Time Study V Actual Production
Time Study V Actual Production
(OP)
When we complete a time study, the production from the floor never achieves the theoretical volume the time study indicates we should get. When an operation is not controlled by another process such as a machine opening and closing, operators doing "Bench Work" achieve a percentage, say 85% of what a time study indicates. Is there an industry accepted standard for this, and where could I find information on it?





RE: Time Study V Actual Production
RE: Time Study V Actual Production
Do you find that 85% is the defacto standard after PF&D is accounted for?
RE: Time Study V Actual Production
Again, it also depends on the type of process. Most of my experience has been with operator-dependent assembly or fabrication, so this rule of thumb is much more applicable. In other situations, such as automated circuit board assembly, the 85% rule may not apply as well. Even then, the type of shop (job, high-volume/low-mix) and the robustness of the material handling and communication systems will play a part. A good example is a powdercoat paint line. If you only need to paint one or two colors, then your efficiency should get up to about the 80%-90% level. But if you need to paint 20 colors and 3 different formulations, then you may be lucky to achieve 50% efficiency.
I suppose the ultimate answer to the original question is: No, there is no industry standard for maximum observable efficiency. I would suggest 85% as a starting point. From there, study the process to figure out what contributes to the factor, and adjust as necessary.
RE: Time Study V Actual Production
RE: Time Study V Actual Production
It seems that your time standards have too much variation; this is what is contributing to your efficiency be at around 85%.
§ Your observed times should have less than 3% variation; most of your variation comes from non-value added activities. Eliminate them or at least reduce them to a minimum before you establish a job standard.
§ Also, how accurate are your effort rating and the allowance for incidental activities? These are another sources for error in your measurement. Again, incidental activities are non-vales added, but you need them for your capacity planning; keep these activities separate and well defined for each job. In many instances you may minimize their impact; for instance in an assembly line or sequential job, size the wip (Kanban) between stations of non-bottleneck operations so that those operators can have incidental time, i.e., water and stretch breaks.
§ Manage your bottlenecks well. They keep the pace of your product or process line. Your manufacturing facility can only make as much product as these ‘pacemakers’ can.
RE: Time Study V Actual Production
I use the 85% rule as a basis for comparison, I have had studies that exceeded and some below that were good representations.
You probably do all of the following already but I will post anyway just in case there is something here you can use.
I will assume you are including PF&D and proceed from there.
How many samples/observations do you include in your studies?
--- More samples will give a higher accuracy potential.
How many operators do you observe and how many observations per operator?
--- Always exclude the very fast and very slow results. They are either exceptional operators that a normal operator cannot do or possibly an intentional attempt to sabotage your study.
Do you study each major task as a whole or do you break it into its elements.
--- Studying each element of each task is very important and will help you identify possible variables more easily. Again, the more observations the better. Total the results for the elements to get your task bottom line. Total tasks for the completed project.
I firmly believe that extreme accuracy, detail, and good documentation are critical to a good time study.
I have seen several operators verbally bashed and a couple even fired because of sloppy time standards. Please, I'm not implying that yours are sloppy, only stating observations made during a 30 year career.
RE: Time Study V Actual Production
Try posting in the Industrial Engineering Forum --- You might get some additional input on this subject.
Good Luck
ietech
RE: Time Study V Actual Production
A second point is the difference between production time for the shop and time spent on an operation on an individual item. Total time for the shop will likely never achieve 100%, operation time for an individual operator should on occasion surpass it.
A study I came across 4-5 years ago stated that shops with no standards (government) will typically operate at about 40-60% efficiency, shops with historical standards at about 60-70, shops with studied standards but lackluster monitoring at 75-85, and shops with studied and monitored standards at 85-95%.
Hope this helps.
Griffy
RE: Time Study V Actual Production
I wonder how are you performing your time study, and for what purpose.
For machine controlled (automatic machine) you cannot assume that the theoretic machine pace will be the production rate. You might include breaking, adjustment and personnal needs. Therefore with automatic machine you might find about 80-85% efficiency, but dont be amazed to find about 110-130% efficiency. The operators have their own tricks how to do it (if they have the motivation).
Operator control operations production might ange from 50 to 130%. The higher value is if you have and incentive plan in the shop .
By definition Time study standard is for average effort but shoud allow an operator to reach 125% efficiency.