What is on standard efficiency & how to calculate.

• What is On-standard efficiency and overall efficiency?
• How to calculate on-standard efficiency and overall efficiency?
• What are the differences between these two efficiency terms?

Workers performance and production line performance is measured in efficiency. 

Efficiency Calculation formula 

 Efficiency (%) = (Total minutes produced / Total minutes attended at work)*100 

In a normal workday, operators spend their total attended time following categories

1. doing standard work
2. doing off-standard work (doing a task which is not familiar to the operator / other than a regular job)
3. doing nothing (lost-time like power failure, machine breakdown, no feeding/no work)

When an operator works on a bundle (garment pieces) they produce standard minutes whether she works on-standard operation or an off-standard operation. But when an operator does nothing but sitting idle due to some reasons is lost time.

If an operator does not get work, that is not her fault. In such cases, if you measure her performance considering all the attended hours, that will reflect a wrong performance. For this reason, on-standard efficiency is measured where only on-standard work hours are considered for calculating efficiency.

Measuring on-standard efficiency is good for operator skill analysis but when it comes for production at the end of the day, or line efficiency, and incentive calculation for the line and individual operator, overall efficiency is used for eligibility level.

How to calculate on-standard efficiency, off-standard efficiency and overall Efficiency

To measure on-standard efficiency, off-standard efficiency and overall Efficiency we need to collect the following data

(A) Total hours worked on the standard work
(B) Standard minutes produced while working on standard work
(C) Total hours worked on off-standard work
(D) Standard minutes produced while working on the off-standard work
(E) Total lost time in hours
(F) During lost-time, practically, no garment will be produced, so no produced minute for lost time hours.

The standard produced minute is calculated as operation SAM x Number of pieces stitched.

On-standard Efficiency (%) = (Total on-standard minute produced *100)/(Total on-standard hours worked * 60) = (B*100)/60*A)

Off-standard Efficiency (%)= (Total  off-standard minute produced *100)/(Total off-standard hours worked * 60) = (D*100)/60*C) 

Overall Efficiency (%) = (B+D)*100/(60*(A+C+E))

If there is no lost time and no off-standard work hours employee's on-standard efficiency and overall efficiency will be the same.

If there is lost time, overall efficiency will be less than the on-standard efficiency.

Lean manufacturing tool series -18 (5 Why)

5 Why? Simple but effective lean tool:

Just like any good mechanic, a good lean expert should have many tools to help them do their job. While a mechanic may be fixing something under the hood of a car, a lean expert will be fixing something under the hood of a business. Unlike a mechanic‟s troubleshooting, sometimes the real reason why something is not functioning inside a business isn‟t readily apparent, and there isn‟t a manual to troubleshoot it. Additionally, it may be masked by other problems that appear to be the real reason, or “root cause”, when in truth, it is only a diversion.
Avoiding this is a very important job of all people who work in a company, primarily a lean expert, or someone who works on the quality team. There are many ways in which the quality team can approach the problem, and the 5 why technique is one of them. It is designed to help get to the real root cause of a problem, so the cause can be addressed through a short term or long term corrective action. The corrective action, then, can be tracked for its effectiveness.
The 5 why system is one in which the simple question “why?” is asked at 5 different levels of a problem to get to the bottom of the situation. It was first used in the early 1970‟s by the Toyota Company, who is often credited with being the pioneer of modern quality.
If used correctly, it can provide a way to help identify the true root cause of the problem by using a feedback system. An added benefit is that it can be used both on an individual basis as well as a part of a group attack. It can, and should, also be integrated into the Kaizen, lean, and Six Sigma methods.
It can also be used in conjunction with other tools, such as root cause analysis software and fishbone diagrams to help aid in the discovery of the true root cause and identifying the cause and effect associated with it. While some other root cause analysis tools are complex and require experts to run them, even a two year old knows how to ask the question “why”, so the much more simplified approach is easy to adopt to the level of each individual worker.
Of course, it may seem like the five why method is too good to be true: a simple, effective way to approach complex technical issues that anyone can apply? This is the exact argument that most “five why” critics have used against the system: it is not as effective as thought.
The biggest argument is that, while it is purported to get to the foundation of the problem, in reality, most people stop at the surface level symptomatic issues that appear to be plaguing them on a daily basis. By asking the question “why?”, most will simply come up with another symptom instead of working their way back to the root cause. They will then fix the additional symptom, proclaiming to have found and corrected the root cause, when in fact the problem they were trying to solve never actually is fixed.
Another pitfall that the critics of this system claim detracts from its effectiveness is the tendency for personnel to stop at their level of knowledge or comfort, instead of digging deeper and thoroughly investigating the limits of their technical knowledge. It is too easy for the “five why” method to reward and promote the “quick fix” answer of simply satisfying the question “why”, instead of more thoroughly finding a technical answer.
Lastly, while simplicity is one of the merits of the system, it is also purported to be one of the downfalls. Because anybody can conduct the five why method, they actually do, and do not seek professional assistance in determining whether the “why” they submit is a true, actual “why” and not a surface level quick fix.

Figure (1) illustrates the typical conduct of solving the answer “why does the pump leak”. As can be seen, it addresses the fact that the seal inside of the pump bell housing is leaking fluid. While many companies and employees would stop there, instead, this technique requires the champion to go much further and address the reason why the seal leaks.
Of course, there can be more than one “why” to every reason, as demonstrated by Figure (1). The seal could leak because of improper installation of the seal, or possibly an inadequate seal design. Each one of those has their own “why” branches, which address the more subsurface issue causing the “why” before it.
As stated earlier, anyone can use this method. However, care and consideration should be taken to at least fully train the personnel who will be in charge of leading the five why inquisition, as it is very easy to scratch the surface of the challenge and never actually dig to the subsurface root causes.

The 5 why technique is a great tool when used in conjunction with other tools as an aide in finding the root cause of a problem. Like any other tool, it should be wielded by someone who understands how to thoroughly investigate problems and conduct a solid root cause analysis.



Prepared by:Md. Tarikul Islam Jony
Mail:jonytex073@gmail.com
+8801912885383