Lean & Six Sigma , History Time LineMay 16, 2017
Pull Production Systems 生産システムを引いて- The benefits and a brief description.May 17, 2017
Setup Reduction Methodology – SMED (金型の単一分交換)
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:
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
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
- Stopwatch analysis
Step 2 - Convert Internal Steps to External
- 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).
Through the elements recorded in Step 1 (Identify Internal & External Steps)
Identify all internal steps, eliminate all unnecessary steps
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?
- 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
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?
- Can locating/centering techniques be employed?
- 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.