What's your process for prioritizing errors and waste in production?

1 What are errors and waste?

Errors and waste are any activities or outcomes that do not add value to the customer or the business. They can be classified into eight types: defects, overproduction, waiting, non-utilized talent, transportation, inventory, motion, and extra processing. These are also known as the eight wastes of lean manufacturing or DOWNTIME.

2 How to measure errors and waste?

To prioritize errors and waste, you need to measure their impact on your production performance and customer satisfaction. You can use various metrics and tools, such as cycle time, throughput, yield, scrap rate, rework rate, customer complaints, and cost of quality. Cycle time measures the time it takes to complete one unit of output from start to finish. Throughput is the number of units of output produced per unit of time. Yield is the ratio of good units to total units produced. Scrap rate is the ratio of defective units to total units produced, while rework rate is the ratio of units that need to be corrected or repaired to total units produced. Additionally, customer complaints can be used as a metric to measure the number and severity of issues reported by customers. Lastly, cost of quality is the total cost of preventing, detecting, and correcting errors and waste.

3 How to rank errors and waste?

Once you have measured the errors and waste in your production, you need to rank them according to their importance and urgency. To do this, you can use various methods such as Pareto analysis, value stream mapping, and failure mode and effects analysis (FMEA). Pareto analysis uses the 80/20 rule to identify the most significant sources of errors and waste that account for 80% of the problems. Value stream mapping visualizes the flow of materials and information from the supplier to the customer and highlights the sources of errors and waste along the way. Lastly, FMEA assesses the potential failure modes, causes, effects, and risks of each process step and assigns a priority number based on their severity, occurrence, and detection.

4 How to eliminate errors and waste?

Once you have ranked the errors and waste in your production, you need to eliminate them using various improvement techniques and tools such as 5S, Kaizen, and Poka-yoke. 5S is a method that organizes the workplace into five stages: sort, set in order, shine, standardize, and sustain. Kaizen is a method that involves continuous small improvements and problem-solving by involving everyone in the process. Poka-yoke is a method that prevents errors and waste by designing the process or the product in a way that makes mistakes impossible or easily detectable.

5 What are poka-yoke techniques?

Poka-yoke is a Japanese term that means "mistake-proofing" or "error prevention" and is a concept that works to eliminate human errors and defects. This is achieved by designing the process or product in such a way that mistakes become impossible or easily detectable. There are two types of poka-yoke techniques. Prevention poka-yoke uses physical or logical controls, like sensors, locks, guides, and checklists, to prevent errors from occurring in the first place. Detection poka-yoke uses alarms, indicators, and counters to detect errors as soon as they occur and alert the operator or stop the process.

6 How to apply poka-yoke techniques?

To apply poka-yoke techniques, you need to identify potential errors and their causes in your process or product, analyze the frequency, severity, and impact of the errors, choose the appropriate poka-yoke technique and device or method to implement it, test and verify its effectiveness and reliability, and monitor and evaluate the results. It is important to make adjustments as needed.

7 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?