Control Plan

As highlighted above, the control plan can be used for any manufacturing organization, not just one who is aiming towards APQP.

I. Improves Product Quality

1. Improves ability to prevent nonconforming products

2. Identifies and manages sources of variation (input variables), and reduces variation in product characteristics (output variables)

3. Reduces scrap and rework

II. Improves Efficiency/Cost

1. Reduces waste in a process, improving throughput/manufacturing efficiency

2. Reduces costs without sacrificing quality

III. Improves Customer Satisfaction

1. Focuses resources on the product/process characteristics most important to the customer and the organization

2. Prevents nonconforming product from reaching the customer

IV. Improves Process Management

1. Establishes a plan for responding to changing process conditions

2. Communicates changes in product/process characteristics, control method, and measurement methodology

3. Monitors processes and assures that process improvements are maintained over the life cycle of the product

4. Employ prevention rather than detection (e.g. use of error-proofing instead of operator dependent work or inspection)

In order to gain the most of out your control plan you need to have done some background work beforehand. If you are following the APQP Process then you would have naturally performed the necessary steps. The Control Plan is generated in phases 3 and 4 of the APQP 5 Phase process, phases 1 and 2 would have given you all of the necessary inputs.

If you are not following the full APQP process and would like to generate a control plan you need to identify the inputs to the control plan and in order to do that, you need to have completed some preparatory documents. If you have AS9100 already in place then a lot of these would naturally have been completed.  

The inputs include (depending on your type of organization):

 Process Flow Diagram (FPD, flowcharts, swimlanes, SIPOC, Turtles etc)

 Process Failure Mode and Effects Analysis (PFMEA)

 Design Reviews (If you are the design authority)

 Product Key Characteristics (From Design Failure Mode and Effects Analysis or could already be identified on the drawing if you are manufacturing only).

 Process Key Characteristics

 Measurement System Analysis (MSA)

 Special Characteristics Matrix

 Lessons learned from similar parts

 Cross-functional team knowledge about the process

 Field or Warranty Issues

The intent of the control plan is to align the plan with your process flow diagram and focus the attention on the high-risk process points as identified in your PFMEA. Is it advised to start the process as early on as possible during the initial stages of development, you should identify what controls you need to put in place to further reduce the risks within the processes.

Prevention is always better than cure so the control plan should focus on using tools such as error-proofing instead of operator dependent work or inspection.

There are three distinct parts to a control plan; the processes, the characteristics and the control methods. Each part has a number of features which need to be identified as applicable.

 
1- Operation / Process Number: List process step, usually listed in the process flow being charted

2 - Process Function/Operation Description: The CRITICAL steps in the production of the part (not every process step or risk from the PFMEA). Remember, you don’t need to enter all PFMEA risks, focus on the higher risk points. The steps can be identified from the Process Flow Diagram

3 - Machine, Device, Jigs and Tools: This is where you would list any specific tools and machinery that are required to control the process, this could be specific gauges, tanks, machine IDs, jigs.

4 - Characteristics: The distinguishing feature, dimension, or property of a process or product on which variable or attributable data can be collected. Use visual aids where applicable

5 - Product/Process Characteristic ID: Either a sequential tracking number or a cross-reference number from other applicable documents such as the Process Flow DIagram or PFMEA.

6 - Product Characteristics: List Product Characteristics that are important. The features or properties of the part, component or assembly that are listed on engineering drawings. The team should identify the product characteristics by referring: Engineering drawings, customer critical characteristics, key/critical characteristics that affect the product. There may be several for each operation-can be dimensional, performance or visual criteria

7 - Process Characteristics: List Process Characteristics that are important. A Process Characteristic (parameters) is a setting made within a process that affects the variation within the operation. The team should identify process characteristics for which variation must be controlled to minimise product variation. There could be one or more process characteristics listed for each product characteristic. Examples include temperature, pressure, speed, feed, torque, flow rate.

8 - Characteristic Classification:

     a. Key Characteristics: An attribute or feature whose variation has a significant influence on product fit, performance, service life, or productibility; that requires specific action for the purpose of controlling variation;    

     b. Critical Items: Those items (e.g., functions, parts, software, characteristics, processes) having a significant effect on the product realisation and use of the product; including safety, performance, form, fit, unction, producibility, service life, etc.; that require specific actions to ensure they are adequately managed. 

Examples include safety CIs, fracture CIs, mission CIs Key Characteristics (KCs), and maintenance tasks critical for safety.

The engineering drawing will typically indicate key/critical characteristics.  However, the user may identify additional characteristics that are critical to quality

9 - Methods: The procedures, instructions and tools to control the process.

10 - Product/Process Specification/Tolerance: Specifications and tolerances are obtained from engineering specifications or a key process characteristic.

11 - Evaluation Measurement Technique: Identifies how the characteristic is going to be measured.  Examples include calipers, attribute gauges (Go/No go), fixtures, test equipment, or visual.

12 - Sample Size & Frequency: This column defines how many parts will be measured and how often.  Examples include: final testing, visual criteria, 100% inspection, SPC, audit, sample size and frequency

13 - Control Method: This column contains a brief description of how the characteristic will be controlled. 

Examples include:

X-bar/R-chart; Np chart; Pre-control chart; Checklist; Log sheet; Mistake proofing; 1st piece inspection; Lab report

14 - Reaction Plan: The reaction plan specifies what happens when the characteristic or parameter is found to be out of control. The Reaction Plan must include Segregation of nonconforming product, Correction Method and Contact Supervisor. 

The Reaction Plan may include Sorting, Rework/Repair or Customer Notification

The actions should normally be the responsibility of the people closest to the process, the operator or supervisor.

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