Time and Methods Study on a Productive Cell

[DiogoGF]

Hello everyone,

I´m conducting a time study on a semi-automatical productive cell. The operator only tasks are quality control, non direct materials replacements and repairs. The activity don't follow any type of cicle or method, the order is at the operator's choice.

To understand the work load i've determined the average duration,frequency for each task (aprox. 20 Tasks) and the distance traveled when performing a specific task.

Now my problem, i can´t figure out how to determine an average distance covered between the different tasks (there about 9 diferent positions in the work place).

I ended up estimating a central point (geometrical point) and determine all the distances for each activity from that same point, but this situation causes a substancial inflation of the actual distance being covered by the operator...

Any suggestions?

 

[DiogoGF]

As we are on the topic does anyone knows or has any references regarding allowable distances and occupancy rate per shift for a given operator (OSHAS, ISO...)?

 

[Hodgepodge]

Hello everyone,

I´m conducting a time study on a semi-automatical productive cell. The operator only tasks are quality control, non direct materials replacements and repairs. The activity don't follow any type of cicle or method, the order is at the operator's choice.

To understand the work load i've determined the average duration,frequency for each task (aprox. 20 Tasks) and the distance traveled when performing a specific task.

Now my problem, i can´t figure out how to determine an average distance covered between the different tasks (there about 9 diferent positions in the work place).

I ended up estimating a central point (geometrical point) and determine all the distances for each activity from that same point, but this situation causes a substancial inflation of the actual distance being covered by the operator...

Any suggestions?

Have you thought about issuing a pedometer to operators to gather data?

 

[DiogoGF]

Yes i have thought of using pedometer, but that won´t enable me to understand the distance covered between diferent tasks, the result will only express the total distance covered by the operator...

 

[Markaich]

Back in the good old days when I was a practicing Work Study Engineer, before any time study was carried out, the method was defined and agreed...it is a fundamental principle that a time standard only applies to a defined method. If the method is pre-determined, then so is distance travelled.

However, if what you describe is a situation where the operator reacts to the machines and there is no predictable, then you need to ensure that any study its completed over a representative period of time. If you can be certain that all activities are observable in, for instance, a day, then the operator should be observed for that day. Using a string diagram us can measure the total distance moved along with the distances between tasks, and the frequency that each route is travelled.

However, I wonder at the purpose of your study. If the machines are controlling the duration of production, rather than the man, surely machine cycle time can be calculated without any need to observe or carry out time study.

With regard to allowances etc, Neither OHSAS nor ISO is likely to publish the data you require as they are concerned with the systems used to manage work rather then the specifics of the work. The International Labour Office (ILO) I think used to publish some information. The BSI did at one time have a publication (a document for discussion) on work recovery rates and related allowances.

Hope all this helps a little
M

 

[Steve Prevette]

Human Factors in Engineering and Design by Sanders and McCormick is an old reliable for reaching distances and lifting limits. It was the textbook the US Navy used in the Operations Research curriculum for its Human Factors course when I was there.

 

[Markaich]

Also Grandjean's work on ergonomics 'Fitting the task to the human' may be useful (I must admit my versionis the less politically correct 'Fitting the task to the man', but I guess the principles are the same.

M