Human error is a common challenge in manufacturing that can lead to costly mistakes, production delays, and even safety hazards. Despite the use of advanced technology and automation, the human element remains integral to manufacturing processes, and errors are an inevitable part of any system involving people. Understanding the causes and types of human errors is crucial for developing strategies to reduce their occurrence and impact. In this blog, discuss practical solutions to minimize these errors.

What is Human Error? 

Human error refers to mistakes made by workers during the manufacturing process. These errors can occur for various reasons, including lack of training, miscommunication, fatigue, or unclear instructions. In a manufacturing environment, even minor errors can lead to defective products, production delays, and increased costs. Recognizing that human error is often a symptom of underlying issues rather than the cause itself is the first step toward effectively reducing it.

Types of Human Errors in Manufacturing 

1. Slips and Lapses:

Slips and lapses are unintentional errors that occur when a person’s attention or memory fails them during a task. 

Slips: A slip occurs when a worker intends to perform one action but accidentally does something else. This could be due to distraction, rushing, or performing a task out of habit without fully engaging in it. Example: A worker might accidentally place a component in the wrong position during assembly because they were momentarily distracted by a noise or conversation.

Lapses: A lapse occurs when a worker forgets to perform a task or skips a step, often because their mind is occupied with something else or they are overconfident in their ability to perform the task without full attention. Example: A worker might forget to tighten a bolt in an assembly because they were thinking about the next step in the process or simply assumed they had already completed the task.

Impact on Manufacturing:

Slips and lapses can lead to minor defects that might not be immediately noticeable but can accumulate over time, resulting in significant quality issues. They can also cause rework, delays, and increased costs if the errors are caught later in the production process.

2. Mistakes:

Mistakes are errors in decision-making or judgment that occur when a person’s knowledge or understanding is insufficient or incorrect. Unlike slips and lapses, which are execution errors, mistakes are errors in planning. Mistakes can happen when a worker is unsure of the correct procedure, misinterprets instructions, or makes an incorrect assumption about the best course of action.

Rule-Based Mistakes: These occur when a worker applies a rule or procedure incorrectly. This can happen when a worker misunderstands the instructions, follows outdated procedures, or tries to apply a familiar rule in a situation where it doesn’t fit. Example: A worker might use the wrong material for a production run because they misread the work order or mistakenly believe that the material is interchangeable with another.

Knowledge-Based Mistakes: These occur when a worker makes an incorrect decision due to a lack of knowledge or experience. This type of mistake often happens in unfamiliar situations where the worker must rely on their judgment rather than established procedures. Example: A new operator might incorrectly set up a machine because they don’t fully understand how it works, leading to incorrect product dimensions or defects.

Impact on Manufacturing:

Mistakes can have a significant impact, potentially leading to widespread defects, production downtime, or even safety incidents if critical procedures are not followed correctly. They often require extensive rework, waste valuable materials, and can delay production schedules.

3. Violations:

Violations are deliberate deviations from established procedures, rules, or standards. These errors occur when a worker knowingly decides to bypass standard operating procedures, often due to perceived time constraints, inefficiency in the prescribed method, or overconfidence in their abilities. Violations can be particularly problematic because they are intentional, often stemming from a belief that the deviation will not result in harm or that the established procedure is unnecessary.

Routine Violations: These occur when workers regularly deviate from procedures because they believe the rules are overly cautious, inefficient, or irrelevant. Over time, these violations can become part of the workplace culture, with workers consistently taking shortcuts. Example: A worker might consistently skip a quality control check because they believe it’s unnecessary or because they’ve never encountered a defect in previous checks.

Situational Violations: These occur when a worker deviates from the procedure due to specific circumstances, such as time pressure, lack of resources, or a perceived need to complete the task more quickly.     Example: A worker might bypass a safety guard on a machine to speed up production, believing that the risk is minimal or that the deadline justifies the action.

Exceptional Violations: These occur in rare situations where a worker feels compelled to deviate from the procedure to deal with an unusual problem or emergency. While these violations might seem justified at the moment, they can still lead to significant risks. Example: A worker might modify machine settings beyond the recommended limits in an attempt to troubleshoot a problem, potentially causing equipment damage or safety hazards.

