Quality 101: Improving Quality Through Lean Concepts
November 21, 2007
Pull systems, one-piece flow, elimination of waste-these are the concepts most often discussed when lean is the topic. Quality at the Source, on the other hand, is rarely front and center when lean improvement efforts are presented.
Even though improved quality is a common outcome of lean transformations every day, the glamorous lean concepts and tools seem to get all the attention. However, just as 5S systems are credited with productivity improvements of up to 10%, Quality at the Source (QATS) can produce dramatic quality improvements in short order.
Quality at the Source can quickly improve quality by providing simple yet powerful tools for employees to use to identify and reduce the waste of defects throughout the value stream. And like many other lean concepts, QATS depends on other lean tools for successful implementation.
The Basic Concept Behind QATSIn an effort to eliminate the waste associated with defects in a process, the implementation of QATS focuses on placing the skills and knowledge in employees’ hands to keep defects from moving through the value stream. To this end, employees are taught the minimum quality standards at each step of the process and empowered to correct defects or remove the defective item before value-added activity is conducted. By catching these defects earlier in the process, quality is improved and the cost of defects is reduced. The basic idea is to quickly inspect through visual means each item or part before adding value. This inspection should take as little time as possible, and quite often only takes seconds.
Defects, after they are identified, should be corrected at the point of discovery whenever possible. This is often the most cost-effective way of correcting defects. If the defect is corrected, a description of the defect and the corrective action must be communicated back to the point in the value stream where the defect occurred. If the defect cannot be corrected on the spot, it should be returned to the point in the value stream where the defect occurred so it can be corrected-or scrapped if the corrective action is not cost effective. In addition to this being the most cost-effective strategy for correcting defects, it also improves employee ownership in the process. This increased ownership is largely due to employees knowing that everyone else in the value stream is observing their work.
While this concept may sound simple on the surface, it can be difficult if an organization consists of multi-skilled employees who are cross-trained for numerous positions. And it becomes even more difficult if these multi-skilled employees rotate through positions on short regular cycles.
The reason for this difficulty is largely due to the amount of knowledge that may need to be transferred to each employee. There may be anywhere from one to 10 or more critical quality points at each process step in the value stream. If there are 10 process steps, then there could be 100 or more different quality points to examine in search of defects in a single value stream. That is a lot of information to teach a workforce and then expect each employee to remember.
To overcome this potential problem QATS uses a three-part structure using other lean concepts and is designed to simplify the task of detecting and correcting defects. These three parts consist of training, visual aids and documentation. Correct use of this three-part approach can greatly improve quality and increase employee ownership of the process.
TrainingThe first step in successful Quality at the Source is training. Employees must be trained not only how to do the job, but with QATS they must be trained on what the critical quality points are at the step in the process where they are working. Additionally, they must be taught how to quickly inspect each item for these quality points. Because lean is intended to increase throughput, QATS inspections must be done quickly and then value-added activity can be conducted.
The QATS inspection should be visual and fast, with the employee looking for each quality point quickly and then moving on to the next point. After all quality points have been inspected, any corrective action necessary can then be initiated.
Visual AidsThe second step in creating Quality at the Source is the development of visual aids. The more common types of visual aids are simple tools used to show such things as standards, examples of good and bad, and methods for inspection. These visual aids come in many different forms, and can be as creative as necessary to produce the desired results. To assist with visual inspection, poke-yokes-mistake-proofing devices-can be used to speed up the inspection process.
One point lessons, or short visual presentations on a single point, also are commonly used with QATS as visual aids designed to show what should be inspected and how to perform the inspection. One point lessons are often created on paper or cardstock from 8½ inches by 11 inches up to poster board size. They rely heavily on photos with very little writing. The concept is to use the visual picture to guide the employee through the process.
In many manufacturing settings sample boards showing bad, marginally bad and good pieces may be used to help employees differentiate the various levels of parts being inspected. This can make it easier to identify and remove defects from the process.
Other types of visual aids include photographs, drawings, diagrams, samples of substitute parts, go/no-go gages and simple electronic tests. The concept behind these visual aids is to make it easier for employees to identify defects before value is added.
DocumentationThe third step for development of a Quality at the Source initiative is documentation. Employees should not be expected to be able to remember each and every critical quality point throughout the value stream, particularly if there are numerous points at each step. To assist the workforce in remembering which items to inspect-and what to look for-documentation is used to provide reinforcement to the quality issues associated with the process.
This documentation should be simple quality checklists, not full-blown quality manuals, work instructions or standard operating procedures (SOPs). This is not intended to suggest that these other very necessary documents should be eliminated. In fact, each and every one of these documentation tools relies on each other for success. SOPs, which reside in the quality manual, can be used as a starting point from which work instructions can be developed that provide the basic steps associated with a task. Then from these work instructions a simple quality checklist can be created to quickly guide the employee through the quality aspects of the task and into the value-added activities.
Bringing It All TogetherAs the three components of Quality at the Source come together, the overall success of an organization’s quality system will improve. Not just a lean tool, QATS can provide great impact on any continuous improvement initiative.
Additionally, QATS brings not just the quality team another tool, but all employees receive a way to contribute to the quality movement of the company. Employees gain ownership through this empowerment and the number of quality contributors can then equal the number of employees in the organization.