454 Appendix III
Generic Mistake-Proofing Worksheet and an Example
A Generic Mistake-Proong Identication
Plant: Plant Name
Plant: XYZ Engine plant
Area: Camshaft machining department
I. Mistake-Proong System:
A brief description of what is used to mistake
proof the process. This may include a device,
an operational practice, or a xture.
I. Mistake-proong system: Proximity
switch on jaws of gantry robot.
Is the mistake-proong approach prevention
or inspection/correction (refer to Key Card)?
II. Type: Inspection/correction.
Where is the mistake-proong system
located in the plant?
III. Location: Camshaft machining—CAM
A brief description of the process being
mistake proofed and how the mistake-
proong system prevents mistakes.
IV. Description: Camshafts entering the
machining process are unloaded by a
gantry robot. The coordinates that the
robot uses to locate the CAM are xed.
If a camshaft is not seated in the crate
correctly, or if the pallet is not in the
right place, the robot can secure the
CAM incorrectly and damage the CAM
or deliver it to the conveyor incorrectly.
What mistake is being addressed and what
is the signicance of this mistake?
V. Purpose: The proximity switch releases
the gripper jaws before the CAM is
damaged. The mistake-proong device
protects the CAM if the CAM is seated
incorrectly in the pallet, or if the pallet
is located incorrectly under the robot.
Is the mistake-proong system operational,
and how is it maintained?
VI. Condition: The proximity switch is in
working condition. The robot’s most
recent calibration and scheduled PM
were completed as indicated in the
VII. Preventive Maintenance Schedule
What is the PM schedule for the mistake-
The condition of the error-proong device and
PM schedule can be gathered from the plant
oor information system (PFIS) or something
similar to that. Maintenance personnel should
also keep a maintenance log in the area.
VII. Preventive maintenance: Weekly
calibration and monthly maintenance.
VIII. How the team recognized the mistake-
What indicator allowed the team to nd
the mistake-proong system?
VIII. How the team recognized the
mistake-proong system: Knew the
CAM seating and pallet location were
critical. Checked to see if there was a