1.5. Dump Time

Cycle time = LT + HT + DT + RT + ST + TT + ADBT (Where, LT-Load, HT-Haul, DT-dump, RT-Return, ST-Spot, TT-Turn, ADBT- Acceleration, Deceleration and braking)

Cycle time is the total time taken to complete one full operational cycle of a scraper. It encompasses several components: Load Time (LT), Haul Time (HT), Dump Time (DT), Return Time (RT), Spotting Time (ST), Turn Time (TT), and the time taken for Acceleration, Deceleration, and Braking (ADBT). Each component contributes to the overall efficiency and productivity of the machine, and understanding these components helps in optimizing the operational process.

Imagine running a race where you have to complete several tasks: warming up (Acceleration), running (Haul), stopping to catch your breath (Dump), returning to start (Return), and taking turns (Turn). Just like a racer must consider each phase to improve their total time, operators must consider each phase of the cycle to enhance the scraper's efficiency.

So, basically you can split the cycle time into 2 parts. One is fixed time, other one is variable time. Fixed in the sense this part of the cycle time does not depend upon your travel distance. So, that is called as fixed time, say your loading, dumping, turning, your accelerating, decelerating. All these things comes under the fixed time. The other one is a variable time, your haul and return is a variable time because it is significantly dependent on your travel distance.

Cycle time is broken into two parts: fixed time and variable time. Fixed time does not change based on how far or fast the scraper travels; it includes tasks like loading, dumping, and turning. Variable time, however, is affected by the distance traveled and the speed of the machine. For instance, hauling material over longer distances will require more time than shorter distances, reflecting the variable nature of this component.

Think of a trip you take: no matter where you go, the time you spend packing your bags and getting ready (fixed time) remains the same. However, the trip duration (variable time) changes based on how far your destination is. Similarly, the fixed and variable times of a scraper's operation help in estimating its overall efficiency.

So, basically the loading time of the scraper is fairly consistent irrespective of the scraper size. ... average load time for the pusher loaded scraper in common earth. Say for example this typical values given for common earth it is 0.8 minute.

The loading time for scrapers remains relatively stable regardless of their size. It is largely dependent on the assistance provided by a pusher. Typically, for standard earth materials, the average loading time is recorded at about 0.8 minutes. This consistency allows operators to rely on manufacturer data to predict performance efficiently.

Consider a fast-food restaurant: whether you are ordering a small meal or a large feast, the time taken to prepare your order (loading time) doesn’t differ much if the kitchen is efficient, just like loading time is somewhat constant for scrapers aided by pushers.

Another important concept which we need to know is about the load growth curve for scraper loading. ... the loading rate will start reducing, that is why we have to draw this kind of load growth curves and you have to find the optimum loading time.

The load growth curve illustrates how loading a scraper to its maximum capacity does not necessarily maximize production; in fact, loading beyond a certain point reduces the loading rate. This phenomenon, referred to as diminishing returns, emphasizes the importance of identifying optimal loading time for efficiency.

Imagine a cereal box: initially, you can easily refill it (fast loading), but as it gets fuller, spilling occurs, making refills slower (reducing loading rate). Like finding the right portion size for your cereal, finding the optimal loading amount for a scraper can significantly impact productivity.

So, the next important component of the cycle time of the scraper is your haul and return time, ... you have to determine the speed of the machine in every section independently.

Haul and return time, a variable component of cycle time, is determined by distance and speed. Different conditions in the haul route can affect the efficiency. It's essential to maintain the haul route even through actions like watering to reduce dust and enhance visibility, which collectively can lower cycle time and boost productivity.

Think of an athlete training on a track: if the track is well-maintained, they can run faster (less haul time) compared to running on a rough terrain where they may trip (longer return time). Just like the athlete needs a good track to maintain speed, scrapers need well-kept haul routes to minimize cycle time.

So, the next important thing which we are going to see as a component of your cycle time is your dump time. ... this is the best way dump before turning...

Dump time varies based on the scraper's size, the material being dumped, and site constraints like congestion. Efficient dumping is critical; dumping before turning is safer and quicker than doing so while loaded. Understanding these dynamics aids in planning operations to minimize dump time.

Consider a truck unloading cargo: unloading while parked safely (dumping before turning) is quicker and reduces accidents compared to unloading while trying to maneuver (turning while loaded). Just like a truck needs to unload properly, scrapers require efficient dumping processes to maximize productivity.

So, far we have discussed about the cycle time of the scraper. ... to reduce your unit production cost.

After reviewing all components of the cycle time, we understand that the fixed and variable times collectively influence productivity and cost. The fixed section consists of loading, dumping, and turning times, while the variable section encompasses haul and return times. Together, effective management of these factors can enhance efficiency and lower costs.

Think of planning a road trip where you must consider gas stops (fixed time) and variable traffic conditions (variable time). By estimating these elements correctly, you can save money and make your trip smoother. Similarly, understanding the cycle time allows for enhanced production planning in scraper operations.

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