Some of the most useful Six Sigma tools for the execution of this type of projects are considered as quality tools and others as specific tools of Six Sigma projects, these tools may be used to promote strategic quality improvements or be used in full under the DMAIC methodology.
During the application of the DMAIC methodology, as part of the implementation of a Six Sigma project, this set of techniques is used to improve the process integrally, based on data and oriented to the solution of problems, focusing on three main areas, to improve Customer satisfaction, reduce cycle time and defects.
Most helpful business tools of Six Sigma used to gain a deep understanding of customer needs, process behavior and product and service improvement used in each of the DMAIC stages are the following:
SIPOC, which seeks to clarify the core process in which the project will be focused, and at the same time to verify that all project stakeholders are agree with the process in question. It begins with a simple definition of the process, it is extended from 4 to 6 steps of the process, the main inputs and outputs of the process are listed and finally the suppliers of each entry and the customers of each output.
Quality Function Deployment (QFD), it is also important to highlight the use of the tool known as the Quality House, for the purpose of translating customer requirements and expectations into appropriate design and product characteristics; translating the requirements (the WHATs) in technical requirements (the HOWs).
HISTOGRAMS, are graphical representations of a variable in the form of bars where the surface of each bar is proportional to the frequency of the observed values. With them we can observe the data, according to their form, frequency and dispersion.
In this way, the histogram, with its upper and lower limits and a measure of central tendency, gives us an insight into how the process behaves in relation to the customer’s expectations, reflected in a KPI (Key performance indicator).
In addition, there are other commonly used graphical tools that allow us to communicate numerical analysis efficiently, including scatter plot, normal probability plots, box charts, among others.
Fishbone diagram, is also known as a “cause and effect diagram” or “Ishikawa diagram”. Considered as a structured tool for brainstorming, it allows us to analyze the different causes that influence a specific effect, with the use of this graph, we can prioritize the areas that present problems and develop ideas to improve them. The causes are grouped into six main areas in the manufacturing processes: personnel, machines, materials, methods, measurements and environment.
The 5 Why’s, is a method based on asking questions to explore the cause-effect relationships that generate a particular problem. The final objective of the 5 Why is to determine the root cause of a defect or problem.
Basically it is applied by asking the question “Why…?” Five times in a row, or times that may be necessary until we get to the root of the problem, as a rule the main cause that generated the problem will be presented in the fifth why.
Design of experiments (DOE), in order to characterize the relationships and drive deep improvements in almost any process with controllable inputs. It allows us to assess which process inputs have a significant impact on the results and define the required level of those inputs to achieve the desired results.
Control Chart, Process Statistical Control Tool (SPC), is used to evaluate the stability of a process and to detect the special causes of variation.
Another of the most useful Six Sigma tools that can be applied is POKA-YOKE, oriented to the implementation of security mechanisms to prevent a process from producing defects by either prevention or detection.