The Simogramme is the graphical representation of simultaneous or successive events in the accomplishment of a work.
The Simogramme (called “Standardized work combination Table-SWCT“) is the graphical representation of simultaneous or successive events in the accomplishment of a job.
This is a graphical study of the activity during repetitive work, and allows to group operations, to multiply or to reorganize posts for a better use of the times. The objective of the Simogramme is to:
- Try to minimize manufacturing times by combining, eliminating or improving some operations.
- Synchronize sequences of operations between multiple operators.
- Study the assignment of several machines to the same operator.
- Differentiate the work of each member.
A Simogramme is nothing more than a Gantt chart. It is simply suitable for short cycles (we don’t talk about dates, but time in seconds). A few tips are to be respected:
- Use different colors for manual times and automatic times.
- Specify on which Part one works (n, N-1…) as well as the operator.
- Use one of the methods of Time Predetermination to set the cycle times for each task.
- Represent at least 2 total cycles on the Simogramme.
1. Break down work into tasks
We’re going to break down the work into small tasks. These must be clearly defined and not leave any doubt as to what they represent.
2. Increase the execution time of each task
For each task one defines an average time. We note that the times we use for this type of study are expressed in TTH (ten thousandths of an hour). The conversion is as follows:
- 1 second = 2.77 TTH (100/36)
- 1 minute = 166.67 TTH (1000/6)
3. Establish the Simogramme
Then we establish the Simogramme of the tasks. It allows you to see the sequence of operations. The times we are going to identify on the Simogramme are:
- manual time Tm: Time corresponding to a physical or mental human work depending solely on the action of the operator.
- Technology Time Tt: Working time whose duration depends only on the technological conditions of execution, the machine works without intervention of the operator.
- Time Technico-Manual Ttm: Time corresponding to the combined actions of the operator and the machine.
- Te Balancing Time : Additional time for the synchronisation of several cycles. This is an artificially added time when, for example, it is not possible to perform a masked time check.
- manual times or Techno-manuals frequency (TMF or TTMF): Tasks that are not performed at each cycle, but at a certain frequency. For example, we control one Part out of five.
4. Determine the cycle time
The cycle represents the sequence of operations that will be repeated wisely according to the need. So in 1 cycle, you can produce several pieces.
5. Deduct the different indicators
- Time Masked T z : time of a work performed by the operator during the execution of another work whose time is already taken into account.
- Residual time T r : these are the times when the operator has no occupation. It corresponds to the difference between the cycle time and the sum of the manual times and the time Technico Manual.
Operator activity rate
Equipment activity rate
- Charge: It is the sum of the manual times and the technical-manual times.
- Cadence: Opening Time/Cycle time
- Availability: Takt Time-load
It is noted that for calculations, we do not take into account the times said frequency (TMF or TTMF), because they can be entrusted to other operators with less load.
6. Optimize the sequence
We will work on the sequence of work to optimize it and get the maximum cadence. We deduct the capacity of a workstation that will give us the number of pieces per day. It will depend on the number of people on the workstation, the breaks, the opening time and of course, the rate we have just calculated.
Take the example of a creper with 2 hotplates. The analysis of a sequence gives us the following steps:
- Put oil on the appliance: 8 TTH
- Pour and spread the dough: 12 TTH
- Bake the first side: 60 DMH
- Flip the crepe: 12 TTH
- Bake the second side: 36 TTH
- Remove Crepe: 8 TTH
- Put Nutella: 20 TTH
- Folding Pancake: 8 TTH
With this data, we can draw the Simogramme. We get this:
At first, we see that the raw cycle time to make a crepe is 164 tth. Taking into account the timing, we observe that the cycle to make two crepes is 164 TTH. In other words, by synchronizing the tasks, two times are reduced to make crepes. We then calculate the different times for a cycle:
- cycle time: 164
- manual Time Tm: 2 * (6, 7, 8) = 72
- Technology Time Tt: 2 * (3, 5) = 192
- Technico-Manual Ttm Time: 2 * (1, 2, 4) = 64
- Te balancing Time : 0
- manual times or Techno-manuals frequency (TMF or TTMF): 0
We measure the different indicators:
- Time Masked T z : 1 times steps 6, 7, and 8 = 36
- Residual time T a : 192 – 36 = 156 These are the times when the operator has no occupation. It corresponds to the difference between technological times and hidden times.
- operator occupancy rate: * 100 = 82.9%
- occupancy rate per machine: * 100 = 78%
- Load: 72 + 64 = 136
- Cadence: For 8 working hours or 80 000 tth, we get a potential crepe number of = 487.8 cycles or 975.6 crepes, total on which we remove 1 since for the first cycle, we will not be able to make the crepe n – 1. So we have 975.6 crepes in total.
- Availability: If we have a need for 1 crepe every 2 minutes on this carnival Sunday, we have an availability of: 333.3 – 136 = 197.33