Becoming Lean - Vision of Demand Flow Manufacturing
Lean manufacturing, total quality management and material flow are often used to describe improved manufacturing systems. This article defines a common vision of demand driven flow manufacturing, building on principles of total quality and lean manufacturing using a work systems redesign framework including elements of the social and technical system.
Work systems redesign starts
with external scan and internal scrutiny. External scan uses tools of
benchmarking and best practices. There are several examples of world-class
companies to review. It is best to perform internal scrutiny, process analysis,
prior to benchmarking. Become a more valuable benchmarking partner and more
quickly apply learnings to a well-understood process.
Start with value stream /
process flow mapping to describe the existing process. Map the material and
information flow. Make obvious improvements without going outside. Define a
clear link to the business strategy and provide management support to
benchmarking and improvement.
External scan and internal
scrutiny improve understanding of the business situation. These are inputs to
business strategy development: participation and operating. The key is to build
commitment of the organization to common purpose and direction. Build
strategies on a foundation of realistic resource planning to deploy the
necessary improvements to business practices.
The operating culture is made up of material and
information flows, work task and technologies, capabilities, workplace design,
structure, rewards and recognition. The following addresses each separately as
they relate to product flow.
Material and Information
Flows:
Material flow should follow a simple path with highly visible process
stages. Design a balanced, synchronized
flow aligned to customer requirements. Use takt time to define time available
based on customer demand per unit of time. Use standard work to define the best
method and right combination of people and machines to produce within takt
time.
Capacity should be reviewed
to identify bottlenecks. Bottlenecks are protected by time buffers of materials
and are a focus to improve process, capacity and input quality. Cellular
manufacturing or flow lines connect separate work processes with minimal
handling. Avoid the mistake of making cells too product specific. A process
cell handles a family of parts and has the benefit of reduced moves and queues.
Disconnected operations are
connected by a pull system. Kanban squares, containers, cards connect the flow.
Kanban buffer stock needs to be carefully planned based on process potential,
anticipated throughput time and safety stock based on expected quality and
potential delays.
Information flow is very
visual. Kanban is one visualization technique. It is very easy to see flow as
represented by buffers, cards or empty spaces. Other visualization techniques
include lines on the floor or workspaces to indicate equipment or inventory
positions, hanging signs, arrows or color codes. Andon lights on equipment or workstations indicate status. Information centers display production and
quality graphs, SPC charts, process descriptions, business / team objectives
and improvement projects.
Planning information is
largely confined to defining requirements, rough-cut capacity planning and
linearity. In a true pull system, a linearity graph showing daily end-product
production rate on a continuous cumulative slope, is provided to the last
operation. Actual production plotted over the target provides a measure of
linearity or how well output tracks to daily rate.
Apply SMED techniques for
set-up time reduction. Enable smaller batches and less work in process. Use
preventive - predictive maintenance - put sensors on machine to predict a
breakdown and react accordingly. Apply
operator daily checklists to clean, verify and lubricate equipment.
Work Tasks and Technologies: Work tasks are defined by
visual and understandable procedures. Total quality control uses quality checks
done concurrently with manufacturing steps. Control the process directly
through monitoring machine variables such as vibration, spindle speed or heat.
Use mistake-proof / failsafe devices to make it impossible to make a mistake.
Apply devices such as locating pins to allow only one possible orientation. A
less desirable, but effective method is operator independent crosscheck and
checklists. Use color codes on drawings - work instructions.
Videotape, analyze and document
existing methods. Then develop efficient standard methods to optimize tasks.
Apply technology appropriate to the task. Don’t invest in all the latest and
greatest machines. Instead invest in sensors to monitor tool wear, simple flow
enhancements such as kanban carts, simple sequencing devices, operator handling
aids and process control devices.
Capabilities: People are cross-trained
and capable of performing multiple tasks. In a cellular arrangement,
multi-skilled people are critical. People are certified to perform a procedure
through repetition and verification. They may lose certification if they don't
perform an operation over calendar interval. Education and training is
encouraged and rewarded. This is not limited to job skills but expands to include
interactive and personal development. People have capability to improve
processes and learn through doing - applying tools to improve their operation.
Kaizen events are an excellent way to impart this knowledge while rapidly
improving the process.
Workplace Design: The workplace shows
attention to methods, ergonomic, safety and handling issues. Everything has a
place and everything in place. Lifts are minimized or eliminated, reaches are
shortened, walking and searching is reduced, lighting is optimized, hazards are
eliminated, the workplace is exceptionally clean, safety equipment available
and noise minimized or source controlled. It is generally an attractive, nice
place to work.
Structure: Leadership aligns the
workforce to common goals and purpose. Management is more effective if aligned
along flow lines. Avoid functional silos: separate manufacturing departments
and staff departments. The flow organization reduces the number of managers in
a flow chain. Resources are either dedicated to the flow or feel first
allegiance to the flow. Functional groups can act as resource pools and centers
of functional excellence and employee development. Everyone feels ownership of
ultimate deliverable. Hand-offs and organizational barriers are minimized.
Rewards and Recognition: Responsible plans and
delivery of recognition support measures and goals. Measures are flow-oriented
such as first pass yield and total cycle time. Customer satisfaction is
measured through a combination of quantitative (such as escaping defects) and
qualitative (such as a survey to determine responsiveness and other customer
satisfiers). Morale is high because people are recognized for individual
supportive behavior and team results. R+ is planned, because what gets planned
gets done.
There is a lot to be done to truly accomplish flow. This is intended to provide structure to the ultimate objective. The main thing is to get started. Get help from experts in addition to involving the majority of your workforce.
Author: Greg Hart, Hart Innovative Solutions, Inc. (585) 235-1720
Home Service 1 www.HartInnovations.com GregHart@HartInnovations.com