1. PLEASE NOTE: freeleansite
PLEASE NOTE: freeleansite.com offers several “Lean Thinking in Action” workshops A 2 hour hands-on workshop on Mistake-proofing is available for your team. See the Workshop tab for details. This presentation is a portion of the material covered …

2. Lean Thinking in Action Observe and document processes, expose waste, remove waste

3. Mistake Proofing Philosophy
People make mistakes.
HOWEVER…
9/19/2018
freeleansite.com

4. Mistake Proofing Philosophy
People make mistakes.
HOWEVER…
Mistakes can be eliminated through the use of devices (poka-yoke) that are used to either detect or prevent defects from occurring in the first place.
9/19/2018
freeleansite.com

5. Mistake Proofing Functions
A defect exists in one of two states:
It is about to occur → PREDICTION
It has already occurred: → DETECTION
There are basic mistake proofing functions to use against defects:
1. Shut down a machine or operation
2. Control a process or operation
3. Warn that a defect (is about to occur or) has occurred
9/19/2018
freeleansite.com

6. Mistake Proofing example – computer disc insertion (… because of continuous improvement obsolete today)
What is the problem?
How does this prevent it?
9/19/2018
freeleansite.com

7. Mistake Proofing example – Computer “Start-Up”
What is the problem?
How does this prevent it?
9/19/2018
freeleansite.com

8. Mistake Proofing example – Machining operation
Dial indicator on machine
Use standard work concepts
What is the problem?
How does this prevent it?
9/19/2018
freeleansite.com

9. Mistake Proofing example – Machining operation
1) Dial indicator on machine
No Go Gage
Go Gage
What is the problem?
How does this prevent it?
Calipers for thickness (POU)
9/19/2018
freeleansite.com

10. Mistake Proofing example – Press operation
1) Dial indicator on machine
Die Press
No Go Gage
Go Gage
Stops
What is the problem?
How does this prevent it?
Quick Clamp set-up (POU)
9/19/2018
freeleansite.com

11. Mistake Proofing example – gas cap
What is the problem?
How does this prevent it?
9/19/2018
freeleansite.com

12. Mistake Proofing Process
Step 1: Identify and Describe the defect/ red flag condition
Step 2: Determine root cause (where the defect is discovered or where it is made)
Step 3: Detail the sequence of events in the documented standard procedure
Step 4: Review the steps that differ from the standard (deviations)
(identify contributing conditions or potential failure modes)
Step 5: Identify the mistake-proof device type required
Step 6: Create device(s) and test for effectiveness (incorporate into Standard Work)
Look for the next opportunity …
NOTE: use FMEA or Process Analysis techniques and 5-Why Analysis to determine root cause.
9/19/2018
freeleansite.com

13. Top Ten causes of errors
Processing omissions: leaving out one or more process steps
Processing errors: process operation not performed according to the standard
Error in setting up: using wrong tooling or incorrect setting/ adjustment
Missing parts: not all parts are included in assembly/ process
Improper part/ item: wrong part installed in assembly
Processing wrong work piece: wrong part machined/ processed
Operations errors: incorrect revision or specification sheet
Adjustment, measurement, dimension errors: Errors in machine adjustments, testing measurements or dimensions of a component or sub-assembly
Errors in equipment, maintenance or repair: Defects caused by incorrect repairs or component replacement
Error in preparation of inspection equipment, fixtures or tools: Damaged inspection tooling; poorly designed fixtures or wrong tools; mis-measurement
analyze process mistake proof incorporate standard work repeat
9/19/2018
freeleansite.com

14. 12 “red flag” conditions (potential for error)
1. Adjustments
2. Unclear or no instructions
3. Undefined process
4. Many units/mixed units
5. Multiple steps
6. Infrequent production
7. Ineffective or lack of standards
8. Multiple handoffs
9. Hand processing
10. Rapid repetition
11. High volume demand or deadline pressures
12. Environmental conditions
9/19/2018
freeleansite.com

15. How do we practice excellence?
First, we must understand what excellence means. Excellence does not mean zero defects outside some arbitrary limits.
Instead, excellence implies producing on target, thus producing product with the probability of practically zero defects.
It is not the ability to ship zero defects, it is the ability to produce zero defects that counts. Installing mass inspections, tests, verifications, reviews or checks only perpetuate attitudes of mediocrity.
We must stop using the word ‘acceptable’ if we want to grow our businesses profitably. Today, excellence survives and acceptable dies.

16. Application
In your Business System / Operational Process,
brainstorm some ideas …
Where would your team insert some Poka-Yoke(s)?
What kinds of problems (mistake) would it prevent?
What ‘hurdles’ might you encounter?

17. Lean Thinking in Action Observe and document processes, expose waste, remove waste