We may think, based in all the information
about Lean Manufacturing, that many tools and methods are well understood,
unfortunately on real live there is many misunderstanding about them, that’s
why I decided to write this article, for one of the most popular and known
tool, SMED.
I have to clarify and specify this is one way
of how to implement this tool, this not perfect obviously, but should give you
an idea of how start the deployment for Setup Reduction.
Definition
of Quick Set Up / Changeover
The absolute minimum amount of time needed to
changeover from one activity to another, to minimize the amount of time the
equipment remains idle, thereby responding faster to customer needs.
Many key ideas developed by Dr Shigeo Shingo,
he called it SMED (Single Minute Exchange of Dies) Means single digit (1-9
min), i.e. Less than 10 minutes
Example: 1000-ton
press ,( Before: 4 hr - After: 3 min)
Improvement: 98.7%, or a factor of 80
Changeover time is the total elapsed time
between the last unit of good production of the previous run, at normal line
efficiency, to the first unit of good production of the succeeding run, at full
line efficiency.
Why do
Quick Setup / Changeover?
·
Improve Flexibility: Changes in customer demands are easy to
accommodate without excess inventory
·
Improve Quality: Quicker feedback from customer/customer
process, reduced process variability
·
Reduce Lead Time: Shrink the time it takes to get product to
the customer
·
Increase Capacity: Improved Operational Availability
·
Reduce Inventory: Dramatic cost
improvements
·
Improve Safety: Simpler setups = safer setups
·
Support Pull System
Implementation: Quicker setup/changeovers facilitate small
lot production, small lot production facilitates pull systems
SMED is
Continuous Improvement
It is a customer driven requirement.
Customers demand:
·
Product
and service diversity
·
Lower
costs
·
Higher
reliability and quality
In essence organizations need to become
leaner!
So organizations must:
·
Produce
smaller lots, more frequently
·
Expand
the scope and diversity of products and services
·
Reduce
quality defects
How long does it take to change a tire on
your car:
·
Hard
·
Easy
Changing
a tire in our car is a chore that will take anywhere from minutes to hours , as
we see on first video.
Why
is it that in the car races they can change the four tires in just a few
seconds as showed on second video?
Here
are some of the differences:
·
They
were prepared
·
Right
tools
·
Only
one bolt per tire
·
Continuous
training
·
Cumulative
experience, on and on...
The
Quick Changeover Methodology for Setup Reduction
Step 1
- Identify Internal & External Steps
Definition
What is an Internal Step?
An internal step is one that must be
performed while the machine or operation is stopped; and therefore is a form of
lost time.
What is an External Step?
An external step is one that can be performed
while the operation is running.
Purpose
for Separating Internal and External
The primary focus of setup reduction is not
on total setup time (internal + external) nor on setup labor time, but on
internal time alone. While reducing
total setup time and setup labor time is desirable, it is only of secondary
importance.
Record the process (use a Simple Time
Recording Sheet, Standard Work Combination Sheet or SOE)
·
Form
a team
·
Interview
operators
·
Videotape
·
Stopwatch
analysis
Step 2
- Convert Internal Steps to External
Objective
·
To
reduce internal setup time. The more setup steps, decisions, adjustments, etc.
that can be done on external time, the better.
·
Wherever
possible, setup steps performed while the operation is stopped (internal) need
to be completed while the operation is running (external).
Analyze all essential internal steps to
determine if opportunity exists to convert internal steps to external steps:
·
Can
adjustment blocks be used in lieu of making machine adjustments?
·
Can
dies be preheated independent of the equipment operation?
·
Can
procedures/techniques be developed to insure that all tools, equipment, and
materials are staged in the immediate work area before the machine is idled?
·
Is
all post setup work (tooling service, cleaning, data tracking, etc.) being done
after the equipment resumes operation?
Example
Other examples:
·
Standardize
common temperature profile for curing
·
Standardize
common screw torque setting
·
Additional
SMT feeder, preload component & QA check
·
Off
line software loading
·
Pre
heating of die set
Step 3
- Reduce Internal Setup Time
Objective
To reduce internal setup time: The internal
setup steps and decisions need to be simple and precise while adjustments got
to be reduced and eliminated.
Analyze the remaining internal setup tasks to
reduce/eliminate adjustments:
·
Can
adjustment blocks or preset gauges be used?
·
Can
tooling presets be used?
·
Is
equipment, fixtures,
and tooling clean and
serviceable?
and tooling clean and
serviceable?
·
Can
locating/centering
techniques be employed?
techniques be employed?
Example
·
Accomplish
setup tasks in parallel where possible (Can additional resources be utilized to
support the setup/changeover?)
·
Use
universal tooling/fixtures where possible
·
Use
quick disconnect fittings for air, power, water and vacuum (no hard pipe) where
possible
·
Eliminate
model specific conveyors and other material handling devices where possible.
Example
Step 4
- Reduce External Setup Time
Objective
·
Since
the maximum external setup time must be less than the time to run a production
lot, reducing external setup time typically is less critical than reducing
internal setup time. · Although external setup time generally is not the constraint to the setup procedure, tools/techniques should be applied to optimize and standardize external setup time… think of resources and cost.
·
Arranged
in sequence of use
·
Shadow
boards used
·
Addressed
and labeled
·
Color
coded
Use setup kits and/or carts
·
May
include fasteners, jig, fixtures, tools, etc.
·
May
be integrated as part of the equipment
·
May
also be utilized for raw materials
Improve Material Handling
·
Provide
adequate access for fork trucks / carts
·
Provide
visual means (Andon) of notifying material handlers of impending changeover
·
Eliminate/minimize
the need for mechanized material movement
Examples
Summary
·
Reduce
external setup time.
·
Improve
workplace organization.
·
Establish
setup kits and carts.
·
Optimize
material handling.
Step 5
- Repeat Steps
·
Standardize/Document: Each step of the setup/changeover must be
standardized and documented through the use of
written procedures and/or checklists.
This is not only necessary to sustain the improvements, but is necessary
for future improvement activities.
·
Train: Everyone involved in the setup/changeovers
must be fully trained. Often the gains
made in setup/changeover improvement activities are lost the first time that
personnel assignments are changed.
Appropriate procedural documentation and training is the only way to
insure that gains are not lost.
·
Measure/Follow-up: Setups/changeovers must become a measured
part of operations. Performance must be
monitored and investigation accomplished when performance deteriorates.
Additional
Options to Consider
This method is focused on the reduction in
setup/changeover duration. However,
there are several ways to eliminate the need for setups/changeovers that should
be considered:
·
Eliminate
part proliferation through design.
·
Make
multiple part numbers and / or parts in one step (i.e.: right hand and left hand).
·
Design
tooling / process to facilitate different parts without changeover.