Transcript

The next lecture in usability testing we have discussed in the previous lecture that usability tests will use three parameters – One is efficiency, throughput and capacity. So now what we will discuss in this lecture is throughput and capacity. These two will be the two measuring quantities where in which your product will be tested keeping users perspective.

Capacity

So how do you define the term Capacity? The term capacity is used to evaluate the productivity of the machine. In agriculture two types of capacities are commonly used, one is field capacity, the other one is throughput capacity. So field capacity is used to evaluate the productivity of machines used to work the soil such as plows, cultivators, and other machines such as drills, sprayers and harvesting. Throughput capacity is a measure of the volume of material that passes through your machine, machines such as grain augers, balers, forage harvesters and combines. If a tillage machine operates at 100% efficiency, it is operating at a hundred percent capacity. This is called us theoretical field capacity.

Theoretical field capacity is determined using the width of the machine and the speed of travel. It can be calculated using units cancellation, but an equalization is also available. (please check the slide) is an empirical value which has come by calculations C suffix T is a theoretical field capacity which is talked about in actual per hour. Then S is the speed of travel. W is the width of the machine. So let us take a simple problem for your understanding. Determine the theoretical capacity of a machine that travels at five miles per hour and has an operating width of 20 feet. So the CT will be calculated (please check the slide) so that is nothing but five into 20 divided by 8.25 which is approximately 12 AC by per hour. So, if the machine travels at a constant speed and uses your constant width it has a theoretical capacity of 12 ac/h. So it has a theoretical capacity of 12 acres per. The difference between theoretical capacity and the effective capacity is Lost capacity. The Lost capacity is an important concern for the machine operator and or manager because it represents lost revenue or resources.

There are two primary causes for lost capacity, lost time not operating and operating the machine with less than the maximum working with. Common causes for lost time includes – Mechanical breakdowns, Taking time to adjust the machine, Stopping to fill seed hoppers, spray tanks, etc., Slow down to turn at the end of the row or crossing waterways etc., Operators rest stops. So, these are all, some of the lost time includes. Many a times in industrial engineering we tried to give all these things as fatigue allowance. We have a standard allowance given. We calculate all the standard allowance added and then say the operator will work at this many minutes and these things are added to it as the fatigue allowances. In the same way, if this is added, then the last time will not be there. But if we exactly calculate the last time, these are all the causes of its failure. So for example, mechanical breakdown, then adjusting the machine height and then stopping when we have to refill the hopper. Then slowing down when you have to turn you cannot run in the same radius and then turn, so you will slow down and then turn. Then operator rest. So the common equation for effective field capacity is (please check the slide) . So, throughput – throughput incorporates time because throughput usually refers to the flow of the material through your machine. The units may be different from those used for capacity. For example, the performance of a hay baler would be evaluated using units of bales per hour or tons per hour, or a solar food dryer for amla candy drying developed at IIT Kanpur has a throughput of 25 kgs, per 16 hours. Why 16 hours? Because as you can’t do it for hour. So one batch takes 16 hours. So we have to do that. The throughput of Baylor also can be evaluated in units of bales per hour. To use these unit additional information is required, including the weight of the hay and two unit conversion values.

Throughput

So let’s try to take a simple problem and solve what is the throughput capacity of a baler that baled 150 tons in 1 week while operating an average of 6 hours per day. The unit of throughput capacity are not identical. They can be tons per week, tons per day, bales per day. For this example, assuming the manufacturer, advertises that the baler has the capacity of six tons per hour and the owner wants to compare the actual performance to the advertised performance, this means effective throughput capacity needs to be calculated in units of tons per hour, so tons per hour equal to one 50 tons per week into one week divided by five days, that is operative then, why one day they are operating six hours. So, if you look into it, it will be five tens per hour will be the final throughput answer. Knowing the actual throughput for the Baylor, the throughput efficiency can be determined. The throughput efficiency will be, E is equal to actual output by input into hundred. So, the actual output was five and the input which was given was six, so the efficiency is 83% page. Like this, you are supposed to calculate for every product which you developed. So the usability test, apart from customers’ feedback, these three are very important from the business perspective. So, no product will be developed for, for individual use. So it will always be looked in terms of business. So when you talk about business, you have to talk about in terms of capacity, efficiency, and throughput. So, these are the three most important usability testing parameters.

Thank you.