After world war II, Japanese decided to bring quality products to global market and focused on Statistical Quality Control (SQC) aiming prevention of problems rather controlling after they have occurred. By late 1960s, nationwide TQC (Total Quality Control - ie companywide) was launched to educate and train all levels of people in usage of statistical techniques in design and manufacturing to ensure quality in all aspects. Dr Deming and Dr Juran, management consultants from US were instrumental to bring this knowledge to Japanese industries. In 1987, the TQC scope further enhanced and brought key management principles for effective promotion of quality culture across the organization. Later, the same was declared as TQM (Total Quality Management) bringing more clarity on management approach centered on quality of all activities. And quality has become way of life in Japanese industries.

ISO (International Organization for Standardization) published its first ISO 9001 standard in 1987, bringing the requirements for Quality Management System for organizations to adopt and deliver quality product/service in a scientific way. The standards requirements were derived from various learning from defense industry practices including TQM principles for quality assurance through preventive action. By applying this standard requirements, organizations can drive quality culture across all activities and at all levels.

The current version ISO9001 (5th edition) was released in Sep 2015 bringing practical approach to the requirements and inclusion of risk based thinking. More emphasis is given to process approach and PDCA concept for effective management and usage of statistical & scientific tools. The standard requirements include all activities across the supply chain focusing on quality - like quality design, Quality machinery, quality manufacturing processes, quality monitoring, quality people, quality installation/service, quality suppliers, quality reviews, continual improvement etc.

This international standard is based on the quality management principles that are key to effective business management.

The typical actions associated with these principles are shown above and these actions will improve organizations performance when applied successfully.

This standard is based on process approach and it enables the organization to control the interrelationships and interdependencies among the processes of the system, so that the overall performance of the organization can be enhanced. The elements of a single process is shown below.

Management of the processes and the system as whole can be achieved using the PDCA cycle with an overall focus on risk-based thinking aimed at taking advantage of opportunities and preventing undesirable results.

The adoption of QMS is a strategic decision of an organization that can help to improve the overall performance and provide a sound basis for sustainable development initiatives. In other words, it is a scientific business management centered on quality of all activities by practicing best business practices and applying statistical and scientific tools for enhanced performance.

And having an ISO 9001 certification gives an assurance to the customers that these organizations comply to standard requirements and have ability to provide products and services that meet customer and applicable statutory and regulatory requirements.

SPC was used during world war II by US military to ensure quality weapons. Later Japanese used that tool very effectively in their manufacturing to ensure quality and reliable products and could benefit greatly. Today, many industries across the world started using SPC as a quality tool for improved performance. International Automotive Task Force (IATF) made SPC as a mandatory tool to be used by auto components manufacturers and included in QMS standard for automotive industry.

Xbar & R charts

The most popular control charts used in SPC are Xbar & R chart pair. They are used for processes having variable data and have sub-group size of 2 or more (generally less than 10) Data is collected in the form of measurements of the product/part feature (like weight, dimension etc) or process instrument readings. Based on the sub-group size decided for a process, data is collected at fixed time intervals for the subgroup size and used for the control charts preparation.

The Xbar chart presents the mean of each sub-group and shows the variation in the sample means. The Range (R) chart indicates how the data is spread. The Upper Control Limit (UCL) and Lower Control Limit (LCL) are derived using constants (varies with sub-group size) and averages. The quality inspectors who are trained in SPC tool can make out the issues based on trends and data beyond the control limits.

The variations due to common causes will fall between the control limits whereas special causes data will fall out of control limits. A process that is in statistical control, there should not be any special causes. Some level of variation is inevitable for most of the processes and it is called common causes.

Few examples of common causes are -

• Normal machine or tooling wear
• Variation in material properties within specification
• Seasonal changes in ambient temperature or humidity

Some examples of special cause variation include -

• Machine malfunction
• Raw material properties out of design specifications
• Broken tool, punch, bit, etc.

The data within the control limits too can be analyzed and inferences can be arrived based on the trends so that non-conformities can be eliminated. Based on the findings from these charts, one can identify the process issues and address them well in advance to avoid the possible defective parts production. When the process is stable its variation should remain in the known set of limits.

Process Capability - Cp & Cpk

Process Capability is a measurement of how the process is performing with respect to a desired outcome. A capable process is one where almost all the measurements fall inside the specification limits.

Commonly used statistical measures for the capability of a process are - Cp & Cpk.

Cpk never exceeds Cp. A perfectly centered distribution will have Cpk = Cp . The outcome of a Process Capability study is a single metric, that indicates the ability of a process to produce output which is within required specifications.

Below table explains typical values of Cpk:

It is a culture that organization which drives incremental (small) or breakthrough (big) improvements in all business elements.

In 1950's, Toyota implemented small improvement program as part of Toyota Product System. These continual small improvements (Kaizen) and Suggestion Scheme resulted in major benefits.

Realizing the benefits, these small improvement programs have become popular across the world.

And continual improvements have become part of ISO 9001 standard requirements. One has to identify the needs or opportunities and demonstrate the continual improvements year on year.

The projects are identified from results of analysis and evaluation, outputs from management reviews / external audits, customer needs, or bench marking with world class companies for better performance.

While these programs follow Plan-Do-Check-Act cycle at high level, there are different programs/steps to achieve robust solutions for sustainable performance.

One such program, Six Sigma was introduced by Motorola in early 1980's and has 5 phases to achieve defect free outcomes or a set goal. The phases are - Define, Measure, Analyze, Improve, Control.

The typical steps in any Continuous Improvement program include:

• Identifying an opportunity - plus identifying CFT team
• Measure the data - current process performance
• Analyze the data / process - to determine the causes for limited performance
• Develop a solution - to eliminate the root causes and improve the performance
• Implement solution
• Evaluate solution - measure the results for its sustainable performance
• Standardization - standardize process parameters / work practices to ensure gains are sustainable.

An organization who adopts the continuous improvement for their manufacturing processes will see immeasurable benefits which include:

• Increased productivity
• Improved quality / Zero defects
• Lowered costs
• Faster delivery
• Improved market share
• Greater customer satisfaction

The strategic elements of performance indicators can be classified as
Q - Quality - example, production quality, reliability/design quality, warranty failure rate
C - Cost - example, production cost, inventory cost, logistics cost
D - Delivery - example, end product delivery time, procurement period, inventory level
S - Service - example, time to repair

Some organizations consider Safety & Morale too - safety is related to product safety, recycling of used product etc

While every process can be measured by selecting right performance indicator, the organizations select few (about 10 to 15) Key Performance Indicators (KPIs) for management review and evaluation at regular intervals.

These KPIs are generally different for each industry and depends upon their business nature and critical success factors. The performances are bench marked with the world class industries and targets are fixed for improvement and to be competitive in the market

Every process should achieve their intended results so as to realize overarching objectives / goals.

Take the simple example of Customer Satisfaction Index (CSI) - The typical processes that influence the CSI in a manufacturing industry are -

• On-time delivery
• Product quality (on receipt)
• Warranty performance
• Service call turnaround time

CodonQMS KPI module provides the following features for effective monitoring & control -

• Creating KPI as per organizational requirement
• Department responsible
• Previous year performance
• Current year target - monthwise
• Month wise performance data
• Trend graph