5W and 1H on SAM

 This article is written by Shobhit Jindal.

Sewing SAM related questions

The 5 Ws and 1 H on garment SAM are as follows.  
  • What is SAM?
  • How to calculate SAM?
  • Why calculate SAM?
  • When to calculate SAM?
  • Where to calculate SAM?
  • Who to calculate SAM?

If you have heard the above questions at the workplace and if you have ever faced them or googled them or if you might have asked someone for clarification and still are not clear to you, then this article is for you.

These questions are commonly asked in the apparel manufacturing business. Still, these are complex to understand for many people in key positions in the industry who hesitate to invest in the IE department in their factory not understanding the benefits of IE.

In this article, I will try to answer questions related to SAM.  My effort is to make it easier to understand all these questions in a single article.

1W. What is SAM (Standard Minute)?

As per ILO definition of SAM is:

The time value arrived at for a task is based on the average rate of output which a qualified worker will naturally achieve without over-exertion provided that they know and adhere to the specified method and provided that they are motivated to apply themselves to their work.

I know this definition is not easy to understand (and also not easy to learn for students to write in exams). So I will try to break this into a few keywords and then I will explain it to you. 
So here are some keywords in this definition:

  • Time value – This is easy. As it says SAM value is a time value that is represented in minutes.
  • Based on the average rate of output- SAM is based on an average rate of output as it is calculated in cycles (PICK TO PICK). Any operation which is done in repeated cycles is considered for the calculation of SAM.
  • Qualified workers- Worker who has the skill, knowledge, and ability to perform the required job. He/ she must know the standard operating procedure of performing the operation i.e. how to pick panels, how to align and stitch, and how to drop after completion. Pick and drop must be ergonomically correct and stitch/ seam should match the approved quality standard.

So combining all three points we can say SAM is basically the average time taken to complete an operation by a qualified worker who has the skills to perform that operation.

Related article: Standard Minute Value (SMV): Its Definition, Calculation Method, and Applications

2W. Why calculate it?

What is the point of calculating the SAM if you don’t know how to use it? SAM value is used for two purposes:

1) To calculate the cost of manufacturing – By multiplying the SAM with the factory per minute cost we get the manufacturing cost of a garment. This can be used for labor cost calculation purposes.

2) To benchmark the time value and monitor improvement – If we benchmark SAM value and make it a target to monitor improvement operation-wise then it will help us to reduce non-value added activities, increase efficiency and production, and thus reduce further SAM and cost. 

I will elaborate on this in detail in my next article.

3W. When to calculate garment SAM?

Well, it depends on product type and style changeover rate in your factory.

If one factory is producing a similar product on a regular basis, then there are not many changeovers as the product remains the same. In this case, recalculation of the operation SAMs through time study should be done after every 4 months. This will help to monitor the improvements on a regular basis. 

If a factory is making different types of apparel products, then SAM should be calculated on the third day of production when the line reaches 60-70% efficiency. Thereafter it should be re-calculated after every 3 days to monitor improvement.

4W. Where to calculate it?

As I said SAM can be calculated for all the activities which are being done in repeated cycles. 
In the apparel manufacturing industry, SAM can be calculated for cutting, sewing, finishing, and packing operations. The operation can be a manual operation or a machine operation.

5W. Who to calculate?

SAM of the garment operations should be calculated by the industrial engineering (IE) department as they are responsible for this activity. Another reason they do not come under the control of the production team or quality control team. 

Normally, the IE department assigns this task to a qualified work study officer or an industrial engineer.

They should define the standard operating procedure of all operations. These are the methods that should be followed to do an operation in the correct manner which produces quality output.

IE should maintain a skill matrix that helps to make a pool of qualified workers for doing multiple operations. IE also works on improvement in operations SAM against measured and targeted SAM so as to increase efficiencies.

Related article:Roles of an IE in the garment industry

1H. How to calculate?

Time study is the most common method used in factories to calculate SAM. Below is the formula used:

SAM = (Cycle Time x Rating factor) + Allowance (%)

Here, Cycle time is the observed time of one complete cycle (from Pick to Pick). We should always record at least 15 mins (a quarter of an hour) of data and then take the average time.

For example, if the operation cycle time is 30 seconds, then we must take at least 30 cycles to calculate SAM. This will help to eliminate the effect of unusual readings with very little or very high timing. Also, any reading where the usual cycle of operation is not followed must not be recorded.

For example, needle breakage while performing an operation, thread breakage, bobbin change, or any other activity that doesn’t constitute the usual operation cycle must be eliminated.

Rating factor – This factor is used when the worker is either very slow or fast in doing the operation. For example, if a particular worker is doing one operation abnormally fast or slow as compared to all other available workers of that operation, then we give him/ her a rating factor to standardize the cycle time accordingly. If a worker is slower than others then we rate them below 100% and if he/ she is fast, then we rate them above 100% accordingly. 

The rating factor is very subjective and can differ from person to person (work-study personnel). That’s why this factor is not much used in a factory while calculating SAM.

Allowances - This is the time that needs to be added for worker fatigue, machine handling, bundle handling time, and other factors such as bobbin change, thread breakage, and needle breakage which we can control a bit but can’t avoid completely. Usually, on average 15%-20% is considered for allowances in the apparel industry.

Another method of calculating the Standard Time of a sewing operation is by using synthetic data which you can get from PMTS-based software. Some of the commonly used SAM calculation software are listed on this page.

About the Author: Shobhit Jindal graduated from NIFT with a degree in apparel production. He has done his MBA from Amity University in Operations. He has a total experience of 8 years in the apparel industry in the fields of Industrial engineering, Quality Control and Process Audit, Production, and Product Development.

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