Impact on Manufacturing:

Violations can lead to severe consequences, including safety incidents, equipment damage, and major product defects. Since these actions are intentional, they can be more difficult to detect and correct, potentially leading to a culture of non-compliance if not addressed promptly.

Strategies to Overcome Human Errors in Manufacturing 

1. Implementing Standardized Work Instructions:

One of the most effective ways to reduce human error is by standardizing work instructions. Clear, detailed instructions ensure that every worker follows the same procedures, reducing variability and mistakes. 

Digital tools like ORCA LEAN Standard Work Software allow manufacturers to create visual work instructions that include images, diagrams, and videos, guiding workers step-by-step through each process. This approach helps to minimize slips and lapses by providing a visual reference that workers can easily follow.

2. Enhancing Training and Skill Development:

Comprehensive training programs are essential to ensuring that workers have the knowledge and skills needed to perform their tasks correctly. These programs should cover both technical skills and the importance of following procedures to prevent errors. Digital Tools can enable manufacturers to create and deliver customized training courses, track employee progress, and provide assessments to reinforce learning. By regularly updating training programs and offering refresher courses, you can reduce mistakes caused by a lack of knowledge or outdated practices.

3. Utilizing Error-Proofing Techniques (Poka-Yoke)

Error-proofing, or Poka-Yoke, is a proactive approach to preventing errors by designing processes that make it difficult or impossible for mistakes to occur. This can involve physical devices that prevent incorrect actions or digital systems that alert workers to potential errors. For example, Mistake-Proofing Software can be used to set up automated checks and alerts during the production process, ensuring that errors are caught before they lead to defects. This approach is particularly effective in reducing mistakes and violations by creating an environment where the correct action is the only option.

4. Improving Communication and Information Sharing:

Effective communication is crucial in preventing errors, especially in complex manufacturing environments where multiple teams are involved. Miscommunication can lead to misunderstandings and mistakes. Digital tools can facilitate real-time communication, enabling workers to share information, ask questions, and clarify instructions quickly. By ensuring that everyone has access to the same information and can communicate easily, you reduce the likelihood of errors caused by miscommunication or missing information.

5. Implementing Real-Time Monitoring and Feedback:

Real-time monitoring systems allow manufacturers to track production processes as they happen, identifying deviations from standard procedures and correcting them immediately. Systems like SCADA (Supervisory Control and Data Acquisition) or MES (Manufacturing Execution Systems) provide real-time data on production performance, alerting managers to potential issues before they escalate. This immediate feedback helps to catch slips, lapses, and violations as they occur, reducing their impact on the overall production process.

6. Designing Ergonomic Workspaces:

An ergonomic workspace reduces physical strain on workers, which can lead to fatigue and errors. By designing workstations that are comfortable and support proper posture, manufacturers can help prevent errors caused by physical discomfort or fatigue. Ergonomic Assessment Tools can be used to evaluate and optimize workspaces, ensuring that they are suited to the tasks being performed. 

For example: Adjustable workbenches, anti-fatigue mats, and supportive seating can all contribute to a more ergonomic environment, reducing the likelihood of errors.

7. Promoting a Culture of Continuous Improvement:

Encouraging a culture of continuous improvement empowers workers to identify potential issues and suggest improvements to processes. This proactive approach helps to catch errors before they occur and fosters a sense of ownership among employees. Tools like Kaizen Software or Continuous Improvement Platforms allow workers to submit suggestions, track progress, and implement changes. By involving employees in the improvement process, you create an environment where errors are seen as opportunities for learning and development, leading to ongoing reductions in human error.

Conclusion

Human error is an unavoidable part of any manufacturing process, but with the right strategies and tools, its impact can be significantly reduced. By implementing standardized work instructions, enhancing training, utilizing error-proofing techniques, improving communication, monitoring processes in real-time, designing ergonomic workspaces, and promoting continuous improvement, manufacturers can minimize the occurrence of human errors. These steps not only improve product quality and efficiency but also create a safer and more productive work environment, ultimately leading to better outcomes for the entire organization.