Author: Alphadi Team

A Histogram is used for the clear presentation of large, complex data sets and facilitates the assessment of data distribution by organizing the data and determining process variation. Data that has already been collected is sorted into classes based on their target values and tolerance limits, all in the same unit of measurement. To determine which classes individual values should be assigned to, the range (R), the number of classes (k), and their width (h) must be calculated. The X-axis is scaled according to the class width, while the Y-axis, once all values are assigned to categories, shows the frequency with which each class occurs.

Heijunka (Japanese for “leveling”) is a Lean management tool used to evenly distribute production capacity and systems, and to translate fluctuating customer demands into a consistent production structure. This involves creating production patterns for product variants over several stages. This is done, among other things, by setting production cycles and identifying suitable sequences. Heijunka focuses on aligning the process with customer demand, and therefore primarily considers customer needs to determine daily production quantities per product family. Important metrics include EPEI (Every Part Every Interval) and pitch.

There are various types of pull systems. We differentiate them based on their objectives into Replenishment, Generic and Kanban. There are additional types such as sequential pull systems and/or combinations thereof. When our main goal with a Generic pull system is to optimize or reduce inventory, we first gradually reduce the maximum inventory level through a Kanban calculation (kMin./kMax). Subsequently, we assess the feasibility of the product or service through a simulation using real data from the past and future.

Gate reviews are milestones that play an important role, especially in Six Sigma projects. They are used to evaluate results generated during a specific phase and ensure well-founded project progress. The project team presents the phase-specific work results to the sponsor, who acts as the project client. If all agreed (sub-)goals have been achieved, the sponsor approves the phase completion, giving the “GO” for entering the next phase; if not, improvements must be made. Gate review meetings take place when the end of a phase, such as the DMAIC roadmap, is approaching. In a Six Sigma project, at least five Gate reviews must be organized.

Gemba (Japanese for “the place where it happens”) is a Lean Managements tool that refers to the location where value-adding activities are performed, such as the production floor or an office workstation. Its key component is the Gemba Walk, which takes the practitioner directly to the actual workplace. The goal is to become familiar with the real work situation, gather facts, and learn to “see” the problems firsthand. This approach helps identify value-adding activities, as well as waste, and uncovers improvement potential and ways to address root causes of problems. Gemba Walks are not limited to specific areas; they can be conducted for any focus topic.

FTA, short for Fault Tree Analysis is a tool from quality management used to capture and represent potential cause-and-effect relationships, often employed in Root Cause Analysis. It is primarily used in aerospace, nuclear industries, and chemistry. Fault Tree Analysis is a structured top-down tool for identifying faults, based on Boolean logic: an event or undesired outcome is represented as a result of various basic and intermediate events, with failure probabilities assigned to individual basic events.

FMEA (short for Failure Mode and Effects Analysis) is used preventively to identify and avoid potential errors that could occur in a product, process, or service. This tool is valuable in Lean Six Sigma projects as it helps uncover and eliminate not only potential errors but also their root causes, thereby preventing further negative consequences, particularly from the customer’s perspective. After listing possible errors (and their causes), they are classified and assessed based on the likelihood of their occurrence and their significance. FMEA also helps calculate useful values like the Risk Priority Number (RPN).

First Pass Yield or FPY, is a metric from quality management used to measure process performance. It reflects the proportion of products produced in a process that are defect-free, meaning they do not require rework. By determining the FPY , it is possible to identify waste (hidden factory), reduce rework, and increase process yield.

A Check Card provides a clear overview of potential defects and their frequency of occurrence. The data is based on the examiner’s own observations. This tool from quality management helps in identifying defects and their causes. Possible defects are categorized, and the Check Card also includes information about the product or process being examined for defects, the examiner, and the testing procedure. Each individual defect that occurs is marked with a tally. Summing up the results afterward allows conclusions to be drawn about the origins of the problem causes and helps in selecting further analyses.

The ISTR, short for Initial Sample Test Report, is a form in which a supplier documents the results collected during the inspection of first articles. This is a central requirement from the customer. The aim is to ensure that the quality of the first articles, i.e., the products manufactured during the test run of a new series production, meets expectations and that the specifications have been realized. The ISTR includes, among other things, contact details and product and inspection information, a table of contents (e.g., core data, details about the equipment, and comments). The inspection results primarily include the inspection tools, target and actual values, and the customer’s decision.