The Human Factor Contribution to Process variations– Part 2

In part 1 of this article, I have emphasized on managing indirect labor and some of the aspect managing indirect labors apply to direct labor as well.   Manufacturer which has a lot of manual assembly process should focus on managing and controlling direct labor, human operator. 
Although there have much advancement in automated manufacturing process, manual product transformation work by human is still very crucial in many cases.  Direct labor has a direct touch to the transformation of the product and it is vital to ensure we have a direct labor workforce that is trained and consistent.  Key tenets to direct labor workforce consistency include training, certification, performance monitoring and retention.


The organization ought to have direct labor training department which specialize in manufacturing process training with certified trainers.  Training system should include interactive classroom training which cover all aspect of the process.  Once the classroom training is completed,  then the operator should be go through on job training  (OJT) on the actual process with proper monitoring from the trainer for a duration according to training procedure.  Training should also include part handling as reject could happen during part handling between process rather than transformation process itself.
It is good practice to organize training approach base on the type of assembly process, its complexity and skill level required for the process.  An example a soldering process operator would require higher level skill set compare to a packing or labeling operator.  The criteria used to certify different work complexity/skill level worker should also be different.


Operators should be certified through an objective evaluation process, which could comprise of written examination and OJT evaluation from certified trainers.   Trainer need to assess on how well the operator follows the work instruction in the process and the output from the process which is free from defect.  Clear criteria for certification could consist of
  • Length of OJT
  • Count of parts the operator produce
  • Operator cycle time
  • Count of defect parts from the OJT operator

Performance monitoring

After operator had been certified, there should be a regular performance monitoring to ensure operator realize that they are being monitored and received feedback about their work.  Performance monitoring could include work attitude, absenteeism, actual work, compliance product rate etc.   There should disciplinary action taken when necessary
There are a few companies who practice recertification on yearly basis.  If this is case, then there must an automated recall system available to do so.   Recertification is compulsory for operator who had been away from the work for quite some time, eg.  maternity leave or transfer to other process.

Cross training

Objective criteria to select operator for cross training is necessary based operator skill level.  It is advisable to limit the number of cross training for each operator.

Staff Retention

It is imperative to have a stable direct workforce as only through a stable direct workforce we can maintain the consistent good quality product. There should be an equally attractive reward and motivation to help reduce attrition rate.

Process input variation contributed by man is the most difficult to handle.  Human is very complex with different personality will operate differently which contribute to variations.  There is no one size fit all approach in dealing with individuals.  Human is the one that give rise to quality problems and they are one who can resolve quality problems as well.

Once there is a consistent process screening the right candidate for the right functional role from top management to working level,  consistent training process for each functional role,  with right motivation and quality mindset,  all the rest of the process input  variation machine, material,  method, measure and environment can be managed and controlled to produce consistent good quality product. 

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