Author: Alphadi Team

In Six Sigma the Control Plan is required in the final phase of the project. Its purpose is to manage and sustain the success achieved in the Improve phase. To do this, the risks associated with the new solution are mitigated through measures. For example, risks identified through an FMEA in the Improve phase can be addressed with preventive actions in the Control phase. These actions are essentially tests for the risks. Typically, the Control plan specifies what, how, when, and who will test, as well as who is responsible and accountable, and what risks exist.

It is important that the tests focus on the risks associated with the solution concept. Often, the Control plan includes a before-and-after graphic of the main Y, with actions to be taken if Y falls below a certain threshold. However, this may not be sufficient for sustainability.

“Bottleneck” and “constraint” are terms used to describe limitations or restrictions in processes, and they are often used interchangeably. A bottleneck is always the slowest activity in a sub-process that, at a given time, cannot deliver what the customer demands. The bottleneck can shift depending on the time period or the product/product group/mix, and can vary over time. Machines, employees, and IT systems can also be bottlenecks.

A constraint is a general limitation that affects the performance of the system, such as the availability of employees or materials, which may be restricted by company policies or contracts. The Theory of Constraints (TOC), developed by Eliyahu M. Goldratt, is a management philosophy that identifies constraints as the key factors for improving overall system performance. When one constraint is resolved, a new constraint emerges.

Benefit and Effort is a tool from Lean Six Sigma used for selecting projects or for evaluating and prioritizing potential solutions within a project.

A work instruction is a document that provides a detailed description of a specific task, explaining who, when, where, and with what tools or methods the task should be performed, as well as any settings or parameters required. Work instructions are typically linked to processes, products, or specific workstations.

If needed, they also explain the purpose and guidelines. Since they are workplace-specific, they are readily available where they are needed. Additionally, they are required for QM-documentation. Work instructions differ from procedural instructions: While work instructions are designed to detail individual tasks, procedural instructions offer an overview of all steps or tasks involved in a procedure and present them in a sequential order.

The Andon signal (Japanese for “paper lantern”) is a method used to visualize the status of a process. Colored signals are used to indicate problems.

An A3 problem-solving report is a report from quality management in A3 size (DIN A3), which compactly presents problem statements and details about their causes, thereby providing a basis for identifying and implementing corrective actions. There are various types of A3 reports, all structured to fit all necessary information on a single sheet of paper. The most well-known is the A3 problem-solving report. In the upper left quadrant, the problem is described, while the lower left quadrant lists the measures for identifying its causes and proposed solutions. The results of the analysis are recorded in the upper right quadrant, and the activities for implementing the solutions are noted in the lower right quadrant.

The „Seven Supplier Questions“ is a tool used to establish a basis for process optimization as well as for identifying problems and areas for improvement, ultimately aiming to achieve a high level of customer satisfaction. The focus is on customer friendliness and service. The processes and the products and services provided are examined and optimized from the customer’s perspective. The questions asked depend on the objectives and the customer. For example, the following questions can be posed: (1) Who is my customer (internal/external)? (2) What does my customer need from me? (3) What expectations does my customer have of me? (4) What am I currently offering them? (5) Where am I falling short of their expectations? (6) What can I do to meet their expectations? (7) What actions will I take?

5 Why is a questioning technique used in quality management to identify one or more root causes of a problem. The identified root causes should be measurable. 5 Why was developed by Taiichi Ohno (Toyota Production System). It is a simple and effective tool to identify the root causes of a problem. By repeatedly asking “Why” the true causes are uncovered. The number 5 is merely a guideline; sometimes you find the root cause after asking “Why” twice, sometimes after asking ten times.

The concept Y=f(x) reflects the type of correlation between the inputs (x’s) and the output Y, which is the result of the process. The process itself is represented by f. This is a level-thinking approach that runs as a common thread through DMAIC. The formula is used when the output (Y) of a process (f) needs to be changed/improved, and the process inputs or causes (x’s) must be identified to achieve the desired state. In Six Sigma, measurements and analyses are conducted for this purpose. At the same time, the concept helps in identifying underlying root causes – also symbolized by x’s – that negatively impact Y. Y=f(x) thus serves as a foundation for process optimization.

TPM, short for Total Productive Maintenance, is a concept developed in Japan to prevent equipment failures. It optimizes and standardizes the maintenance concept. TPM is based on the principles of autonomous maintenance, aiming to increase equipment effectiveness, but has now expanded to eight TPM pillars – including continuous improvement, autonomous and planned maintenance, quality preservation, and application in administration – with fundamental components such as PDCA, Kaizen, and 5S serving as the foundation. TPM is a holistic concept and requires the participation and support of all employees for successful implementation.