4.2.1. When Trucks are Less Than the Balanced Number

Another important thing you have to keep in mind is, for any machine whatever maybe the mission we have discussed about different types of machines so far. All the machines we are concerned about the safe gravimetric capacity of the machine. For every machine what is this safe operating load in terms of weight is given by the manufacturer, so that we call it as a gravimetric capacity. So, only that capacity your machine can take because the structural frame of the machine is designed to handle that particular load only. So, we are not supposed to load the machine beyond the gravimetric capacity.

Gravimetric capacity is essentially the maximum weight that a machine can handle safely, as defined by the manufacturer. It is crucial to adhere to this limit because the machine's structural integrity is specifically designed to support this weight. If a machine is overloaded beyond its gravimetric capacity, it may experience significant damage, reduced efficiency, and increased maintenance costs. Therefore, always verify the weight of the load against the machine's gravimetric capacity to ensure safe operation.

Imagine you're carrying a backpack. If you load it with too many books, it might break or hurt your back. Similarly, machines, like trucks, can only carry so much weight before they start to suffer damage.

Check the load weight against the gravimetric capacity of the truck, how to check that? For that you need to know what is the unit weight of your material, if you know the density of your material you can multiplied by the volumetric load you will get the actual weight of material in the truck, you will get the truck load. That should be within the rated gravimetric capacity of the machine given by the manufacturer, check truck load is less than rated gravimetric payload.

To ensure that the load does not exceed the truck's gravimetric capacity, you need to calculate the actual weight of the material being loaded. This can be done by first determining the density of the material (weight per unit volume) and then multiplying that by the volume of the load. The resulting weight must always be less than the truck's rated gravimetric payload to avoid overloading.

Think of it like filling a bucket with water. If you know how much one liter of water weighs (about 1 kg), and you want to fill the bucket, you need to ensure you don’t exceed that bucket’s weight limit. If the bucket can only hold 5 kg safely, then you can only fill it with up to 5 liters of water.

So, many times you can see that people will put these side boards, and in the trucks commonly you can see they put the side boards and try to increase the volume of the truck. If the material which you are going to handle is less denser, in that case, it will not create much problem, you have to check whether the loaded weight in the truck is within the gravimetric capacity. But if the material is going to be denser like wet sand or other denser material, what happens is there are more chances that your machine may be overloaded. That means the weight of material in the truck will be above the safe gravimetric capacity defined by the manufacturer.

Using sideboards to increase the volume of a truck may seem beneficial for transporting more material. However, this can lead to overloading, especially if the material is dense, like wet sand. Overloading a truck can cause excessive wear and damage to the machine components—especially tires—which are a significant part of operating costs.

It's like trying to carry a heavy stack of bricks in a shopping cart. If you overload the cart, the wheels might break or the cart might tip over. Keeping the cart within its weight limit ensures that it remains functional and doesn’t get damaged.

So, you have to replace the truck with a new truck, that will result in huge ownership cost for you. So, that is why you should not overload the truck.

Overloading trucks continuously can lead to their premature breakdown, resulting in costly replacements. The financial burden of frequent truck purchases accumulates over time, making it essential to prioritize safe loading practices to avoid these expenses.

Consider driving a car that’s always overloaded with heavy cargo. Over time, the brakes, tires, and suspension will wear out much faster, leading you to spend money on repairs or even buying a new car sooner than expected. If you had stuck to the limit, you would save money in the long run.

Now let us see how to balance the interdependent machines, trucks and the excavators. I hope you remember earlier we have discussed how to balance the interdependent machines your scraper and the pusher? In a similar manner we are going to discuss how to balance the number of trucks and the excavator?

Balancing the number of trucks with the capacity of excavators is crucial for optimizing productivity in a construction operation. A recommended practice is ensuring that the truck capacity is 4 to 5 times that of the bucket capacity of the excavator. This enables both machines to operate efficiently without significant wait times, effectively maximizing output.

Think of a restaurant kitchen where there are chefs cooking food and servers bringing out dishes. If there are too many servers but not enough chefs, the servers will be idle waiting for food, reducing efficiency. However, if there are too many chefs and not enough servers, the chefs will be overloaded with dishes waiting to be served. Balancing the number of chefs and servers can maximize the restaurant's efficiency.

So, when I round it to lower number, say I got 7.4 now I am going to round it to 7. When I round it to lower than the balanced number that means trucks are less than what is needed. So, trucks are more critical for the production, so here the loader will have the idle time, loader will be waiting for the truck, so truck cycle time will control the productivity of this stream.

If the number of trucks is less than the balanced number, the loader may end up waiting for trucks to arrive, resulting in idle time. In this scenario, the truck cycle time dictates the overall productivity because it controls how quickly the loader can work. It’s essential to ensure a sufficient number of trucks are available to avoid bottlenecks in operation.

Imagine a pizza store where there’s only one delivery car. If the car is out delivering, the chefs can’t create more pizzas because there’s nowhere to send them. This waiting leads to lost productivity since the chefs can’t work at their maximum potential without the deliveries happening smoothly.

In the case when I round it to the number greater than the balanced number. So, in this case, number of trucks are greater than the balance number, so the trucks will have the idle time, truck will be waiting for the loader, loader will be critical here.

If the number of trucks exceeds the balanced number, then the trucks may be left waiting for the loader, leading to idle trucks. In this case, the loader's cycle time becomes the limiting factor for overall productivity since the trucks cannot operate until the loader has finished loading them. Hence, it's vital to find a balance for maximum efficiency.

Think about a factory with more workers than the amount of tasks available. If there are 10 workers but only 5 tasks, the extra workers will end up standing around waiting for work. This affects productivity as more workers are left idle.

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