Producing a part to the quality and precision agreed with the customer depends heavily on the accuracy of the machine. That accuracy — of the machine and of the equipment around it — therefore has to be controlled, and quality maintenance is how.
Quality maintenance means joining quality assurance to machine control: following the quality characteristics of the part and the way the machine is run, and holding both inside the conditions that have been set.
A quality-maintenance standard table sets out the relationship between each quality characteristic and the standard setting of the machine, so that the part comes out inside the specified tolerance.
1. Quality assurance and quality maintenance
Quality assurance is everything done to be confident that what comes out is the quality the customer wants. It starts at the design, runs through the selection of production inputs and the control of the process, and ends by preventing a part that is not right from reaching the customer.
Quality maintenance is quality assurance applied to the machines and equipment — from designing or buying them, to keeping them in a condition that produces good parts at all times. It works by establishing the relationships between the quality characteristic and the accuracy of the machine, between the quality characteristic and the machine’s settings, and between the quality characteristic and the working method — and those relationships are established precisely so that they can then be controlled.
2. What quality maintenance sets out to do
Quality maintenance is quality assurance on the machine side, in order to:
- Give confidence in the quality that maintenance of the machine produces
- Establish the machine and equipment conditions under which no defect is produced
- Prevent quality problems by controlling those conditions
- Measure how far the conditions have drifted, so the chance of a defect can be predicted and prevented in advance
3. Quality maintenance and the five pillars
The basic requirement of quality maintenance is that the machines, equipment and tools are in good condition and at their most effective — and equally that the environment, the skills and the working methods are such that quality can happen at all. To meet that requirement, the objective of producing no defects has to be added into each of the five pillars: individual improvement, autonomous maintenance, planned maintenance, initial-phase management, and education and training.
In the diagram, individual improvement takes on quality improvement and quality problem-solving. Autonomous maintenance adds the skills of noticing and correcting quality problems. Planned maintenance adds checks on the quality conditions into the periodic maintenance plan, so that drift can be tracked against what is acceptable.
Initial-phase management has to build in, from the start, the conditions believed to produce quality — in the design of the machine and in the design of the product alike. And the fifth pillar, education and training, is the mechanism that creates both the awareness and the skill to deal with quality problems at all.
Why this pillar is necessary
Raising the quality and precision of the product is at present in a period of rapid change. Consumers want a guarantee that covers more than it used to, so holding quality high and steady has become the important thing in production today.
It is made possible by creating production conditions free of defects — zero defect — from the planning and design of the product, through installing and choosing the production technology, through manufacturing itself, and finally through scanning, so that any defect that does arise cannot slip through to the customer’s hands.
All of it is the activity that takes place under quality maintenance, one of the pillars of TPM — or, to put it another way, quality maintenance is the pillar responsible for zero defect within TPM.
Read next
- FMEA: Prevention Rather Than Cure, and the Ten Steps That Keep It From Becoming Paperwork
- Quality Maintenance: The QM Matrix and Separating What You Control From What You Do Not
Reference
- ธานี อ่วมอ้อ. การบำรุงรักษาด้วยตนเอง. กรุงเทพฯ: สถาบันเพิ่มผลผลิตแห่งชาติ, 2547.
- ธานี อ่วมอ้อ. การบำรุงรักษาทวีผลแบบทุกคนมีส่วนร่วม. พิมพ์ครั้งที่ 2. กรุงเทพฯ: สถาบันเพิ่มผลผลิตแห่งชาติ, 2546.
- Development Program: Implementing Total Productive Maintenance. Tokyo: Japan Institute of Plant Maintenance, 1996.