it will take to complete a large sewing order.

So, if you know your equipment model number, so refer to the appropriate equipment handbook look for the appropriate model number and choose a production value directly. So, if you know the dozing distance, say the dozing distance is 60 meter and the model number is say F. So, you can directly calculate the production value.

Manufacturers often provide production curves that allow operators to determine productivity based on the specific model of the bulldozer and the dozing distance. By using these curves, estimators can select corresponding production values instantly, saving time on calculations. However, actual operating conditions must be applied to these ideal values to ensure accuracy.

Consider a recipe book that gives you baking times based on specific oven types and conditions. If you're using a similar oven, you can trust the times given. But if your oven has quirks or extra heat, you may need to adjust times. Similarly, while the production curves offer good estimates, the estimator must consider actual site conditions.

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