Can you assure that any manufactured product is exactly the same as another one? The answer is within the sixth principle of Toyota Way. Repeatability and reproducibility in manufacturing processes are key to deliver quality at the first time and to reduce waste or non-added value activities.
For instance, think about the manufacturing process for a tempered glass for automobile, this product has different technical specifications such as primary radius, secondary radius, length, width, thickness and many others which conform the perfect piece that will fit onto the vehicle. Despite the aforementioned, each glass final product is different, each one has different primary or secondary radius on even different thickness. The important fact is that any manufacturing company tries to minimise those differences in order to have a controlled process that deliver suitable products for their consumers or customers. Therefore, we need techniques that improve processes to achieve this repeatability and reproducibility. We can find two which are commonly used nowadays, Standardisation of Processes and Procedures and Six Sigma.
And here’s Toyota Way Principle #6:
“Standardised tasks and processes are the foundation for continuous improvement and employee empowerment.”
SOP (Standard Operating Procedure):
A standard operating procedure is a set of step-by-step instructions compiled by an organisation to help workers carry out complex routine operations. Standard Operating Procedures aim to achieve efficiency, quality output and uniformity of performance, while reducing miscommunication and failure to comply with industry regulations.
In order to maintain and improve the continuous improvement wheel, we need a Quality Assurance Unit. They are individuals who are responsible for monitoring whether the study report and tests are meeting the SOP. SOPs can also provide employees with a reference to common business practices, activities, or tasks. New employees use a SOP to answer questions without having to interrupt supervisors to ask how an operation is performed. The international quality standard ISO 9001 essentially requires the determination of processes (documented as standard operating procedures) used in any manufacturing process that could affect the quality of the product.Moreover, standard operating procedures are extensively used to assist with working safely. They are usually preceded by various methods of analyzing tasks or jobs to be performed in a workplace, including an approach called job safety analysis, in which hazards are identified and their control methods described. Procedures must be suited to the literacy levels of the user, and as part of this, the readability of procedures is important.
Six Sigma (6σ)
It is a set of techniques and tools for process improvement. It seeks to improve the quality of the output of a process by identifying and removing the causes of defects and minimizing variability in manufacturing and business processes. It uses a set of quality management methods such as statistical methods, and creates a special infrastructure of people within the organization who are experts in these methods. It is deeply linked to the standardisation of processes as one can’t live without the other. A standardised process needs to take into account six sigma methods so that quality of the final product reaches the zero-defects policies.
The term Six Sigma is originated from terminology associated with statistical modeling of processes. A six sigma process is one in which 99.99966% of all chances to produce some feature of a part are statistically expected to be free of defects (3,4 defective features per million opportunities).
When you have a standard process and apply experimentation with modifications to the standard, you can figure out how to do things faster or better or with higher rates of quality. Experimentation and improvement is predictable only when you have predictable, repeatable processes on which you can experiment. You can sometimes luck into a best practice, but the likelihood of that occurring is low.
Standardise your processes, whether they are good or bad, and then start looking for ways to improve.