Choosing between task automation or a manual Position often exceeds the cost of the operation.
Choosing between task automation or a manual Position often exceeds the cost of the operation. Below you will find a ” pragmatic ” guide that includes only this concept of cost.
The continuation and the final choice will be weighted according to your social situation, strategic wish…
Step 1: identify the investment factor
First step, identify the investment factor. This represents the ratio between the cost of a machine and the manual cost. It is calculated according to the following equation:
FI = T * D/CO
- T: The number of teams required, 1, 2, 3
- D: necessary expenditure of equipment capable of replacing one person in 1 shift
- CO: Annual cost of an operator
It is understandable, at the most this ratio will be low, at least we will be profitable to invest in automation. And generally, if the ratio is less than 3, it does not seem interesting to invest on automation unless specific problem of ergonomics, safety…
Step 2: choose the type of Assembly
The choice between manual process or automatic process type will depend on different criteria as Partvolume s, the number of design changes and the investment factor. This choice is tabulated in the table below which reads as follows.
2.1: choosing the line
The choice of the line depends on the annual quantity of Parts to be produced and the number of Partin our Assembly.
2.2: column selection
We will choose our column according to the variety of design of our products. Thus, we will calculate the following reports:
The first is to identify the total number of “potential” Partof our Assembly. In other words, this is the number of possible options for the same product.
Y = number of alternatives/total number of Parts
The second is to identify the frequency of change of the product requiring a change of process (machining head, feeding bowl…), considering the total life of the machine.
C = total number of Parts of our Assembly/number of Partunchanged
2.3 read our type of Assembly
|Nb of assemblies to be produced per year and per team in million (VA)||Nb of parts in our assembly (n)|
The product has a shelf life of at least 3 years without significant variations in demand. Parts do not require manual assembly and there are less than 2% defects
There are several versions of products but do not require manual mounting and there are less than 2% defects.
|There are several versions of products, some parts require a manual assembly, there is variation in demand or we have a low investment interest.|
|FI ≥ 3||FI < 3|
|Y ≤ 1.5||Y > 1.5||Y ≤ 1.5||Y > 1.5|
|C ≤ 0.5||C > 0.5||C ≤ 0.5||C > 0.5||C ≤ 0.5||C > 0.5||C ≤ 0.5||C > 0.5|
|VA > 0,7||n ≥ 7||AF||AF||AP||AP||AF||AF||AP||AP||AP||MA|
|n < 7||AI||AI||AI||AI||AI||AI||AI / MM||AI / MM||AP||MA|
|0,5 < VA ≤ 0,7||n ≥ 25||AF||AP||AP||AP||AF / AP||AP||AP||AP||AP||MA|
|15 ≤ n < 25||AF / AP||AF / AP||AP||AP||AF / MM||AP / MM||AP / MM||AP / MM||AP||MA|
|10 ≤ n < 15||AI||AI||AI||AP / AI||AI||AI||MM / AI||MM / AP||AP||MA|
|7 ≤ n < 10||AI||AI||AI||AI / AP||AI||AI / MM||MM||MM||AP / MM||MA|
|n < 7||AI||AI||AI||AI / MM||AI||AI / MM||MM||MM||MM / AR||MA|
|0,1 < VA ≤ 0,5||n ≥ 10||Ai / AP||AP||AP||AP||AI / MM||AP / MM||AP / MM||AP||AP||MA|
|n < 10||MM||MM||MM||MM||MM||MM||MM||MM / MA||MA / AR||MA|
|VA ≤ 0,1||MM||MM / MA||MM / MA||MA||MM / MA||MA||MA||MA||MA||MA|
Step 3: conclude on the choice
The table allows us to help us in the choice of the type of Assembly we need to make. The reading is as follows:
Assembly line having several manuals workstation. The transfer of the parts is done by hand between workstation. A buffer is present between workstation.
Manual assembly line with machine support for the various Handlings to reduce the operating time.
Automatic machine having X ” heads ” working at once, performing one task at a time and with automatic feed Rails.
Automatic machine having X ” heads ” running at once, performing one task at a time and with manual power.
Automatic machine consisting of X robots performing a task in the same sequence.
Automatic machine consisting of X robots performing each X tasks in the same sequence.
Another technique is simply to compare the cost to the part between a manual or automatic model that over the life of the product (especially where the life of the product is smaller than the amortization time. In which case the amortization time will be taken.
To help with the calculation, we will issue several assumptions such as semi-automation, or the larger than anticipated increase in demand.