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Convert From QC to QA Mentality
Creating a culture of quality-focused production processes will minimize defects in the final product
By Bob Yenkner
The traditional dental laboratory expends many man-hours and labor dollars in an effort to find errors before they escape into the customer’s hands (and even the patient’s mouth). The main methodology used in this effort is known as Quality Control.
Quality Control in the typical dental laboratory employs visual inspection of every product before it leaves the laboratory, and often employs magnifying devices to examine fine detail before the product is released into the external market. Most laboratories conduct a final QC check, performed most often by the owner or a laboratory manager, with very little emphasis on in-process checking. Studies have shown that 100% inspection (QC) of the parts is only 95% effective, meaning that 5% of the restorations produced will have a problem that is not detected. Is it a coincidence that many laboratories have a remake rate factor of 5% to 7%? The failure of the QC approach is rooted in its philosophy that detection of errors is possible. The number of variables in any given process makes it impossible for every error to be detected.
So what is the difference between Quality Control and Quality Assurance? Simply put, Quality Control is product oriented and focuses on defect identification. Quality Assurance is process oriented and focuses on defect prevention. Quality Control activities are typically performed after the product is manufactured. Quality Assurance activities, on the other hand, are determined before production work begins, and these activities are performed while the product is being produced. Quality Control emphasizes the examination of products to uncover defects and then make a decision whether to allow or deny product release. Quality Assurance attempts to improve and stabilize production (and associated processes) to avoid, or at least minimize, issues that could lea d to defect(s) in the final product.
The QA approach places an emphasis on four efforts to support a solid and viable effort. The quality of the output is at risk if any of these four aspects is deficient in any way.
1. Defined and well-managed processes: Each aspect of the production process is documented and understood by technicians and supervisors.
2. Competence: Those involved in the production process possess the knowledge, skills, experience, and qualifications to carry out the production processes.
3. Soft elements: Production processes must be carried out in a business environment of integrity, confidence, organizational culture, motivation, and team spirit.
4. Visual Controls: Technicians must have visual controls to see what constitutes a good/bad product (thus minimizing subjectivity).
There are a number of tools that will help drive a Quality Assurance culture:
• Kaizen: A culture of sustained continuous improvement focusing on eliminating waste in all systems and processes of an organization.
• Poke-yoke: A device within a process that either prevents a mistake from being made or makes the mistake obvious at a glance.
• Visual controls: A visual workplace set up with signs, labels, and color-coded markings, so that anyone unfamiliar with the process can, in a matter of minutes, grasp what is going on, understand the process, and know what is expected to be done correctly.
• Value Stream Mapping (VSM): A visual representation of any given process to identify where defects can be inadvertently introduced into the process step.
• Root-Cause Analysis: Any structured approach that identifies factors that resulted in the nature, the magnitude, the location, and the timing of the harmful outcomes (consequences)
• Workplace Organization (6S): Six elements (Sort, Stabilize, Shine, Standardize, Sustain, Safety) to eliminate waste of excess movement and cluttered work areas.
Building a quality assurance culture in your business will result in employees not only following established quality guidelines but also talking about and carrying out quality-focused actions to ensure that fewer mistakes are made throughout the production processes.
Bob Yenkner is the owner of Practical Process Improvements (PPI) in Higganum, Connecticut.