What is Cycle Time in the Manufacturing Process?
Cycle time is often confused with throughput time and takt time, but it is nevertheless a separate manufacturing performance indicator used to measure the duration of specific production processes and to get vital insight into your production efficiency.
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What is Cycle Time?
Cycle time is the time it takes to complete a single manufacturing operation on one unit, or several at once, from start to finish, meaning that a product passes through one stage of its production.
You can approach it in two ways:
– By including the steps that support the process like loading and unloading, called Effective Cycle Time. This approach measures the cycle from the beginning of a process until the start of the next process in the workstation.
– By not accounting for anything else but the time a unit is actually worked on and altered, called Equipment Cycle Time.
Any way you measure it, cycle time is an important KPI that allows managers to keep a finger on the pulse of the company’s productivity.
It is a good measure to gauge the duration of different tasks in the production process, providing manufacturers with insights that would allow for better scheduling and improvements in efficiency.
A defined CT will also provide factory floor workers with information on what is expected from them in terms of process times.
Additionally, you should make a distinction between:
– The typical cycle time, which you achieve under normal conditions, on average;
– The ideal cycle time, which is the theoretical minimal processing time of one unit.
How to Calculate Cycle Time?
If products are processed one-by-one, cycle time is calculated by dividing the total amount of goods processed in a workstation by the duration of the process.
CT (per 1 product) = Process duration/Total amount of goods processed
That means if you have one single workstation that assembles a product from start to finish, its CT is the duration of one assembly.
When a CNC machine processes 90 units in an hour, its productivity is 90 units/h, and therefore its CT is 60 / 90 = 0.67 minutes or 40 seconds per unit.
If you are working with batches, the CT corresponds to the processing time of the batch:
CT (per batch) = Process duration for a batch of goods
Let’s say you are a small town baker and, in 30 minutes, your oven bakes a batch of 60 loaves of bread – then your baking operation’s CT is 30 minutes, which is the time it takes to cook the bread. It is the same for any quantity between 1 and 60 (you could not bake a loaf any faster).
What is Cycle Time Loss?
Cycle time loss is incurred whenever equipment runs slower than it ideally does, and whenever small stops that do not qualify as downtime occur in the cycle.
Ideal cycle time, or the theoretical minimal processing time, is the benchmark used for measuring cycle time loss.
This benchmark is usually specified by the original equipment manufacturer, but you can also do a survey of cycle times and use the maximum operating speed achieved as the ideal.
Cycle time loss is the difference between the actual and the ideal CT.
To find it, you need to measure the total run time of the process and subtract the ideal CT for all the units processed.
Cycle Time Loss = Run Time – (Total Units x Ideal Cycle Time)
How to Reduce Cycle Times?
Cycle times can be reduced by minimizing cycle time loss, i.e. by eliminating obstructions and other inconsistencies from the processes.
It can be affected by direct human factors like the aptitude level or agility of the operator, but it can also be influenced by maintenance practices, quality requirements, issues with the materials, etc.
Therefore, cycle times can be improved by good employee training, by using proper maintenance practices, and by bringing up the quality standards of raw materials – in other words, by improving aspects directly related to a process.
And by reducing cycle times, you can also reduce throughput times.
Cycle Time vs. Throughput Time
Cycle time and throughput time are closely related and due to this, they are often confused with one another.
While the former measures the duration of isolated tasks, the latter sums up all of the time a product spends in the manufacturing process as a whole.
Broken down, throughput time consists of:
– Processing time
– Inspection time
– Move time
– Queue time
You can speak of cycle time and throughput time as interchangeable terms only if your whole manufacturing process consists of only one operation, and that is mostly not the case.
Read more about Throughput Time.
Cycle Time vs. Takt Time
Takt time is the processing rhythm that the shop floor uses at a given time. It is decided by taking both cycle time and demand into consideration.
When goods are produced sequentially, takt time is used to indicate how much time should be spent on one unit to make sure products are finished on time and that there is a minimal amount of idle time.
For example, if you need to produce 160 units a day and 2 workers have one 8-hour shift to do the job, then the takt time would be (2 x 8 x 60) / 160 = 6 minutes.
Even if your typical cycle time is actually 3 minutes, i.e. your workers could process the necessary amount of units to meet demand in half the time, you may want to slow down the process in order to ensure that your workers would not rush and that they would have something to do at all times.
If demand is high, then takt time can be equal to cycle time, but never shorter; if demand happens to be low, then takt time is greater than CT.
Cycle Time in a Manufacturing ERP
A manufacturing ERP system allows you to set cycle times for your operations. It uses that information to accurately schedule production operations, so you would have a concise overview of your production calendar.
This means that these cycle times should be realistic, not theoretical.
As such, the meaning of “cycle time” in a manufacturing ERP may be much looser and more simplistic than what the theory says.
It should be measured, e.g. with a stopwatch on the shop floor – the clock is started when the first operation activity (or a production stage comprising of several operations) is started, and stopped at the end of the last activity.
For a manufacturing ERP, cycle times may even include several operations, inspection, waiting, and move times, which in theory are all different concepts. But keep in mind that it is required for accurate scheduling purposes only, and all such details should not (and often cannot) be micromanaged in the ERP system.
A bonus is that when shop floor workers report their activities, the ERP can provide statistics on how the actual cycle times differ from what is defined in the system.
That will give you the chance to detect trends, identify inefficiencies and shortcomings related to your production equipment, materials, or your shop floor workers.
Thanks to its massive data collection and analysis capabilities, a manufacturing ERP software is a much more efficient way to keep up with cycle times than spreadsheets or pen-and-paper methods.
Not to be confused with throughput time or takt time, cycle time is the time a unit spends in a specific production operation.
It is used to get insight into the production processes, detect inefficiencies, and to provide workers with expectations regarding their pace of working.
Ideal cycle time is the benchmark against which CT is measured, with the difference being regarded as cycle time loss – these may incur due to short stops and slower processing.
Cycle times can be improved by practicing better training, maintenance, and material quality assurance.
Additionally, a manufacturing ERP can be used to efficiently collect data regarding cycle time, and to analyze it.
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