It could be said that the Lean system is, in a sense, much more effective in consistently pulling the workflow after itself than in pushing them one by one.
With constantly changing production volumes, production can adapt much more efficiently and reorient to current demand using the Lean system. However, managing a consistent workflow in real time when one interval in a manufacturing process is directly dependent on a previous interval often becomes a difficult task. To meet demand and execute the process in the simplest and most efficient way, you need to define the duration of the work to produce the product or each intermediate production interval in time.
What is Takt Time?
This term is derived from the German word “takt”, which means rhythm or impulse. Takt Time was first used as a unit of measurement in the 1930s in Germany for the manufacture of aircraft. Twenty years later, this has significantly contributed to Toyota becoming the world's largest car company from a small Japanese carmaker.
Takt Time is the speed at which you have to complete a product, or one of the intermediate stages of production to meet customer needs. For example, if you receive a new product order every 3 hours, your team must produce the product in 3 hours or less to meet demand.
Takt Time is an indicator of your sales and can be easily attributed to your heart rate. This allows production capacity to be optimized to meet demand in the most appropriate way without accumulating excessive stocks or raw materials. The unit of measurement used is the time required to produce one unit of output. For example, how many seconds need to be produced per unit of output.
Production costs and non-compliance with time interval limits result in additional costs:
- Finished production storage and additional transportation costs
- Additional costs of purchasing and storing raw materials because raw materials are stored for too long
- Early wage costs
- The cost of missed opportunities to produce other goods while waiting for a shortage of supply
- Capital costs for overcapacity
At certain stages, lagging behind the production flow also leads to additional costs:
- Nepatenkinti klientai ateityje gali sumažinti užsakymus
- Overtime costs to compensate for delays
- Expedited shipping costs for late completion of the order on time
How to Calculate Takt Time?
To calculate the Takt Time, you must divide the available production time by the production demand over full production time period. For example: if one work shift lasts 8 working hours and the demand for products in 8 hours is 120 units, means (8 * 60) / 120 = 4 minutes. This means that we have a 4 minute interval to produce one product unit.
We recommend that you include in the calculation formula only the amount of time your team will be actively working to create value for their customers. This means that you should exclude breaks, scheduled maintenance, and shifts (if any). The Takt Time Calculator will help you more accurately calculate the production Clock Time for a product or intermediate operation.
As you can see, defining the time required to meet a customer’s needs is not rocket science. With this data, you can think carefully about how to manage team capacity according to customer needs.
Takt Time, Cycle Time and Order Lead Time
People tend to confuse Takt Time with Order Lead Time, which is no less important in the Lean methodology. We have already discussed in detail the difference between Run Time and Cycle Time, so let’s focus on the 3 main time intervals measured in flow production.
Lead Time - is the time period from the received order to the delivery of the product to the customer. Calculated according to the formula: Order execution time = Order delivered to the customer - Order received from the customer.
Cycle Time - is the time your team spends actively working on order. Can be calculated: Cycle time = Production time interval for ordering / Production quantity in units.
Takt time - is the maximum amount of time to produce a product that you need to adhere to fit to the time iterval of ordering divided by the quantity of products. Calculated according to the formula: Tactile time = Net working time / Total production in the order in units.
For example, the Lead Time is four days and the Cycle time is two days. The time taken to complete an order shows the entire time interval, but not the work done by the production capacity. You may have 25 days to complete the Order, but if you solve the problem or produce the product within 2 days, the Cycle Time will count as 2 days.
Why is Takt Time so important?
To optimize a team’s production capacity, it is very important to define team capabilities. This is critical to reducing waste of resources and production capacity. Takt Timing will help maintain a continuous workflow and reduce Mura (lots of short delays, and longer downtime) in the workflow. Also, scheduling employment time by optimizing raw material costs is extremely valuable, as it helps to avoid overproduction.
Unexpected production downtime
To calculate Takt Time, formula should subtract the average unplanned downtime from the total available time as soon as it becomes known. Even if unforeseen downtime is only a theoretical time interval, it still better predicts a prospective production schedule in the current circumstances. However, in the absence of unforeseen workflow disruptions, some overproduction may occur; it is also undesirable.
On the other hand, this method avoids the need for constant schedule adjustments, such as overtime, unless the downtime is significantly higher than average.
There are other arguments why unplanned downtime should not be included in Takt Time calculations:
- Regular and quality service should prevent unplanned equipment failure
- Unplanned downtime (whether due to equipment failure or staff fault) will actually lead to production shortcomings and will still need to be rectified, such as overtime.
- These negative consequences should lead to long-term corrective actions, such as scheduling regular maintenance.
- Try to keep unplanned downtime steady, so the initial result will be more accurate
In the end
Proper understanding of the terms Cycle Time, Order Execution Time, and Tact Time is the first step in allowing project managers and Lean practitioners to move one step forward in solving day-to-day production optimization challenges.