Seven Basic Quality tools documents
Definition of Quality Management -- it is a method for ensuring that all the activities necessary to design, develop and implement a product or service are effective and efficient with respect to the system and its performance. It is also a principle set by the company to endure the continuous advocacy of quality services and products, or the further improvement of it.
Welcome to QT-charts knowledge base section. Hopefully you will find some of them useful in your work.
(Read articles below to learn more.)
Design for
Maintainability
Original
text on www.freequality.org
Definition
Maintainability
is the degree to which a product can be maintained or repaired easily,
economically, and efficiently. Design for maintainability (DFMaint) encompasses
the measures taken to reduce the time and other resources spent in keeping a
product performing well. It benefits the end user by reducing the total
ownership costs through less downtime (lost productivity), lower maintenance
costs, less inventory, fewer tools, and improved safety.
DFMaint
can be a differentiating feature for otherwise commodity products. Although it
may increase the costs to manufacture a product, DFMaint can also increase
market share and extend the product lifecycle.
DFMaint
is presented in this tutorial as an approach for durable goods. However, it can
also be adapted appropriately for software, service, operations, and processes.
How to Apply Design
for Maintainability
DFMaint Features
The
following features are commonly found in easily maintained products and
systems:
- Relatively
few components in the final assembly
- Standard
components and fasteners
- Conformance
to national, international, and industry standards and codes
- Components
that are easily replaced
- Components
that can be easily removed with standard tools
- Components
that are install only one way
- Space
around or inside the product to perform maintenance activities
- Nondestructive
disassembly
- Safety
precautions protect maintenance workers from hazards
- Owner’s
manuals and other appropriate documentation (e.g., wiring diagrams, help
facilities, or videos showing how to perform minor repairs)
- Consistent
labels to identify parts
- Installed
product required no or minimal adjustment
- Self-diagnostics,
built in tests, or indicators that isolate problems quickly and
automatically
- Steamlined
testing, calibration, and troubleshooting procedures
- Simple
after-sale processes that ensure service can be received promptly
DFMaint
in the Product Development Process
The
features of DFMaint products are obvious. Yet they can easily be overlooked
unless DFMaint is a deliberate consideration in the product development process.
Furthermore,
DFMaint should be considered early in the product design process when the
product concept is flexible and change costs are low. The following closed-loop
process outlines this approach:
- Form
a team that represents design, manufacturing, product maintenance, and
customer support functions.
- Gather
and analyze data from service technicians, field personnel, customer
surveys, and warranty records. (See related tutorial on such analysis
tools as failure modes and effects analysis [FMEA], fault-tree analysis
[FTA], Pareto analysis, and Ishikawa diagrams at this website.)
- Identify
and prioritize maintenance issues. Develop concepts to address the
greatest concerns.
- Incorporate
the selected maintenance concepts into the product. (See related tutorials
on design for manufacturing [DFM] and durability at this website.)
- Analyze,
test, and improve the product, allowing the design to evolve as
maintenance concepts are reviewed and revised.
- After
product engineers finalize the design, release the product to
manufacturing.
- Evaluate
the performance of the product in the field through customer feedback,
warranty information, surveys, and service records. Use this information
to inform the design of new products.
- Modify
the product as required by critical safety, economics, and performance
demands.
- Repeat
the DFMaint process with the next generation product.
Measuring DFMaint Results
Maintenance
cost benchmarks are collected by the Plant Maintenance Resource Center (http://plant-maintenance.com/benchmarking.shtml).
These benchmarks can help a firm assess its competency in comparison with
industry benchmark companies.
Maintenance
metrics address three factors: product design attributes, after-sale costs, and
product performance. Typical measures include
- conformance
to specifications
- frequency
of repairs
- repair
costs
- total
ownership costs
- training
costs
- maintenance
work orders per year
- downtime
- total
maintenance hours
- number
of maintenance personnel
Example
In
the early 2000s, GE’s Electro-Motive Division (EMD) was compelled to modify
designs for its railway locomotives. New EPA requirements mandated a
significant reduction in NOx emissions produced by locomotives. Since redesign
was unavoidable, the division decided to take the opportunity to improve the
maintainability of the equipment at the same time. Such improvements would
improve the safety and reduce the required maintenance hours of the equipment.
Following
an interative design process, engineers not only surpassed the mandatory EPA
standards, they incorporated several DFMaint features into the new product:
- An
easily removable hood
- Track-level
access to the traction motor speed probe
- Solid-state
components to replace more fragile fuses
- Simpler
processes for insulation testing
- Reconfiguration
and consolidation of electrical wiring and pneumatic piping onto separate
sides of the underframe
- Advanced
software to help technicians isolate defective components
- Clearer
messaging on the crew’s cab display screens to accurate convey important
maintenance-related information
- A
wireless remote monitoring and communications system the provide early
alerts of predicted health and maintenance events
- An
ergonomic cab to improve the engineer’s comfort and reduce fatigue
Most
importantly, the new design did not alter the basic engine dimensions, nor does
it require additional workforce training or tooling.
Further Information about
Design for Maintainability
Significant
content for this article was found at the website for the Reliability Center
(RAC), an information analysis center affiliated with the U.S. Department of
Defense. A broad range of quality assurance information can be found at their
website http://rac.iitri.org.
Additional Sources
Markeset, Tore and Uday Kumar. Design and
development of product support and maintenance concepts for industrial systems.
Journal of Quality in
Maintenance Engineering Vol. 9 Iss. 4 (2003): 376 – 392.
Vantuono,
William C. Design for maintainability. Railway
Age Vol. 204 No. 7 (July 2003): 31.