Process Control and Improvement Strategies

Understanding Process Control

Process control is the practice of implementing measures to ensure operations achieve their objectives. It involves using specific tools and techniques to maintain ongoing performance and drive continuous improvement.

Traditional Process Control Approach

The traditional approach to control typically follows these steps:

1. Set Standards and Objectives

   Establish clear standards, specifications, or objectives for a process or individual performance.

2. Check Performance

   Verify performance against the defined standards. This step is often straightforward.

3. Compare Results

   Compare actual results with expected outcomes. It is unlikely that exact results will perfectly meet expectations; there will always be some variation or deviation.

4. Determine Problems and Take Corrective Action

   Identify issues and implement corrective actions. However, such actions often address only a symptom, not the root cause of poor performance. True corrective action requires exploring the underlying causes within the system and its processes, making fundamental changes to eliminate variations.

Limitations of the Traditional Approach

The traditional approach has significant drawbacks:

• It is event-oriented.
• It is individual-oriented.
• It does not focus on the system and its processes.

Statistical Process Control (SPC)

Statistical Process Control (SPC) utilizes mathematical techniques to understand a process and ensure that results are consistent with objectives. SPC focuses on process stability and variation reduction.

Achieving Process Stability

If a process is stable, it can operate at a higher level of reliability by applying the following steps:

• Stratify: Sorting data into meaningful groups or categories for analysis.
• Experiment: Establishing a planned change and meticulously recording the results to understand its impact.
• Disrupt: Systematically dividing the process into smaller, manageable threads for detailed examination and improvement.

Process Control Philosophies

• Japanese Approach: Often illustrated by the U-shaped curve, emphasizing continuous improvement and minimizing variation around a target.
• American Approach: Establishes a range of acceptable values, within which all results are considered satisfactory.

Types of Process Controls

• Preventive Control: Actions taken to ensure there are no deviations in the quality and quantity of inputs before a process begins.
• Concurrent Control: Actions taken during a process to ensure that standards are met as operations unfold.
• Reprocessing Control: Actions undertaken to correct a problem or defect before the product or service leaves the process.
• Damage Control: Actions taken post-sale to replace a defective product or mitigate negative impacts.

Consistent Design Principles

Consistent design prioritizes simplicity over complexity without sacrificing the functionality that customers expect.

Role of Multidisciplinary Design Teams

Multidisciplinary design teams are more likely to produce designs that work better, are easier to manufacture, sell, and service.

Poka-Yoke: Error Proofing

Poka-Yoke (pronounced po-kay / yo-kay) is a method for detecting and preventing flaws in the process, often through mechanical devices or other error-proofing techniques. Examples include:

• Guide pins
• Photocells
• Checklists

Total Productive Maintenance (TPM)

Total Productive Maintenance (TPM) is an approach to equipment maintenance that aims for zero failures, maximizing equipment effectiveness and operational uptime.