Author: Alphadi Team

The binomial distribution is a discrete distribution that represents the frequency of characteristics with two possible outcomes. For example, it can be used to model the number of defects in a production process.

The poisson distribution is a special case of the binomial distribution. It describes the number of errors per unit that occur within a given unit.

The hypergeometric distribution is used when samples are drawn from small populations without replacement. An example is lottery numbers.

The normal distribution is the most important distribution function for continuous data. Most statistical methods are based on normally distributed data.

The log-normal distribution is steep on the left and right-skewed, and it does not take values less than 0. It is often used to describe process times.

The Weibull distribution is very flexible in its shape. Through the parameter values, the curve can be adjusted to fit various patterns. Examples include lifetime analyses.

The 8D Report  refers to a document that can be requested in the event of a complaint between a customer and a supplier to permanently eliminate defects/errors and improve the supplier’s processes. Additionally, the Report can help restore the trust between the customer and the supplier. 8D stands for the eight disciplines used to address the complaint: (1) Forming the team (2) Describing the problem (3) Implementing immediate actions (4) Identifying the root causes (5) Selecting and implementing corrective actions (6) Verifying corrective actions (7) Taking preventive measures (8) Closing the problem-solving process.

DPMO stands for Defects per Million Opportunities, a metric from Six Sigma used to indicate the defect rate or the average number of defects per million opportunities.

DPMO is used when the number of opportunities for defects in a part is countable. The value is calculated by dividing the number of defects either by the number of defect opportunities or by the number of units produced times the opportunities per unit, and then multiplying the result by 1,000,000. DPMO, like PPM and DPU, is used for evaluating processes and enables a comparison of process capability with the aim of providing a basis for process optimization.

In the Measure phase of a Six Sigma projects , data must be collected to illustrate the pain (Y), meaning that the current state (as-is) should be depicted over time and in terms of process capability. Depending on the Datentyp for Y, this can be represented as DPMO, ppm or Cp/CpK. The Data Collection Plan serves as a type of “work instruction” for the team, specifying how, in what quantity, when, and which data should be collected. This data is then compiled, analyzed, and presented. Collecting data to represent the large Y is a “must” in the Data Collection Plan, but also the influencing factors (x’s) from the Define phase can be collected and presented in the Measure phase to provide initial insights for the Analyze phase.

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.