This pillar is oriented towards maintaining the quality level of the products. We seek to eliminate the causes of non-quality, so that every minute of the process time is a useful minute, producing a “good” product.
By definition, ” quality maintenance is to establish the conditions which prevent the appearance of defects and to check the conditions to reduce defects to 0 “1. The key concept is to focus on the actions of preventing the appearance of the defect and not the measures of reaction to the non-quality. This quality control can only be carried out when the processes, methods or the competence of the staff are at a high level of performance through the pre-implementation of self-maintenance, the improvement on a case by case basis, the Planned Maintenance and Staff Training2.
The stages of quality maintenance
Step 1: Look for the causes of non-quality
- Get to know the current quality standards.
- To identify the characteristics of the quality via a défauthèque for example.
- Identify via a 4M analysis (machine, labor, material, method) potential causes.
- Make a pareto of the causes of non-quality.
- Select the priority cause via the Pareto and the Gain/cost matrix.
Step 2: Follow the PM analysis process to repair the anomalies
Once the cause of the problem is identified, the PM Analysis makes it possible to clearly identify gaps and identify the best solution.
Step 3: Set the standard value and the tolerances of the control
- set the ideal state to the right: the challenge is to define values neither too restrictive nor not enough to avoid over-quality or sub-quality. Design Of Experiments will have to be implemented for that.
- identify the most appropriate means of measurement: Gage R & R is the best tool to help in this step.
- be able to reproduce the defect: the total control of the quality comes when we are able to reproduce the defect or to remove it wisely.
Step 4: Synthesize checkpoints and reduce control times
- streamline the values to be controlled: example, within the close tolerance framework, it may be appropriate to have a single tolerance to limit the number of control tools or errors.
- Streamline points of control: in the same way as before, checkpoints may be redundant.
- Streamline Control tools: This saves time, reduces the possibility of errors or even requires maintenance and less management of the measuring tools.
Step 5: Establish the QA matrix and QM and integrate the results into the maintenance standards
To facilitate the detection of problems and increase our responsiveness in their resolution, we will set up the QA Matrix (Quality Assurance). On the same table, this matrix is the default/localization link. By reading it, at the onset of the defect, the operator can easily act on the parameter or parameters that generate the defect.
Finally, in order to maintain the good quality practices implemented in the previous stages, it is a question of setting up the Matrix QM (Quality maintenance) which synthesizes all the control points and standards for the services involved in the process (quality, maintenance, Production…).
Setting up the culture of quality
Finally, this pillar aims to put in place the culture of quality and the basic principles of quality. This goes through trainings on:
1 – JIPM (1996) – TPM Total Productive Maintenance Encyclopedia
2 – K. Shirose (1996) – TPM – Total Productive Maintenance: New implementation Program in fabrication and assembly industries
J. Buffer (2011) – The TPM guide