BOUNDARY BOARD GUIDELINES
PURPOSE
Boundary samples are used as a supplement to the part inspection standard (e.g. visual or sensory) when the characteristics are difficult to define or communicate by any other method. Although the general QA specifications go a long way toward defining the message we are trying to communicate, the use of quality boundary boards is an effort to clearly communicate the “meaning” of each grade/category/level to our employees.
SCOPE
This procedure is applicable to all [company name] facilities.
DEFINITIONS
A. Category 4 – Not defective.
When we audit/inspect/observe a part we first decide if the part is “good”. If the answer to the first question is “yes” then there is “no defect found” and the part is a category 4.
B. Category 1 – Piece cannot be installed as is; needs rework or remake.
If we note some sort of defect on the part, then our next question is “is the defect severe enough that we need to pull stock” and if the answer to that question is “yes” then the part is a category 1.
C. Category 2 – Likely to result in customer complaint; needs rework or remake.
If we don’t feel the need to go through our inventory (or hold the last truck, or 100% verify the order), then we have to decide if we are going to reject the part, and if the answer to that question is “yes” then the part is a category 2, else it is a category 3.
D. Category 3 – Not likely to result in customer complaint; acceptable “as-is”.
Acceptable “as-is” - Meeting/exceeding our customer’s expectations.
E. Station Boundary Board – Defect samples displayed in each work station showing the possible defects that can occur at the station.
F. Cell Boundary Board – Defect samples displayed in each cell packaging area showing the possible defects that can occur in the cell.
FUNCTION
• The intent is to clearly communicate the “meaning” of each grade/category/level to our employees through the use of samples and photographs.
Proposed boundary samples must be representative of confirmed process capability and be consistently achieved.
• They are constructed to provide clear, consistent, controlled criteria for conditions that cannot be measured for pass/fail; e.g., visual or tactile conditions - burrs, discoloration, damage, etc.
An improvement over urban legend ("We always passed them looking like that").
• Preliminary boundary samples should be discussed prior to tooling and process development to determine quality expectations and process capability.
Boundary samples may also be created to define problems discovered in both production preparation and mass production stages.
PROCEDURE
• Select The Samples
Study the VMP for each operation, and determine what defects would be typical for this process by reviewing the content listed under “quality checks.” Use the defect code listing to organize and plan how many samples you will need, and which locations are applicable. Remember that the individual Station Boundary Boards will contain samples of the possible defects that can occur at the station, while the Cell Boundary Boards contain samples of all the possible defects that can occur at the cell.
Collect samples (and photographs) of defects to enable the operator to determine if the observed defect is acceptable, marginal, or not acceptable. In some cases, the condition cannot be described with a photo, and for those conditions we could gather that physical example under each picture or in an area all to themselves.
• Construct The Boundary Boards
Help our employees to associate color coding with the quality concepts. Although “one size fits all” is the goal, recognize that because of our manufacturing (process) diversity this will be a challenge.
They need to be readable and reviewable from a reasonable distance from the board. Magnified pictures can help.
The higher the board, the greater potential for neck injury.
Depending on the condition being observed, may want the sample chained to the board so that they can be viewed closely at any ambient light angle.
• Engineering / Sales and Marketing Approval
Essentially these are attribute gages, and should be treated like a 1st article inspection process to ensure that all interested parties agree if the observed defect is acceptable, marginal, or not acceptable. A minimum of four equivalent sets of boundary samples must be prepared and sent to Corporate Quality Assurance for review.
Boundary sample approval is based on internal quality standards, consumer acceptance impact, part design characteristics, and supplier process capability.
After approval, one set will be retained by Corporate Quality Assurance as a master, and the remaining boundary samples will be provided to the individual locations to be used as a working set.
NOTE: Certain processes may require additional samples, please consult with Corporate Quality Assurance for specific quantity requirements.
• Train The Operators
Perform an attribute R&R study to ensure the operators interpret the board properly. Take 10-15 samples that are a mix of good and bad and test 3-4 operators (or all of them as training) and ensure the operators are on the same page.
• Maintenance Of Boundary Boards
The boundary samples should be located at the point of decision and should also be protected from damage or degradation.
Physical samples have an opportunity to deteriorate over time, and need to be verified as accurate for their original intent from time to time, and should be part of a methodical review process.
========================================================
That's a rough draft of what I have so far -- what else does it need to be complete?